查看更多>>摘要：? 2022 Elsevier B.V.There is a pressing need to improve climate-resilient crops as a consequence of increasingly erratic climatic behavior that threatens global food security. Current scientific efforts aim to elucidate the complex mechanisms behind drought resistance in cultivated barley (Hordeum vulgare L ssp. vulgare). To develop new cultivars with enhanced tolerance to drought and ensure the well-being of the crop under adverse conditions. Understanding the impact of water stress on barley plants is a complex challenge due to the involvement of redundant regulatory pathways governed by multiple genes. Many of these pathways and associated major or genes controlling various morphological and physiological responses to drought at various stages of plant growth. Hence, a broad understanding of such molecular regulation is a key to developing barley cultivars with superior drought tolerance. In addition, changing breeding procedures to accommodate screening for drought responses is a major step. Justification of such changes should be based on expected outcomes. Our current understanding of drought regulatory pathways points out that improvement at both water extraction and its utilization are needed to elevate final yields under water deficit conditions. The current review is an in-depth review, that aims to develop a complete picture of the drought tolerance mechanisms in barley and to provide insights into the manipulation of drought stress responses in barley.
查看更多>>摘要：? 2022 Elsevier B.V.Plants are subjected to various environmental stresses that influence their growth, metabolism, productivity and survival. Nevertheless, plants respond to these stresses by inducing certain morpho-physiological, biochemical, molecular and genetic changes. Some of these changes conferring stress tolerance include the formation of cork/abscission layers and tyloses, gum deposition, synthesis of pathogenesis-related proteins, increased cell lignification and synthesis of signaling molecules. Phytomelatonin is a signaling molecule uniformly distributed in diverse plant parts and regulates physio-biochemical responses under abiotic and biotic stresses. It confers stress tolerance to plants by delaying leaf senescence, reducing photosynthetic inhibition, acting as a biostimulator and improving the antioxidant status. Studies have shown the positive effects of exogenously applied phytomelatonin for stress mitigation that leads to improved seed germination, plant growth, yield and chlorophyll content. Recent research has shown the hidden potential of phytomelatonin in plant tissue culture, wherein it can be used for the production of various stress enzymes and other organic compounds like silymarin. Herein, the review highlights the potential of phytomelatonin in plants along with its underlying mechanism of action to alleviate stress in plants. Also numerous crosstalks of phytomelatonin with other signaling molecules have been highlighted, including nitric oxide, reactive nitrogen species, calcium calmodulin and phytohormones to alleviate stress. It also provides detailed insight into the genetic regulation of stress tolerance in plants, along with brushing the-omics approach of phytomelatonin synthesis and functioning. The present review paves the path for detailed research on the development of transgenic and in-vitro aspect of phytomelatonin in the plant tissue culture.
查看更多>>摘要：? 2022 Elsevier B.V.Dear Editor in Chief, June 26, 2022 In the published version of this article, there were errors. In the text of the article in the materials and methods section (2.9. Quantitative real-time RT-PCR analysis), CAT should be changed to TUB. There were errors in 8th row of Table 2 and the corrected table appears below. The authors regret these errors and would like to apologise for any inconvenience caused.
查看更多>>摘要：? 2022 Elsevier B.V.Microbiome-based rhizospheric engineering has emerged as a promising approach towards attaining agricultural sustainability. While the top-down approach of acclimatizing the rhizospheric microbiome to stressors is relatively easy to perform, the mechanisms involved in plant growth promotion by directed evolution are yet to be understood. The present study aimed to understand the mechanism of stress management by a salt stress-acclimatized microbiome, generated through indirect plant-mediated selection over multiple plant (Vigna radiata) growth cycles, with a focus on the emission of volatile compounds. A culture bank was generated by isolation of bacterial strains from the stress-acclimatised microbiome, using group-specific media. Characterization of the strains was performed by examining their potential plant growth-promoting (PGP) traits followed by phylogenetic affiliation using 16S rRNA sequencing. The strains exhibited strong tolerance to salinity stress when grown on artificial root exudate medium and V8 medium, at different salt concentrations. Based on PGP scoring, the eleven best performing bacterial strains were assessed for their ability to impact plant morphology and growth attributes in a split plate assay allowing only volatile compounds to be exchanged, using Arabidopsis as a model plant. An alteration in the seedling morphology of Arabidopsis was observed due to the production of volatile bioactive compounds by some of the strains. To delineate the specific volatiles produced by the bacterial strains responsible for such an impact on Arabidopsis seedlings, the volatiles emitted by selected strains were collected and analyzed by GC-MS. A correlation could be drawn between the specific volatiles produced by key bacterial members of the acclimatized microbiome e.g. Bacillus haynesii, Pseudomonas monteilii and Ochrobactrum soli, and their contribution towards alleviation of salinity stress in A. thaliana. A detailed analysis of the volatilomes emitted by stress-acclimatized bacterial strains revealed the identity of crucial metabolites, for instance hydrocarbons like 7 methyl-hexadecane, 2-(2-butoxyethoxy) ethanol or sulfur containing volatiles, which could at least partially contribute to plant growth promotion and stress tolerance. This work opens up new avenues for rhizospheric engineering as a way towards more resilient and sustainable crop production.
查看更多>>摘要：? 2022 Elsevier B.V.Cytosolic K+ retention is an important determinant of salinity tolerance in many crops. However, it remains unclear whether this trait is also crucial for wild rice species. In this work, contrasting pairs of cultivated (Oryza sativa L.) and wild (Oryza alta; Oryza punctata) rice species were used to understand the mechanistic basis of salinity stress tolerance in rice and the role of K+ retention in this process. Non-invasive Microelectrode Ion Flux Measuring (MIFE) measurements showed that NaCl and ROS-induced K+ efflux from the elongation root zone were significantly (2–3-fold) higher in the wild rice species compared with their cultivated counterparts. Cultivated rice group showed relatively lower K+ efflux but greater H+ efflux in response to NaCl and ROS treatments. Pharmacological experiments revealed that tetraethylammonium chloride (TEA) and gadolinium chloride (GdCl3) markedly suppressed NaCl and ROS-induced K+ efflux (>80 % inhibition), suggesting the involvement of GORK and NSCC channels in stress-induced K+ efflux. Sodium orthovanadate suppressed H+ efflux (>90 % inhibition), suggesting the role of H+-ATPase as a major source in salt-induced H+ efflux in salt tolerant cultivars. Collectively, our results indicate that, while possessing high root K+ retention ability in the mature zone, wild rice species show higher sensitivity to NaCl and ROS in the elongation zone. It is suggested that stress-induced K+ efflux in this zone may operate as a “metabolic switch” by inhibiting energy consuming anabolic reactions and allowing energy to be saved for adaptations and repairs, which may provide an advantage to wild rice in conditions with high salinity.
查看更多>>摘要：? 2022 Elsevier B.V.The growth and production of fruit trees are adversely affected by heavy metal pollution in orchard lands. Plant metal homeostasis and resistance are regulated by metal tolerance proteins (MTP), which function as divalent cation transporters. To understand the possible role of MTPs in fruit trees, we identified 20 MdMTPs in the apple genome. Phylogenetic and collinear relationship analyses revealed that they belonged to Zn-MTP, Fe/Zn-MTP and Mn-MTP subfamilies, and have gone through two tandem and six segmental duplication events under purifying selection. All MdMTPs were predicted to form homodimer, with each monocase containing a conserved cation efflux domain (CED), the typical structural feature of MTP family, and one or two HXXXD or DXXXD residues. Further spatiotemporal expression analyses indicated that all MdMTP genes were ubiquitously expressed, and most of them were induced by at least three heavy metal ions, in roots, stems or leaves. Yeast and Arabidopsis mutant complementation experiments verified the function of MdMTP11.1 in response to heavy metal stress. Our findings provide an important genetic foundation for the functional elucidation of MdMTP genes, which can be used as the potential gene candidates for the breeding of new fruit tree cultivars with improved tolerance to heavy metal stress.
查看更多>>摘要：? 2022 Elsevier B.V.AtHB23 is a homeodomain-leucine zipper I transcription factor, previously characterized as a modulator of lateral root initiation and higher-order roots development. The role of this gene in response to salinity stress was largely unknown. To elucidate the role of AtHB23 in response to salinity stress, we combined histochemical β-glucuronidase (GUS) analysis, root phenotyping, starch staining, optic and transmission electron microscopy, expression studies by RT-qPCR, and transcriptome analysis of silenced, overexpressor, and crossed plants. We revealed that the expression pattern of AtHB23 is regulated by NaCl in the primary and lateral roots, affecting the root phenotype. A severe reduction in primary root length, a significant increment in the initiation of lateral roots, and a low survival rate in salinity conditions were observed in AtHB23-silenced plants, whereas AtHB23 overexpressors showed the opposite phenotype. These developmental defects were explained by the degradation of starch granules and an alteration in starch metabolism. The AtHB23-target gene LAX3 is repressed in the tip of the primary root and affected by NaCl. We conclude that the lack of AtHB23 severely compromises plant survival and adaptation to salt stress conditions because this gene mediates starch granule turnover.
查看更多>>摘要：? 2022Climate change produces more frequent and intense drought events during seed development that can affect seed quality. Germination is critical to ensure plant growth and reproductive success but it can be impacted by various abiotic stresses. Here, we studied the effect of drought stress during sunflower seed development on the germination of the progeny. We applied different scenarios of drought stress during seed development in sunflower inbred lines and hybrids and assessed seed germination of the progeny. Drought stress during seed development provided tolerance to water, hypoxic, cold and salt stresses during seed germination and also induced lower dormancy. We established that the induction of these traits was not transgenerational but maternally transmitted and could be reproduced in sunflower hybrids. Drought stress during seed development decreased pericarp thickness and induced higher leakage of soluble electrolytes from pericarp but it also modified embryo metabolism. A metabolomics analysis showed that ABA, oligosaccharides and polyphenols accumulated differently in drought stress seeds and could also participate in the seed tolerance to abiotic stress conditions during germination. Altogether our results reveal an adaptative process that allows sunflower plants exposed to drought stress during their reproductive stage to produce seeds with higher fitness. Besides bringing novel insight on natural adaption of plant populations to climate change, these results may have implications for the seed industry through the production of seeds resilient to higher climatic variability during the establishment of sunflower crop.
查看更多>>摘要：? 2022 Elsevier B.V.Haloxylon ammodendron is a typical desert xerophyte with worthy genetic resources, therefore, it is necessary to explore the resistance genes of H. ammodendron, and to improve the stress tolerance of other plant species through genetic engineering. In this study, a heat shock transcription factor gene, HaHSFA1, was firstly cloned from H. ammodendron and overexpressed in Arabidopsis thaliana. The sensitivity of transgenic plants to exogenous ABA, osmotic stress and salt stress were analyzed; the effects of overexpression of HaHSFA1 in Arabidopsis on salt tolerance were deeply investigated. The results indicated that overexpression of HaHSFA1 increased chlorophyll content in Arabidopsis, and the growth of plants was promoted. The leaf soluble sugar and proline contents in OE lines were significantly increased compared with those in WT. OE lines maintained lower osmotic potential and higher shoot water content. Overexpression of HaHSFA1 in Arabidopsis also enhanced antioxidant activity, which may be important for protecting plasma membrane integrity in cells. Overexpression of HaHSFA1 in Arabidopsis improved root activity and increased selective absorption and transport capacity for K+ over Na+, which was of great significance to reduce the toxic effect of Na+. This study indicated that overexpression of HaHSFA1 from H. ammodendron significantly elevates the salt tolerance of Arabidopsis, and HaHSFA1 has potential application values in improving abiotic stress tolerance in crops by genetic engineering.
查看更多>>摘要：? 2022 Elsevier B.V.Rice (Oryza sativa L.), being a high silicon (Si)-accumulator, is a major global food crop for more than half of the world's population. However, both salinity and drought, two of the most challenging abiotic stresses in rice-growing areas globally, threaten world food security. Both symbiosis with arbuscular mycorrhizal fungi (AMF) and supplementing paddy soils with Si have been shown to improve rice growth during drought and salinity-stress. However, their combined impact is poorly understood. AMF may absorb Si through their spores and hyphae and thus help accumulate root Si. In turn, Si can affect mycorrhizal responsiveness but the underlying mechanisms remain largely unknown. This review explores (i) how Si and AMF act to mitigate salinity and drought stress in rice plants and (ii) how they can be applied together. We also identify areas for future study and discuss how the combined presence of arbuscular mycorrhizas (AMs) and Si in paddy soils can generate more sustainable rice productivity.
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