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Environmental and experimental botany
Pergamon Press,
Environmental and experimental botany

Pergamon Press,

0098-8472

Environmental and experimental botany/Journal Environmental and experimental botanySCIISTP
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    Comparative metabolomic analysis reveals the involvement of catechins in adaptation mechanism to cold stress in tea plant (Camellia sinensis var. sinensis)

    Wang L.Di T.Peng J.Li Y....
    11页
    查看更多>>摘要：? 2022 Elsevier B.V.Cold stress is a major environmental factor that affects tea production and quality. In this study, the global profiles of metabolites in response to cold acclimation (CA) of three tea plant cultivars with contrasting cold tolerances were investigated using UPLC/MS and GC/MS analyses. A total of 167 and 68 metabolites, which were CA responsive and showed differential accumulation in the susceptible and resistant cultivars under CA, were found from UPLC/MS and GC/MS analyses, respectively. The analysis revealed that higher levels of primary metabolites (amino acids, ascorbic acid, intermediates of the tricarboxylic acid cycle, and carbohydrates) were present in the resistant cultivar. Flavonoids (kaempferol, quercetin, myricetin, and catechin), which are secondary metabolites, also showed high accumulation in the cold-resistant cultivar. Accordingly, under CA, catechin component content in the four cold-resistant accessions was higher than that in the three cold-susceptible accessions, indicating that catechins play important roles in the cold response. Moreover, exogenous epigallocatechin gallate (EGCG) application conferred tolerance to freezing stress in tea plants. Tea leaves treated with EGCG exhibited decreased levels of relative electrolyte leakage and malondialdehyde content and increased reactive oxygen species scavenging activity and Fv/Fm under freezing conditions. Expression analysis of cold-regulated genes indicated that EGCG facilitated the transcriptional activation of CsICE1-CsCBF-CsCOR pathway to improve the freezing tolerance of tea plants. Taken together, the induction of stress tolerance-related metabolites was greater in the cold-resistant cultivar than in susceptible cultivars. This study highlights the important roles of catechins, especially EGCG, in cold tolerance.
      原文链接:
    • NSTL
    • Elsevier

    The NADP-malate dehydrogenase (SmNADP-mdh), a C4 pathway gene from Suaeda monoica enhanced photosynthesis and biomass yield in C3 plants

    Haque M.I.Pandya D.K.Jha B.Rathore M.S....
    13页
    查看更多>>摘要：? 2022 Elsevier B.V.Enhanced photosynthesis and biomass have been achieved in C3 plants by over-expressing NADP dependent malate dehydrogenase (SmNADP-mdh), a C4 pathway gene from Suaeda monoica. Over-expression of the SmNADP-mdh improved seed germination, seedling growth and accumulation of pigments, sugar, starch and C H N S elements in transgenic tobacco under in vitro conditions. Transgenic tobacco exhibited higher NADP-MDH activity, membrane stability index, photosynthesis efficiency, improved stomatal conductance, carboxylation efficiency, photosystem II (PSII) operating efficiency, electron transfer rate, photochemical quenching and better accumulation of sugar and starch at elevated (1200 ppm) CO2 (eCO2). Chlorophyll a fluorescence analysis showed improved pool size, electron transfer, water-splitting activity, photosynthetic performance indexes and efficient working of PSII at eCO2 in transgenic tobacco over-expressing SmNADP-mdh. The higher expression of antioxidant defence genes indicated better scavenging and lesser accumulation of ROS at eCO2. Results suggest the potential of a single-cell C4 halophytic NADP-mdh gene in the development of smart agriculture to improve the photosynthetic efficiency and biomass yield in C3 plants.
      原文链接:
    • NSTL
    • Elsevier

    Tomato UVI4 homologue modulates cell expansion to participate heat-stimulated hypocotyl elongation

    Zhang P.Di S.Zhang J.Liu G....
    13页
    查看更多>>摘要：? 2022 Elsevier B.V.Raising incubation temperature during seed germination is a conventional strategy to promote the efficiency of seed emergence from soil, which requires robust hypocotyl elongation. Tomato hypocotyl elongation is a consequence of active cell division and expansion, both of which require precisely regulated cell cycle progression. Anaphase-promoting complex/cyclosome (APC/C) is a multiple subunit E3 ubiquitin ligase which degrades certain mitotic cyclins and inhibit M-specific CDK/cyclin complex activity during cell cycle from G2 to M phase. Little is known about the function of APC/C regulators during tomato hypocotyl elongation. Here, we isolated tomato homologue SlUVI4 based on the homology with the negative regulator of APC/C, UVI4 in Arabidopsis. SlUVI4 had high expression in hypocotyls after the seed germination and gradually reduced its transcription during the hypocotyl elongation. We probed SlUVI4 function in heat-stimulated hypocotyl elongation through genetic, physiological and cytological analyses. Both overexpression and loss-of-function of SlUVI4 resulted in defective hypocotyl growth with opposite cell sizes. Microscopic analyses of hypocotyl sections revealed that SlUVI4 plays important roles in repressing cell expansion. Heat repressed SlUVI4 transcription to stimulate cell expansion and hypocotyl elongation. Inhibition of auxin polar transportation activated SlUVI4 transcription and abolished heat-induced cell expansion and hypocotyl elongation. Exogenous auxin repressed SlUVI4 transcription and enhanced hypocotyl elongation under heat condition. Partial loss of function of SlUVI4 largely abrogated heat-stimulated hypocotyl cell expansion. Taken together, our findings illustrate that SlUVI4 is involved in auxin-mediated hypocotyl elongation stimulated by heat.
      原文链接:
    • NSTL
    • Elsevier

    Calcium signaling in coordinating plant development, circadian oscillations and environmental stress responses in plants

    Gahlot P.Kumar D.Verma S.Negi N.P....
    18页
    查看更多>>摘要：? 2022 Elsevier B.V.Calcium (Ca2+) is an intracellular second messenger involved in many signal transduction pathways in plants. The perception of environmental and internal cues leads to alterations in the cytosolic Ca2+ signatures which translate into changes in gene expression and cellular functions. Herein, we review the novel roles of Ca2+ signalling in coordinating plant stem cell niche homeostasis for root and shoot development. We also summarize the regulatory networks between Ca2+ signalling and other plant signalling pathways which commence into activation or repression of genes involved in regulating vegetative to reproductive phase transition and light-mediated plant growth responses. The possible functions of Ca2+ in the input pathway as a second messenger, external stimuli and the output of the clock regulating the rhythmicity of the plant circadian system are being reviewed. Additionally, we have also highlighted the new insights into the roles of Ca2+ signalling components in the perception and regulation of abiotic/ biotic stress responses in plants.
      原文链接:
    • NSTL
    • Elsevier

    Soil drought decreases oil synthesis and increases protein synthesis in cottonseed kernel during the flowering and boll formation of cotton

    Li Y.Hu W.He J.Zou J....
    15页
    查看更多>>摘要：? 2022 Elsevier B.V.In cotton production, drought is particularly prominent in the flowering and boll formation stage, which significantly affects the cottonseed yield and quality. As the two main storage products in cottonseed kernel, the formation of oil and protein will be affected inescapably under soil drought. Still, the effects of soil drought on the synthesis of cottonseed oil and protein are poorly investigated. To this end, experiments were conducted using two cultivars with contrasting drought tolerance (Dexiamian 1 and Yuzaomian 9110) under three water levels [soil relative water content: control (75 ± 5)%, mild drought (60 ± 5)% and severe drought (45 ± 5)%] from 2017 to 2019. We examined the responses of metabolic activities in cottonseed kernels to drought. Otherwise, 13CO2 and 15N-urea isotope labeling were applied to verify the trend of oil and protein accumulation under soil drought. Results showed that drought decreased cottonseed yield per plant due to the decreases of single-seed weight and cottonseed number. And drought decreased oil content (% dry weight?1) and increased protein content (% dry weight?1) in cottonseed kernel. According to the findings, drought decreased 13C content and limited the flow of carbon into oil synthesis pathway; moreover, drought decreased the expression of GhPEPC1 and GhDGAT and activities of phosphoenolpyruvate carboxylase (PEPCase) and diacylglycerol acyltransferase (DGAT), which restrained oil accumulation. Increased protein content under drought was attributed to the increased translocation of plant nitrogen to cottonseed kernel, higher expression of GhGS and GhGOGAT, glutamine synthetase (GS) and glutamate synthase (GOGAT) activities. The Yuzaomian 9110 was more sensitive to drought stress with a higher loss of cottonseed yield and yield components than Dexiamian 1. This study provides insight into the physiological mechanisms of cottonseed oil and protein synthesis under drought and provides a theoretical basis for the utilization of cottonseed oil and protein in the future.
      原文链接:
    • NSTL
    • Elsevier

    Deciphering the plant microbiome to improve drought tolerance: Mechanisms and perspectives

    Ali S.Tyagi A.Park S.Bae H....
    19页
    查看更多>>摘要：? 2022 Elsevier B.V.Plants being sessile are constantly challenged by numerous abiotic stressors that jeopardize their survival. Drought stress is a major constraint in sustainable agriculture that affects plant distribution, growth, and productivity. Plants use multidimensional adaptation tactics at cellular, molecular, and biochemical levels to combat drought stress. These adaptive strategies have been extensively studied, and a variety of drought-resistance genes have recently been discovered. However, translating this information from the laboratory to field conditions is still a major challenge. Hence, developing novel long-term and successful drought mitigation strategies is an important aim in agriculture, as it is critical to ensure food security. One such approach is to explore the plant microbiome, which has recently become a research frontier. Plant microbiome engineering is being examined as a new aspect of sustainable agriculture, with the potential to improve crop resilience to drought. Plants restructure their microbiome against drought stress by employing the “cry for help” strategy, which can both alleviate stress and can improve health and nutrition availability. Mechanistic insights into the complex feedback between microbes and plants during and after water stress are required to fully harness the potential of above- and below-ground microbiome. The use of high-throughput tools to investigate the ecological, biochemical, physiological, and molecular aspects of the plant microbiome under drought stress will improve our ability to improve the drought resilience of crops in the future. This review highlights recent findings on the impact of drought and related signaling in plants. We also discuss the function of the plant microbiome in drought resistance in plants, as well as possible future research directions. Furthermore, we discuss the roles of multiomics, synthetic microbial communities (SynComs,) and host-mediated microbiome engineering for developing drought-resilient microbial communities in sustainable agriculture. Finally, we assess the challenges encountered and make recommendations for future endeavors to extend plant microbiome applications from the lab to the field.
      原文链接:
    • NSTL
    • Elsevier

    SlSNAT2, a chloroplast-localized acetyltransferase, is involved in Rubisco lysine acetylation and negatively regulates drought stress tolerance in tomato

    Wang X.Liu Y.Wang F.Xia P....
    12页
    查看更多>>摘要：? 2022 Elsevier B.V.Drought stress seriously inhibits crop growth and yields and constrains photosynthesis, which is a key biological process. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is a key enzyme in the carbon assimilation process, and while its activity is reportedly significantly inhibited under drought stress, little is known about the underlying molecular mechanism. We identified a chloroplast-localized acetyltransferase, SlSNAT2, negatively regulates drought tolerance in tomato. The slsnat2 mutants were conduced to endogenous abscisic acid accumulation in tomato and could promote scavenging of reactive oxygen species through the enhanced activity of antioxidant enzymes. Knocking out this gene could therefore improve photosynthesis under drought stress. Moreover, SlSNAT2 could catalyze the Lys acetylation of rbcL, a large Rubisco subunit. And SlSNAT2 knockout lines were found to maintain higher levels of Rubisco activity under drought stress in the absence of SlSNAT2-catalyzed acetylation of rbcL than wild type plants. Our results demonstrate that SlSNAT2 functions as a negative regulator of drought tolerance. Accordingly, SlSNAT2 could be targeted in molecular designs for tomato breeding.
      原文链接:
    • NSTL
    • Elsevier

    Chalcogens reduce grain Cd accumulation by enhancing Cd root efflux and upper organ retention in wheat (Triticum aestivum L.)

    Zhang D.Zhang Y.Zhou H.Wang H....
    12页
    查看更多>>摘要：? 2022 Elsevier B.V.A seedling-stage sand culture experiment and whole growth period pot experiment were conducted together to investigate the effects of chalcogenide elements (S, Se, Te) on the morphology, photosynthesis, Cd absorption, Cd and mineral nutrient transport, and transporter gene expression of wheat under Cd stress. Compared with S, Se and Te can alleviate wheat Cd toxicity and reduce Cd accumulation more efficiently. Compared with control conditions, S reduced the root Cd concentration by about 20 %, while SeIV and TeIV reduced the root Cd concentration by more than 60 % and the shoot Cd concentration by about 30 %. Chalcogens reduced Cd uptake by increasing root diameter (by about 50 %) and inhibiting lateral root formation under SeIV and TeIV treatments compared to Cd treatment alone. Moreover, chalcogens accelerated Cd efflux by up-regulating TaTM20, thereby reducing Cd accumulation. Meanwhile, chalcogens enhanced Cd isolation in the cell wall and vacuole, reduced the active Cd proportion by increasing synthesis of chelates, and improved wheat Cd tolerance. Spraying Se and Te increased both the photosynthetic rate and yield, while also improving mineral nutrient contents (including magnesium, calcium, zinc, iron, manganese, copper, and molybdenum contents) in wheat grains. Selenomethionine (SeMet) was more effective in reducing upper organ Cd reactivation and inhibiting Cd transport from upper organs to grains, which was able to reduce grain Cd content by 27 % in the 5 mg/kg Cd treatment. Additionally, SeIV and TeIV reduced grain Cd content by 14 % and 16 %, respectively; while SeVI increased Cd content by 11 %. The current study reveals the mechanism by which chalcogens alleviate Cd toxicity and reduce grain Cd accumulation, which provides valuable insights for safe wheat production despite Cd soil contamination.
      原文链接:
    • NSTL
    • Elsevier

    Genome-wide identification and functional analyses of heat shock transcription factors involved in heat and drought stresses in ryegrass

    Ma G.Shen J.Yu H.Huang X....
    13页
    查看更多>>摘要：? 2022 Elsevier B.V.Italian ryegrass (Lolium multiflorum) is one of the most important and widely cultivated cool-season forage and turfgrass around the world. Heat and drought are two key factors limiting its growth and distribution. Heat shock transcription factors (Hsfs) are important regulators involved in various abiotic stresses; however, how the Hsf family responds to heat and drought stresses and the roles of LmHsfs in heat and drought tolerance remain to be determined in Italian ryegrass. In the present study, 16 putative Hsf genes were identified by whole-genome bioinformatics analysis, including eight HsfAs, five HsfBs, and three HsfCs. The subcellular localization, physiological and biochemical characteristics, conserved domains, gene structure, and phylogenetic relationship of the Hsf family were systematically analyzed in silico. Gene expression profiling analyses revealed that all Hsfs were responsive to heat and drought stresses. Most Hsfs, including LmHsfA2, LmHsfA3, LmHsfA4, LmHsfA5, LmHsfA6, LmHsfA7, LmHsfA8, LmHsfB1, and LmHsfB2, were induced to the highest expression levels at 1 h of heat stress treatment, while the majority of LmHsfs were up-regulated with a peak at 10 d of drought stress treatment. Subsequently, the biological function of LmHsfA5 which was induced by both heat and drought stresses was analyzed. Heterologous overexpression of LmHsfA5 improved heat and drought tolerance in transgenic Arabidopsis. The qRT-PCR analysis showed that the expression of APX2 and HSP18.2 were significantly induced in LmHsfA5-overexpressing lines under both normal and heat stress conditions. What's more, yeast one-hybrid, dual-luciferase assay, and electrophoretic mobility shift assay exhibited that LmHsfA5 could bind to the promoters of LmHSP18.2 and LmAPX2 and induce their expression, indicating that LmHsfA5 may positively regulate heat and drought tolerance via directly activating the expression of LmHSP18.2 and LmAPX2 in ryegrass. This study provides a basis for further research on LmHsfs functions in abiotic stress.
      原文链接:
    • NSTL
    • Elsevier

    Differential effects of elevated atmosphere CO2 concentration on root growth in association with regulation of auxin and cytokinins under different nitrate supply

    Fan N.Yang Z.Hao T.Zhuang L....
    9页
    查看更多>>摘要：? 2022 Elsevier B.V.An extensive root system is one of the highly desirable traits for plant growth and adaptation to environmental stresses which is affected by the availability of atmosphere CO2 and nitrogen (N) nutrition. The objectives of this study were to examine the interactive effects of elevated CO2 and nitrogen on root growth and underlying regulatory mechanisms related to hormones metabolism in tall fescue (Festuca arundinacea). Plants (cv. ‘Barlexas’) were hydroponically grown in nutrient solution with low N (0.25 mM) and moderate N (4 mM) conditions and exposed to ambient CO2 concentration (400 μmol·mol?1) or elevated CO2 concentration (800 μmol·mol?1) for 35 days. Elevated CO2 differentially promoted root growth under different nitrate levels. The longest root length, root biomass and all types of roots including the length, number, volume and surface area of both crown and lateral roots were enhanced by elevated CO2 under moderate nitrate but without significant effects on crown root number under low nitrate condition. The extent of elevated CO2-promotion on lateral root was greater under moderate nitrate than that under low nitrate condition. The improvement of elevated CO2 on root growth under moderate nitrate condition was related with increased content of indoleacetic acid (IAA) and isopentenyl adenosine (iPA) through up-regulating genes in auxin synthesis, cytokinin synthesis and down-regulating cytokinin degradation gene. Our results indicated that elevated CO2 had differential promotive effects on crown and lateral root growth in tall fescue under low and moderate nitrate conditions in association with the regulation of endogenous auxin and cytokinin metabolism.
      原文链接:
    • NSTL
    • Elsevier