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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  [2805 journals]
  • Editorial Board
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103




      PubDate: 2016-04-09T08:24:18Z
       
  • Biochemical and molecular responses underlying differential arsenic
           tolerance in rice (Oryza sativa L.)
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Most Champa Begum, Mohammad Saiful Islam, Monirul Islam, Ruhul Amin, Mohammad Sarwar Parvez, Ahmad Humayan Kabir
      The arsenic (As) is a toxic element causing major health concern worldwide. Arsenate stress caused no significant reduction in growth parameters and shoot electrolyte leakage but showed increased root arsenate reductase activity along with relatively lower root As content and shoot translocation rate in As-tolerant BRRI 33 than in As-sensitive BRRI 51. It indicates that As inhibition and tolerance mechanisms are driven by root responses. Interestingly, As stress showed consistent decrease in phosphate content and expression of phosphate transporters (OsPT8, OsPT4, OsPHO1;2) under both high and low phosphate conditions in roots of BRRI 33, suggesting that limiting phosphate transport mainly mediated by OsPHO1;2 directs less As accumulation in BRRI 33. Further, BRRI 33 showed simultaneous increase in OsPCS1 (phytochelatin synthase) expression and phytochelatins (PCs) content in roots under As exposure supporting the hypothesis that root As sequestration acts as ‘firewall system’ in limiting As translocation in shoots. Furthermore, increased CAT, POD, SOD, GR, along with elevated glutathione, methionine, cysteine and proline suggests that strong antioxidant defense plays integral part to As tolerance in BRRI 33. Again, BRRI 33 self-grafts and plants having BRRI 33 rootstock combined with BRRI 51 scion had no adverse effect on morphological parameters but showed reduced As translocation rate, increased root arsenate reductase activity, shoot PC synthesis and root OsPHO1;2 expression due to As stress. It confirms that signal driving As tolerance mechanisms is generated in the roots. These findings can be implemented for As detoxification and As-free transgenic rice production for health safety.


      PubDate: 2016-04-09T08:24:18Z
       
  • Understanding the physiological effects of UV-C light and exploiting its
           agronomic potential before and after harvest
    • Abstract: Publication date: August 2016
      Source:Plant Physiology and Biochemistry, Volume 105
      Author(s): Laurent Urban, Florence Charles, Maria Raquel Alcântara de Miranda, Jawad Aarrouf
      There is an abundant literature about the biological and physiological effects of UV-B light and the signaling and metabolic pathways it triggers and influences. Much less is known about UV-C light even though it seems to have a lot of potential for being effective in less time than UV-B light. UV-C light is known since long to exert direct and indirect inhibitory and damaging effects on living cells and is therefore commonly used for disinfection purposes. More recent observations suggest that UV-C light can also be exploited to stimulate the production of health-promoting phytochemicals, to extent shelf life of fruits and vegetables and to stimulate mechanisms of adaptation to biotic and abiotic stresses. Clearly some of these effects may be related to the stimulating effect of UV-C light on the production of reactive oxygen species (ROS) and to the stimulation of antioxidant molecules and mechanisms, although UV-C light could also trigger and regulate signaling pathways independently from its effect on the production of ROS. Our review clearly underlines the high potential of UV-C light in agriculture and therefore advocates for more work to be done to improve its efficiency and also to increase our understanding of the way UV-C light is perceived and influences the physiology of plants.


      PubDate: 2016-04-09T08:24:18Z
       
  • Photosynthetic responses to phytoplasma infection in Chinese jujube
    • Abstract: Publication date: August 2016
      Source:Plant Physiology and Biochemistry, Volume 105
      Author(s): Zhiguo Liu, Jin Zhao, Mengjun Liu
      Phytoplasma is one of the most devastating plant pathogens. Jujube witches' broom (JWB) is a typical and highly fatal phytoplasma disease of Chinese jujube (Ziziphus jujuba Mill.), which is widely cultivated in Asia. To further elucidate the mechanism of plant-phytoplasma interaction, we first compared the effects of phytoplasma infection on photosynthetic pigments and activities between a JWB-resistant cultivar (Xingguang) and a susceptible cultivar (Pozao). Total chlorophyll and carotenoid levels were significantly decreased in the susceptible cultivar at later stages of infection, but were remarkably increased in the resistant cultivar at the earlier stages. Compared to uninfected plant, a significant decrease in the main photochemical parameters (F v /F m , Φ PSII and qP) was recorded at the initial stages of infection in the resistant cultivar, but occurred at later stages in the susceptible cultivar. Meanwhile, the qRT-PCR results of four key photosynthesis-related genes (ZjGluTR, ZjCBP, ZjRubisco and ZjRCA2) demonstrated that the expression patterns were similar in uninfected cultivars, but up-regulated in resistant cultivar and down-regulated in the susceptible one at 12 wks after grafting inoculation. Collectively, our data indicated that the resistant cultivar ‘Xingguang’ undergoes a decrease in initial stage (inhibiting phytoplasma multiplication) and then a rapid enhancement of photosynthetic activity (helping jujube recovery) in response to phytoplasma infection, while the susceptible cultivar ‘Pozao’ displays a later decrease in photosynthetic activity. The novel photosynthetic response pattern of the resistant cultivar may contribute to its stronger immunity to phytoplasma infection, which provides new insights into plant-phytoplasma interactions.


      PubDate: 2016-04-09T08:24:18Z
       
  • The stay-green phenotype of TaNAM-RNAi wheat plants is associated with
           maintenance of chloroplast structure and high enzymatic antioxidant
           activity
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Mariana L. Checovich, Andrea Galatro, Jorge I. Moriconi, Marcela Simontacchi, Jorge Dubcovsky, Guillermo E. Santa-María
      TaNAM transcription factors play an important role in controlling senescence, which in turn, influences the delivery of nitrogen, iron and other elements to the grain of wheat (Triticum aestivum) plants, thus contributing to grain nutritional value. While lack or diminished expression of TaNAMs determines a stay-green phenotype, the precise effect of these factors on chloroplast structure has not been studied. In this work we focused on the events undergone by chloroplasts in two wheat lines having either control or diminished TaNAM expression due to RNA interference (RNAi). It was found that in RNAi plants maintenance of chlorophyll levels and maximal photochemical efficiency of photosystem II were associated with lack of chloroplast dismantling. Flow cytometer studies and electron microscope analysis showed that RNAi plants conserved organelle ultrastructure and complexity. It was also found that senescence in control plants was accompanied by a low leaf enzymatic antioxidant activity. Lack of chloroplast dismantling in RNAi plants was associated with maintenance of protein and iron concentration in the flag leaf, the opposite being observed in control plants. These data provide a structural basis for the observation that down regulation of TaNAMs confers a functional stay-green phenotype and indicate that the low export of iron and nitrogen from the flag leaf of these plants is concomitant, within the developmental window studied, with lack of chloroplast degradation and high enzymatic antioxidant activity.


      PubDate: 2016-04-09T08:24:18Z
       
  • Proteomics analysis of compatibility and incompatibility in grafted
           cucumber seedlings
    • Abstract: Publication date: August 2016
      Source:Plant Physiology and Biochemistry, Volume 105
      Author(s): Qing Xu, Shi-Rong Guo, Lin Li, Ya-Hong An, Sheng Shu, Jin Sun
      Graft compatibility between rootstock and scion is the most important factor influencing the survival of grafted plants. In this study, we used two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF MS) to investigate differences in leaf proteomes of graft-compatible and graft-incompatible cucumber (Cucumis sativus L.)/pumpkin (Cucurbita L.) combinations. Cucumber seedlings were used as the scions and two pumpkin cultivars with strongly contrasting grafting compatibilities were used as the rootstocks. Non-grafted and self-grafted cucumber seedlings served as control groups. An average of approximately 500 detectable spots were observed on each 2-DE gel. A total of 50 proteins were differentially expressed in response to self-grafting, compatible-rootstock grafting, and incompatible-rootstock grafting and were all successfully identified by MALDI-TOF/TOF MS. The regulation of Calvin cycle, photosynthetic apparatus, glycolytic pathway, energy metabolism, protein biosynthesis and degradation, and reactive oxygen metabolism will probably contribute to intensify the biomass and photosynthetic capacity in graft-compatible combinations. The improved physiological and growth characteristics of compatible-rootstock grafting plants are the result of the higher expressions of proteins involved in photosynthesis, carbohydrate and energy metabolism, and protein metabolism. At the same time, the compatible-rootstock grafting regulation of stress defense, amino acid metabolism, and other metabolic functions also plays important roles in improvement of plant growth.


      PubDate: 2016-04-09T08:24:18Z
       
  • Analysis of anthocyanins and flavonols in petals of 10 Rhododendron
           species from the Sygera Mountains in Southeast Tibet
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Lin Liu, Liang-Ying Zhang, Shu-Li Wang, Xin-Yu Niu
      Flower color is one of the major ornamental characteristics of the genus Rhododendron, but few studies on flower color in alpine Rhododendron have been reported. In our study, the flower colors and the pigment constituents of petals from 10 Rhododendron species sampled in the Sygera Mountains of Southeast Tibet were analyzed using high-performance liquid chromatography-diode array detection and mass spectrometry (HPLC-DAD-ESI-MS2). The color analysis showed that the 10 Rhododendron species could be divided into five color groupings: yellow, red, red-purple, purple-violet, and purple. A total of 5 anthocyanin compounds and 23 flavonol compounds were tentatively identified and quantified. There were obvious differences in the composition of anthocyanin and flavonol among the petals of the 10 Rhododendron species. The color parameter L* decreased as the TA (total anthocyanin) content increased in the red-purple group. However, there was no obvious correlation between the L* value and the TA content in the other sampled Rhododendron species. In this study, the TA values of most of the Rhododendron species were quite low, but the TF (total flavonol) content was high. These results indicate the existence of copigmentation effects in these 10 Rhododendron species.


      PubDate: 2016-04-07T08:23:07Z
       
  • Role of vacuolar membrane proton pumps in the acidification of protein
           storage vacuoles following germination
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Karl A. Wilson, Burzin J. Chavda, Gandhy Pierre-Louis, Adam Quinn, Anna Tan-Wilson
      During soybean (Glycine max (L.) Merrill) seed development, protease C1, the proteolytic enzyme that initiates breakdown of the storage globulins β-conglycinin and glycinin at acidic pH, is present in the protein storage vacuoles (PSVs), the same subcellular compartments in seed cotyledons where its protein substrates accumulate. Actual proteolysis begins to be evident 24 h after seed imbibition, when the PSVs become acidic, as indicated by acridine orange accumulation visualized by confocal microscopy. Imidodiphosphate (IDP), a non-hydrolyzable substrate analog of proton-translocating pyrophosphatases, strongly inhibited acidification of the PSVs in the cotyledons. Consistent with this finding, IDP treatment inhibited mobilization of β-conglycinin and glycinin, the inhibition being greater at 3 days compared to 6 days after seed imbibition. The embryonic axis does not appear to play a role in the initial PSV acidification in the cotyledon, as axis detachment did not prevent acridine orange accumulation three days after imbibition. SDS-PAGE and immunoblot analyses of cotyledon protein extracts were consistent with limited digestion of the 7S and 11S globulins by protease C1 starting at the same time and proceeding at the same rate in detached cotyledons compared to cotyledons of intact seedlings. Embryonic axis removal did slow down further breakdown of the storage globulins by reactions known to be catalyzed by protease C2, a cysteine protease that normally appears later in seedling growth to continue the storage protein breakdown initiated by protease C1.
      Graphical abstract image

      PubDate: 2016-04-04T10:38:10Z
       
  • Characterization and expression profiling of MYB transcription factors
           against stresses and during male organ development in Chinese cabbage
           (Brassica rapa ssp. pekinensis)
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Gopal Saha, Jong-In Park, Nasar Uddin Ahmed, Md Abdul Kayum, Kwon-Kyoo Kang, Ill-Sup Nou
      MYB proteins comprise a large family of plant transcription factors that play regulatory roles in different biological processes such as plant development, metabolism, and defense responses. To gain insight into this gene superfamily and to elucidate its roles in stress resistance, we performed a comprehensive genome-wide identification, characterization, and expression analysis of MYB genes in Chinese cabbage (Brassica rapa ssp. pekinensis). We identified 475 Chinese cabbage MYB genes, among which most were from R2R3-MYB (256 genes) and MYB-related (202) subfamilies. Analysis of sequence characteristics, phylogenetic classification, and protein motif structures confirmed the existence of several categories (1R, 2R, 3R, 4R, and 5R) of Chinese cabbage MYB genes, which is comparable with MYB genes of other crops. An extensive in silico functional analysis, based on established functional properties of MYB genes from different crop species, revealed 11 and four functional clades within the Chinese cabbage R2R3-MYB and MYB-related subfamilies, respectively. In this study, we reported a MYB-like group within the MYB-related subfamily contains 77 MYB genes. Expression analysis using low temperature-treated whole-genome microarray data revealed variable transcript abundance of 1R/2R/3R/4R/5R-MYB genes in 11 clusters between two inbred lines of Chinese cabbage, Chiifu and Kenshin, which differ in cold tolerance. In further validation tests, we used qRT-PCR to examine the cold-responsive expression patterns of 27 BrMYB genes; surprisingly, the MYB-related genes were induced more highly than the R2R3-MYB genes. In addition, we identified 10 genes with corresponsive expression patterns from a set of salt-, drought-, ABA-, JA-, and SA-induced R2R3-MYB genes. We identified 11 R2R3-MYBs functioning in resistance against biotic stress, including 10 against Fusarium oxysporum f.sp. conglutinans and one against Pectobacterium carotovoram subsp. caratovorum. Furthermore, based on organ-specific expression data, we identified nine R2R3-MYBs that were constitutively expressed in male reproductive tissue, which may provide an important key for studying male sterility in Chinese cabbage. The extensive annotation and transcriptome profiling reported in this study will be useful for understanding the involvement of MYB genes in stress resistance in addition to their growth regulatory functions, ultimately providing the basis for functional characterization and exploitation of the candidate MYB genes for genetic engineering of Chinese cabbage.


      PubDate: 2016-04-04T10:38:10Z
       
  • Tomato plants acclimate better to elevated temperature and high light than
           to treatment with each factor separately
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Milena Gerganova, Antoaneta V. Popova, Daniela Stanoeva, Maya Velitchkova
      The influence of two factors – high temperature and high light intensity, acting separately or simultaneously on the pigment composition, fluorescent characteristics, membrane integrity and synthesis of protective substances was investigated in tomato plants (Solanum lycopersicum cv. M 82). Moderate elevated temperatures (38/29 °C) were applied under optimum or high light intensity for 2 and 6 days and after that the plants are allowed to recover for 5 days at optimum conditions. Parameters of chlorophyll fluorescence were used to evaluate the alterations of photosystem I and photosystem II activity and malondialdehyde content was determined as a measure of stress-induced peroxidation of membrane lipids. The response of treated plants to high light and elevated temperature was estimated by analyzing the accumulation of anthocyanins. Both stress factors exhibit different impact on studied parameters – high light intensity influences considerably quantum yield of photosystem II and photochemical quenching that is compensated to some extent when applied at elevated temperature. High temperature reduces strongly non-photochemical quenching. Data obtained show that after two days under particular conditions, the plants tend to acclimate, but this is achieved after longer treatment – 6 days. During the recovery period the activity of photosystem I and the quantum yield of photosystem II recover almost completely, while the values of non-photochemical quenching although slightly higher, did not reach the levels at the beginning of treatment.


      PubDate: 2016-04-04T10:38:10Z
       
  • Impact of silicon on Indian mustard (Brassica juncea L.) root traits by
           regulating growth parameters, cellular antioxidants and stress modulators
           under arsenic stress
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Chandana Pandey, Ehasanullah Khan, Medha Panthri, Rudra Deo Tripathi, Meetu Gupta
      Arsenic (As) is an emerging pollutant causing inhibition in growth and development of plants resulting into phytotoxicity. On the other hand, silicon (Si) has been suggested as a modulator in abiotic and biotic stresses that, enhances plant's physiological adaptations in response to several stresses including heavy metal stress. In this study, we used roots of hydroponically grown 14 day old seedlings of Brassica juncea var. Varuna treated with 150 μM As, 1.5 mM Si and both in combination for 96 h duration. Application of Si modulated the effect of As by improving morphological traits of root along with the development of both primary and lateral roots. Changes observed in root traits showed positive correlation with As induced cell death, accumulation of reactive oxygen species (ROS), nitric oxide (NO) and intracellular superoxide radicals (O2 −). Addition of 1.5 mM Si during As stress increased accumulation of As in roots. Mineral nutrient analysis was done using energy-dispersive X-ray fluorescence (EDXRF) technique and positively correlated with increased cysteine, proline, MDA, H2O2 and activity of antioxidant enzymes (SOD, CAT and APX). The results obtained from the above biochemical approaches support the protective and active role of Si in the regulation of As stress through the changes in root developmental process.


      PubDate: 2016-04-04T10:38:10Z
       
  • Evaluation of a novel promoter from Populus trichocarpa for mature xylem
           tissue specific gene delivery
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Van Phap Nguyen, Jin-Seong Cho, Young-Im Choi, Sang-Won Lee, Kyung-Hwan Han, Jae-Heung Ko
      Wood (i.e., secondary xylem) is an important raw material for many industrial applications. Mature xylem (MX) tissue-specific genetic modification offers an effective means to improve the chemical and physical properties of the wood. Here, we describe a promoter that drives strong gene expression in a MX tissue-specific manner. Using whole-transcriptome genechip analyses of different tissue types of poplar, we identified five candidate genes that had strong expression in the MX tissue. The putative promoter sequences of the five MX-specific genes were evaluated for their promoter activity in both transgenic Arabidopsis and poplar. Among them, we found the promoter of Potri.013G007900.1 (called the PtrMX3 promoter) had the strongest activity in MX and thus was further characterized. In the stem and root tissues of transgenic Arabidopsis plants, the PtrMX3 promoter activity was found exclusively in MX tissue. MX-specific activity of the promoter was reproduced in the stem tissue of transgenic poplar plants. The PtrMX3 promoter activity was not influenced by abiotic stresses or exogenously applied growth regulators, indicating the PtrMX3 promoter is bona fide MX tissue-specific. Our study provides a strong MX-specific promoter for MX-specific modifications of woody biomass.


      PubDate: 2016-04-04T10:38:10Z
       
  • Impact of cluster thinning on transcriptional regulation of anthocyanin
           biosynthesis-related genes in ‘Summer Black’ grapes
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Xiaojun Xi, Qian Zha, Aili Jiang, Yihua Tian
      Cluster thinning is an agronomic practice that strongly affects anthocyanin biosynthesis in the skin of grape berries. However, the impact of cluster thinning on anthocyanin biosynthesis has not been fully elucidated at the molecular level. Here, we investigated its effects on the berry quality, the biosynthesis of anthocyanins, and the expression levels of related genes from the onset of véraison to harvest in ‘Summer Black’ grapes. It was observed that the total soluble solid and anthocyanin content in berry skin significantly increased under cluster thinning, whereas the berry weight and titratable acidity showed no differences from the beginning of véraison to harvest. The expression level of most anthocyanin biosynthesis-related genes was significantly up-regulated by cluster thinning from the beginning of véraison and was higher at its end compared to the control. Up-regulation of flavonoid 3′,5′-hydroxylase (F3′5′H) and O-methyltransferase (OMT) expression, and down-regulation of flavonoid 3′-hydroxylase (F3′H) expression were observed, which might be the cause of shift in the anthocyanin profile. These findings provide insights into the molecular basis of the relationship between cluster thinning and anthocyanin biosynthesis in the grape berry skin.


      PubDate: 2016-04-04T10:38:10Z
       
  • Maize cytokinin dehydrogenase isozymes are localized predominantly to the
           vacuoles
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): David Zalabák, Patricie Johnová, Ondřej Plíhal, Karolina Šenková, Olga Šamajová, Eva Jiskrová, Ondřej Novák, David Jackson, Amitabh Mohanty, Petr Galuszka
      The maize genome encompasses 13 genes encoding for cytokinin dehydrogenase isozymes (CKXs). These enzymes are responsible for irreversible degradation of cytokinin plant hormones and thus, contribute regulating their levels. Here, we focus on the unique aspect of CKXs: their diverse subcellular distribution, important in regulating cytokinin homeostasis. Maize CKXs were tagged with green fluorescent protein (GFP) and transiently expressed in maize protoplasts. Most of the isoforms, namely ZmCKX1, ZmCKX2, ZmCKX4a, ZmCKX5, ZmCKX6, ZmCKX8, ZmCKX9, and ZmCKX12, were associated with endoplasmic reticulum (ER) several hours after transformation. GFP-fused CKXs were observed to accumulate in putative prevacuolar compartments. To gain more information about the spatiotemporal localization of the above isoforms, we prepared stable expression lines of all ZmCKX–GFP fusions in Arabidopsis thaliana Ler suspension culture. All the ER-associated isoforms except ZmCKX1 and ZmCKX9 were found to be targeted primarily to vacuoles, suggesting that ER-localization is a transition point in the intracellular secretory pathway and vacuoles serve as these isoforms' final destination. ZmCKX9 showed an ER-like localization pattern similar to those observed in the transient maize assay. Apoplastic localization of ZmCKX1 was further confirmed and ZmCKX10 showed cytosolic/nuclear localization due to the absence of the signal peptide sequence as previously reported. Additionally, we prepared GFP-fused N-terminal signal deletion mutants of ZmCKX2 and ZmCKX9 and clearly demonstrated that the localization pattern of these mutant forms was cytosolic/nuclear. This study provides the first complex model for spatiotemporal localization of the key enzymes of the cytokinin degradation/catabolism in monocotyledonous plants.


      PubDate: 2016-03-30T10:26:24Z
       
  • Exogenous application of pectin-derived oligosaccharides to grape berries
           modifies anthocyanin accumulation, composition and gene expression
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Daniel Villegas, Michael Handford, José Antonio Alcalde, Alonso Perez-Donoso
      Anthocyanins are secondary metabolites synthesized in grape berry skins via the phenylpropanoid pathway, with functions ranging from skin coloration to protection against pathogens or UV light. Accumulation of these compounds is highly variable depending on genetics, environmental factors and viticultural practices. Besides their biological functions, anthocyanins improve wine quality, as a high anthocyanin content in berries has a positive impact on the color, total phenolic concentration and, ultimately, the price of wine. The present work studies the effect of the pre-veraison application of pectin derived oligosaccharides (PDO) on the synthesis and accumulation of these compounds, and associates the changes observed with the expression of key genes in the phenylpropanoid pathways. To this end, pre-veraison Cabernet Sauvignon bunches were treated with PDO to subsequently determine total anthocyanin content, the anthocyanin profile (by HPLC-DAD) and gene expression (by qRT-PCR), using Ethrel and water treatments for comparison. The results show that PDO were as efficient as Ethrel in generating a significant rise in total anthocyanin content at 30 days after treatment (dat), compared with water treatments (1.32, 1.48 and 1.02 mg e.Mv-3G/g FW respectively) without any undesirable effect on berry size, soluble solids, tartaric acid concentration or pH. In addition, a significant alteration in the anthocyanin profile was observed. Specifically, a significant increase in the relative concentration of malvidin was observed for both PDO and Ethrel treatments, compared with water controls (52.8; 55.0 and 48.3%, respectively), with a significant rise in tri-hydroxylated forms and a fall in di-hydroxylated anthocyanins. The results of gene expression analyses suggest that the increment in total anthocyanin content is related to a short term increase in phenylalanine ammonia-lyase (PAL) expression, mediated by a decrease in MYB4A expression. A longer term increase in UDP-glucose flavonoid 3-O-glucosyltransferase (UFGT) expression, probably mediated by a rise in MYBA1 was also observed. Regarding the anthocyanin profile, despite the increase observed in MYB5A expression in PDO and Ethrel treatments, no changes in flavonoid 3′-hydroxylase (F-3′-H); flavonoid 3′5′-hydroxylase (F-3′5′-H) or O-methyltransferase (OMT) could be related with the profile modifications described. Overall, this study highlights that application of PDO is a novel means of altering specific grape berry anthocyanins, and could be a means of positively influencing wine quality without the addition of agrochemicals.
      Graphical abstract image

      PubDate: 2016-03-30T10:26:24Z
       
  • Expression analysis of ROS producing and scavenging enzyme-encoding genes
           in rubber tree infected by Pseudocercospora ulei
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Daniela Martins Koop, Maryannick Rio, Xavier Sabau, Saulo Emilio Almeida Cardoso, Chantal Cazevieille, Julie Leclercq, Dominique Garcia
      South American Leaf Blight (SALB), caused by the ascomycete Pseudocercospora ulei, is responsible for the low productivity of rubber trees in Latin America and is a serious threat to rubber plantations in Asia and Africa, where the rubber trees are derived from highly susceptible clones. Three contrasted genotypes were chosen for their levels of resistance to the pathogen: FX2784 (totally resistant), MDF180 (partially resistant) and PB314 (susceptible). Array analyses were previously performed to identify genes differentially expressed in resistant and susceptible genotypes. Twenty-one genes were selected for further gene expression analysis in non-inoculated and inoculated genotypes from 24 to 216 h post infection (hpi). These genes are involved in ROS production (HbRBOHA, HbRBOHB, HbRBOHC, HbRBOHD), ROS-scavenging systems (cytoplasmic and chloroplastic HbCuZnSOD, HbMnSOD, HbCAT, HbAPX1, HbAPX2, HbMDHAR, HbGCL1, HbGCL2, HbOASTL, HbGPX, HbDHAR), and leaf senescence (HbCASP, HbPCYST, HbWRKY2, HbPLY, HbKAT2). First, a genotype-dependent level of expression was observed. The genes HbRBOHA, HbCuZnSOD cyto, HbCAT, HbGCL and HbWRKY2 were constitutively expressed at lower levels in the MDF180 genotype than in the FX2784 and PB314 genotypes. Conversely, the levels of expression of HbDHAR, HbGPX and HbPCYST were higher in the older, non-inoculated leaves of MDF180. Lower production of ROS and efficient regeneration of reduced ascorbate ensure a balanced redox intracellular state in this genotype. Second, inoculation of the leaves induced few modifications in the expression level of the studied genes. In the MDF180 partially resistant genotype, an increase in the expression level of HbRBOHB, HbRBOHD 48 hpi and a decrease in the expression level of HbDHAR 216 hpi were observed. In the FX2784 totally resistant genotype, an increase in the expression level of HbRBOHD and HbCuZnSOD cyto and a decrease in HbCAT were observed 48 hpi. This transitory variation could be associated with the oxidative burst classically observed in hypersensitive response (HR). The increase in the synthesis of reduced glutathione in this genotype could ensure redox balance and consequently cell homeostasis. In the PB314 susceptible genotype, HbROHC, HbCuZnSOD chloro was up-regulated 216 hpi concomitantly with a decrease in the expression level of HbCAT, consequently causing an accumulation of H2O2 and programmed cell death. The level of expression of a transcription factor, HbWRKY2, was also modulated by the P. ulei infection with early transient up-regulation in the FX2784 totally resistant genotype and permanent up-regulation in the MDF180 partially resistant genotype. These results complement studies on genetic determinism of SALB resistance and a recent publication on Hevea glutathione reductase gene.


      PubDate: 2016-03-30T10:26:24Z
       
  • Hydrogen sulfide mediates nicotine biosynthesis in tobacco (Nicotiana
           tabacum) under high temperature conditions
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Xiaodong Chen, Qian Chen, Xiaoming Zhang, Ruijing Li, Yujie Jia, Abd_Allah Ef, Aiqun Jia, Liwei Hu, Xiangyang Hu
      Hydrogen sulfide (H2S) acts as a signal to induce many physiological processes in plants, but its role in controlling the biosynthesis of secondary metabolites is not well established. In this study, we found that high temperature (HT) treatment induced nicotine biosynthesis in tobacco (Nicotiana tabacum) and promoted the rapid accumulation of H2S. Furthermore, HT triggered the biosynthesis of jasmonic acid (JA), a plant hormone that promotes nicotine biosynthesis. Suppression of the H2S signal using chemical inhibitors or via RNAi suppression of l-cysteine desulphydrase (L-CD) in transgenic plants, compromised JA production and nicotine biosynthesis under HT treatments, and these inhibitory effects could be reversed by applying exogenous H2S. Based on these data, we propose that H2S is an important trigger of nicotine biosynthesis in tobacco under HT conditions, and that H2S acts upstream of JA signaling by modulating the transcription of genes associated with JA biosynthesis.
      Graphical abstract image

      PubDate: 2016-03-30T10:26:24Z
       
  • Eclipta yellow vein virus enhances chlorophyll destruction, singlet oxygen
           production and alters endogenous redox status in Andrographis paniculata
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Asifa Khan, Suaib Luqman, Nusrat Masood, Dhananjay Kumar Singh, Sana Tabanda Saeed, Abdul Samad
      The infection of Eclipta yellow vein virus [EcYVV-IN, Accession No. KC476655], recently reported for the first time, on Andrographis paniculata was studied for redox-mediated alteration mechanism in infected plants. A. paniculata, an important medicinal plant, is used in traditional Indian, Chinese and modern system of medicine. Andrographolide, one of the foremost components of this plant, is known for its varied pharmacological properties. Our investigation provides insight into the effect of virus-induced changes in the singlet oxygen quenching due to the alteration in pigment content (chlorophyll and carotenoids) as well as activation of plant secondary metabolism along with defense activation leading to changes in enzymatic and non-enzymatic redox status. Due to infection, a reduction in carotenoid content was observed which leads to reduced quenching of singlet oxygen. An increased level of enzymatic (SOD and APX) and non-enzymatic antioxidant (DPPH, FRAP, RP, NO, TAC and TP) activities were also observed in virus-infected plants with a positive correlation (>0.9). However, CAT activity was diminished which could be either due to its proteolytic degradation or inactivation by superoxide anions (O2−.), NO or peroxynitrite radicals. A significant (p < 0.05) increase in total phenolic content was observed in the infected plants while no considerable difference was seen in the total flavonoid content. Our results highlighted the alteration in redox status caused by virus-induced biotic stress on the plants and could be useful for understanding the after effects of viral infection This study could also be helpful in developing biomimetic methods for improving the production of secondary metabolites of pharmaceutical importance.


      PubDate: 2016-03-30T10:26:24Z
       
  • Blue light alters miR167 expression and microRNA-targeted auxin response
           factor genes in Arabidopsis thaliana plants
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Pavel P. Pashkovskiy, Alexander V. Kartashov, Ilya E. Zlobin, Sergei I. Pogosyan, Vladimir V. Kuznetsov
      The effect of blue LED (450 nm) on the photomorphogenesis of Arabidopsis thaliana Col-0 plants and the transcript levels of several genes, including miRNAs, photoreceptors and auxin response factors (ARF) was investigated. It was observed that blue light accelerated the generative development, reduced the rosette leaf number, significantly reduced the leaf area, dry biomass and led to the disruption of conductive tissue formation. The blue LED differentially influenced the transcript levels of several phytochromes (PHY a, b, c, d, and e), cryptochromes (CRY 1 and 2) and phototropins (PHOT 1 and 2). At the same time, the blue LED significantly increased miR167 expression compared to a fluorescent lamp or white LEDs. This increase likely resulted in the enhanced transcription of the auxin response factor genes ARF4 and ARF8, which are regulated by this miRNA. These findings support the hypothesis that the effects of blue light on A. thaliana are mediated by auxin signalling pathway involving miRNA-dependent regulation of ARF gene expression.


      PubDate: 2016-03-30T10:26:24Z
       
  • Regulation of Arabidopsis thaliana plasma membrane glucose-responsive
           regulator (AtPGR) expression by A. thaliana storekeeper-like transcription
           factor, AtSTKL, modulates glucose response in Arabidopsis
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Moon-Soo Chung, Sungbeom Lee, Ji-Hee Min, Ping Huang, Hyun-Woo Ju, Cheol Soo Kim
      Biochemical, genetic, physiological, and molecular research in plants has demonstrated a central role of glucose (Glc) in the control of plant growth, metabolism, and development, and has revealed networks that integrate light, stresses, nutrients, and hormone signaling. Previous studies have reported that AtPGR protein as potential candidates for Glc signaling protein. In the present study, we characterized transcription factors that bind to the upstream region of the AtPGR gene isolated using the yeast one-hybrid screening with an Arabidopsis cDNA library. One of the selected genes (AtSTKL) appeared to confer elevated sensitivity to Glc response. Overexpression of AtSTKLs (AtSTKL1 and AtSTKL2) increased the sensitivity to Glc during the post-germination stages. In contrast, atstkl1 and atstkl2 antisense lines displayed reduced sensitivity to high Glc concentration during the early seedling stage. Furthermore, we showed that the two AtSTKLs bind to the 5′-GCCT-3′ element of the upstream promoter region of the AtPGR gene in vitro and repress the beta-glucuronidase (GUS) activity in AtPGR promoter-GUS (P999-GUS) transgenic plants. Green fluorescent protein (GFP)-tagged AtSTKLs were localized in the nuclei of transgenic Arabidopsis cells. Collectively, these results suggest that AtSTKL1 and AtSTKL2 function both as repressors of AtPGR transcription and as novel transcription factors in the Glc signaling pathway.


      PubDate: 2016-03-30T10:26:24Z
       
  • Barley (Hordeum distichon L.) roots synthesise volatile aldehydes with a
           strong age-dependent pattern and release (E)-non-2-enal and
           (E,Z)-nona-2,6-dienal after mechanical injury
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Benjamin M. Delory, Pierre Delaplace, Patrick du Jardin, Marie-Laure Fauconnier
      In the context of chemical ecology, the analysis of the temporal production pattern of volatile organic compounds (VOCs) in root tissues and the emission rate measurement of root-emitted VOCs are of major importance for setting up experiments to study the implication of these compounds in biotic interactions. Such analyses, however, remain challenging because of the belowground location of plant root systems. In this context, this study describes the evolution of the root VOC production pattern of barley (Hordeum distichon L.) at five developmental stages from germination to the end of tillering and evaluates the emission of the identified VOCs in an artificial soil. VOCs produced by crushed root tissues and released by unexcavated root systems were analysed using dynamic sampling devices coupled to a gas chromatography-mass spectrometry methodology (synchronous SCAN/SIM). The results showed that, at each analysed developmental stage, crushed barley roots produced mainly four volatile aldehydes: hexanal; (E)-hex-2-enal; (E)-non-2-enal; and (E,Z)-nona-2,6-dienal. Higher total and individual VOC concentrations were measured in 3-day-old seminal roots compared with older phenological stages. For each developmental stage, the lipoxygenase (LOX) activity was greater for linoleic acid than α-linolenic acid and the greatest LOX activities using linoleic and α-linolenic acids as substrates were measured in 7- and 3-day-old roots, respectively. The analysis of VOCs released by barley roots into the soil showed that (E)-non-2-enal and (E,Z)-nona-2,6-dienal were the only VOCs emitted in quantifiable amounts by mechanically injured roots.


      PubDate: 2016-03-30T10:26:24Z
       
  • Phenolic compounds as indicators of drought resistance in shrubs from
           Patagonian shrublands (Argentina)
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): M. Celeste Varela, Idris Arslan, Mariana A. Reginato, Ana M. Cenzano, M. Virginia Luna
      Summary Plants exposed to drought stress, as usually occurs in Patagonian shrublands, have developed different strategies to avoid or tolerate the lack of water during their development. Production of phenolic compounds (or polyphenols) is one of the strategies used by some native species of adverse environments to avoid the oxidative damage caused by drought. In the present study the relationship between phenolic compounds content, water availability and oxidative damage were evaluated in two native shrubs: Larrea divaricata (evergreen) and Lycium chilense (deciduous) of Patagonian shrublands by their means and/or by multivariate analysis. Samples of both species were collected during the 4 seasons for the term of 1 year. Soil water content, relative water content, total phenols, flavonoids, flavonols, tartaric acid esters, flavan-3-ols, proanthocyanidins, antioxidant capacity and lipid peroxidation were measured. According to statistical univariate analysis, L. divaricata showed high production of polyphenols along the year, with a phenolic compound synthesis enhanced during autumn (season of greatest drought), while L. chilense has lower production of these compounds without variation between seasons. The variation in total phenols along the seasons is proportional to the antioxidant capacity and inversely proportional to lipid peroxidation. Multivariate analysis showed that, regardless their mechanism to face drought (avoidance or tolerance), both shrubs are well adapted to semi-arid regions and the phenolic compounds production is a strategy used by these species living in extreme environments. The identification of polyphenol compounds showed that L. divaricata produces different types of flavonoids, particularly bond with sugars, while L. chilense produces high amount of non-flavonoids compounds. Synthesis These results suggest that flavonoid production and accumulation could be a useful indicator of drought tolerance in native species.
      Graphical abstract image

      PubDate: 2016-03-26T13:28:10Z
       
  • Mechanisms involved in the regulation of photosynthetic efficiency and
           carbohydrate partitioning in response to low- and high-temperature
           flooding triggered in winter rye (Secale cereale) lines with distinct pink
           snow mold resistances
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): E. Pociecha, M. Rapacz, M. Dziurka, I. Kolasińska
      In terms of climate changes and global warming, winter hardiness could be determined by unfavorable environmental conditions other than frost. These could include flooding from melting snow and/or rain, coincident with fungal diseases. Therefore, we designed an experiment to identify potential common mechanisms of flooding tolerance and snow mold resistance, involving the regulation of photosynthetic efficiency and carbohydrate metabolism at low temperatures. Snow mold-resistant and susceptible winter rye (Secale cereale) plants were characterized by considerably different patterns of response to flooding. These differences were clearer at low temperature, thus confirming a possible role of the observed changes in snow mold tolerance. The resistant plants were characterized by lower PSII quantum yields at low temperature, combined with much higher energy flux for energy dissipation from the PSII reaction center. During flooding, the level of soluble carbohydrates increased in the resistant plants and decreased in the susceptible ones. Thus increase in resistant line was connected with a decrease in the energy dissipation rate in PSII/increased photosynthetic activity (energy flux for electron transport), a lower rate of starch degradation and higher rates of sucrose metabolism in leaves. The resistant lines accumulated larger amounts of total soluble carbohydrates in the crowns than in the leaves. Irrespective of flooding treatment, the resistant lines allocated more sugars for cell wall composition, both in the leaves and crowns. Our results clearly indicated that studies on carbohydrate changes at low temperatures or during anoxia should investigate not only the alterations in water-soluble and storage carbohydrates, but also cell wall carbohydrates. The patterns of changes observed after low and high-temperature flooding were different, indicating separate control mechanisms of these responses. These included changes in the photosynthetic apparatus, starch accumulation and cell wall carbohydrate accumulation.


      PubDate: 2016-03-26T13:28:10Z
       
  • Seasonal dynamic of morpho-physiological properties and the lipid
           
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Olga Rozentsvet, Tatyana Grebenkina, Viktor Nesterov, Elena Bogdanova
      The changes in morpho-physiological properties and lipid composition have been studied in the leaves of the plant Plantago media collected from two different places in the Middle Volga region during the summer of 2010. The plants gathered from the first plot (P1 plants) grew on plain ground in the midst of typical meadow-steppe perennial plants. The plants of the second group (P2 plants) grew on a flat slope of the South–West exposition, in the grass community. The leaves of the plants Р1 had lower specific area densities but larger areas and masses; they accumulated more levels lipid peroxide products. The changes in lipid compositions depended on the growth phase and habitats. Correlations between morpho-physiological parameters and certain lipids have been established. The amounts of galactolipids (GL) have been shown to correlate with the leaf areas. When the leaf areas were reduced, a ratio between phosphatidylcholines (PC) and phosphatidylethanolamines (PE) decreased. The result of our study showed that gradual changes of morphometrical parameters were accompanied by the alterations in biomass structure and modifications in lipids and fatty acids (FA).


      PubDate: 2016-03-26T13:28:10Z
       
  • iTRAQ-based proteomic analysis reveals the mechanisms of silicon-mediated
           cadmium tolerance in rice (Oryza sativa) cells
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Jie Ma, Huachun Sheng, Xiuli Li, Lijun Wang
      Silicon (Si) can alleviate cadmium (Cd) stress in rice (Oryza sativa) plants, however, the understanding of the molecular mechanisms at the single-cell level remains limited. To address these questions, we investigated suspension cells of rice cultured in the dark environment in the absence and presence of Si with either short- (12 h) or long-term (5 d) Cd treatments using a combination of isobaric tags for relative and absolute quantitation (iTRAQ), fluorescent staining, and inductively coupled plasma mass spectroscopy (ICP-MS). We identified 100 proteins differentially regulated by Si under the short- or long-term Cd stress. 70% of these proteins were down-regulated, suggesting that Si may improve protein use efficiency by maintaining cells in the normal physiological status. Furthermore, we showed two different mechanisms for Si-mediated Cd tolerance. Under the short-term Cd stress, the Si-modified cell walls inhibited the uptake of Cd ions into cells and consequently reduced the expressions of glycosidase, cell surface non-specific lipid-transfer proteins (nsLTPs), and several stress-related proteins. Under the long-term Cd stress, the amount of Cd in the cytoplasm in Si-accumulating (+Si) cells was decreased by compartmentation of Cd into vacuoles, thus leading to a lower expression of glutathione S-transferases (GST). These results provide protein-level insights into the Si-mediated Cd detoxification in rice single cells.
      Graphical abstract image

      PubDate: 2016-03-26T13:28:10Z
       
  • The memory of iron stress in strawberry plants
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Florinda Gama, Teresa Saavedra, José Paulo da Silva, Maria Graça Miguel, Amarilis de Varennes, Pedro José Correia, Maribela Pestana
      To provide information towards optimization of strategies to treat Fe deficiency, experiments were conducted to study the responses of Fe-deficient plants to the resupply of Fe. Strawberry (Fragaria × ananassa Duch.) was used as model plant. Bare-root transplants of strawberry (cv. ‘Diamante’) were grown for 42 days in Hoagland's nutrient solutions without Fe (Fe0) and containing 10 μM of Fe as Fe-EDDHA (control, Fe10). For plants under Fe0 the total chlorophyll concentration of young leaves decreased progressively on time, showing the typical symptoms of iron chlorosis. After 35 days the Fe concentration was 6% of that observed for plants growing under Fe10. Half of plants growing under Fe0 were then Fe-resupplied by adding 10 μM of Fe to the Fe0 nutrient solution (FeR). Full Chlorophyll recovery of young leaves took place within 12 days. Root ferric chelate-reductase activity (FCR) and succinic and citric acid concentrations increased in FeR plants. Fe partition revealed that FeR plants expressively accumulated this nutrient in the crown and flowers. This observation can be due to a passive deactivation mechanism of the FCR activity, associated with continuous synthesis of succinic and citric acids at root level, and consequent greater uptake of Fe.


      PubDate: 2016-03-21T19:13:23Z
       
  • Arabidopsis DREB1B in transgenic Salvia miltiorrhiza increased tolerance
           to drought stress without stunting growth
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Tao Wei, Kejun Deng, Yonghong Gao, Yu Liu, Meiling Yang, Lipeng Zhang, Xuelian Zheng, Chunguo Wang, Wenqin Song, Chengbin Chen, Yong Zhang
      Multiple stress response genes are controlled by transcription factors in a coordinated manner; therefore, these factors can be used for molecular plant breeding. CBF1/DREB1B, a known stress-inducible gene, was isolated from Arabidopsis thaliana and introduced into Salvia miltiorrhiza under the control of the CaMV35S or RD29A promoter. Under drought stress, relative water content, chlorophyll content, and the net photosynthetic rate were observed to be higher in the transgenic lines than in the wild type (WT). Moreover, O2 − and H2O2 accumulation was observed to be lower in the transgenic lines. Additional analyses revealed that the AtDREB1B transgenic plants generally displayed lesser malondialdehyde (MDA) but higher superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities than the WT under drought stress. Quantitative real-time polymerase chain reaction of a subset of genes involved in photosynthesis, stress response, carbohydrate metabolism, and cell protection further verified that AtDREB1B could enhance tolerance to drought by activating different downstream DREB/CBF genes in the transgenic plants. Furthermore, no growth inhibition was detected in transgenic S. miltiorrhiza plants that expressed AtDREB1B driven by either the constitutive CaMV35S promoter or the stress-inducible RD29A promoter. Together, these results suggest that AtDREB1B is a good candidate gene for increasing drought tolerance in transgenic S. miltiorrhiza.


      PubDate: 2016-03-21T19:13:23Z
       
  • Effect of mitochondrial ascorbic acid synthesis on photosynthesis
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): M.E. Senn, G.E. Gergoff Grozeff, M.L. Alegre, F. Barrile, M.C. De Tullio, C.G. Bartoli
      Ascorbic acid (AA) is synthesized in plant mitochondria through the oxidation of l-galactono-1,4-lactone (l-GalL) and then distributed to different cell compartments. AA-deficient Arabidopsis thaliana mutants (vtc2) and exogenous applications of l-GalL were used to generate plants with different AA content in their leaves. This experimental approach allows determining specific AA-dependent effects on carbon metabolism. No differences in O2 uptake, malic and citric acid and NADH content suggest that AA synthesis or accumulation did not affect mitochondrial activity; however, l-GalL treatment increased CO2 assimilation and photosynthetic electron transport rate in vtc2 (but not wt) leaves demonstrating a stimulation of photosynthesis after l-GalL treatment. Increased CO2 assimilation correlated with increased leaf stomatal conductance observed in l-GalL-treated vtc2 plants.


      PubDate: 2016-03-21T19:13:23Z
       
  • Involvement of ethylene in gibberellic acid-induced sulfur assimilation,
           photosynthetic responses, and alleviation of cadmium stress in mustard
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Asim Masood, M. Iqbal R. Khan, Mehar Fatma, Mohd Asgher, Tasir S. Per, Nafees A. Khan
      The role of gibberellic acid (GA) or sulfur (S) in stimulation of photosynthesis is known. However, information on the involvement of ethylene in GA-induced photosynthetic responses and cadmium (Cd) tolerance is lacking. This work shows that ethylene is involved in S-assimilation, photosynthetic responses and alleviation of Cd stress by GA in mustard (Brassica juncea L.). Plants grown with 200 mg Cd kg−1 soil were less responsive to ethylene despite high ethylene evolution and showed photosynthetic inhibition. Plants receiving 10 μM GA spraying plus 100 mg S kg−1 soil supplementation exhibited increased S-assimilation and photosynthetic responses under Cd stress. Application of GA plus S decreased oxidative stress of plants grown with Cd and limited stress ethylene formation to the range suitable for promoting sulfur use efficiency (SUE), glutathione (GSH) production and photosynthesis. The role of ethylene in GA-induced S-assimilation and reversal of photosynthetic inhibition by Cd was substantiated by inhibiting ethylene biosynthesis with the use of aminoethoxyvinylglycine (AVG). The suppression of S-assimilation and photosynthetic responses by inhibiting ethylene in GA plus S treated plants under Cd stress indicated the involvement of ethylene in GA-induced S-assimilation and Cd stress alleviation. The outcome of the study is important to unravel the interaction between GA and ethylene and their role in Cd tolerance in plants.


      PubDate: 2016-03-21T19:13:23Z
       
  • A carnivorous sundew plant prefers protein over chitin as a source of
           nitrogen from its traps
    • Abstract: Publication date: July 2016
      Source:Plant Physiology and Biochemistry, Volume 104
      Author(s): Andrej Pavlovič, Miroslav Krausko, Lubomír Adamec
      Carnivorous plants have evolved in nutrient-poor wetland habitats. They capture arthropod prey, which is an additional source of plant growth limiting nutrients. One of them is nitrogen, which occurs in the form of chitin and proteins in prey carcasses. In this study, the nutritional value of chitin and protein and their digestion traits in the carnivorous sundew Drosera capensis L. were estimated using stable nitrogen isotope abundance. Plants fed on chitin derived 49% of the leaf nitrogen from chitin, while those fed on the protein bovine serum albumin (BSA) derived 70% of its leaf nitrogen from this. Moreover, leaf nitrogen content doubled in protein-fed in comparison to chitin-fed plants indicating that the proteins were digested more effectively in comparison to chitin and resulted in significantly higher chlorophyll contents. The surplus chlorophyll and absorbed nitrogen from the protein digestion were incorporated into photosynthetic proteins – the light harvesting antennae of photosystem II. The incorporation of insect nitrogen into the plant photosynthetic apparatus may explain the increased rate of photosynthesis and plant growth after feeding. This general response in many genera of carnivorous plants has been reported in many previous studies.
      Graphical abstract image

      PubDate: 2016-03-21T19:13:23Z
       
  • Biochemical changes in black oat (avena strigosa schreb) cultivated in
           vineyard soils contaminated with copper
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Eduardo Girotto, Carlos A. Ceretta, Liana V. Rossato, Julia G. Farias, Gustavo Brunetto, Alcione Miotto, Tadeu L. Tiecher, Lessandro de Conti, Cledimar R. Lourenzi, Roberta Schmatz, Admir Giachini, Fernando T. Nicoloso
      Soils used for the cultivation of grapes generally have a long history of copper (Cu) based fungicide applications. As a result, these soils can accumulate Cu at levels that are capable of causing toxicity in plants that co-inhabit the vineyards. The aim of the present study was to evaluate growth parameters and oxidative stress in black oat plants grown in vineyard soils contaminated with high levels of Cu. Soil samples were collected from the Serra Gaúcha and Campanha Gaúcha regions, which are the main wine producing regions in the state of Rio Grande do Sul, in southern Brazil. Experiments were conducted in a greenhouse in 2009, with soils containing Cu concentrations from 2.2 to 328.7 mg kg−1. Evaluated parameters included plant root and shoot dry matter, Cu concentration in the plant's tissues, and enzymatic and non-enzymatic biochemical parameters related to oxidative stress in the shoots of plants harvested 15 and 40 days after emergence. The Cu absorbed by plants predominantly accumulated in the roots, with little to no translocation to the shoots. Even so, oat plants showed symptoms of toxicity when grown in soils containing high Cu concentrations. The enzymatic and non-enzymatic antioxidant systems of oat plants were unable to reverse the imposed oxidative stress conditions.


      PubDate: 2016-03-21T19:13:23Z
       
  • A combined application of biochar and phosphorus alleviates heat-induced
           adversities on physiological, agronomical and quality attributes of rice
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Shah Fahad, Saddam Hussain, Shah Saud, Shah Hassan, Mohsin Tanveer, Muhammad Zahid Ihsan, Adnan Noor Shah, Abid Ullah, Nasrullah, Fahad Khan, Sami Ullah, Hesham Alharby, Wajid Nasim, Chao Wu, Jianliang Huang
      Present study examined the influence of high-temperature stress and different biochar and phosphorus (P) fertilization treatments on the growth, grain yield and quality of two rice cultivars (IR-64 and Huanghuazhan). Plants were subjected to high day temperature-HDT (35 °C ± 2), high night temperature-HNT (32 °C ± 2), and control temperature-CT (28 °C ± 2) in controlled growth chambers. The different fertilization treatments were control, biochar alone, phosphorous (P) alone and biochar + P. High-temperature stress severely reduced the photosynthesis, stomatal conductance, water use efficiency, and increased the leaf water potential of both rice cultivars. Grain yield and its related attributes except for number of panicles, were reduced under high temperature. The HDT posed more negative effects on rice physiological attributes, while HNT was more destructive for grain yield. High temperature stress also hampered the grain appearance and milling quality traits in both rice cultivars. The Huanghuazhan performed better than IR-64 under high-temperature stress with better growth and higher grain yield. Different soil fertilization treatments were helpful in ameliorating the detrimental effects of high temperature. Addition of biochar alone improved some growth and yield parameters but such positive effects were lower when compared with the combined application of biochar and P. The biochar+P application recorded 7% higher grain yield (plant−1) of rice compared with control averaged across different temperature treatments and cultivars. The highest grain production and better grain quality in biochar+P treatments might be due to enhanced photosynthesis, water use efficiency, and grain size, which compensated the adversities of high temperature stress.


      PubDate: 2016-03-21T19:13:23Z
       
  • Evidences for growth-promoting and fungicidal effects of low doses of
           tricyclazole in barley
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Manoj Kumar, Ramesh Chand, Kavita Shah
      The effect of increasing concentrations (5–100 mg L−1) of tricyclazole (TCZ), an important fungicide commonly used for control of spot blotch disease, was investigated for changes in physiological and biochemical parameters in 10 and 20-days-old barley plants (Hordeum vulgare L., cv. RD-2508). A 10 mg L−1 dose of TCZ supplemented with nutrient solution in barley plants reflected a lowered infection with a significant increase in plant growth, plant biomass, leaf chlorophyll level, altered reactive oxygen species (ROS) formation and altered activity of key antioxidant enzymes viz. superoxide dismutase (SOD, EC: 1.15.1.1), catalase (CAT, EC: 1.11.1.6), ascorbate peroxidase (APX, EC: 1.11.1.1) and guaiacol peroxidase (GPX, EC: 1.11.1.7). To our knowledge this is the first report that provides evidence for TCZ to act both as a fungicide as well as to have plant growth-promoting activity. The study suggests that this dual property of tricyclazole has a potential for integration in disease management programs in barley. Application of low doses of TCZ can fit in well with environment friendly strategies for sustainable barley crop production, more yield and minimal soil contamination.
      Graphical abstract image

      PubDate: 2016-03-21T19:13:23Z
       
  • Anthocyanins and flavonols are responsible for purple color of Lablab
           purpureus (L.) sweet pods
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Baolu Cui, Zongli Hu, Yanjie Zhang, Jingtao Hu, Wencheng Yin, Ye Feng, Qiaoli Xie, Guoping Chen
      Lablab pods, as dietary vegetable, have high nutritional values similar to most of edible legumes. Moreover, our studies confirmed that purple lablab pods contain the natural pigments of anthocyanins and flavonols. Compared to green pods, five kinds of anthocyanins (malvidin, delphinidin and petunidin derivatives) were found in purple pods by HPLC-ESI-MS/MS and the major contents were delphinidin derivatives. Besides, nine kinds of polyphenol derivatives (quercetin, myricetin, kaempferol and apigenin derivatives) were detected by UPLC-ESI-MS/MS and the major components were quercetin and myricetin derivatives. In order to discover their molecular mechanism, expression patterns of biosynthesis and regulatory gens of anthocyanins and flavonols were investigated. Experimental results showed that LpPAL, LpF3H, LpF3′H, LpDFR, LpANS and LpPAP1 expressions were significantly induced in purple pods compared to green ones. Meanwhile, transcripts of LpFLS were more abundant in purple pods than green or yellow ones, suggestind that co-pigments of anthocyanins and flavonols are accumulated in purple pods. Under continuously dark condition, no anthocyanin accumulation was detected in purple pods and transcripts of LpCHS, LpANS, LpFLS and LpPAP1 were remarkably repressed, indicating that anthocyanins and flavonols biosynthesis in purple pods was regulated in light-dependent manner. These results indicate that co-pigments of anthocyanins and flavonols contribute to purple pigmentations of pods.


      PubDate: 2016-03-21T19:13:23Z
       
  • Manganese-induced regulations in growth, yield formation, quality
           characters, rice aroma and enzyme involved in 2-acetyl-1-pyrroline
           biosynthesis in fragrant rice
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Meijuan Li, Umair Ashraf, Hua Tian, Zhaowen Mo, Shenggang Pan, Shakeel Ahmad Anjum, Meiyang Duan, Xiangru Tang
      Micro-nutrient application is essential for normal plant growth while a little is known about manganese (Mn)-induced regulations in morpho-physiological attributes, aroma formation and enzyme involved in 2-acetyl-1-pyrroline (2-AP) biosynthesis in aromatic rice. Present study aimed to examine the influence of four levels of Mn i.e., Mn1 (100 mg MnSO4 pot−1), Mn2 (150 mg MnSO4 pot−1), Mn3 (200 mg MnSO4 pot−1), and Mn4 (250 mg MnSO4 pot−1) on the growth, yield formation, quality characters, rice aroma and enzyme involved in 2-acetyl-1-pyrroline biosynthesis in two fragrant rice cultivars i.e., Meixiangzhan and Nongxiang 18. Pots without Mn application were served as control (Ck). Each pot contained 15 kg of soil. Effects on agronomic characters, quality attributes, 2-AP contents and enzymes involved in 2-AP biosynthesis have been studied in early and late season rice. Results depicted that Mn improved rice growth, yield and related characters, and some quality attributes significantly. It further up-regulated proline, pyrroline-5-carboxylic acid (P5C) (precursors of 2-AP), soluble proteins and activities of proline dehydrogenase (ProDH), Δ1 pyrroline-5-carboxylic acid synthetase (P5CS) ornithine aminotransferase (OAT) that led to enhanced 2-AP production in rice grains. Moreover, higher Mn levels resulted in increased grain Mn contents in both rice cultivars. Along with growth and yield improvement, Mn application significantly improved rice aromatic contents. Overall, Nongxiang 18 accumulated more 2-AP contents than Meixiangzhan in both seasons under Mn application. This study further explored the importance of Mn in rice aroma formation and signifies that micro-nutrients can play significant roles in rice aroma synthesis; however, intensive studies at molecular levels are still needed to understand the exact mechanisms of Mn to improve rice aroma formation.


      PubDate: 2016-03-21T19:13:23Z
       
  • Genome-wide characterization and comparative analysis of the MLO gene
           family in cotton
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Xiaoyan Wang, Qifeng Ma, Lingling Dou, Zhen Liu, Renhai Peng, Shuxun Yu
      In plants, MLO (Mildew Locus O) gene encodes a plant-specific seven transmembrane (TM) domain protein involved in several cellular processes, including susceptibility to powdery mildew (PM). In this study, a genome-wide characterization of the MLO gene family in G. raimondii L., G. arboreum L. and G. hirsutum L. was performed. In total, 22, 17 and 38 homologous sequences were identified for each species, respectively. Gene organization, including chromosomal location, gene clustering and gene duplication, was investigated. Homologues related to PM susceptibility in upland cotton were inferred by phylogenetic relationships with functionally characterized MLO proteins. To conduct a comparative analysis between MLO candidate genes from G. raimondii L., G. arboreum L. and G. hirsutum L., orthologous relationships and conserved synteny blocks were constructed. The transcriptional variation of 38 GhMLO genes in response to exogenous application of salt, mannitol (Man), abscisic acid (ABA), ethylene (ETH), jasmonic acid (JA) and salicylic acid (SA) was monitored. Further studies should be conducted to elucidate the functions of MLO genes in PM susceptibility and phytohormone signalling pathways.


      PubDate: 2016-03-17T21:23:37Z
       
  • Inhibiting ethylene perception with 1-methylcyclopropene triggers
           molecular responses aimed to cope with cell toxicity and increased
           respiration in citrus fruits
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Beatriz Establés-Ortiz, Paco Romero, Ana-Rosa Ballester, Luis González-Candelas, María T. Lafuente
      The ethylene perception inhibitor 1-methylcyclopropene (1-MCP) has been critical in understanding the hormone's mode of action. However, 1-MCP may trigger other processes that could vary the interpretation of results related until now to ethylene, which we aim to understand by using transcriptomic analysis. Transcriptomic changes in ethylene and 1-MCP-treated ‘Navelate’ (Citrus sinensis L. Osbeck) oranges were studied in parallel with changes in ethylene production, respiration and peel damage. The effects of compounds modifying the levels of the ethylene co-product cyanide and nitric oxide (NO) on fruit physiology were also studied. Results suggested that: 1) The ethylene treatment caused sub-lethal stress since it induced stress-related responses and reduced peel damage; 2) 1-MCP induced ethylene-dependent and ethylene-independent responsive networks; 3) 1-MCP triggered ethylene overproduction, stress-related responses and metabolic shifts aimed to cope with cell toxicity, which mostly affected to the inner part of the peel (albedo); 4) 1-MCP increased respiration and drove metabolism reconfiguration for favoring energy conservation but up-regulated genes related to lipid and protein degradation and triggered the over-expression of genes associated with the plasma membrane cellular component; 5) Xenobiotics and/or reactive oxygen species (ROS) might act as signals for defense responses in the ethylene-treated fruit, while their uncontrolled generation would induce processes mimicking cell death and damage in 1-MCP-treated fruit; 6) ROS, the ethylene co-product cyanide and NO may converge in the toxic effects of 1-MCP.


      PubDate: 2016-03-17T21:23:37Z
       
  • Toxicity of canavanine in tomato (Solanum lycopersicum L.) roots is due to
           alterations in RNS, ROS and auxin levels
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Urszula Krasuska, Olga Andrzejczak, Paweł Staszek, Wojciech Borucki, Agnieszka Gniazdowska
      Canavanine (CAN) is non-proteinogenic aminoacid and a structural analog of arginine (Arg). Naturally, CAN occurs in legumes e.g. jack bean and is considered as a strong allelochemical. As a selective inhibitor of inducible nitric oxide synthase in mammalians, it could act as a modifier of nitric oxide (NO) concentration in plants. Modifications in the content of endogenous reactive nitrogen species (RNS) and reactive oxygen species (ROS) influence root structure and architecture, being also under hormonal control. The aim of the work was to investigate regulation of root growth in tomato (Solanum lycopersicum L. cv. Malinowy Ożarowski) seedling by application of CAN at concentration (10 and 50 μM) leading to 50% or 100% restriction of root elongation. CAN at higher concentration led to slight DNA fragmentation, increased total RNA and protein level. Decline in total respiration rate after CAN supplementation was not associated with enhanced membrane permeability. Malformations in root morphology (shorter and thicker roots, limited number of lateral roots) were accompanied by modification in NO and ONOO− localization; determined mainly in peridermal cells and some border cells. Although, CAN resulted in low RNS production, addition of exogenous NO by usage of NO donors did not reverse its negative effect, nor recovery effect was detected after roots imbibition in Arg. To build up a comprehensive view on mode of action of CAN as root growth inhibitor, it was shown an elevated level of auxin. To summarize, we demonstrated several secondary mode of action of CAN, indicating its toxicity in plants linked to restriction in RNS formation accompanied by simultaneous overaccumulation of ROS.


      PubDate: 2016-03-17T21:23:37Z
       
  • External potassium (K+) application improves salinity tolerance by
           promoting Na+-exclusion, K+-accumulation and osmotic adjustment in
           contrasting peanut cultivars
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Koushik Chakraborty, Debarati Bhaduri, Har Narayan Meena, Kuldeepsingh Kalariya
      Achieving salt-tolerance is highly desirable in today's agricultural context. Apart from developing salt-tolerant cultivars, possibility lies with management options, which can improve crop yield and have significant impact on crop physiology as well. Thus present study was aimed to evaluate the ameliorative role of potassium (K+) in salinity tolerance of peanut. A field experiment was conducted using two differentially salt-responsive cultivars and three levels of salinity treatment (control, 2.0 dS m−1, 4.0 dS m−1) along with two levels (with and without) of potassium fertilizer (0 and 30 kg K2O ha−1). Salinity treatment incurred significant changes in overall physiology in two peanut cultivars, though the responses varied between the tolerant and the susceptible one. External K+ application resulted in improved salinity tolerance in terms of plant water status, biomass produced under stress, osmotic adjustment and better ionic balance. Tolerant cv. GG 2 showed better salt tolerance by excluding Na+ from uptake and lesser accumulation in leaf tissue and relied more on organic osmolyte for osmotic adjustment. On the contrary, susceptible cv. TG 37A allowed more Na+ to accumulate in the leaf tissue and relied more on inorganic solute for osmotic adjustment under saline condition, hence showed more susceptibility to salinity stress. Application of K+ resulted in nullifying the negative effect of salinity stress with slightly better response in the susceptible cultivar (TG 37A). The present study identified Na+-exclusion as a key strategy for salt-tolerance in tolerant cv. GG 2 and also showed the ameliorating role of K+ in salt-tolerance with varying degree of response amongst tolerant and susceptible cultivars.
      Graphical abstract image

      PubDate: 2016-03-17T21:23:37Z
       
  • Comparative analyses of light-induced anthocyanin accumulation and gene
           expression between the ray florets and leaves in chrysanthemum
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Yan Hong, Li-wen Yang, Meng-ling Li, Si-lan Dai
      Light is one of the key environmental factors that affect anthocyanin biosynthesis. However, the underlying molecular mechanism remains unclear, and many problems regarding phenotypic change and corresponding gene regulation have not been solved. In the present study, comparative analyses of light-induced anthocyanin accumulation and gene expression between the ray florets and leaves were performed in Chrysanthemum × morifolium ‘Purple Reagan’. After contrasting the variations in the flower color phenotype and relative pigment content, as well as expression patterns of structural and regulator genes responsible for anthocyanin biosynthesis and photoreceptor between different plant organs under light and dark conditions, we concluded that (1) both the capitulum and foliage are key organs responding to light for chrysanthemum coloration; (2) compared with flavones, shading makes a greater decrease on the anthocyanins accumulation; (3) most of the structural and regulatory genes in the light-induced anthocyanin pathway specifically express in the ray florets; and (4) CmCHS, CmF3H, CmF3′H, CmANS, CmDFR, Cm3GT, CmMYB5-1, CmMYB6, CmMYB7-1, CmbHLH24, CmCOP1 and CmHY5 are key genes for light-induced anthocyanin biosynthesis in chrysanthemum ray florets, while on the transcriptional level, the expressions of CmPHYA, CmPHYB, CmCRY1a, CmCRY1b and CmCRY2 are insignificantly changed. Moreover, the inferred comprehensive effect of multiple signals on the accumulation of anthocyanins and transmission channel of light signal that exist between the leaves and ray florets were further discussed. These results further our understanding of the relationship between the gene expression and light-induced anthocyanin biosynthesis, and lay foundations for the promotion of the molecular breeding of novel flower colors in chrysanthemums.


      PubDate: 2016-03-17T21:23:37Z
       
  • Characterization of Arabidopsis thaliana FLAVONOL SYNTHASE 1 (FLS1)
           -overexpression plants in response to abiotic stress
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Nguyen Hoai Nguyen, Jun Hyeok Kim, Jaeyoung Kwon, Chan Young Jeong, Wonje Lee, Dongho Lee, Suk-Whan Hong, Hojoung Lee
      Flavonoids are an important group of secondary metabolites that are involved in plant growth and contribute to human health. Many studies have focused on the biosynthesis pathway, biochemical characters, and biological functions of flavonoids. In this report, we showed that overexpression of FLS1 (FLS1-OX) not only altered seed coat color (resulting in a light brown color), but also affected flavonoid accumulation. Whereas fls1-3 mutants accumulated higher anthocyanin levels, FLS1-OX seedlings had lower levels than those of the wild-type. Besides, shoot tissues of FLS1-OX plants exhibited lower flavonol levels than those of the wild-type. However, growth performance and abiotic stress tolerance of FLS1-OX, fls1-3, and wild-type plants were not significantly different. Taken together, FLS1 can be manipulated (i.e., silenced or overexpressed) to redirect the flavonoid biosynthetic pathway toward anthocyanin production without negative effects on plant growth and development.


      PubDate: 2016-03-17T21:23:37Z
       
  • Salt-responsive mechanisms in chromosome segment substitution lines of
           rice (Oryza sativa L. cv. KDML105)
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Noppawan Nounjan, Jonaliza L. Siangliw, Theerayut Toojinda, Supachitra Chadchawan, Piyada Theerakulpisut
      Two chromosome segment substitution lines of Khao Dawk Mali 105 (KDML105) rice that carry quantitative trait loci for drought tolerance located on chromosome 8 (DT-QTL8) designated CSSL8-94 and CSSL8-116 were investigated for co-expression network and physiological responses to salinity compared to their parents (KDML105; drought and salt sensitive recurrent parent, and DH103; drought tolerant QTL donor). These CSSL lines show different salt-response traits under salt stress (CSSL8-94 shows higher tolerance than CSSL8-116) and possess different segments of DT-QTL8. To identify specific biological process(es) associated with salt-stress response, co-expression network analysis was constructed from each DT-QTL segment. To evaluate differential physiological mechanisms responding to salt stress, all rice lines/cultivar were grown for 21 d in soils submerged in nutrient solutions, then subjected to 150 mM NaCl for 7 d. Physiological parameters related to co-expression network analysis (photosynthetic parameters) and salt responsive parameters (Na+/K+ ratio, proline content, malondialdehyde and ascorbate peroxidase activity; EC1.11.1.1) were investigated along with the expression analysis of related genes. Physiological responses under salt stress particularly photosynthesis-related parameters of CSSL8-94 were similar to DH103, whereas those of CSSL8-116 were similar to KDML105. Moreover, expression levels of photosynthesis-related genes selected from the co-expression networks (Os08g41460, Os08g44680, Os06g01850, Os03g07300 and Os02g42570) were slightly decreased or stable in CSSL8-94 and DH103 but were dramatically down-regulated in CSSL8-116 and KDML105. These differential responses may contribute to the photosynthesis systems of CSSL8-94 being less damaged under salt stress in comparison to those of CSSL8-116. It can be concluded that the presence of the specific DT-QTL8 segment in CSSL8-94 not only confers drought tolerant traits but also enhances its salt tolerant ability.


      PubDate: 2016-03-17T21:23:37Z
       
  • Genome-wide identification and characterization of WRKY transcriptional
           factor family in apple and analysis of their responses to waterlogging and
           drought stress
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Dong Meng, Yuanyuan Li, Yang Bai, Mingjun Li, Lailiang Cheng
      As one of the largest transcriptional factor families in plants, WRKY genes play significant roles in various biotic and abiotic stress responses. Although the WRKY gene family has been characterized in a few plant species, the details remain largely unknown in the apple (Malus domestica Borkh.). In this study, we identified a total of 127 MdWRKYs from the apple genome, which were divided into four subgroups according to the WRKY domains and zinc finger motif. Most of them were mapped onto the apple's 17 chromosomes and were expressed in more than one tissue, including shoot tips, mature leaves, fruit and apple calli. We then contrasted WRKY expression patterns between calli grown in solid medium (control) and liquid medium (representing waterlogging stress) and found that 34 WRKY genes were differentially expressed between the two growing conditions. Finally, we determined the expression patterns of 10 selected WRKY genes in an apple rootstock, G41, in response to waterlogging and drought stress, which identified candidate genes involved in responses to water stress for functional analysis. Our data provide interesting candidate MdWRKYs for future functional analysis and demonstrate that apple callus is a useful system for characterizing gene expression and function in apple.


      PubDate: 2016-03-13T02:54:02Z
       
  • Comparative proteomic analysis of seed embryo proteins associated with
           seed storability in rice (Oryza sativa L) during natural aging
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Jiadong Gao, Hua Fu, Xinqiao Zhou, Zhongjian Chen, Yi Luo, Baiyuan Cui, Guanghui Chen, Jun Liu
      Seed storability is considered an important trait in rice breeding; however, the underlying regulating mechanisms remain largely unknown. Here, we carried out a physiological and proteomic study to identify proteins possibly related to seed storability under natural conditions. Two hybrid cultivars, IIYou998 (IIY998) and BoYou998 (BY998), were analyzed in parallel because they share the same restorer line but have significant differences in seed storability. After a 2-year storage period, the germination percentage of IIY998 was significantly lower than that of BY998, whereas the level of malondialdehyde was reversed, indicating that IIY998 seeds may suffer from more severe damage than BY998 during storage. However, we did not find correlation between activities of antioxidant enzymes of superoxide dismutase, peroxidase, and catalase and seed storability. We identified 78 embryo proteins in embryo whose abundance varied more than 3-fold different during storage or between IIY998 and BY998. More proteins changed in abundance in IIY998 embryo (67 proteins) during storage than in BY998 (10 proteins). Several redox regulation proteins, mainly glutathione-related proteins, exhibited different degree of change during storage between BY998 and IIY998 and might play an important role protecting embryo proteins from oxidation. In addition, some disease/defense proteins, including DNA-damage-repair/toleration proteins, and a putative late embryogenesis abundant protein were significantly downregulated in IIY998, whereas their levels did not change in BY998, indicating that they might be correlated with seed storability. Further studies on these candidate seed storage proteins might help improve our understanding of seed aging.


      PubDate: 2016-03-09T02:49:25Z
       
  • Optimization of methyl jasmonate and β-cyclodextrin for enhanced
           production of taraxerol and taraxasterol in (Taraxacum officinale Weber)
           cultures
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Kiran Sharma, Rasheeduz Zafar
      Context Taraxacum officinale Weber (TO) commonly known as “dandelion”, is a tropical Asian medicinal plant which contains taraxasterol (TX) and taraxerol (TA) in its roots, which are reported to be commercially important anticancer compounds. Objective The main objective of the present study was to evaluate the increase in yield of TX and TA through elicitation by addition of abiotic elictors like methyl jasmonate (MJ) and β-cyclodextrin (CD), to the root callus suspension cultures of TO. Materials and methods The root callus suspension was maintained on Murashige and Skoog's (MS) medium MS + IAA + BA + 2, 4-D (0.5 ppm + 1 ppm + 0.5 ppm). The concentrations of the abiotic elicitors MJ and CD were optimized using central composite design (CCD) and quantification of TA and TX in elicited cultures was done by High Performance Liquid Chromatography (HPLC) analysis. Result It was observed that MJ at a concentration of 0.2 mM showed good increase in content of TX to 0.032% w/w and at concentrations 0.05 mM, 0.1 mM and 0.2 mM showed similar increase in TA content to 0.018% w/w, whereas CD at the concentration of 25 mM showed highest increase in TX content to 0.036% w/w and at the concentrations of 25 mM, 50 mM showed increase in TA content to 0.023% w/w as compared to the plant root (PR) which showed content of TX as 0.0299% w/w and TA as 0.0169% w/w. Discussion and conclusion From the present investigation it was concluded that out of the two abiotic elicitors MJ and CD, CD was found to be more effective to increase TA and TX content in Dandelion cell cultures.
      Graphical abstract image

      PubDate: 2016-03-09T02:49:25Z
       
  • Arsenic stress induces changes in lipid signalling and evokes the stomata
           closure in soybean
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Ana L. Armendariz, Melina A. Talano, Ana L. Villasuso, Claudia Travaglia, Graciela E. Racagni, Herminda Reinoso, Elizabeth Agostini
      Soybean (Glycine max) is often exposed to high arsenic (As) level in soils or through irrigation with groundwater. In previous studies on As-treated soybean seedlings we showed deleterious effect on growth, structural alterations mainly in root vascular system and induction of antioxidant enzymes. However, there are not reports concerning signal transduction pathways triggered by the metalloid in order to develop adaptive mechanisms. Phosphatidic acid (PA), a key messenger in plants, can be generated via phospholipase D (PLD) or via phospholipase C (PLC) coupled to diacylglycerol kinase (DGK). Thus, changes in PA and in an enzyme involved in its metabolism (PLD) were analysed in soybean seedlings treated with 25 μM AsV or AsIII. The present study demonstrated that As triggers the PA signal by PLD and also via PLC/DGK mainly after 48 h of As treatment. DGPP, other lipid messenger produced by phosphorylation of PA by PAK increased in As treated roots. Arsenic also induced rapid and significant stomatal closure after 1.5 h of treatment, mainly with AsIII, probably as an adaptive response to the metalloid to reduce water loss by transpiration. This report constitute the first evidence that shows the effects of As on lipid signalling events in soybean seedlings which would be crucial in adaptation and survival of soybean seedlings under As stress.


      PubDate: 2016-03-09T02:49:25Z
       
  • Copper excess promotes propagation and induces proteomic change in root
           cultures of Hyoscyamus albus L.
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Ari Sako, Jebunnahar Kandakar, Noriko Tamari, Ataru Higa, Kenichi Yamaguchi, Yoshie Kitamura
      Hyoscyamus albus L. seedlings respond positively to copper (Cu) excess. In the present study, to understand how roots cope with Cu excess, propagation and proteome composition in the presence of Cu were examined using a root culture system. When H. albus roots were cultured in a medium without Cu, root growth deteriorated. However, in the presence of Cu, root growth increased in a concentration-dependent manner, and vigorous lateral root development was observed at 200 μM Cu. Cu accumulation in the roots increased with the Cu supply. Subcellular fractionation revealed that the highest amount of Cu was present in the cell wall-containing fraction, followed by the soluble fraction. However, the highest specific incorporation of Cu, in terms of fresh weight, was in the mitochondria-rich fraction. High Cu levels enhanced respiration activity. Comparative proteomic analysis revealed that proteins involved in carbohydrate metabolism, de novo protein synthesis, cell division, and ATP synthesis increased in abundance, whereas the proteasome decreased. These results indicate that Cu promotes propagation of H. albus roots through the activation of the energy supply and anabolism. Newly propagated root tissues and newly generated proteins that bind to Cu may provide space and reservoirs for deposition of additional Cu.
      Graphical abstract image

      PubDate: 2016-03-09T02:49:25Z
       
  • Reactive oxygen species, essential molecules, during plant–pathogen
           interactions
    • Abstract: Publication date: June 2016
      Source:Plant Physiology and Biochemistry, Volume 103
      Author(s): Daymi Camejo, Ángel Guzmán-Cedeño, Alexander Moreno
      Reactive oxygen species (ROS) are continually generated as a consequence of the normal metabolism in aerobic organisms. Accumulation and release of ROS into cell take place in response to a wide variety of adverse environmental conditions including salt, temperature, cold stresses and pathogen attack, among others. In plants, peroxidases class III, NADPH oxidase (NOX) locates in cell wall and plasma membrane, respectively, may be mainly enzymatic systems involving ROS generation. It is well documented that ROS play a dual role into cells, acting as important signal transduction molecules and as toxic molecules with strong oxidant power, however some aspects related to its function during plant-pathogen interactions remain unclear. This review focuses on the principal enzymatic systems involving ROS generation addressing the role of ROS as signal molecules during plant-pathogen interactions. We described how the chloroplasts, mitochondria and peroxisomes perceive the external stimuli as pathogen invasion, and trigger resistance response using ROS as signal molecule.


      PubDate: 2016-03-09T02:49:25Z
       
  • Transcriptomics of tomato plants infected with TYLCSV or expressing the
           central TYLCSV Rep protein domain uncover changes impacting pathogen
           response and senescence
    • Abstract: Publication date: Available online 2 March 2016
      Source:Plant Physiology and Biochemistry
      Author(s): Alessandra Lucioli, Carlo Perla, Alessandra Berardi, Francesca Gatti, Laura Spanò, Mario Tavazza
      To establish a successful infection viruses need to overcome plant innate immune responses and redirect host gene expression for their multiplication and diffusion. Tomato yellow leaf curl Sardinia virus (TYLCSV) is a geminivirus, which causes significant economic losses in tomato. The multifunctional replication associated geminivirus protein (Rep) has an important role during viral infection. In particular, the Rep central domain spanning from aa 120 to 180 is known to interact with viral and host factors. In this study, we used long serial analysis of gene expression to analyse the transcriptional profiles of transgenic tomato plants expressing the first 210 amino acids of TYLCSV Rep (Rep210) and TYLCSV-infected wild-type tomato plants (Wt-Ty). Also, we compared these profiles with those of transgenic Rep130 tomatoes. Comparison of Wt-Ty and Rep210 libraries with the wild-type one identified 118 and 203 differentially expressed genes (DEGs), respectively. Importantly, 55% of Wt-Ty DEGs were in common with Rep210, and no ones showed opposite expression. Conversely, a negligible overlap was found between Rep130 DEGs and Wt-Ty and Rep210 ones. TYLCSV- and Rep210-repressed genes, but not induced ones, overlapped with the leaf senescence process. Interestingly, TYLCSV upregulates expression of genes involved in the negative regulation of programmed cell death (PCD), several of which were also regulated by the abscisic acid. Rep210 upregulated genes related to defence response, immune system processes and negative regulation of PCD. Collectively, our results support a model in which the Rep central domain has a pivotal role in redirecting host plant gene expression.


      PubDate: 2016-03-03T02:29:28Z
       
  • Simultaneous determination of shikimic acid, salicylic acid and jasmonic
           acid in wild and transgenic Nicotiana langsdorffii plants exposed to
           abiotic stresses
    • Abstract: Publication date: Available online 2 March 2016
      Source:Plant Physiology and Biochemistry
      Author(s): Elisa Scalabrin, Marta Radaelli, Gabriele Capodaglio
      The presence and relative concentration of phytohormones may be regarded as a good indicator of an organism’s physiological state. The integration of the rolC gene from Agrobacterium rhizogenes and of the rat glucocorticoid receptor (gr) in Nicotiana langsdorffii Weinmann plants has shown to determine various physiological and metabolic effects. The analysis of wild and transgenic N. langsdorffii plants, exposed to different abiotic stresses (high temperature, water deficit, and high chromium concentrations) was conducted, in order to investigate the metabolic effects of the inserted genes in response to the applied stresses. The development of a new analytical procedure was necessary, in order to assure the simultaneous determination of analytes and to obtain an adequately low limit of quantification. For the first time, a sensitive HPLC-HRMS quantitative method for the simultaneous determination of salicylic acid, jasmonic acid and shikimic acid was developed and validated. The method was applied to 80 plant samples, permitting the evaluation of plant stress responses and highlighting some metabolic mechanisms. Salicylic, jasmonic and shikimic acids proved to be suitable for the comprehension of plant stress responses. Chemical and heat stresses showed to induce the highest changes in plant hormonal status, differently affecting plant response. The potential of each genetic modification toward the applied stresses was marked and particularly the resistance of the gr modified plants was evidenced. This work provides new information in the study of N. langsdorffii and transgenic organisms, which could be useful for the further application of these transgenes.
      Graphical abstract image

      PubDate: 2016-03-03T02:29:28Z
       
 
 
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