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Journal Cover Plant Physiology and Biochemistry
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   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0981-9428
   Published by Elsevier Homepage  [3043 journals]
  • Seasonal dynamics of photosynthetic activity in the representive brown
           macroalgae Sagrassum thunbergii (Sargassaceae Phaeophyta)
    • Authors: Di Zhang; Quan Sheng Zhang; Xiao Qi Yang
      Abstract: Publication date: November 2017
      Source:Plant Physiology and Biochemistry, Volume 120
      Author(s): Di Zhang, Quan Sheng Zhang, Xiao Qi Yang
      The present study evaluates the seasonal photosynthetic performances of Sargassum thunbergii via chlorophyll fluorescence technique. During summer and early winter, no significant change was observed in maximum photochemical efficiency (Fv/Fm), and performance index (PIabs). During late winter and early spring, Fv/Fm, and PIabs decreased significantly, implying that S. thunbergii photosystem II (PSII) suffered apparent photoinhibition. Subsequently, PSII gradually recovered during late spring and summer, as evidenced by an increase of both parameters. Throughout the year, the maximum decrease in the slope of MR/MR0 maintained low values indicated that photosystem I (PSI) was incative, the initial rate of P700+ re-reduction maintained low value indicated that cyclic electron transport (CET) were inactive; nevertheless, a seasonal down-regulation of both PSI and CET during late winter and early spring could be detected. The weak performance of PSI and CET can potentially limit the flexibility in response to winter stress and result in a delayed recovery of PSII. In conclusion, the seasonal variability of S. thunbergii photosynthetic activity was characterized by three periods: active state, down-regulation and restoration. The rapid growth during early spring was accompanied by weak photosynthetic performance, indicating that the carbohydrates consumed during this period were derived from previously stored starch.

      PubDate: 2017-10-08T12:15:29Z
      DOI: 10.1016/j.plaphy.2017.09.025
      Issue No: Vol. 120 (2017)
       
  • De novo transcriptome sequencing of Camellia sasanqua and the analysis of
           major candidate genes related to floral traits
    • Authors: Hui Huang; En-Hua Xia; Hai-Bin Zhang; Qiu-Yang Yao; Li-Zhi Gao
      Abstract: Publication date: November 2017
      Source:Plant Physiology and Biochemistry, Volume 120
      Author(s): Hui Huang, En-Hua Xia, Hai-Bin Zhang, Qiu-Yang Yao, Li-Zhi Gao
      Camellia sasanqua is one of the most famous horticultural plants in Camellia (Theaceae) due to its aesthetic appeal as landscape plant. Knowledge regarding the genetic basis of flowering time, floral aroma and color in C. sasanqua is limited, but is essential to breed new varieties with desired floral traits. Here, we described the de novo transcriptome of young leaves, flower buds and flowers of C. sasanqua. A total of 60,127 unigenes were functionally annotated based on the sequence similarity. After analysis, we found that two floral integrator genes, SOC1 and AP1, in flowering time pathway showed evidence of gene family expansion. Compared with 1-deoxy-D-xylulose-5-phosphate pathway, some genes in the mevalonate pathway were most highly expressed, suggesting that this might represent the major pathway for terpenoid biosynthesis related to floral aroma in C. sasanqua. In flavonoid biosynthesis pathway, PAL, CHI, DFR and ANS showing significantly higher expression levels in flowers and flower buds might have important role in regulation of floral color. The top five most transcription factors (TFs) families in C. sasanqua transcriptome were MYB, MIKC, C3H, FAR1 and HD-ZIP, many of which have a direct relationship with floral traits. In addition, we also identified 33,540 simple sequence repeats (SSRs) in the C. sasanqua transcriptome. Collectively, the C. sasanqua transcriptome dataset generated from this study along with the SSR markers provide a new resource for the identification of novel regulatory transcripts and will accelerate the genetic improvement of C. sasanqua breeding programs.

      PubDate: 2017-10-08T12:15:29Z
      DOI: 10.1016/j.plaphy.2017.08.028
      Issue No: Vol. 120 (2017)
       
  • Bacteria and smoke-water extract improve growth and induce the synthesis
           of volatile defense mechanisms in Vitis vinifera L.
    • Authors: María Victoria Salomon; Patricia Piccoli; Iván Funes Pinter; Wendy Ann Stirk; Manoj Kulkarni; Johannes van Staden; Rubén Bottini
      Pages: 1 - 9
      Abstract: Publication date: November 2017
      Source:Plant Physiology and Biochemistry, Volume 120
      Author(s): María Victoria Salomon, Patricia Piccoli, Iván Funes Pinter, Wendy Ann Stirk, Manoj Kulkarni, Johannes van Staden, Rubén Bottini
      Sustainable agricultural practices have been developed as alternative to the use of agrochemicals, and viticulture is not exempt of that. Plant growth promoting rhizobacteria (PGPR) and smoke water extracts (SW) are environmentally-friendly alternative to those agrochemicals. The aim of this study was to investigate the single or combined effects of SW and the PGPR Pseudomonas fluorescens (Pf) and Bacillus licheniformis (Bl) on the physiology and biochemistry of grapevines plants. After 38 days, single applications of SW solutions and bacterial suspensions increase rooting and root length. Combined treatments had a slight positive effect compared to the water control. At the end of 60-days pot trial, grapevine treated with 1:1000 SW and Pf applied alone showed increases in stem length, leaf area and fresh weight of the roots, shoot and leaves, although not significantly differences from the water control were found. In addition, Pf augmented chlorophyll relative content, all treatments decreased the stomatal conductance (mainly 1:500 SW, Pf and 1:1000 SW + Bl), as well as lipid peroxidation in roots (mainly in bacterial treatments), and induced the synthesis of mono and sesquiterpenes in leaves, where the effect was enhanced in combined treatments. In conclusion, PGPR and SW are effective to improve growth of V. vinifera cuttings as well as to increase the plants defense mechanisms that may help them to cope with biotic and abiotic stresses.

      PubDate: 2017-09-23T10:55:07Z
      DOI: 10.1016/j.plaphy.2017.09.013
      Issue No: Vol. 120 (2017)
       
  • Separation of peroxidases from Miscanthus x giganteus, their partial
           characterisation and application for degradation of dyes
    • Authors: Robajac Dragana; Gligorijević Nikola; Dželetović Željko; Andrejić Gordana; Nedić Olgica
      Pages: 179 - 185
      Abstract: Publication date: November 2017
      Source:Plant Physiology and Biochemistry, Volume 120
      Author(s): Robajac Dragana, Gligorijević Nikola, Dželetović Željko, Andrejić Gordana, Nedić Olgica
      Due to wide applicative potential of peroxidases (POXs), the search for novel sources and forms, possibly with better characteristics and performances, is justified. In this study, POXs from Miscanthus x giganteus rhizomes grown in chernozem-like soil and mine tailings were examined. Higher activity of POXs in samples originating from the metal-contaminated soil was found. The quantity of acidic isoforms was much greater than basic. The rates of reactions catalysed by acidic POX isoforms decreased slightly at 50 °C, whereas stability of basic isoforms was affected at 40 °C. Concentrations of Zn, Mn and Fe were higher in rhizomes grown in mine tailings, and negatively correlated with the concentration of proteins. Basic POX isoforms effectively degraded CBB R250, while Amidoblack 10b was predominantly degraded by acidic isoforms. Thus, Miscanthus x giganteus can be used as a source of POXs which can be applied for dye decomposition and, possibly, waste water management.

      PubDate: 2017-10-14T12:47:55Z
      DOI: 10.1016/j.plaphy.2017.10.009
      Issue No: Vol. 120 (2017)
       
  • Effect of lignite on alleviation of salt toxicity in soybean (Glycine max
           L.) plants
    • Authors: Salar Farhangi-Abriz; Neda Nikpour-Rashidabad
      Pages: 186 - 193
      Abstract: Publication date: November 2017
      Source:Plant Physiology and Biochemistry, Volume 120
      Author(s): Salar Farhangi-Abriz, Neda Nikpour-Rashidabad
      Salt toxicity of agricultural land is a natural phenomenon which is due to agricultural irrigation. This toxicity is harmful to crop productivity via increasing oxidative stress products. In a factorial controlled trial, four levels of lignite-enriched soil (soil lignite content: none, 50, 75 and 100 g kg−1) were exposed to three levels of soil salinity (0, 5 and 10 dS m−1 NaCl). Then reactive oxygen species (ROS) generation (hydrogen peroxide and superoxide radical), lipid peroxidation, antioxidant enzymes activities (peroxidase, catalase and super oxide dismutase), proline, glycine betaine, soluble sugars and soluble protein contents of soybean plants were compared across different lignite concentration and saline toxicity. Under the 5 and 10 dS m−1 NaCl, sodium entry to the leaf and root cells, hydrogen peroxide concentration, superoxide radical generation, lipid peroxidation and osmoprotectants creation increased and consequently plant growth reduced (12–49%). Lignite applications by improving the cation exchange capacity of soil (8–16%), enriched the leaf and root cells with potassium (5–26%), calcium (40–56%), magnesium (30–42%) and inhibited the sodium entry to the cells, and consequently increased potassium/sodium ratio and reduced oxidative stress, antioxidant activities and synthesis of osmoprotectants in soybean leading to increased plant biomass (18–37%). Lignite usage in 75 and 100 g kg−1 soil showed a better effect than 50 g kg−1 soil on reducing harmful effects of salt toxicity. Soil enrichment with lignite improves plant tolerance to salt toxicity via decreased oxidative stress.

      PubDate: 2017-10-14T12:47:55Z
      DOI: 10.1016/j.plaphy.2017.10.007
      Issue No: Vol. 120 (2017)
       
  • A wheat NBS-LRR gene TaRGA19 participates in Lr19-mediated resistance to
           Puccinia triticina
    • Authors: Li Jianyuan; Wang Xiaodong; Zhang Lirong; Meng Qingfang; Zhang Na; Yang Wenxiang; Liu Daqun
      Pages: 1 - 8
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Li Jianyuan, Wang Xiaodong, Zhang Lirong, Meng Qingfang, Zhang Na, Yang Wenxiang, Liu Daqun
      Wheat leaf rust, caused by Puccinia triticina (Pt), is one of the most severe fungal diseases on wheat globally. Rational utilization of wheat leaf rust resistance (Lr) genes is still the best choice for control this disease. Wheat seedlings carrying Lr19 showed a high resistance phenotype to all Pt races in China. So far, all the cloned seedling Lr genes including Lr1, Lr10 and Lr21, encode protein with NBS-LRR domain. In this study, a wheat gene with NBS-LRR domain from previously established Lr19-resistance-related cDNA library was cloned and designated as TaRGA19. Full length of this gene was amplified by rapid amplification of cDNA ends (RACE). By blast against IWGSC wheat genome database, we have noticed that TaRGA19 was located on chromosome 2DS, which was different from Lr19 located on chromosome 7DL. Compared with susceptible Thatcher line, expression level of TaRGA19 was upregulated in wheat isogenic lines carrying Lr19 (TcLr19) after inoculation of Pt race THTS. By particle bombardment, TaRGA19-GFP fused protein was localized on plasma membrane of epidermal cells. Using virus-induced gene silencing (VIGS), TaRGA19-knockdown plants of TcLr19 showed reduced resistance and few sporulation phenotype upon Pt challenge. Further histological observation indicated that Pt hyphal growth at the infection sites was less suppressed in the TaRGA19-knockdown plants. In conclusion, we speculate this TaRGA19 gene was involved in the Lr19-mediated resistance to wheat leaf rust along with other components.

      PubDate: 2017-08-28T10:21:39Z
      DOI: 10.1016/j.plaphy.2017.08.009
      Issue No: Vol. 119 (2017)
       
  • GsSNAP33, a novel Glycine soja SNAP25-type protein gene: Improvement of
           plant salt and drought tolerances in transgenic Arabidopsis thaliana
    • Authors: Zaib-un Nisa; Ali Inayat Mallano; Yang Yu; Chao Chen; Xiangbo Duan; Sikandar Amanullah; Abida Kousar; Abdul Wahid Baloch; Xiaoli Sun; Dina Tabys; Yanming Zhu
      Pages: 9 - 20
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Zaib-un Nisa, Ali Inayat Mallano, Yang Yu, Chao Chen, Xiangbo Duan, Sikandar Amanullah, Abida Kousar, Abdul Wahid Baloch, Xiaoli Sun, Dina Tabys, Yanming Zhu
      The N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) superfamily, specifically the SNAP25-type proteins and t-SNAREs, have been proposed to regulate cellular processes and plant resistance mechanisms. However, little is known about the role of SNAP25-type proteins in combating abiotic stresses, specifically in wild soybean. In the current study, the isolation and functional characterization of the putative synaptosomal-associated SNAP25-type protein gene GsSNAP33 from wild soybean (Glycine soja) were performed. GsSNAP33 has a molecular weight of 33,311 Da and comprises 300 amino acid residues along with Qb-Qc SNARE domains. Multiple sequence alignment revealed the highest similarity of the GsSNAP33 protein to GmSNAP33 (91%), VrSNAP33 (89%), PvSNAP33 (86%) and AtSNAP33 (63%). Phylogenetic studies revealed the abundance of SNAP33 proteins mostly in dicotyledons. Quantitative real-time PCR assays confirmed that GsSNAP33 expression can be induced by salt, alkali, ABA and PEG treatments and that GsSNAP33 is highly expressed in the pods, seeds and roots of Glycine soja. Furthermore, the overexpression of the GsSNAP33 gene in WT Arabidopsis thaliana resulted in increased germination rates, greater root lengths, improved photosynthesis, lower electrolyte leakage, higher biomass production and up-regulated expression levels of various stress-responsive marker genes, including KINI, COR15A, P5Cs, RAB18, RD29A and COR47 in transgenic lines compared with those in WT lines. Subcellular localization studies revealed that the GsSNAP33-eGFP fusion protein was localized to the plasma membrane, while eGFP was distributed throughout whole cytoplasm of onion epidermal cells. Collectively, our findings suggest that GsSNAP33, a novel plasma membrane protein gene of Glycine soja, might be involved in improving plant responses to salt and drought stresses in Arabidopsis.

      PubDate: 2017-08-28T10:21:39Z
      DOI: 10.1016/j.plaphy.2017.07.029
      Issue No: Vol. 119 (2017)
       
  • Potassium improves photosynthetic tolerance to and recovery from episodic
           drought stress in functional leaves of cotton (Gossypium hirsutum L.)
    • Authors: Rizwan Zahoor; Wenqing Zhao; Haoran Dong; John L. Snider; Muhammad Abid; Babar Iqbal; Zhiguo Zhou
      Pages: 21 - 32
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Rizwan Zahoor, Wenqing Zhao, Haoran Dong, John L. Snider, Muhammad Abid, Babar Iqbal, Zhiguo Zhou
      To investigate whether potassium (K) application enhances the potential of cotton (Gossypium hirsutum L.) plants to maintain physiological functions during drought and recovery, low K-sensitive (Siza 3) and -tolerant (Simian 3) cotton cultivars were exposed to three K rates (0, 150, and 300 K2O kg ha−1) and either well-watered conditions or severe drought stress followed by a recovery period. Under drought stress, cotton plants showed a substantial decline in leaf water potential, stomatal conductance, photosynthetic rate, and the maximum and actual quantum yield of PSII, resulting in greater non-photochemical quenching and lipid peroxidation as compared to well-watered plants. However, plants under K application not only showed less of a decline in these traits but also displayed greater potential to recover after rewatering as compared to the plants without K application. Plants receiving K application showed lower lipid peroxidation, higher antioxidant enzyme activities, and increased proline accumulation as compared to plants without K application. Significant relationships between rates of photosynthetic recovery and K application were observed. The cultivar Siza 3 exhibited a more positive response to K application than Simian 3. The results suggest that K application enhances the cotton plant's potential to maintain functionality under drought and facilitates recovery after rewatering.

      PubDate: 2017-08-28T10:21:39Z
      DOI: 10.1016/j.plaphy.2017.08.011
      Issue No: Vol. 119 (2017)
       
  • RdreB1BI enhances drought tolerance by activating AQP-related genes in
           transgenic strawberry
    • Authors: Xianbin Gu; Zhihong Gao; Yichao Yan; Xiuyun Wang; Yushan Qiao; Yahua Chen
      Pages: 33 - 42
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Xianbin Gu, Zhihong Gao, Yichao Yan, Xiuyun Wang, Yushan Qiao, Yahua Chen
      The dehydration-responsive element binding protein (DREB) family of transcription factors is associated with abiotic stress responses during plant growth and development. This study focussed on the subfamily member DREB1B, which was initially described as highly and specifically responsive to low temperature. However, here it is shown that DREB1B is not only involved in cold tolerance but also other abiotic stress tolerances, such as that of drought. To further understand the genetic improvement effects of the drought tolerance provided by RdreB1BI in transgenic strawberry, drought stress responses of transgenic plants were evaluated at the morphological, physiological, and transcriptional levels. Transactivation assays revealed that RdreB1BI could activate the FvPIP2;1 like 1 promoter. RdreB1BI transgenic plants showed enhanced drought tolerance on the basis of lower rates of electrolyte leakage (EL), higher relative water content (RWC), and less stomatal aperture as well as increased peroxidase (POD) and superoxide dismutase (SOD) activities and less malondialdehyde (MDA) accumulation. The transgenic plants also accumulated higher levels of drought-related regulatory genes and functional gene transcripts, including those of PIP, NAC, RD22, ABI, and NCED. Together, these results demonstrate that RdreB1BI plays an essential role in the regulation of the drought stress response. DREB1B transcription constitutes a useful strategy to exploit in transgenic plants for coping with abiotic stresses, at least cold and drought stresses. The approach may be helpful for genetic engineering horticultural plants to have increased environmental adaptations.

      PubDate: 2017-08-28T10:21:39Z
      DOI: 10.1016/j.plaphy.2017.08.013
      Issue No: Vol. 119 (2017)
       
  • Effects of exposure to nano and bulk sized TiO2 and CuO in Lemna minor
    • Authors: Jasna Dolenc Koce
      Pages: 43 - 49
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Jasna Dolenc Koce
      Nanoparticles of TiO2 and CuO are among most commonly used nanoparticles, and elevated concentrations of them are expected to be found in all environments, including aquatic. A standard growth inhibition test ISO/CD 20079 was used to determine the toxicity of nano sized and larger micro sized (bulk) particles in the concentrations of 0.1, 1, 10, 100 and 1000 μM CuO and TiO2 on common duckweed (Lemna minor L.). Both nano and bulk CuO particles caused changes in the structure and function of treated plants. The number of fronds and colonies decreased by as much as 78%, the length of roots and fronds decreased by 99% and 14%, respectively. Furthermore, photochemical efficiency was reduced by up to 35%, and the activities of antioxidative enzymes guaiacol peroxidase, ascorbate peroxidase and glutathione reductase increased by more than 240%. The altered physiological state of the CuO exposed plants was also reflected in the elevated occurrence of necrosis and bleaching in the duckweed colonies. Nano sized particles of CuO proved more phytotoxic than bulk particles, and the effects of both studied CuO sizes were concentration dependent. On the other hand, both bulk and nano sized particles of TiO2 caused no severe phytotoxic effects, there was no concentration dependence and they could be considered as non-harmful to common duckweed.

      PubDate: 2017-08-28T10:21:39Z
      DOI: 10.1016/j.plaphy.2017.08.014
      Issue No: Vol. 119 (2017)
       
  • Seed priming by sodium nitroprusside improves salt tolerance in wheat
           (Triticum aestivum L.) by enhancing physiological and biochemical
           parameters
    • Authors: Qasim Ali; M.K. Daud; Muhammad Zulqurnain Haider; Shafaqat Ali; Muhammad Rizwan; Nosheen Aslam; Ali Noman; Naeem Iqbal; Faisal Shahzad; Farah Deeba; Iftikhar Ali; Shui Jin Zhu
      Pages: 50 - 58
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Qasim Ali, M.K. Daud, Muhammad Zulqurnain Haider, Shafaqat Ali, Muhammad Rizwan, Nosheen Aslam, Ali Noman, Naeem Iqbal, Faisal Shahzad, Farah Deeba, Iftikhar Ali, Shui Jin Zhu
      The germination, seedling vigor, crop establishment and yield of agronomically important crops is negatively affected by soil salinity. The current study aimed to investigate the ability of exogenous fertigation by sodium nitroprusside (SNP) to induce salt tolerance in four high yielding wheat cultivars (Sahar-06, Punjab-11, Millat-11 and Galaxy-13) that differ in their response to salt stress in terms of biomass production, oxidative defense mechanisms and grain yield. Three levels of SNP (0, 0.1 and 0.2 mM) were used for seed soaking. During soaking the seeds were kept in the dark. After soaking for 12 h the seeds were air-dried for 5 h before sowing. Salinity caused a significant reduction in biomass and grain yield, while it increased proline (Pro), ascorbic acid (AsA), hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents. Cultivar Sahar-06 and Galaxy-13 were found more tolerant to salinity based on shoot length root fresh and dry wights, 100 grain weight, decreased MDA and H2O2 accumulation, phenolic and ascorbic acid (AsA) contents, accumulation of proline, activities of SOD, POD and CAT as compared to the other cultivars. Seed priming with SNP was effective in reducing the adverse effects of salt stress induced oxidative stress on plant biomass and grain yield in all the studied wheat cultivars, but maximum amelioration of salt stress tolerance by SNP treatment was found in cv. Sahar-06. The increased salt tolerance in wheat plants by SNP seed priming might be due to the role of NO in improving seed vigor and germination and early establishment of seedlings with better growth. 0.1 mM SNP was found the most effective in improving salt tolerance, as compared to other SNP concentations. Exogenous SNP fertigation increased the activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and the contents of AsA, Pro and total phenolics content (TPC) in the salt stressed wheat plants. Our data indicate that SNP-priming induced salt tolerance by up-regulating the antioxidative defense mechanisms resulting in better biomass production and grain yield.

      PubDate: 2017-09-18T10:44:03Z
      DOI: 10.1016/j.plaphy.2017.08.010
      Issue No: Vol. 119 (2017)
       
  • Physiological and antioxidant responses of winter wheat cultivars to
           strigolactone and salicylic acid in drought
    • Authors: Mojde Sedaghat; Zeinolabedin Tahmasebi-Sarvestani; Yahya Emam; Ali Mokhtassi-Bidgoli
      Pages: 59 - 69
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Mojde Sedaghat, Zeinolabedin Tahmasebi-Sarvestani, Yahya Emam, Ali Mokhtassi-Bidgoli
      Strigolactones are considered as important regulators of plant growth and development. Recently positive regulatory influence of strigolactones in plant in response to drought and salt stress has been revealed. Salicylic acid, a phytohormone, has reported to be involved in a number of stress responses such as pathogen infection, UV irradiation, salinity and drought. Considering the concealed role of strigolactones in agronomic crops drought tolerance and possible interaction among salicylic acid and strigolactone, we investigated the effects of exogenous application of GR24 and salicylic acid on two winter wheat cultivars under drought conditions. Foliar GR24 and salicylic acid were applied on drought sensitive and drought tolerant winter wheat cultivars at tillering and anthesis stages in 40% and 80% of field capacity moisture levels. Strigolactones and salicylic acid treated plants showed higher tolerance to drought stress with regard to lower electrolyte leakage and higher relative water content, leaf stomatal limitation, membrane stability index and antioxidant enzyme activities. Salicylic acid application dampened malondialdehyde content in wheat plants. Drought tolerance of wheat plants were intensified in most of the cases when theses phytohormones were used together, suggesting a possible interaction between salicylic acid and strigolactones in drought situations.

      PubDate: 2017-09-18T10:44:03Z
      DOI: 10.1016/j.plaphy.2017.08.015
      Issue No: Vol. 119 (2017)
       
  • Sphingosine kinase AtSPHK1 functions in fumonisin B1-triggered cell death
           in Arabidopsis
    • Authors: Xiaoya Qin; Ruo-Xi Zhang; Shengchao Ge; Tao Zhou; Yun-Kuan Liang
      Pages: 70 - 80
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Xiaoya Qin, Ruo-Xi Zhang, Shengchao Ge, Tao Zhou, Yun-Kuan Liang
      The fungal toxin Fumonisin B1 (FB1) is a strong inducer to trigger plant hypersensitive responses (HR) along with increased long chain bases (LCB) and long chain base phosphates (LCBP) contents, though the regulatory mechanism of FB1 action and how the LCB/LCBP signalling cassette functions during the process is still not fully understood. Here, we report sphingosine kinase 1 (SPHK1) as a key factor in FB1-induced HR by modulating the salicylic acid (SA) pathway and reactive oxygen species (ROS) accumulation in Arabidopsis thaliana. Overexpression of SPHK1 increases the FB1-induced accumulations of ROS and SA. The double mutant that simultaneously overexpresses SPHK1 and suppresses the SPPASE or DPL1, two enzymes are mainly responsible for Phyto-sphingosine-1-phosphate (Phyto-S1P) removal, showed enhanced susceptibility to FB1 killing and FB1-induced SA activation than the plants overexpress SPHK1 alone. Exogenous sphingosine-1-phosphate (S1P) can modulate the transcription of the SA-responsive marker gene PR1 in a concentration-dependent biphasic manner. Suppression of SPHK1 decreases SA production whereas promotes jasmonic acid (JA) biosynthesis in response to FB1 applications. Our findings indicate a role of SPHK1 in modulating FB1-triggered cell death via SA and JA pathway interactions.

      PubDate: 2017-09-18T10:44:03Z
      DOI: 10.1016/j.plaphy.2017.08.008
      Issue No: Vol. 119 (2017)
       
  • Effects of nitrogen-deficiency on efficiency of light-harvesting apparatus
           in radish
    • Authors: M.D. Cetner; H.M. Kalaji; V. Goltsev; V. Aleksandrov; K. Kowalczyk; W. Borucki; A. Jajoo
      Pages: 81 - 92
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): M.D. Cetner, H.M. Kalaji, V. Goltsev, V. Aleksandrov, K. Kowalczyk, W. Borucki, A. Jajoo
      Nitrogen starvation has been stated to reduce chlorophyll a and accessory pigments, decrease photosynthetic efficiency, as well as modify chloroplast thylakoid membranes. However, the impact of N-deficiency on light-dependent reactions of photosynthesis has not been well understood. In this study, efficiency and structure of light-harvesting complex under N-deficiency conditions were investigated in two radish cultivars (Raphanus sativus var. sativus ‘Fluo HF1’ and ‘Suntella F1’). Light-dependent reactions of photosynthesis were investigated by measuring in vivo chlorophyll a prompt fluorescence signal. Acquired data were utilised in two ways: by plotting fast induction curves and calculating OJIP-test biophysical parameters. Detailed analysis of difference curves as well as OJIP-test results showed that major disturbances were associated with photosystem II and its subunits, including decoupling of light-harvesting complexes, dysfunction of oxygen-evolving complex, and reaction centres inactivation. The maximum quantum yield of photosystem II primary photochemistry was severely restricted, causing an inhibition in electron transport through successive protein complexes in the thylakoid membrane. Structural changes were demonstrated by recording images using Transmission Electron Microscopy (TEM). TEM investigations showed intensive starch accumulation under N-deficiency. Rare thylakoid stacks distributed in tiny layers of stroma around grains and chloroplast periphery were observed in cells of N-deficient plants. The application of principal component analysis (PCA) on OJIP-test results allowed characterizing the dynamics of stress response and separating parameters according to their influence on plants stress response. ‘Suntella F1’ genotype was found to be more sensitive to nitrogen deficiency as compared to ‘Fluo HF1’ genotype.

      PubDate: 2017-09-18T10:44:03Z
      DOI: 10.1016/j.plaphy.2017.08.016
      Issue No: Vol. 119 (2017)
       
  • Influence of bacterial strains on Oryza sativa grown under arsenic tainted
           soil: Accumulation and detoxification response
    • Authors: Vishvas Hare; Pankaj Chowdhary; Vinay Singh Baghel
      Pages: 93 - 102
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Vishvas Hare, Pankaj Chowdhary, Vinay Singh Baghel
      The present study was conducted to study the role of bacterial inoculants in growth, accumulation and tolerance responses in rice grown in arsenic (As) contaminated soil. Results revealed that out of five isolated bacterial strains, strain BBAU/MMM1 (Babasaheb Bhimrao Ambedkar University/Mari Matamandir) exhibited resistant to As(III) to the level of 400 μM As(III) in comparison to other strain which showed toxicity. The isolated strain BBAU/MMM1 1was characterized as gram negative, rod shape, showed positive test nitrate, citrate, catalase and phosphate solubilization with high production of IAA and siderophore. Arsenic treated rice seedlings supplemented with bacterial inoculants BBAU/MMM1 showed increased growth characteristics viz., root length (35.41%), shoot length (32.8%) and fresh weight (30.31%) in comparison to rice treated with As(III) only. In addition, reduced lipid peroxidation and induces cysteine, GSH (reduced glutathione), GSSG (Oxidized glutathione) and antioxidant enzymatic activities were also observed in bacterial supplemented rice seedlings. Further, reduced metal accumulation in root (1351.46–968.67 μg g−1fw), shoot (488.01–378.02 μg g−1fw) and reduced translocation factor (0.583–0.390) in As(III) treated rice seedlings inoculated with bacterial strains clearly reflect protective response of bacterial strain against As toxicity. Thus, isolated bacterial strain could be used as bioremediator as well as growth inducer in paddy field contaminated with arsenic.

      PubDate: 2017-09-18T10:44:03Z
      DOI: 10.1016/j.plaphy.2017.08.021
      Issue No: Vol. 119 (2017)
       
  • Allantoin contributes to the stress response in cadmium-treated
           Arabidopsis roots
    • Authors: Maryam Nourimand; Christopher D. Todd
      Pages: 103 - 109
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Maryam Nourimand, Christopher D. Todd
      Ureides are nitrogen-rich compounds, derived from purine catabolism. A dual role for ureides, and for allantoin in particular, in both nitrogen recycling and the abiotic stress response has been recently identified. Previous work on the effect of allantoin on cadmium (Cd)-exposed Arabidopsis revealed that high concentration of allantoin in allantoinase-negative mutant (aln-3) leaves alleviates Cd toxicity via inducing antioxidant mechanisms in these plants. In the present study, we evaluate whether allantoin has a similar protective role in roots. Both wild type and aln-3 roots contain higher amounts of internal Cd compared to leaves. Likewise, aln-3 roots are more resistant to Cd, reflected in fresh and dry weight, and stimulated antioxidant enzyme activity, including superoxide dismutase (SOD) and catalase (CAT), resulting in lower reactive oxygen species concentration. In contrast with wild-type leaves, high levels of Cd in Col-0 roots reduces transcript abundance of uricase, leading to a significant decline in allantoin level of treated roots at 1000 and 1500 μM CdCl2. This metabolite change is also accompanied by decreasing the activity of antioxidant enzymes (SOD and CAT). Additionally, contrary to wild-type leaves, root genotype has a significant effect on CAT activity under Cd treatment, suggesting the possible different sources of damage and oxidative stress response in these two tissues.

      PubDate: 2017-09-18T10:44:03Z
      DOI: 10.1016/j.plaphy.2017.08.012
      Issue No: Vol. 119 (2017)
       
  • Cyanobacteria growing on tree barks possess high amount of sunscreen
           compound mycosporine-like amino acids (MAAs)
    • Authors: Anjali Singh; Madhu Bala Tyagi; Ashok Kumar
      Pages: 110 - 120
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Anjali Singh, Madhu Bala Tyagi, Ashok Kumar
      The present study describes cyanobacterial species composition and their dominance in biological crusts from barks of different trees, roof top of building and soil of agricultural field. An attempt was also made to explore the presence of photoprotective compounds such as mycosporine-like amino acids (MAAs) in the crust samples. Microscopic examination and growth studies revealed the presence of Oscillatoria species in all the crust samples excluding the crust of roof top of a building. Study on the abundance of dominant genera showed marked differences among various crust samples but Hapalosiphon, Lyngbya, Oscillatoria and Scytonema sp. were the most dominant genera, Oscillatoria being dominant in three crust samples. Screening for the presence of photoprotective compounds showed the presence of major peaks in the range of 308–334 nm thereby pointing to the presence of MAAs in all the crust samples. The highest amount of MAAs was found in the crust of Borassus flabellifer (15,729 nmol g dry wt−1 of bark) followed by crust of roof top (14,543 nmol g dry wt−1 of crust). MAAs were separated and partially purified employing HPLC, the most common MAA present in all the crusts was identified as mycosporine-glycine. Presence of mycosporine-glycine (M-Gly) was further confirmed by FTIR and NMR. Test of in vitro colonization on the bark of Mangifera indica and Azadirachta indica by three isolates namely Hapalosiphon, Oscillatoria and Scytonema sp. showed sign of active colonization. It is felt that identification of all the MAAs other than M-Gly may prove useful in future studies especially for assessing their significance in the protection mechanism of cyanobacteria/algae against various types of abiotic stresses.

      PubDate: 2017-09-18T10:44:03Z
      DOI: 10.1016/j.plaphy.2017.08.020
      Issue No: Vol. 119 (2017)
       
  • Relative contribution of Na+/K+ homeostasis, photochemical efficiency and
           antioxidant defense system to differential salt tolerance in cotton
           (Gossypium hirsutum L.) cultivars
    • Authors: Ning Wang; Wenqing Qiao; Xiaohong Liu; Jianbin Shi; Qinghua Xu; Hong Zhou; Gentu Yan; Qun Huang
      Pages: 121 - 131
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Ning Wang, Wenqing Qiao, Xiaohong Liu, Jianbin Shi, Qinghua Xu, Hong Zhou, Gentu Yan, Qun Huang
      In this study, the role of specific components of different coping strategies to salt load were identified. A pot experiment was conducted with four cotton (Gossypium hirsutum L.) cultivars (differing in salt-sensitivity) under salinity stress. Based on observed responses in growth performance and physiological characteristics, CZ91 was the most tolerant of the four cultivars, followed by cultivars CCRI44 and CCRI49, with Z571 being much more sensitive to salt stress. To perform this tolerant response, they implement different adaptative mechanisms to cope with salt-stress. The superior salt tolerance of CZ91 was conferred by at least three complementary physiological mechanisms: its ability to regulate K+ and Na+ transport more effectively, its higher photochemical efficiency and better antioxidant defense capacity. However, only one or a few specific components of these defense systems play crucial roles in moderately salt tolerant CCRI44 and CCRI49. Lower ROS load in CCRI44 may be attributed to simultaneous induction of antioxidant defenses by maintaining an unusually high level of SOD, and higher activities of CAT, APX, and POD during salt stress. CCRI49 could reduce the excess generation of ROS not only by maintaining a higher selective absorption of K+ over Na+ in roots across the membranes through SOS1, AKT1, and HAK5, but also by displaying higher excess-energy dissipation (e.g., higher ETR, PR and qN) during salt stress. Overall, our data provide a mechanistic explanation for differential salt stress tolerance among these cultivars and shed light on the different strategies employed by cotton cultivars to minimize the ill effects of stress.

      PubDate: 2017-09-06T10:27:33Z
      DOI: 10.1016/j.plaphy.2017.08.024
      Issue No: Vol. 119 (2017)
       
  • Genome-wide analysis of the YABBY family in soybean and functional
           
    • Authors: Shu-Ping Zhao; Dan Lu; Tai-Fei Yu; Yu-Jie Ji; Wei-Jun Zheng; Shuang-Xi Zhang; Shou-Cheng Chai; Zhan-Yu Chen; Xi-Yan Cui
      Pages: 132 - 146
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Shu-Ping Zhao, Dan Lu, Tai-Fei Yu, Yu-Jie Ji, Wei-Jun Zheng, Shuang-Xi Zhang, Shou-Cheng Chai, Zhan-Yu Chen, Xi-Yan Cui
      YABBY family is a plant specific transcription factor family, with the typical N-terminal C2C2 type zinc finger domain and the C-terminal YABBY conservative structure domain, which plays important biological roles in plant growth, development and morphogenesis. In this study, a total of 17 YABBY genes were identified in the soybean genome. The results of this research showed that 17 soybean YABBY genes were located on 11 chromosomes. Analysis of putative cis-acting elements showed that soybean YABBY genes contained lots of MYB and MYC elements. Quantitative Real-time PCR (qRT-PCR) showed that the expressions of GmYABBY3, GmYABBY10 and GmYABBY16 were more highly sensitive in drought, NaCl and ABA stresses. And the transient expression in Arabidopsis protoplasts showed that GmYABBY3 protein distributed uniformly the whole cells, while GmYABBY10 protein was mainly localized in the membranes and cytoplasm and GmYABBY16 protein was localized the nucleus and membranes. To further identify the function of GmYABBY10, we obtained the transgenic Arabidopsis overexpression GmYABBY10. Based on germination and seedling root arrays in transgenic Arabidopsis, we found that the rates of wild type seeds was a litter higher than that of GmYABBY10 transgenic seeds under both PEG and NaCl treatment. While the root length and root surface of wild type seedlings were bigger than those of GmYABBY10 transgenic seedlings. When seedlings were grown in soil, the survival rates of wild type were higher than those of transgenic plants under both PEG and NaCl treatment, which indicated that GmYABBY10 may be a negatively regulator in plant resistances to drought and salt stresses. This study provided valuable information regarding the classification and functions of YABBY genes in soybean.

      PubDate: 2017-09-06T10:27:33Z
      DOI: 10.1016/j.plaphy.2017.08.026
      Issue No: Vol. 119 (2017)
       
  • Differential accumulation of flavonoids and phytohormones resulting from
           the canopy/rootstock interaction of citrus plants subjected to
           dehydration/rehydration
    • Authors: Ivanildes C. dos Santos; Alex-Alan Furtado de Almeida; Carlos P. Pirovani; Márcio Gilberto Cardoso Costa; Maria Fatima das Graças Fernandes da Silva; Barbara Sayuri Bellete; Luciano Freschi; Walter Soares Filho; Maurício Antônio Coelho Filho; Abelmon da Silva Gesteira
      Pages: 147 - 158
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Ivanildes C. dos Santos, Alex-Alan Furtado de Almeida, Carlos P. Pirovani, Márcio Gilberto Cardoso Costa, Maria Fatima das Graças Fernandes da Silva, Barbara Sayuri Bellete, Luciano Freschi, Walter Soares Filho, Maurício Antônio Coelho Filho, Abelmon da Silva Gesteira
      Water scarcity can elicit drastic changes in plant metabolic and hormonal regulation, which may be of fundamental importance to stress tolerance. The study of plant the metabolic alterations in response to water deficit, especially the effects of the rootstocks level, is important to elucidate the mechanisms associated to drought tolerance. To verify the influence of rootstock and grafting on the tolerance to drought in citrus plants, we analyzed the growth, phytohormone levels and flavonoid profiles in grafted and ungrafted citrus plants subjected to different soil water regimes on plant status (well-watered, moderate drought and severe drought and rehydrated) under field conditions. The experiments were conducted under field conditions in the Brazilian Agricultural Research Corporation (EMBRAPA), Cruz das Almas, BA, Brazil. Water deficit reduced the total leaf area per plant in all canopy/rootstock combinations. Self-grafting reduce root volume, area and length when compared to ungrafted plants. Drought-induced increases in salicylic acid and abscisic acid associated with concomitant reductions in indoleacetic acid were observed in most canopy/rootstock combinations. However, plants with 'Sunki Maravilha' rootstocks exhibited the most pronounced changes in hormonal levels upon drought stress. Associated to these hormonal changes, drought also significantly affected flavonoid content and profile in both leaves and roots of the distinct citrus combinations. Glycosylated (GFs) and polimethoxylated flavonoids were predominantly found in leaves, whereas prenylated coumarins were found in the roots. Leaf levels of GFs (vicenin, F11, rutin and rhoifolin) were particularly modulated by drought in plants with ‘Rangpur Santa Cruz’ lime rootstock, whereas root levels of prenylated coumarins were most regulated by drought in plants with the 'Sunki Maravilha' root system. Taken together, these data indicate that the impacts of water deficit restriction on growth, hormonal balance and flavonoid profiles significantly varies depending on the canopy/rootstock combinations.

      PubDate: 2017-09-06T10:27:33Z
      DOI: 10.1016/j.plaphy.2017.08.019
      Issue No: Vol. 119 (2017)
       
  • Biochemical characterization and homology modeling of polyamine oxidase
           from cyanobacterium Synechocystis sp. PCC 6803
    • Authors: Khanittha Samasil; Leonor Lopes de Carvalho; Pirkko Mäenpää; Tiina A. Salminen; Aran Incharoensakdi
      Pages: 159 - 169
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Khanittha Samasil, Leonor Lopes de Carvalho, Pirkko Mäenpää, Tiina A. Salminen, Aran Incharoensakdi
      The intracellular polyamine contents are regulated not only by polyamine biosynthesis and transport but also by polyamine degradation catalyzed by copper-dependent amine oxidase (DAO) and FAD-dependent polyamine oxidase (PAO). The genome sequence of Synechocystis sp. PCC 6803 reveals the presence of at least one putative polyamine oxidase gene, slr5093. The open reading frame of slr 5093 encoding Synechocystis polyamine oxidase (SynPAO, E.C. 1.5.3.17) was expressed in Escherichia coli. The purified recombinant enzyme had the characteristic absorption spectrum of a flavoprotein with absorbance peaks at 380 and 450 nm. The optimum pH and temperature for the oxidation of both spermidine and spermine are 8.5 and 30 °C, respectively. The enzyme catalyzed the conversion of spermine and spermidine to spermidine and putrescine, respectively, with higher catalytic efficiency when spermine served as substrate. These results suggest that SynPAO is a polyamine oxidase involved in a polyamine back-conversion pathway. Based on the structural analysis, Gln94, Tyr403 and Thr440 in SynPAO are predicted to be important residues in the active site.

      PubDate: 2017-09-06T10:27:33Z
      DOI: 10.1016/j.plaphy.2017.08.018
      Issue No: Vol. 119 (2017)
       
  • Stress-induced changes of growth, yield and bioactive compounds in lemon
           balm cultivars
    • Authors: Krisztina Szabó; Péter Radácsi; Péter Rajhárt; Márta Ladányi; Éva Németh
      Pages: 170 - 177
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Krisztina Szabó, Péter Radácsi, Péter Rajhárt, Márta Ladányi, Éva Németh
      The aim of the present study was to investigate the impact of water deficiency on five Melissa officinalis genotypes. For three months water supply of 70% (control) and 40% (stress) of soil water capacity treatments have been adjusted in a pot experiment. Considering the morphological data, the different genetic potentials of cultivars were manifested only under optimum water regimes while under drought they merged into one homogeneous basic population representing the species. The biomass data decreased for all cultivars under drought stress, but the degree of loss was genotype specific. Genotype dependence of the change in essential oil accumulation was clearly proved by the data. Three of the cultivars (‘Gold Leaf’, ‘Lorelei’ and ‘Quedlinburger Niederliegende’) showed the same essential oil content both in control and stress treatments. Under drought stress the cultivar ‘Lemona’ produced only 35% of its essential oil content, however cv. ‘Soroksár’ reacted with 58% increase of essential oil accumulation to drought treatment. Considering the non-volatile bioactive compounds a unique response of the investigated accessions to drought stress was demonstrated. Cultivar ‘Lorelei’ showed an increased accumulation of total hydroxicinnamic acid derivatives content while cv. ‘Gold Leaf’ and ‘Soroksár’ clearly reacted with higher accumulation of total flavonoid fraction. In the case of cv. ‘Quedlinburger Niederliegende’ the remarkable decline in total flavonoid content is the most obvious stress reaction. The rosmarinic acid content of all genotypes showed lower accumulation level in consequence of lower water supply.

      PubDate: 2017-09-06T10:27:33Z
      DOI: 10.1016/j.plaphy.2017.07.019
      Issue No: Vol. 119 (2017)
       
  • Functional identification of MdPIF1 as a Phytochrome Interacting Factor in
           Apple
    • Authors: Li-Jie Zhou; Ke Mao; Yu Qiao; Han Jiang; Yuan-Yuan Li; Yu-Jin Hao
      Pages: 178 - 188
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Li-Jie Zhou, Ke Mao, Yu Qiao, Han Jiang, Yuan-Yuan Li, Yu-Jin Hao
      Light plays a central role in regulating both apple plant yield and fruit quality formation; however, the Phytochrome interacting factors (PIFs), which are the main components of Phytochrome-mediated light signal transduction in apple, have rarely been characterized. Here, we isolated and identified a PIF-like protein(MdPIF1) in apple, which is similar to AtPIF1. MdPIF1 was constitutively expressed at different levels in various apple tissues, and the transcription level of MdPIF1 was significantly induced during seed germination. A functional complementation assay in the Arabidopsis PIF1-deletion mutant pil5 suggested that MdPIF1 was a negative regulator in the Phy-mediated inhibition of hypocotyl elongation under far-red light conditions. MdPIF1-overexpression promoted hypocotyl elongation, while inhibiting seed germination and PIF1 deletion-induced the bleaching phenotype in the pil5 mutant. In addition, expression analysis indicated that MdPIF1 was involved in the germination of apple seeds and dormancy breaking of apple buds. Moreover, MdPIF1 inhibited the growth of apple calli via Phy-mediated pathways. These findings build a solid foundation for studies on Phytochrome-mediated light signal transduction and molecular breeding in apple.

      PubDate: 2017-09-06T10:27:33Z
      DOI: 10.1016/j.plaphy.2017.08.027
      Issue No: Vol. 119 (2017)
       
  • Deciphering the interplay among genotype, maturity stage and
           low-temperature storage on phytochemical composition and transcript levels
           of enzymatic antioxidants in Prunus persica fruit
    • Authors: George A. Manganaris; Pavlina Drogoudi; Vlasios Goulas; Georgia Tanou; Egli C. Georgiadou; George E. Pantelidis; Konstantinos A. Paschalidis; Vasileios Fotopoulos; Athanasios Manganaris
      Pages: 189 - 199
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): George A. Manganaris, Pavlina Drogoudi, Vlasios Goulas, Georgia Tanou, Egli C. Georgiadou, George E. Pantelidis, Konstantinos A. Paschalidis, Vasileios Fotopoulos, Athanasios Manganaris
      The aim of this study was to understand the antioxidant metabolic changes of peach (cvs. ‘Royal Glory’, ‘Red Haven’ and ‘Sun Cloud’) and nectarine fruits (cv. ‘Big Top’) exposed to different combinations of low-temperature storage (0, 2, 4 weeks storage at 0 °C, 90% R.H.) and additional ripening at room temperature (1, 3 and 5 d, shelf life, 20 °C) with an array of analytical, biochemical and molecular approaches. Initially, harvested fruit of the examined cultivars were segregated non-destructively at advanced and less pronounced maturity stages and qualitative traits, physiological parameters, phytochemical composition and antioxidant capacity were determined. ‘Big Top’ and ‘Royal Glory’ fruits were characterized by slower softening rate and less pronounced ripening-related alterations. The coupling of HPLC fingerprints, consisted of 7 phenolic compounds (chlorogenic, neochlorogenic acid, catechin, epicatechin, rutin, quecetin-3-O-glucoside, procyanidin B1) and spectrophotometric methods disclosed a great impact of genotype on peach bioactive composition, with ‘Sun Cloud’ generally displaying the highest contents. Maturity stage at harvest did not seem to affect fruit phenolic composition and no general guidelines for the impact of cold storage and shelf-life on individual phenolic compounds can be extrapolated. Subsequently, fruit of less pronounced maturity at harvest were used for further molecular analysis. ‘Sun Cloud’ was proven efficient in protecting plasmid pBR322 DNA against ROO attack throughout the experimental period and against HO attack after 2 and 4 weeks of cold storage. Interestingly, a general down-regulation of key genes implicated in the antioxidant apparatus with the prolongation of storage period was recorded; this was more evident for CAT, cAPX, Cu/ZnSOD2, perAPX3 and GPX8 genes. Higher antioxidant capacity of ‘Sun Cloud’ fruit could potentially be linked with compounds other than enzymatic antioxidants that further regulate peach fruit ripening.

      PubDate: 2017-09-06T10:27:33Z
      DOI: 10.1016/j.plaphy.2017.08.022
      Issue No: Vol. 119 (2017)
       
  • Glycosylation is important for FcXTH1 activity as judged by its structural
           and biochemical characterization
    • Authors: Ángela Méndez-Yañez; Dina Beltrán; Constanza Campano-Romero; Sebastián Molinett; Raúl Herrera; María Alejandra Moya-León; Luis Morales-Quintana
      Pages: 200 - 210
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Ángela Méndez-Yañez, Dina Beltrán, Constanza Campano-Romero, Sebastián Molinett, Raúl Herrera, María Alejandra Moya-León, Luis Morales-Quintana
      Xyloglucan endotransglycosylase/hydrolases (XTH) may have endotransglycosylase (XET) and/or hydrolase (XEH) activities. Previous studies suggest that XTHs might play a key role in ripening of Fragaria chiloensis fruit as FcXTH1 transcripts increase as fruit softens. FcXTH1 protein sequence contains a conserved N-glycosylation site adjacent to catalytic residues. The FcXTH1 structure was built through comparative modeling methodology, the structure displays a β-jellyroll–type folding with a curvature generated by eight antiparallel β-sheets that holds the catalytic motif that is oriented towards the central cavity of the protein. Through Molecular Dynamic Simulations (MDS) analyses the protein-ligand interactions of FcXTH1 were explored, finding a better interaction with xyloglucans than cellulose. Nevertheless, the stability of the protein-ligand complex depends on the glycosylation state of FcXTH1: better energy interactions were determined for the glycosylated protein. As a complement, the molecular cloning and heterologous expression of FcXTH1 in Pichia pastoris was performed, and the recombinant protein was active and displayed strict XET activity. A KM value of 17.0 μM was determined for xyloglucan oligomer. The deglycosylation of FcXTH1 by PNGase-F treatment affects its biochemical properties (increase KM and reduce kcat/KM ratio) and reduces its stability. As a conclusion, glycosylation of FcXTH1 is important for its biological function.
      Graphical abstract image

      PubDate: 2017-09-11T10:29:21Z
      DOI: 10.1016/j.plaphy.2017.08.030
      Issue No: Vol. 119 (2017)
       
  • Plant growth-promoting endophyte Piriformospora indica alleviates salinity
           stress in Medicago truncatula
    • Authors: Liang Li; Lei Li; Xiaoyang Wang; Pengyue Zhu; Hongqing Wu; Shuting Qi
      Pages: 211 - 223
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Liang Li, Lei Li, Xiaoyang Wang, Pengyue Zhu, Hongqing Wu, Shuting Qi
      Piriformospora indica, a cultivable root endophytic fungus, induces growth promotion as well as biotic stress resistance and tolerance to abiotic stress in a broad range of host plants. In this study, the potential protection for M Medicago truncatula plants from salinity stress by P. indica was explored. The improved plant growth under severe saline condition was exhibited in P. indica-colonized lines. Moreover, the antioxidant enzymes activities and hyphae density in roots were increased by the endophyte under high salt concentration. Conversely, reduced malondialdehyde (MDA) activity, Na+ content and relative electrolyte conductivity (REC) were observed in P. indica colonized plants. Especially, osmoprotectant proline accumulated and the expression of Delta 1-Pyrroline-5-carboxylate synthetase gene (P5CS2) was induced. The defense related genes PR1 and PR10 and the transcription factors MtAlfin1-like and C2H2-type zinc finger protein MtZfp-c2h2 were induced by P. indica colonization as well. Further work indicated that salinity resistance was increased in overexpressing P5CS2, MtAlfin1-like and MtZfp-c2h2 transgenic M. truncatula plants. Interestingly, our data showed that the transcription factors MtAlfin1-like and MtZfp-c2h2 were positively contributed to P. indica colonization. These results demonstrate that tolerance to salinity stress was conferred by P. indica in M. truncatula via accumulation of osmoprotectant, stimulating antioxidant enzymes and the expression of defense-related genes. This work revealed the potential application of P. indica's as a plant growth-promoting fungus for the target improvement either in crop protection or in the salinized soil improvement indirectly.

      PubDate: 2017-09-11T10:29:21Z
      DOI: 10.1016/j.plaphy.2017.08.029
      Issue No: Vol. 119 (2017)
       
  • Spectral phasor analysis reveals altered membrane order and function of
           root hair cells in Arabidopsis dry2/sqe1-5 drought hypersensitive mutant
    • Authors: Florencia Sena; Mariana Sotelo-Silveira; Soledad Astrada; Miguel A. Botella; Leonel Malacrida; Omar Borsani
      Pages: 224 - 231
      Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119
      Author(s): Florencia Sena, Mariana Sotelo-Silveira, Soledad Astrada, Miguel A. Botella, Leonel Malacrida, Omar Borsani
      Biological membranes allow the regulation of numerous cellular processes, which are affected when unfavorable environmental factors are perceived. Lipids and proteins are the principal components of biological membranes. Each lipid has unique biophysical properties, and, therefore the lipid composition of the membrane is critical to maintaining the bilayer structure and functionality. Membrane composition and integrity are becoming the focus of studies aiming to understand how plants adapt to its environment. In this study, using a combination of di-4-ANEPPDHQ fluorescence and spectral phasor analysis, we report that the drought hypersensitive/squalene epoxidase (dry2/sqe1-5) mutant with reduced major sterols such as sitosterol and stigmasterol in roots presented higher membrane fluidity than the wild type. Moreover, analysis of endomembrane dynamics showed that vesicle formation was affected in dry2/sqe1-5. Further analysis of proteins associated with sterol rich micro domains showed that dry2/sqe1-5 presented micro domains function altered.
      Graphical abstract image

      PubDate: 2017-09-18T10:44:03Z
      DOI: 10.1016/j.plaphy.2017.08.017
      Issue No: Vol. 119 (2017)
       
  • Impact of reduced atmospheric CO2 and varied potassium supply on
           carbohydrate and potassium distribution in grapevine and grape berries
           (Vitis vinifera L.)
    • Authors: Zelmari A. Coetzee; Rob R. Walker; Alain J. Deloire; Célia Barril; Simon J. Clarke; Suzy Y. Rogiers
      Abstract: Publication date: Available online 13 October 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Zelmari A. Coetzee, Rob R. Walker, Alain J. Deloire, Célia Barril, Simon J. Clarke, Suzy Y. Rogiers
      To assess the robustness of the apparent sugar-potassium relationship during ripening of grape berries, a controlled-environment study was conducted on Shiraz vines involving ambient and reduced (by 34%) atmospheric CO2 concentrations, and standard and increased (by 67%) soil potassium applications from prior to the onset of ripening. The leaf net photoassimilation rate was decreased by 35% in the reduced CO2 treatment. The reduction in CO2 delayed the onset of ripening, but at harvest the sugar content of the berry pericarp was similar to that of plants grown in ambient conditions. The potassium content of the berry pericarp in the reduced CO2 treatment was however higher than for the ambient CO2. Berry potassium, sugar and water content were strongly correlated, regardless of treatments, alluding to a ternary link during ripening. Root starch content was lower under reduced CO2 conditions, and therefore likely acted as a source of carbohydrates during berry ripening. Root carbohydrate reserve replenishment could also have been moderated under reduced CO2 at the expense of berry ripening. Given that root potassium concentration was also less in the vines grown in the low CO2 atmosphere, these results point toward whole-plant fine-tuning of carbohydrate and potassium partitioning aimed at optimising fruit ripening.

      PubDate: 2017-10-14T12:47:55Z
      DOI: 10.1016/j.plaphy.2017.10.008
       
  • A harpin elicitor induces the expression of a coiled-coil nucleotide
           binding leucine rich repeat (CC-NB-LRR) defense signaling gene and others
           functioning during defense to parasitic nematodes
    • Authors: Weasam A.R. Aljaafri; Brant T. McNeece; Bisho R. Lawaju; Keshav Sharma; Prakash M. Niruala; Shankar R. Pant; David H. Long; Kathy S. Lawrence; Gary W. Lawrence; Vincent P. Klink
      Abstract: Publication date: Available online 13 October 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Weasam A.R. Aljaafri, Brant T. McNeece, Bisho R. Lawaju, Keshav Sharma, Prakash M. Niruala, Shankar R. Pant, David H. Long, Kathy S. Lawrence, Gary W. Lawrence, Vincent P. Klink
      The bacterial effector harpin induces the transcription of the Arabidopsis thaliana NON-RACE SPECIFIC DISEASE RESISTANCE 1/HARPIN INDUCED1 (NDR1/HIN1) coiled-coil nucleotide binding leucine rich repeat (CC-NB-LRR) defense signaling gene. In Glycine max, Gm-NDR1-1 transcripts have been detected within root cells undergoing a natural resistant reaction to parasitism by the syncytium-forming nematode Heterodera glycines, functioning in the defense response. Expressing Gm-NDR1-1 in Gossypium hirsutum leads to resistance to Meloidogyne incognita parasitism. In experiments presented here, the heterologous expression of Gm-NDR1-1 in G. hirsutum impairs Rotylenchulus reniformis parasitism. These results are consistent with the hypothesis that Gm-NDR1-1 expression functions broadly in generating a defense response. To examine a possible relationship with harpin, G. max plants topically treated with harpin result in induction of the transcription of Gm-NDR1-1. The result indicates the topical treatment of plants with harpin, itself, may lead to impaired nematode parasitism. Topical harpin treatments are shown to impair G. max parasitism by H. glycines, M. incognita and R. reniformis and G. hirsutum parasitism by M. incognita and R. reniformis. How harpin could function in defense has been examined in experiments showing it also induces transcription of G. max homologs of the proven defense genes ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1), TGA2, galactinol synthase, reticuline oxidase, xyloglucan endotransglycosylase/hydrolase, alpha soluble N-ethylmaleimide-sensitive fusion protein (α-SNAP) and serine hydroxymethyltransferase (SHMT). In contrast, other defense genes are not directly transcriptionally activated by harpin. The results indicate harpin induces pathogen associated molecular pattern (PAMP) triggered immunity (PTI) and effector-triggered immunity (ETI) defense processes in the root, activating defense to parasitic nematodes.

      PubDate: 2017-10-14T12:47:55Z
      DOI: 10.1016/j.plaphy.2017.10.004
       
  • The imbalance between C and N metabolism during high nitrate supply
           inhibits photosynthesis and overall growth in maize (Zea mays L.)
    • Authors: Iñigo Saiz-Fernández; Nuria De Diego; Břetislav Brzobohatý; Alberto Muñoz-Rueda; Maite Lacuesta
      Abstract: Publication date: Available online 12 October 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Iñigo Saiz-Fernández, Nuria De Diego, Břetislav Brzobohatý, Alberto Muñoz-Rueda, Maite Lacuesta
      Nitrogen (N) is an important regulator of photosynthetic carbon (C) flow in plants, and an adequate balance between N and C metabolism is needed for correct plant development. However, an excessive N supply can alter this balance and cause changes in specific organic compounds associated with primary and secondary metabolism, including plant growth regulators. In previous work, we observed that high nitrate supply (15 mM) to maize plants led to a decrease in leaf expansion and overall biomass production, when compared with low nitrate supply (5 mM). Thus, the aim of this work is to study how overdoses of nitrate can affect photosynthesis and plant development. The results show that high nitrate doses greatly increased amino acid production, which led to a decrease in the concentration of 2-oxoglutarate, the main source of C skeletons for N assimilation. The concentration of 1-aminocyclopropane-1-carboxylic acid (and possibly its product, ethylene) also rose in high nitrate plants, leading to a decrease in leaf expansion, reducing the demand for photoassimilates by the growing tissues and causing the accumulation of sugars in source leaves. This accumulation of sugars, together with the decrease in 2-oxoglutarate levels and the reduction in chlorophyll concentration, decreased plant photosynthetic rates. This work provides new insights into how high nitrate concentration alters the balance between C and N metabolism, reducing photosynthetic rates and disrupting whole plant development. These findings are particularly relevant since negative effects of nitrate in contexts other than root growth have rarely been studied.

      PubDate: 2017-10-14T12:47:55Z
      DOI: 10.1016/j.plaphy.2017.10.006
       
  • Effects of prolonged drought on stem non-structural carbohydrates content
           and post-drought hydraulic recovery in Laurus nobilis L.: The possible
           link between carbon starvation and hydraulic failure
    • Authors: Patrizia Trifilò; Valentino Casolo; Fabio Raimondo; Elisa Petrussa; Francesco Boscutti; Maria Assunta Lo Gullo; Andrea Nardini
      Abstract: Publication date: Available online 12 October 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Patrizia Trifilò, Valentino Casolo, Fabio Raimondo, Elisa Petrussa, Francesco Boscutti, Maria Assunta Lo Gullo, Andrea Nardini
      Drought-induced tree decline is a complex event, and recent hypotheses suggest that hydraulic failure and carbon starvation are co-responsible for this process. We tested the possible role of non-structural carbohydrates (NSC) content on post-drought hydraulic recovery, to verify the hypothesis that embolism reversal represents a mechanistic link between carbon starvation and stem hydraulics. Measurements were performed in laurel plants subjected to similar water stress levels either over short or long term, to induce comparable embolism levels. Plants subjected to mild and prolonged water shortage (S) showed reduced growth, adjustment of turgor loss point driven by changes in both osmotic potential at full turgor and bulk modulus of elasticity, a lower content of soluble NSC and a higher content of starch with respect to control (C) plants. Moreover, S plants showed a lower ability to recover from xylem embolism than C plants, even after irrigation. Our data suggest that plant carbon status might indirectly influence plant performance during and after drought via effects on xylem hydraulic functioning, supporting the view of a possible mechanistic link between the two processes.
      Graphical abstract image

      PubDate: 2017-10-14T12:47:55Z
      DOI: 10.1016/j.plaphy.2017.10.003
       
  • Top Bending Panicle1 is involved in brassinosteroid signaling and
           regulates the plant architecture in rice
    • Authors: Yun Lin; Zhigang Zhao; Shirong Zhou; Linglong Liu; Weiyi Kong; Haiyuan Chen; Wuhua Long; Zhiming Feng; Ling Jiang; Jianmin Wan
      Abstract: Publication date: Available online 12 October 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Yun Lin, Zhigang Zhao, Shirong Zhou, Linglong Liu, Weiyi Kong, Haiyuan Chen, Wuhua Long, Zhiming Feng, Ling Jiang, Jianmin Wan
      Brassinosteroids (BRs) regulate several aspects of plant growth and development. Although extensive studies have shown that BR signaling is conservative in higher plants, the molecular mechanism of regulating plant architecture in rice still remains to be explored. Here, we characterized a rice mutant named top bending panicle1 (tbp1). Compared to wild type, tbp1 mutant plants displayed semi-dwarf stature, erect leaves, small and round grains, as well as more tillers. Remarkably, the panicles of tbp1 plants were shorter and denser, and the tops of the panicles were curved by rolling of the base of flag leaves, which was later verified as due to reduced bulliform cell numbers. Map-based cloning, together with transgenic complementation and RNA-interference tests, revealed that TBP1 is a member of the somatic embryogenesis receptor kinases (SERKs) family involved in BR signaling. Furthermore, bimolecular fluorescence complementation and co-immunoprecipitation analysis demonstrated that a substitution at 61st amino acid (His61Leu) in the tbp1 mutant may result in a reduction of the interaction between TBP1 and OsBRI1 (BR receptor in rice). Taken together, our results demonstrate that TBP1 plays a significant role in regulating plant architecture via the brassinosteroid signaling pathway.

      PubDate: 2017-10-14T12:47:55Z
      DOI: 10.1016/j.plaphy.2017.10.001
       
  • Mechanisms of desiccation tolerance in the bromeliad Pitcairnia burchellii
           Mez: Biochemical adjustments and structural changes
    • Authors: Evandro Alves Vieira; Kleber Resende Silva; Aline Oriani; Camila Fernandes Moro; Marcia Regina Braga
      Abstract: Publication date: Available online 10 October 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Evandro Alves Vieira, Kleber Resende Silva, Aline Oriani, Camila Fernandes Moro, Marcia Regina Braga
      Rocky outcrops represent the diversity center of vascular desiccation tolerant (DT) plants. Vegetation in this environment is exposed to an extended dry season and extreme conditions due to rocky soils and high sun exposure. In this study, we demonstrated that Pitcairnia burchellii, a bromeliad from rocky outcrops, tolerates intense desiccation for about 90 days due to strategies as accumulation of compatible osmolytes and antioxidant substances together with leaf morphological changes. In dehydrated plants, an increase in antioxidant activity was observed and the vacuolization of parenchyma cells was accompanied by proline accumulation in leaves and rizomes. Precursors related to phenylpropanoid pathway increased significantly during plant dehydration. Accordingly, increases in anthocyanin and phenolic contents as well as lignin deposition were observed in leaves of dehydrated plants. Cell divisions and a decrease in stored starch were observed in the rhizomes indicating starch mobilization. Anatomical analyses revealed the presence of a more developed water-storage tissue in dehydrated leaves. During desiccation, leaves curl upwards and the adaxial V deep water-storage tissue is supported by two larger lateral vascular bundles. Cell wall folding and an increased proportion of arabinose-containing polymers was observed in leaves under dehydration, suggesting increasing of cell wall flexibility during desiccation. Such biochemical and morphological changes are consistent with the ability of P. burchellii to tolerate intense desiccation and behave as a resurrection species.

      PubDate: 2017-10-14T12:47:55Z
      DOI: 10.1016/j.plaphy.2017.10.002
       
  • Understanding the role of DNA polymerase λ gene in different growth and
           developmental stages of Oryza sativa L. indica rice cultivars
    • Authors: Sayantani Sihi; Soumitra Maiti; Sankar Bakshi; Arup Nayak; Shubho Chaudhuri; Dibyendu Narayan Sengupta
      Abstract: Publication date: Available online 4 October 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Sayantani Sihi, Soumitra Maiti, Sankar Bakshi, Arup Nayak, Shubho Chaudhuri, Dibyendu Narayan Sengupta
      DNA polymerase λ (Pol λ) is the only member of DNA polymerase family X present in plants. The enzyme is ddNTP sensitive as it contains the conserved C-terminal Pol β domain. The 1.1 kb partial coding sequence isolated spanned the whole 3′ regions of the gene containing functionally important domains of the Pol λ gene. Comparative in silico studies from both indica and japonica cultivars involving homology modelling showed that the model for the partial Pol λ gene was stable and acceptable. The alignment of both the protein models showed a RMS value of 0.783. Apart from this, expression of Pol λ and its relative activity is studied during different development stages of three different indica rice cultivars (IR29, Nonabokra and N22). Enhanced accumulation and higher activity of Pol λ during the early seedling stage was detected. Higher expression and activity were observed in the anthers, which was probably necessary for DNA repair during microspore formation. However, during the maturation stage of seed development and plant growth, expression and the activity of Pol λ decreased due to slow metabolic activity and a reduced rate of cell division respectively. Furthermore, the expression and activity of Pol λ were found to be higher in IR29 in comparison to Nonabokra and N22. IR29 is a rice cultivar susceptible to environmental stresses and hence it encounters higher DNA damages. The enhanced presence and activity of the Pol λ enzyme in IR29 with respect to the other two cultivars, which are more tolerant to the environmental stresses during various developmental stages, is therefore explainable.

      PubDate: 2017-10-08T12:15:29Z
      DOI: 10.1016/j.plaphy.2017.09.027
       
  • Hydrogen sulfide alleviates the cold stress through MPK4 in Arabidopsis
           thaliana
    • Authors: Xinzhe Du; Zhuping Jin; Danmei Liu; Guangdong Yang; Yanxi Pei
      Abstract: Publication date: Available online 3 October 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Xinzhe Du, Zhuping Jin, Danmei Liu, Guangdong Yang, Yanxi Pei
      Hydrogen sulfide (H2S) is a gaseous signaling molecule that mediates physiological processes in animals and plants. In this study, we investigated the relationship of H2S and mitogen activated protein kinase (MAPK) under cold stress in Arabidopsis. H2S up-regulated MAPK expression levels and was involved in the cold stress-related upregulation of MAPK genes expression. We then chose MPK4 whose expression level was influenced the most by H2S as a target and found that H2S's ability to alleviate cold stress required MPK4. Both H2S and MPK4 regulated the expression levels of the cold response genes inducer of CBF expression 1 (ICE1), C-repeat-binding factors (CBF3), cold responsive 15A (COR15A) and cold responsive 15B (COR15B). H2S inhibited the opening of stomata under cold stress, which required the participation of MPK4. In conclusion, MPK4 is a downstream component of H2S-related cold-stress resistance, and H2S and MPK4 both regulated the cold response genes and stomatal movement to response the cold stress.

      PubDate: 2017-10-08T12:15:29Z
      DOI: 10.1016/j.plaphy.2017.09.028
       
  • Enzymatic characterization and crystal structure analysis of Chlamydomonas
           reinhardtii dehydroascorbate reductase and their implications for
           oxidative stress
    • Authors: Hsin-Yang Chang; Shu-Tseng Lin; Tzu-Ping Ko; Shu-Mei Wu; Tsen-Hung Lin; Yu-Ching Chang; Kai-Fa Huang; Tse-Min Lee
      Abstract: Publication date: Available online 3 October 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Hsin-Yang Chang, Shu-Tseng Lin, Tzu-Ping Ko, Shu-Mei Wu, Tsen-Hung Lin, Yu-Ching Chang, Kai-Fa Huang, Tse-Min Lee
      Dehydroascorbate reductase (DHAR) is a key enzyme for glutathione (GSH)-dependent reduction of dehydroascorbate (DHA) to recycled ascorbate (AsA) in plants, and plays a major role against the toxicity of reactive oxygen species (ROS). Previously, we proposed that the increase of AsA regeneration via enhanced DHAR activity modulates the ascorbate-glutathione cycle activity against photooxidative stress in Chlamydomonas reinhardtii. In the present work, we use site-directed mutagenesis and crystal structure analysis to elucidate the molecular basis of how C. reinhardtii DHAR (CrDHAR1) is involved in the detoxification mechanisms. Mutagenesis data show that the D21A, D21N and C22A mutations result in severe loss of the enzyme's function, suggesting crucial roles of Asp-21 and Cys-22 in substrate binding and catalysis. The mutant K11A also exhibits reduced redox activity (∼50%). The crystal structure of apo CrDHAR1 further provides insights into the proposed mechanism centering on the strictly conserved Cys-22, which is suggested to initiate the redox reactions of DHA and GSH. Furthermore, in vitro oxidation of the recombinant CrDHAR1 in the presence of 1 mM H2O2 has minor effects on the K m for the substrates but significantly reduces the k cat. The enzyme's activity and its mRNA abundance in the C. reinhardtii cells are increased by treatment with 0.2–1 mM H2O2 but decreased when H2O2 is ≥ 1.5 mM. The latter decrease is accompanied by oxidative damage and lower AsA concentrations. These biochemical and physiological data provide new insights into the catalytic mechanism of CrDHAR1, which protects the C. reinhardtii cells from oxidative stress-induced toxicity.

      PubDate: 2017-10-08T12:15:29Z
      DOI: 10.1016/j.plaphy.2017.09.026
       
  • Penicillium expansum (compatible) and Penicillium digitatum (non-host)
           pathogen infection differentially alter ethylene biosynthesis in apple
           fruit
    • Authors: Laura Vilanova; Núria Vall-llaura; Rosario Torres; Josep Usall; Neus Teixidó Christian Larrigaudière; Jordi Giné-Bordonaba
      Abstract: Publication date: Available online 30 September 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Laura Vilanova, Núria Vall-llaura, Rosario Torres, Josep Usall, Neus Teixidó Christian Larrigaudière, Jordi Giné-Bordonaba
      The role of ethylene on inducing plant resistance or susceptibility to certain fungal pathogens clearly depends on the plant pathogen interaction with little or no-information available focused on the apple-Penicillium interaction. Taken advantage that Penicillium expansum is the compatible pathogen and P. digitatum is the non-host of apples, the present study aimed at deciphering how each Penicillium spp. could interfere in the fruit ethylene biosynthesis at the biochemical and molecular level. The infection capacity and different aspects related to the ethylene biosynthesis were conducted at different times post-inoculation. The results show that the fruit ethylene biosynthesis was differently altered during the P. expansum infection than in response to other biotic (non-host pathogen P. digitatum) or abiotic stresses (wounding). The first symptoms of the disease due to P. expansum were visible before the initiation of the fruit ethylene climacteric burst. Indeed, the ethylene climacteric burst was reduced in response to P. expansum concomitant to an important induction of MdACO3 gene expression and an inhibition (ca. 3-fold) and overexpression (ca. 2-fold) of ACO (1-Aminocyclopropane-1-carboxylic acid oxidase) and ACS (1-Aminocyclopropane-1-carboxylic acid synthase) enzyme activities, indicating a putative role of MdACO3 in the P. expansum-apple interaction which may, in turn, be related to System-1 ethylene biosynthesis. Indeed, System-1 is auto-inhibited by ethylene and is characteristic of non-climateric or pre-climacteric fruit. Accordingly, we hypothesise that P. expansum may ‘manipulate’ the endogenous ethylene biosynthesis in apples, leading to the circumvention or suppression of effective defences hence facilitating its colonization.
      Graphical abstract image

      PubDate: 2017-10-08T12:15:29Z
      DOI: 10.1016/j.plaphy.2017.09.024
       
  • Inside Front Cover - Editorial Board Page/Cover image legend if applicable
    • Abstract: Publication date: October 2017
      Source:Plant Physiology and Biochemistry, Volume 119


      PubDate: 2017-09-30T03:46:52Z
       
  • The influence of different light quality and benzene on gene expression
           and benzene degradation of Chlorophytum comosum
    • Authors: Arnon Setsungnern; Chairat Treesubsuntorn; Paitip Thiravetyan
      Abstract: Publication date: Available online 28 September 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Arnon Setsungnern, Chairat Treesubsuntorn, Paitip Thiravetyan
      Benzene, a carcinogenic compound, has been reported as a major indoor air pollutant. Chlorophytum comosum (C. comosum) was reported to be the highest efficient benzene removal plant among other screened plants. Our previous studies found that plants under light conditions could remove gaseous benzene higher than under dark conditions. Therefore, C. comosum exposure to airborne benzene was studied under different light quality at the same light intensity. C. comosum could remove 500 ppm gaseous benzene with the highest efficiency of 68.77% under Blue:Red = 1:1 LED treatments and the lowest one appeared 57.41% under white fluorescent treatment within 8 days. After benzene was uptaken by C. comosum, benzene was oxidized to be phenol in the plant cells by cytochrome P450 monooxygenase system. Then, phenol was catalyzed to be catechol that was confirmed by the up-regulation of phenol 2-monooxygenase (PMO) gene expression. After that, catechol was changed to cic, cis-muconic acid. Interestingly, cis,cis-muconic acid production was found in the plant tissues higher than phenol and catechol. The result confirmed that NADPH-cytochrome P450 reductase (CPR), cytochrome b5 (cyt b5), phenol 2-monooxygenase (PMO) and cytochrome P450 90B1 (CYP90B1) in plant cells were involved in benzene degradation or detoxification. In addition, phenol, catechol, and cis,cis-muconic acid production were found under the Blue-Red LED light conditions higher than under white fluorescent light conditions due to under LED light conditions gave higher NADPH contents. Hence, C. comosum under the Blue-Red LED light conditions had a high potential to remove benzene in a contaminated site.

      PubDate: 2017-09-30T03:46:52Z
      DOI: 10.1016/j.plaphy.2017.09.021
       
  • DNA demethylation activates genes in seed maternal integument development
           in rice (Oryza sativa L.)
    • Authors: Yifeng Wang; Haiyan Lin; Xiaohong Tong; Yuxuan Hou; Yuxiao Chang; Jian Zhang
      Abstract: Publication date: Available online 27 September 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Yifeng Wang, Haiyan Lin, Xiaohong Tong, Yuxuan Hou, Yuxiao Chang, Jian Zhang
      DNA methylation is an important epigenetic modification that regulates various plant developmental processes. Rice seed integument determines the seed size. However, the role of DNA methylation in its development remains largely unknown. Here, we report the first dynamic DNA methylomic profiling of rice maternal integument before and after pollination by using a whole-genome bisulfite deep sequencing approach. Analysis of DNA methylation patterns identified 4238 differentially methylated regions underpin 4112 differentially methylated genes, including GW2, DEP1, RGB1 and numerous other regulators participated in maternal integument development. Bisulfite sanger sequencing and qRT-PCR of six differentially methylated genes revealed extensive occurrence of DNA hypomethylation triggered by double fertilization at IAP compared with IBP, suggesting that DNA demethylation might be a key mechanism to activate numerous maternal controlling genes. These results presented here not only greatly expanded the rice methylome dataset, but also shed novel insight into the regulatory roles of DNA methylation in rice seed maternal integument development.

      PubDate: 2017-09-30T03:46:52Z
      DOI: 10.1016/j.plaphy.2017.09.018
       
  • Genome-wide transcriptome profiling of genes associated with arsenate
           toxicity in an arsenic-tolerant rice mutant
    • Authors: Sun-Goo Hwang; Sandeep Chapagain; Jae Woo Lee; A-Reum Han; Cheol Seong Jang
      Abstract: Publication date: Available online 27 September 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Sun-Goo Hwang, Sandeep Chapagain, Jae Woo Lee, A-Reum Han, Cheol Seong Jang
      The presence of arsenic (As) in polluted environments, such as ground water, affects the accumulation of As in rice grains and causes a serious threat to human health. However, the precise molecular regulations related to As toxicity and tolerance in rice remain largely unknown. In the present study, we developed an arsenic-tolerant type 1 (ATT1) rice mutant by γ-irradiation mutagenesis and performed genome-wide transcriptome analysis for the characterization of As-responsive genes. Toxicity inhibited transcriptional regulation of putative genes involved in photosynthesis, mitochondrial electron transport, and lipid biosynthesis metabolism in wild-type (WT) and ATT1 rice mutant. However, many cysteine biosynthesis-related genes were significantly upregulated in both plants. We also attempted to elucidate the putative genes associated with As tolerance by comparing transcriptomes and identified ATT1-specific transcriptional regulation of genes involved in stress and RNA-protein synthesis. This analysis identified 50 genes that had DNA polymorphisms in upstream regions that differed from those in the exon regions, which suggested that genetic variations in the upstream regions might enhance As tolerance in the mutants. Therefore, the expression profiles of the genes evaluated in this study may improve understanding of the functional roles of As-related genes in response to As tolerance mechanisms and could potentially be used in molecular breeding to limit As accumulation in rice grains.

      PubDate: 2017-09-30T03:46:52Z
      DOI: 10.1016/j.plaphy.2017.09.019
       
  • Drought-induced embolism in stems of sunflower: A comparison of in vivo
           micro-CT observations and destructive hydraulic measurements
    • Authors: Tadeja Savi; Andrea Miotto; Francesco Petruzzellis; Adriano Losso; Serena Pacilè; Giuliana Tromba; Stefan Mayr; Andrea Nardini
      Abstract: Publication date: Available online 23 September 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Tadeja Savi, Andrea Miotto, Francesco Petruzzellis, Adriano Losso, Serena Pacilè, Giuliana Tromba, Stefan Mayr, Andrea Nardini
      Vulnerability curves (VCs) are a useful tool to investigate the susceptibility of plants to drought-induced hydraulic failure, and several experimental techniques have been used for their measurement. The validity of the bench dehydration method coupled to hydraulic measurements, considered as a 'golden standard', has been recently questioned calling for its validation with non-destructive methods. We compared the VCs of a herbaceous crop plant (Helianthus annuus) obtained during whole-plant dehydration followed by i) hydraulic flow measurements in stem segments (classical destructive method) or by ii) in vivo micro-CT observations of stem xylem conduits in intact plants. The interpolated P50 values (xylem water potential inducing 50% loss of hydraulic conductance) were −1.74 MPa and −0.87 MPa for the hydraulic and the micro-CT VC, respectively. Interpolated P20 values were similar, while P50 and P80 were significantly different, as evidenced by non-overlapping 95% confidence intervals. Our results did not support the tension-cutting artefact, as no overestimation of vulnerability was observed when comparing the hydraulic VC to that obtained with in vivo imaging. After one scan, 25% of plants showed signs of x-ray induced damage, while three successive scans caused the formation of a circular brownish scar in all tested plants. Our results support the validity of hydraulic measurements of samples excised under tension provided standard sampling and handling protocols are followed, but also show that caution is needed when investigating vital plant processes with x-ray imaging.

      PubDate: 2017-09-23T10:55:07Z
      DOI: 10.1016/j.plaphy.2017.09.017
       
  • Identification of TPS family members in apple (Malus x domestica Borkh.)
           and the effect of sucrose sprays on TPS expression and floral induction
    • Authors: Lisha Du; Siyan Qi; Juanjuan Ma; Libo Xing; Sheng Fan; Songwen Zhang; Youmei Li; Yawen Shen; Dong Zhang; Mingyu Han
      Abstract: Publication date: Available online 22 September 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Lisha Du, Siyan Qi, Juanjuan Ma, Libo Xing, Sheng Fan, Songwen Zhang, Youmei Li, Yawen Shen, Dong Zhang, Mingyu Han
      Trehalose (α-D-glucopyranosyl α-D-glucopyranoside) is a non-reducing disaccharide that serves as a carbon source and stress protectant in apple trees. Trehalose-6-phosphate (T6P) is the biosynthetic precursor of trehalose. It functions as a crucial signaling molecule involved in the regulation of floral induction, and is closely related to sucrose. Trehalose-6-phosphate synthase (TPS) family members are pivotal components of the T6P biosynthetic pathway. The present study identified 13 apple TPS family members and characterized their expression patterns in different tissues and in response to exogenous application of sucrose during floral induction. ‘Fuji’ apple trees were sprayed with sucrose prior to the onset of floral induction. Bud growth, flowering rate, and endogenous sugar levels were then monitored. The expression of genes associated with sucrose metabolism and flowering were also characterized by RT-quantitative PCR. Results revealed that sucrose applications significantly improved flower production and increased bud size and fresh weight, as well as the sucrose content in buds and leaves. Furthermore, the expression of MdTPS1, 2, 4, 10, and 11 was rapidly and significantly up-regulated in response to the sucrose treatments. In addition, the expression levels of flowering-related genes (e.g., SPL genes, FT1, and AP1) also increased in response to the sucrose sprays. In summary, apple TPS family members were identified that may influence the regulation of floral induction and other responses to sucrose. The relationship between sucrose and T6P or TPS during the regulation of floral induction in apple trees is discussed.

      PubDate: 2017-09-23T10:55:07Z
      DOI: 10.1016/j.plaphy.2017.09.015
       
  • Phosphate stresses affect ionome and metabolome in tea plants
    • Authors: Zhaotang Ding; Sisi Jia; Yu Wang; Jun Xiao; Yinfei Zhang
      Abstract: Publication date: Available online 14 September 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Zhaotang Ding, Sisi Jia, Yu Wang, Jun Xiao, Yinfei Zhang
      In order to study the response of tea plants to P stress, we conducted the ionomic and metabolomic analysis by ICP-OES, GC-MS and LC-MS. The results demonstrated that P was antagonistic with S, and was cooperative with Cu, Zn, Mn and Fe under P-deficiency. However, P was antagonistic with Mn, Fe and S, and was cooperative with Cu and Zn under P-excess. Moreover, P-deficiency or excess reduced the syntheses of flavonoids and phosphorylated metabolites. P-deficiency decreased the amount of glutamate and increased the content of glutamine, while P-excess decreased the content of glutamine. Besides, P-deficiency increased three organic acids and decreased three organic acids. P-excess increased the contents of malic acid, oxalic acid, ribonic acid and etc. involved in primary metabolism, but decreased the contents of p-coumaric acid, indoleacrylic acid, related to secondary metabolism. Furthermore, the contents of Mn and Zn were found to be positively related to the amounts of myricetin and quercetin, and the content of Mn to be positively related to the amount of arabinose. The results implied that the P stresses severely disturbed the metabolism of minerals and metabolites in tea plants, which influenced the yield and quality of tea.

      PubDate: 2017-09-18T10:44:03Z
      DOI: 10.1016/j.plaphy.2017.09.007
       
  • Iron deficiency stimulates anthocyanin accumulation in grapevine apical
           leaves
    • Authors: Leila Caramanico; Laura Rustioni; Gabriella De Lorenzis
      Abstract: Publication date: Available online 9 September 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Leila Caramanico, Laura Rustioni, Gabriella De Lorenzis
      Iron chlorosis is a diffuse disorder affecting Mediterranean vineyards. Beside the commonly described symptoms of chlorophyll decrease, apex reddening was recently observed. Secondary metabolites, such as anthocyanins, are often synthetized to cope stresses in plants. The present work aimed to evaluate grapevine responses to iron deficiency, in term of anthocyanin metabolism (reflectance spectrum, total anthocyanin content, HPLC profile and gene expression) in apical leaves of Cabernet sauvignon and Sangiovese grown in hydroponic conditions. Iron supply interruption produced after one month an increasing of anthocyanin contents associated to a more stable profile in both cultivars. In Cabernet sauvignon, the higher red pigment accumulation was associated to a lower intensity of chlorotic symptoms, while in Sangiovese, despite the activation of the metabolism, the lower anthocyanin accumulation was associated to a stronger decrease in chlorophyll concentration. Gene expression data showed a significant increase of anthocyanin biosynthesis. The effects on the expression of structural and transcription factor genes of phenylpropanoid pathway were cultivar dependent. F3H, F3′H, F3′5′H and LDOX genes, in Cabernet sauvignon, and AOMT1 and AOMT genes, in Sangiovese, were positively affected by the treatment in response to iron deficiency. All the data supports the hypothesis of an anthocyanin biosynthesis stimulation rather than a decreased degradation due to iron chlorosis.
      Graphical abstract image

      PubDate: 2017-09-11T10:29:21Z
      DOI: 10.1016/j.plaphy.2017.09.004
       
  • Reactions of tobacco genotypes with different antioxidant capacities to
           powdery mildew and Tobacco mosaic virus infections
    • Authors: Gábor Gullner; Csilla Juhász; Adél Németh; Balázs Barna
      Abstract: Publication date: Available online 8 September 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Gábor Gullner, Csilla Juhász, Adél Németh, Balázs Barna
      The interactions of powdery mildew (Golovinomyces orontii) and Tobacco mosaic virus (TMV) with tobacco lines having down or upregulated antioxidants were investigated. Xanthi-nc, its salicylic acid-deficient NahG mutant, a paraquat-sensitive Samsun (PS) and its paraquat tolerant (PT) mutant were used. Cell membrane damage caused by H2O2 was significantly higher in NahG than Xanthi, whereas it was lower in PT than in PS. Leakage of ions from PT was reduced by the powdery mildew infection. On the other hand TMV inoculation led to a 6-fold and 2-fold elevation of ion leakage from hypersensitive resistant NahG and Xanthi leaves, respectively, whereas ion leakage increased slightly from susceptible PS leaves. G. orontii infection induced ribonuclease (RNase) enzyme activity in extracts from Xanthi and NahG (about 200–250% increase) and weakly (about 20–30% increase) from PS and PT lines. Pre-treatment with protein kinase inhibitor staurosporine or protein phosphatase inhibitor okadaic acid very strongly inhibited mildew development on tobacco lines. Our experiments suggest that protein kinases inhibited by staurosporine seem to be important factors, while protein phosphatases inhibited by okadaic acid play less significant role in TMV-induced lesion development. Both powdery mildew and TMV infections up-regulated the expression of PR-1b, PR-1c and WRKY12 genes in all tobacco lines to various extents.

      PubDate: 2017-09-11T10:29:21Z
      DOI: 10.1016/j.plaphy.2017.09.003
       
  • Glutathione-induced alleviation of cadmium toxicity in Zea mays
    • Authors: Mei Li; Pengfei Hao; Fangbin Cao
      Abstract: Publication date: Available online 8 September 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Mei Li, Pengfei Hao, Fangbin Cao
      Glutathione (GSH) is known to alleviate cadmium (Cd) stress in many plant species. However, the comprehensive mechanisms responsible for this effect in maize are still need more investigation. Here, a combination of physiological and molecular approaches was utilized in GSH-Cd treated maize seedlings, which revealed that GSH reversed the adverse effects of Cd, as reflected by plant growth, plant hormones, vacuole, stoma development, gene expression, etc. Plant growth, root cell viability, photosynthetic capacity, redox equilibrium, and cell ultrastructure recovery following GSH treatment, coupled with the strong up-regulation of Cd tolerance-related genes (e.g., phytochelatin synthetase-like protein, MYB and WRKY transcription factors, and CYP450), demonstrated the efficient activation of cellular defense against Cd toxicity. The addition of GSH significantly elevated GSH/GSSG ratio and the activity of γ-glutamylcysteine synthetase in both shoots and roots and markedly reduced Cd concentration in shoots. Ethylene emission rate and abscisic acid (ABA) content were significantly reduced after GSH application in the presence of Cd, except ABA content in leaves. These findings highlighted the significance of GSH in alleviating Cd-stress in maize and indicate a promising strategy for safe food production.
      Graphical abstract image

      PubDate: 2017-09-11T10:29:21Z
      DOI: 10.1016/j.plaphy.2017.09.005
       
  • Cell wall pectin methyl-esterification and organic acids of root tips
           involve in aluminum tolerance in Camellia sinensis
    • Authors: Dongqin Li; Zaifa Shu; Xiaoli Ye; Jiaojiao Zhu; Junting Pan; Weidong Wang; Pinpin Chang; Chuanlei Cui; Jiazhi Shen; Wanping Fang; Xujun Zhu; Yuhua Wang
      Abstract: Publication date: Available online 7 September 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Dongqin Li, Zaifa Shu, Xiaoli Ye, Jiaojiao Zhu, Junting Pan, Weidong Wang, Pinpin Chang, Chuanlei Cui, Jiazhi Shen, Wanping Fang, Xujun Zhu, Yuhua Wang
      Tea plant (Camellia sinensis (O.) Kuntze) can survive from high levels of aluminum (Al) in strongly acidic soils. However, the mechanism driving its tolerance to Al, the predominant factor limiting plant growth in acid condition, is still not fully understood. Here, two-year-old rooted cuttings of C. sinensis cultivar ‘Longjingchangye’ were used for Al resistance experiments. We found that the tea plants grew better in the presence of 0.4 mM Al than those grew under lower concentration of Al treatments (0 and 0.1 mM) as well as higher levels treatment (2 and 4 mM), confirming that appropriate Al increased tea plant growth. Hematoxylin staining assay showed that the apical region was the main accumulator in tea plant root. Subsequently, immunolocalization of pectins in the root tip cell wall showed a rise in low-methyl-ester pectin levels and a reduction of high-methyl-ester pectin content with the increasing Al concentration of treatments. Furthermore, we observed the increased expressions of C. sinensis pectin methylesterase (CsPME) genes along with the increasing de-esterified pectin levels during response to Al treatments. Additionally, the levels of organic acids increased steadily after treatment with 0.1, 0.4 or 2 mM Al, while they dropped after treatment with 4 mM Al. The organic acids secretion from root followed a similar trend. Similarly, a gradual increase in malate dehydrogenase (MDH), citrate synthase (CS) and glycolate oxidase (GO) enzyme activities and relevant metabolic genes expression were detected after the treatment of 0.1, 0.4 or 2 mM Al, while a sharp decrease was resulted from treatment with 4 mM Al. These results confirm that both pectin methylesterases and organic acids contribute to Al tolerance in C. sinensis.

      PubDate: 2017-09-11T10:29:21Z
      DOI: 10.1016/j.plaphy.2017.09.002
       
  • Cloning and expression profiling of the PacSnRK2 and PacPP2C gene families
           during fruit development, ABA treatment, and dehydration stress in sweet
           cherry
    • Authors: Xinjie Shen; Xiao Guo; Di Zhao; Qiang Zhang; Yuzhuang Jiang; Yantao Wang; Xiang Peng; Yan Wei; Zefeng Zhai; Wei Zhao; Tianhong Li
      Abstract: Publication date: Available online 6 September 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Xinjie Shen, Xiao Guo, Di Zhao, Qiang Zhang, Yuzhuang Jiang, Yantao Wang, Xiang Peng, Yan Wei, Zefeng Zhai, Wei Zhao, Tianhong Li
      Plant SNF1-related protein kinase 2 (SnRK2) and protein phosphatase 2C (PP2C) family members are core components of the ABA signal transduction pathway. SnRK2 and PP2C proteins have been suggested to play crucial roles in fruit ripening and improving plant tolerance to drought stress, but supporting genetic information has been lacking in sweet cherry (Prunus avium L.). Here, we cloned six full-length SnRK2 genes and three full-length PP2C genes from sweet cherry cv. Hong Deng. Quantitative PCR analysis revealed that PacSnRK2.2, PacSnRK2.3, PacSnRK2.6, and PacPP2C1–3 were negatively regulated in fruits in response to exogenous ABA treatment, PacSnRK2.4 and PacSnRK2.5 were upregulated, and PacSnRK2.1 expression was not affected. The ABA treatment also significantly promoted the accumulation of anthocyanins in sweet cherry fruit. The expression of all PacSnRK2 and PacPP2C genes was induced by dehydration stress, which also promoted the accumulation of drought stress signaling molecules in the sweet cherry fruits, including ABA, soluble sugars, and anthocyanin. Furthermore, a yeast two-hybrid analysis demonstrated that PacPP2C1 interacts with all six PacSnRK2s, while PacPP2C3 does not interact with PacSnRK2.5. PacPP2C2 does not interact with PacSnRK2.1 or PacSnRK2.4. These results indicate that PacSnRK2s and PacPP2Cs may play a variety of roles in the sweet cherry ABA signaling pathway and the fruit response to drought stress.

      PubDate: 2017-09-06T10:27:33Z
      DOI: 10.1016/j.plaphy.2017.08.025
       
  • Silicon improves seed germination and alleviates drought stress in lentil
           crops by regulating osmolytes, hydrolytic enzymes and antioxidant defense
           system
    • Authors: Sajitha Biju; Sigfredo Fuentes; Dorin Gupta
      Abstract: Publication date: Available online 5 September 2017
      Source:Plant Physiology and Biochemistry
      Author(s): Sajitha Biju, Sigfredo Fuentes, Dorin Gupta
      Silicon (Si) has been widely reported to have beneficial effect on mitigating drought stress in plants. However, the effect of Si on seed germination under drought conditions is still poorly understood. This research was carried out to ascertain the role of Si to abate polyethylene glycol-6000 mediated drought stress on seed germination and seedling growth of lentil. Results showed that drought stress significantly decreased the seed germination traits and increased the concentration of osmolytes (proline, glycine betaine and soluble sugars), reactive oxygen species (hydrogen peroxide and superoxide anion) and lipid peroxides in lentil seedlings. The activities of hydrolytic enzymes and antioxidant enzymes increased significantly under osmotic stress. The application of Si significantly enhanced the plants ability to withstand drought stress conditions through increased Si content, improved antioxidants, hydrolytic enzymes activity, decreased concentration of osmolytes and reactive oxygen species. Multivariate data analysis showed statistically significant correlations among the drought-tolerance traits, whereas cluster analysis categorised the genotypes into distinct groups based on their drought-tolerance levels and improvements in expression of traits due to Si application. Thus, these results showed that Si supplementation of lentil was effective in alleviating the detrimental effects of drought stress on seed germination and increased seedling vigour.

      PubDate: 2017-09-06T10:27:33Z
      DOI: 10.1016/j.plaphy.2017.09.001
       
 
 
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