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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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    Impact of heat and drought stresses on grain nutrient content in chickpea: Genome-wide marker-trait associations for protein, Fe and Zn

    Samineni, SrinivasanMahendrakar, Mahesh D.Shankar, NidhiHotti, Avinalappa...
    16页
    查看更多>>摘要：Chickpea is a cheap source of protein and micronutrients to the poor and vegetarian population living in southAsia and sub-Saharan Africa. Due to changes in climatic conditions and cropping systems, the crop is being exposed to severe drought and heat stress during its reproductive period, which leads to significant yield losses and fluctuations in grain nutrient accumulation. The study was conducted with 140 diverse genotypes under nonstress, drought, and heat stress conditions to estimate their effects on grain nutrient (protein, Fe and Zn) contents and identify the marker-trait associations. Analysis of variance revealed highly significant differences among genotypes for nutrient content under respective planting conditions. The seed yield was negatively associated with the grain Fe (r = -0.37, -0.25, 0.11) and Zn (r = -0.49, -0.35, -0.72) under respective planting conditions. The PCA indicated that PC1 was positively associated with grain Fe in non-stress and heat, while Zn in all planting conditions, whereas PC2 was positively influenced by protein content followed by grain yield. Cluster analysis identified eight clusters, of which cluster VI showed maximum cluster means for Fe (73 mg kg-1) and Zn (48.1 mg kg-1). The Genome-wide association study revealed, a total of 181 MTAs for grain Fe, Zn, and protein content in all three growing conditions. A total of 4, 2, and 48 SNPs for grain Fe and Zn content, whereas, 66, 46, 15 SNPs for grain protein content have shown significant association under non-stress, drought, and heat stress, respectively. One SNP each on chr1 (S1_35622241; P < 3.47 x10-6) and chr4 (S4_44607232; P < 1.35 x10-5) was co-associated under drought and non-stress conditions for protein and Fe, respectively. The identified robust MTAs will be validated and used in marker-assisted selection towards the rapid development of nutrient-rich varieties.
      原文链接:
    • NSTL
    • Elsevier

    The transcription factor GmbHLH3 confers Cl-/salt tolerance to soybean by upregulating GmCLC1 expression for maintenance of anion homeostasis

    Liu, XunPi, BoyiDu, ZiyiYang, Teng...
    13页
    查看更多>>摘要：Chloride channels (CLCs)-mediated anion homeostasis plays a crucial role for plants to adapt to Cl-/salt stress; however, the transcriptional regulation of CLCs gene expression in response to Cl-/salt stress is not understood to date. Here, a novel bHLH transcription factor, GmbHLH3, upstream of the GmCLC1 gene, was identified by gene co-expression network analysis. GmbHLH3 localizes to the nucleus and can bind to the G-box at position 550 of GmCLC1 promoter to up-regulate its expression. GmbHLH3-overexpressed soybean hairy root-composite plants and transgenic Arabidopsis exhibited enhanced tolerance to Cl-/salt stress, which was reflected by plant growth phenotype, leaf dead cells, cell membrane damage and lipid peroxidation, and Arabidopsis seed germination. NaCl-treated GmbHLH3-overexpressed soybean plants displayed up-regulated GmCLC1 expression, higher accumulation of Cl- and NO3- in roots for restricting the transport to shoots, and thus maintaining lower Cl-/NO3- ratio in whole plants. Similar effects of GmbHLH3 on the tissue distribution of Cl- and NO3-, and maintenance of anion homeostasis were further verified in transgenic Arabidopsis plants. These findings provide a valuable theoretical basis for further exploration of the transcriptional regulatory molecular networks of plant CLC family members in response to Cl- toxicity under salt stress, as well as seeking molecular genetic improvement approaches for Cl-/salt tolerance in soybean and other crops.
      原文链接:
    • NSTL
    • Elsevier

    Drought deteriorated the nutritional quality of cottonseed by altering fatty acids and amino acids compositions in cultivars with contrasting drought sensitivity

    Li, YuxiaZou, JieZhu, HonghaiHe, Jiaqi...
    13页
    查看更多>>摘要：Cottonseed is an excellent source of vegetable oil and plant protein for food industry due to its natural ability of high oil and protein content. This study is designed to examine the influence of drought stress on the yield and quality of cottonseed kernels. Cottonseed yield and kernel yield per plant, as well as oil yield and protein yield, were significantly decreased under drought. The oil concentration (%/dry weight) decreased, but protein concentration (%/dry weight) increased significantly in response to drought. Total unsaturated fatty acids (UFA) and total essential amino acids (EAA) concentrations decreased notably under severe drought. Moreover, the decrease of polyunsaturated to saturated fatty acids ratio (PUFA/SFA), health-promoting index (HPI), unsaturation index (UI), and the increased atherogenicity index (AI), indicated the lower unsaturation of fatty acids which induced an unhealthy oil under drought stress. Otherwise, the variations of essential amino acids index (EAAI), nutritional value (NI), score ratio coefficient of amino acid (SRC) and biological value (BV) forecasted a diminished amino acids quality under drought stress. Results suggested that drought stress decreased cottonseed yield and deteriorated cottonseed nutritional values. The present research is a leading report describing the influences of drought on the nutritional quality indices in cottonseed. In addition, this study contributes to understanding the response of cottonseed nutritional value to soil moisture stress.
      原文链接:
    • NSTL
    • Elsevier

    Elevated CO2 and high endogenous ABA level alleviate PEG-induced short-term osmotic stress in tomato plants

    Li, ShenglanWang, XiziLiu, XiaojuanThompson, Andrew J....
    16页
    查看更多>>摘要：Elevated CO2 concentration (e[CO2]) alleviates the impact of drought stress on plants where abscisic acid (ABA) is involved. To explore the mechanisms by which tomato plants respond to short-term osmotic stress, Solanum lycopersicum cv. Ailsa Craig (AC), a transgenic line overproducing ABA (sp5), and an ABA-deficient mutant (flacca) were hydroponically grown under ambient CO2 (400 ppm) and e[CO2] (800 ppm) and then exposed to 10% or 15% (w/v) polyethylene glycol (PEG) 6000 for 24 h before transferring to PEG-free nutrient solution for 24 h. Under non-stress condition, e[CO2] decreased root hydraulic conductance (K-root), which was overridden by high endogenous ABA in sp5 through increasing specific leaf area and root branching intensity. Basically, e[CO2] improved stress resistance through enhanced water status. PEG stress decreased stomatal conductance and osmotic potential in AC but these effects were less pronounced in sp5, which exhibited a stronger osmotic adjustment (OA) and improved plant fitness. A greater flexibility of hydraulic system and a reduced sensitivity of K-root to ABA might confer sp5 a great ability to recover from PEG stress. On the contrary, high stomatal density, size and pore aperture offlacca rendered plants suffering severe stress. Moreover, the premise that PEG stress could mimic soil water deficit was the sufficient achievement of OA. Our results indicate that e[CO2] and high endogenous ABA level could improve osmotic stress resistance in tomato plants via osmotic and hydraulic adjustments.
      原文链接:
    • NSTL
    • Elsevier

    Chrysanthemum lavandulifolium homolog ClMAD1 modulates the floral transition during temperature shift

    Zhang, XinyiZhang, PengWang, GeBao, Zhilong...
    15页
    查看更多>>摘要：Flower initiation and development in chrysanthemum requires accurate cell division and expansion, which are regulated by a complex network involved with many cell cycle regulators. Mitotic arrest deficiency 1 (MAD1) is a key component of spindle assembly checkpoint, which was reported to regulate floral transition in Arabidopsis through the interaction with Suppressor of FRIGIDA 4 (SUF4) to modulate Flowering Locus C (FLC) transcription. So far, no MAD1, SUF4 and FLC ho-mologous genes, and related studies were reported in chrysanthemum. Here we first isolated and clone ClMAD1 and ClSUF4 homologs in Chrysanthemum lav-andulifolium. Both ClMAD1 and ClSUF4 localized in nuclei, and their expression varied in different tissues. Overexpression of ClMAD1 in Arabidopsis promoted endopolyploidization in leaves, and restored cell cycle and flowering phenotypes of mad1 mutants to different extents. Overexpression of ClSUF4 in Arabidopsis resulted in significantly late flowering, which was correlated with enhanced transcription of FLC and reduced transcription of FT gene. ClMAD1 was predicted to have three coiled-coil (CC) domains, which is one more than that in Arabidopsis. Similar to AtSUF4, ClSUF4 was predicted to have two Zn-C2H2 domains. Protein-protein interaction assays revealed that ClSUF4 could interact with AtMAD1, and the third coiled-coil domain of ClMAD1 not the full-length protein. All these data suggest that both ClMAD1 and ClSUF4 are functional homologs. We further isolated their downstream signaling component ClFLC-like (ClFLCl) genes. ClFLCl had high expression in leaves at vegetative growth stage, and significantly reduced after the bolting suggesting a negative role in the floral transition. Long-term cold treatment significantly repressed the transcription of ClFLCl genes. Temperature shift promoted floral transition of chrysanthemum, which is correlated with the fluctuation of ClMAD1, ClSUF4 and ClFLCl transcription. Taken together, we reported a novel machinery on the regulation of floral transition in chrysanthemum that ClMAD1 interacts with ClSUF4 to modulate ClFLCl-mediated floral transition during the temperature shift.
      原文链接:
    • NSTL
    • Elsevier

    Potassium mitigates salt-stress impacts on photosynthesis by alleviation of the proton diffusion potential in thylakoids

    Che, YanhuiFan, DayongWang, ZihanXu, Nan...
    12页
    查看更多>>摘要：Addition of K+ improves the tolerance of the photosynthetic apparatus to salt stress, but the primary, underlying mechanism is unclear, prompting our study. The main aim of this study was to elucidate the primary mechanism by which supplemental K+ alleviates the effects of salinity stress on photosynthetic parameters in mulberry seedlings. K+ contents in leaves and chloroplasts, plasma-membrane ATPase activity, photosynthetic properties and expression of genes encoding photosynthetic proteins and ion channels/transporters were measured. K+ addition during salt stress improved H+-ATPase activity in plasma-membranes, restored photosynthetic linear and cyclic electron flow, restored the activity of key Photosystem I (PSI) and PSII proteins, and increased darkadapted PSII photochemical yield F-v/F-m, while reducing non-photochemical quenching. Among the genes encoding ion channels/transporters, that of the Two-Pore-K+ channel in thylakoid membranes (TPK3) was notably responsive to NaCl/K+ treatments: relative to the control (CK) treatment, it decreased slightly in the CK+K treatment, but increased in the NaCl treatment and increased further in the NaCl+K treatment. The above observations are consistent with our hypothesis that K+ supplementation in salt stress restores a high stromal [K+] which, by utilizing TPK3, minimizes a transient, proton diffusion potential that otherwise develops as protons exit the thylakoid lumen through the ATP synthase; thus, rapid charge compensation by K+ movement accelerates both the proton efflux from the lumen and the associated ATP synthesis to enhance carbon assimilation, thereby improving linear as well as cyclic electron flow. The hypothesis pinpoints the primary physicochemical mechanism by which potassium mitigates salt-stress impacts on photosynthesis. It rationalizes both the existence of a K+ channel in thylakoid membranes and the maintenance of a high stromal [K+].
      原文链接:
    • NSTL
    • Elsevier