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Authors: Mingjuan Zhai, Yating Chen, Xiaowu Pan, Ying Chen, Jiahao Zhou, Xiaodan Jiang, Zhijin Zhang, Guiqing Xiao and Haiwen Zhang.
Plant, Cell & Environment (2024)
One-sentence summary: The OsEIN2-OsEIL1/2 ethylene pathway has negative effect on rice tolerance to low temperature stress through transcriptionally repressing OsICE1-mediated chilling response.
Abstract: "Low temperature severely affects rice development and yield. Ethylene signal is essential for plant development and stress response. Here, we reported that the OsEIN2-OsEIL1/2 pathway reduced OsICE1-dependent chilling tolerance in rice. The overexpressing plants of OsEIN2, OsEIL1 and OsEIL2 exhibited severe stress symptoms with excessive reactive oxygen species (ROS) accumulation under chilling, while the mutants (osein2 and oseil1) and OsEIL2-RNA interference plants (OsEIL2-Ri) showed the enhanced chilling tolerance. We validated that OsEIL1 and OsEIL2 could form a heterodimer and synergistically repressed OsICE1 expression by binding to its promoter. The expression of OsICE1 target genes, ROS scavenging- and photosynthesis-related genes were downregulated by OsEIN2 and OsEIL1/2, which were activated by OsICE1, suggesting that OsEIN2-OsEIL1/2 pathway might mediate ROS accumulation and photosynthetic capacity under chilling by attenuating OsICE1 function. Moreover, the association analysis of the seedling chilling tolerance with the haplotype showed that the lower expression of OsEIL1 and OsEIL2 caused by natural variation might confer chilling tolerance on rice seedlings. Finally, we generated OsEIL2-edited rice with an enhanced chilling tolerance. Taken together, our findings reveal a possible mechanism integrating OsEIN2-OsEIL1/2 pathway with OsICE1-dependent cascade in regulating chilling tolerance, providing a practical strategy for breeding chilling-tolerant rice."
Authors: Chong Yang, Huihui Wang, Qiqi Ouyang, Guo Chen, Xiaoyu Fu, Dianyun Hou and Huawei Xu.
Plants (2023)
Abstract: "Significant progress has been made in the functions of auxin efflux transporter PIN-FORMED (PIN) genes for the regulation of growth and development in rice. However, knowledge on the roles of OsPIN genes in abiotic stresses is limited. We previously reported that the mutation of OsPIN1b alters rice architecture and root gravitropism, while the role of OsPIN1b in the regulation of rice abiotic stress adaptations is still largely elusive. In the present study, two homozygous ospin1b mutants (C1b-1 and C1b-2) were employed to investigate the roles of OsPIN1b in regulating abiotic stress adaptations. Low temperature gradually suppressed OsPIN1b expression, while osmotic stress treatment firstly induced and then inhibited OsPIN1b expression. Most OsPIN genes and auxin biosynthesis key genes OsYUC were up-regulated in ospin1b leaves, implying that auxin homeostasis is probably disturbed in ospin1b mutants. The loss of function of OsPIN1b significantly decreased rice chilling tolerance, which was evidenced by decreased survival rate, increased death cells and ion leakage under chilling conditions. Compared with the wild-type (WT), ospin1b mutants accumulated more hydrogen peroxide (H2O2) and less superoxide anion radicals (O−2) after chilling treatment, indicating that reactive oxygen species (ROS) homeostasis is disrupted in ospin1b mutants. Consistently, C-repeat binding factor (CBF)/dehydration-responsive element binding factor (DREB) genes were downregulated in ospin1b mutants, implying that OsDREB genes are implicated in OsPIN1b-mediated chilling impairment. Additionally, the mutation of OsPIN1b led to decreased sensitivity to abscisic acid (ABA) treatment in seed germination, impaired drought tolerance in the seedlings and changed expression of ABA-associated genes in rice roots. Taken together, our investigations revealed that OsPIN1b is implicated in chilling and drought tolerance in rice and provide new insight for improving abiotic stress tolerance in rice."
Authors: Junhong Guo, Gerrit T. S. Beemster, Fulai Liu, Zongming Wang and Xiangnan Li.
International Journal of Molecular Sciences (2023
Abstract: "Abscisic acid (ABA) plays a vital role in the induction of low temperature tolerance in plants. To understand the molecular basis of this phenomenon, we performed a proteomic analysis on an ABA-deficit mutant barley (Az34) and its wild type (cv Steptoe) under control conditions (25/18 °C) and after exposure to 0 °C for 24 h. Most of the differentially abundant proteins were involved in the processes of photosynthesis and metabolisms of starch, sucrose, carbon, and glutathione. The chloroplasts in Az34 leaves were more severely damaged, and the decrease in Fv/Fm was larger in Az34 plants compared with WT under low temperature. Under low temperature, Az34 plants possessed significantly higher activities of ADP-glucose pyrophosphorylase, fructokinase, monodehydroascorbate reductase, and three invertases, but lower UDP-glucose pyrophosphorylase activity than WT. In addition, concentrations of proline and soluble protein were lower, while concentration of H2O2 was higher in Az34 plants compared to WT under low temperature. Collectively, the results indicated that ABA deficiency induced modifications in starch and sucrose biosynthesis and sucrolytic pathway and overaccumulation of reactive oxygen species were the main reason for depressed low temperature tolerance in barley, which provide novel insights to the response of barley to low temperature under future climate change."
Authors: Jingyu Zhang, Yuhao Cao, Jia Tang, Xujie He, Ming Li, Chen Li, Xiaolin Ren and Yuduan Ding.
Horticulturae (2023)
Abstract: "Gibberellins (GAs) are plant hormones indispensable in regulating the growth and development of fruits. Recent studies have shown that GAs play important roles in delaying horticultural crop ripening and senescence, enhancing the internal and external quality of horticultural crops and resistance to stress and disease. We reviewed the role of GAs in the postharvest physiology of fruits in recent years. GAs are closely related to their ability to retard fruit senescence. GAs could effectively improve fruit storage quality and significantly increase flesh hardness, reduce respiration intensity, inhibit the release of endogenous ethylene, and effectively inhibit fruit softening and ripening. It can also improve the intrinsic and extrinsic quality of fruit storage by improving fruit shape, regulating color, delaying the reduction of soluble solids, promoting sugar accumulation, and delaying vitamin loss. GAs also play a role in postharvest biotic and abiotic stress resistance. The GA treatment effectively reduces the cold damage index, reduces the production and accumulation of superoxide anion(O2−), improves the antioxidant capacity of fruits, and maintains the integrity of cell membranes during low-temperature storage. Moreover, GAs could effectively control some postharvest fruit diseases. In conclusion, GAs play an important role in the physiological regulation of postharvest fruits and have important application prospects in postharvest fruits."
Authors: Junhong Guo, Hongyan Wang, Shengqun Liu, Yongjun Wang, Fulai Liu and Xiangnan Li.
Functional Plant Biology (2022)
Abstract: "Low temperature is one of the major environmental stresses that limit crop growth and grain yield in wheat (Triticum aestivum L.). Drought priming at the vegetative stage could enhance wheat tolerance to later cold stress; however, the transgenerational effects of drought priming on wheat offspring’s cold stress tolerance remains unclear. Here, the low temperature responses of offspring were tested after the parental drought priming treatment at grain filling stage. The offspring plants from parental drought priming treatment had a higher abscisic acid (ABA) level and lower osmotic potential (Ψo) than the control plants under cold conditions. Moreover, parental drought priming increased the antioxidant enzyme activities and decreased hydrogen peroxide (H2O2) accumulation in offspring. In comparison to control plants, parental drought priming plants had a higher ATP concentration and higher activities of ATPase and the enzymes involved in sucrose biosynthesis and starch metabolism. The results indicated that parental drought priming induced low temperature tolerance in offspring by regulating endogenous ABA levels and maintaining the redox homeostasis and the balance of carbohydrate metabolism, which provided a potential approach for cold resistant cultivation in wheat."
Authors: Huawei Xu, Xiaoyi Yang, Yanwen Zhang, Huihui Wang, Shiyang Wu, Zhuoyan Zhang, Golam Jalal Ahammed, Chunzhao Zhao and Hao Liu.
Frontiers in Plant science (2022)
Abstract: "Phytohormone auxin plays a vital role in plant development and responses to environmental stresses. The spatial and temporal distribution of auxin mainly relies on the polar distribution of the PIN-FORMED (PIN) auxin efflux carriers. In this study, we dissected the functions of OsPIN9, a monocot-specific auxin efflux carrier gene, in modulating chilling tolerance in rice. The results showed that OsPIN9 expression was dramatically and rapidly suppressed by chilling stress (4°C) in rice seedlings. The homozygous ospin9 mutants were generated by CRISPR/Cas9 technology and employed for further research. ospin9 mutant roots and shoots were less sensitive to 1-naphthaleneacetic acid (NAA) and N-1-naphthylphthalamic acid (NPA), indicating the disturbance of auxin homeostasis in the ospin9 mutants. The chilling tolerance assay showed that ospin9 mutants were more tolerant to chilling stress than wild-type (WT) plants, as evidenced by increased survival rate, decreased membrane permeability, and reduced lipid peroxidation. However, the expression of well-known C-REPEAT BINDING FACTOR (CBF)/DEHYDRATION-RESPONSIVE ELEMENT-BINDING PROTEIN 1 (DREB)-dependent transcriptional regulatory pathway and Ca2+ signaling genes was significantly induced only under normal conditions, implying that defense responses in ospin9 mutants have probably been triggered in advance under normal conditions. Histochemical staining of reactive oxygen species (ROS) by 3′3-diaminobenzidine (DAB) and nitroblue tetrazolium (NBT) showed that ospin9 mutants accumulated more ROS than WT at the early stage of chilling stress, while less ROS was observed at the later stage of chilling treatment in ospin9 mutants. Consistently, antioxidant enzyme activity, including catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), improved significantly during the early chilling treatments, while was kept similar to WT at the later stage of chilling treatment, implying that the enhanced chilling tolerance of ospin9 mutants is mainly attributed to the earlier induction of ROS and the improved ROS scavenging ability at the subsequent stages of chilling treatment. In summary, our results strongly suggest that the OsPIN9 gene regulates chilling tolerance by modulating ROS homeostasis in rice."
Authors: Yanglin Ding and Shuhua Yang.
Developmental Cell (2022)
Abstract: "The dramatic temperature fluctuations spurred by climate change inhibit plant growth and threaten crop productivity. Unraveling how plants defend themselves against temperature-stress-induced cellular impairment is not only a crucial fundamental issue but is also of critical importance for agricultural sustainability and food security. Here, we review recent developments in elucidating the molecular mechanisms used by plants to sense and respond to cold and heat stress at multiple levels. We also describe the trade-off between plant growth and responses to high and low temperatures. Finally, we discuss possible strategies that could be used to engineer temperature-stress-tolerant, high-yielding crops."
Authors: Yang Zhang, Ruhong Ming, Madiha Khan, Yue Wang, Bachar Dahro, Wei Xiao, Chunlong Li and Ji-Hong Liu.
Plant Biotechnology Journal (2022)
Abstract: "Plant ethylene-responsive factors (ERFs) play essential roles in cold stress response, but the molecular mechanisms underlying this process remain poorly understood. In this study, we characterized PtrERF9 from trifoliate orange (Poncirus trifoliata (L.) Raf.), a cold-hardy plant. PtrERF9 was up-regulated by cold in an ethylene-dependent manner. Overexpression of PtrERF9 conferred prominently enhanced freezing tolerance, which was drastically impaired when PtrERF9 was knocked down by virus-induced gene silencing. Global transcriptome profiling indicated that silencing of PtrERF9 resulted in substantial transcriptional reprogramming of stress-responsive genes involved in different biological processes. PtrERF9 was further verified to directly and specifically bind with the promoters of glutathione S-transferase U17 (PtrGSTU17) and ACC synthase1 (PtrACS1). Consistently, PtrERF9-overexpressing plants had higher levels of PtrGSTU17 transcript and GST activity, but accumulated less ROS, whereas the silenced plants showed the opposite changes. Meanwhile, knockdown of PtrERF9 decreased PtrACS1 expression, ACS activity and ACC content. However, overexpression of PtrERF9 in lemon, a cold-sensitive species, caused negligible alterations of ethylene biosynthesis, which was attributed to perturbed interaction between PtrERF9, along with lemon homologue ClERF9, and the promoter of lemon ACS1 gene (ClACS1) due to mutation of the cis-acting element. Taken together, these results indicate that PtrERF9 acts downstream of ethylene signaling and functions positively in cold tolerance via modulation of ROS homeostasis by regulating PtrGSTU17. In addition, PtrERF9 regulates ethylene biosynthesis by activating PtrACS1 gene, forming a feedback regulation loop to reinforce the transcriptional regulation of its target genes, which may contribute to the elite cold tolerance of Poncirus trifoliata."
Authors: Pingping Fang, Yu Wang, Mengqi Wang, Feng Wang, Cheng Chi, Yanhong Zhou, Jie Zhou, Kai Shi, Xiaojian Xia, Christine Helen Foyer and Jingquan Yu.
Antioxidants (2021)
Abstract: "Brassinosteroids (BRs) play a critical role in plant responses to stress. However, the interplay of BRs and reactive oxygen species signaling in cold stress responses remains unclear. Here, we demonstrate that a partial loss of function in the BR biosynthesis gene DWARF resulted in lower whilst overexpression of DWARF led to increased levels of C-REPEAT BINDING FACTOR (CBF) transcripts. Exposure to cold stress increased BR synthesis and led to an accumulation of brassinazole-resistant 1 (BZR1), a central component of BR signaling. Mutation of BZR1 compromised the cold- and BR-dependent increases in CBFs and RESPIRATORY BURST OXIDASE HOMOLOG 1(RBOH1) transcripts, as well as preventing hydrogen peroxide (H2O2) accumulation in the apoplast. Cold- and BR-induced BZR1 bound to the promoters of CBF1, CBF3 and RBOH1 and promoted their expression. Significantly, suppression of RBOH1 expression compromised cold- and BR-induced accumulation of BZR1 and related increases in CBF transcripts. Moreover, RBOH1-dependent H2O2 production regulated BZR1 accumulation and the levels of CBF transcripts by influencing glutathione homeostasis. Taken together, these results demonstrate that crosstalk between BZR1 and reactive oxygen species mediates cold- and BR-activated CBF expression, leading to cold tolerance in tomato (Solanum lycopersicum)."
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Authors: Junduo Li, Kai Lv, Jieping Wu, Yaping Xie, Junxia Zhang, Ningbo Zhang and Weirong Xu.
Journal of Agricultural and Food Chemistry (2023)
Abstract: "Melatonin (MEL) is an antioxidant molecule that enhances plant tolerance to environmental stress. However, the mechanisms by which MEL regulates cold signaling pathways in grapes under cold stress remain elusive. Here, we investigated the physiological and transcriptomic changes in grape seedlings treated with exogenous MEL to determine their protective role under cold stress. Results showed that 150 μM MEL effectively attenuated cold-induced cell damage by reducing reactive oxygen species (ROS) and preserving the chloroplast structure and function. MEL also inhibited tannin degradation, which contributed to its protective effect. Exogenous MEL promoted the synthesis of endogenous MEL, abscisic acid, auxin, and cytokinin while inhibiting gibberellin. Transcriptomic profiling revealed 776 differentially expressed transcripts in MEL-treated samples compared to controls. Functional analysis of a candidate hub gene, VvHSFA6b, showed that its overexpression in grape calli enhances cold tolerance by activating jasmonic acid synthesis pathway genes, promoting JA accumulation, and inhibiting JAZ-repressed transcription factors."
Authors: Jingqiu Xia, Jiawen Liang, Mengmeng Yu, Rui Wang, Chen Sun, Huishan Song, Qinghua Xu, Jing Cang, Yuying Wang and Da Zhang.
Environmental and Experimental Botany (2024)
Highlights • TaMED25 is involved in JA signal pathway. • TaMED25 expression responded to low temperature stress in wheat. • Overexpression of TaMED25 gene enhances freeze resistance in Arabidopsis plants. • TaMED25 is localized in the nucleus. • TaMED25 interacts with TaJAZ7, TaMYC2 and TaICE41 proteins.
Abstract: "The MEDIATOR (MED) complex is a molecular bridge that regulates transcription by connecting transcription factors (TFs) and specific gene promoters. The MED subunit 25 (MED25) can interact with specific TFs in the phytohormone signaling pathways to regulate the transcription of downstream genes and affect various physiological processes in plants. Although MED25 plays an important role in adaptation to abiotic stresses, it is still unclear whether MED25 is involved in freezing tolerance in wheat. In this study, we found that the expression of TaMED25 was significantly increased under extremely low temperatures (–25 °C) in Dongnongdongmai1 (Dn1) plants, a variety of winter wheat with excellent cold-stress resistance,and hypothesized that TaMED25 may be a novel regulator of freezing tolerance in this wheat variety. To further characterize the function of TaMED25 in freezing tolerance, we cloned TaMED25 from Dn1 plants and overexpressed it in Arabidopsis thaliana. The results showed that the overexpression of TaMED25 improved freezing tolerance in Arabidopsis plants, with decreased relative conductivity, enhanced ability to effectively scavenge reactive oxygen species (ROS), and increased expression of cold-responsive genes. Furthermore, we proposed that TaMED25 mediates jasmonate-induced cold resistance in plants, possibly by interacting with TaJAZ7 and TaMYC2 of the jasmonate signaling pathway and TaICE41 of the ICE–CBF–COR pathway. Our findings reveal the functions of MED25 in plants and provide a scientific basis for an in-depth analysis of the transcriptional regulation mechanism of freezing tolerance in winter wheat."
Authors: Jieyang Jin, Mingyue Zhao, Tingting Jing, Jingming Wang, Mengqian Lu, Yuting Pan, Wenkai Du, Chenjie Zhao, Zhijie Bao, Wei Zhao, Xiaoyan Tang, Wilfried Schwab and Chuankui Song.
Plant Physiology (2023)
Abstract: "Cold and drought stresses severely limit crop production and can occur simultaneously. Although some transcription factors and hormones have been characterized in plants subjected each stress, the role of metabolites, especially volatiles, in response to cold and drought stress exposure is rarely studied due to lack of suitable models. Here, we established a model for studying the role of volatiles in tea (Camellia sinensis) plants experiencing cold and drought stresses simultaneously. Using this model, we showed that volatiles induced by cold stress promote drought tolerance in tea plants by mediating reactive oxygen species and stomatal conductance. Needle trap micro-extraction combined with GC-MS identified the volatiles involved in the crosstalk and showed that cold-induced (Z)-3-hexenol improved the drought tolerance of tea plants. In addition, silencing CsADH2 (Camellia sinensis alcohol dehydrogenase 2) led to reduced (Z)-3-hexenol production and significantly reduced drought tolerance in response to simultaneous cold and drought stress. Transcriptome and metabolite analyses, together with plant hormones comparison and abscisic acid (ABA) biosynthesis pathway inhibition experiments, further confirmed the roles of ABA in (Z)-3-hexenol-induced drought tolerance of tea plants. (Z)-3-hexenol application and gene silencing results supported the hypothesis that (Z)-3-hexenol plays a role in the integration of cold and drought tolerance by stimulating the dual function glucosyltransferase UGT85A53, thereby altering ABA homeostasis in tea plants. Overall, we present a model for studying the roles of metabolites in plants under multiple stresses and reveal the roles of volatiles in integrating cold and drought stresses in plants."
Authors: Lihui Wang, Bo Wu, Guoyu Chen, Hui Chen, Yuquan Peng, Hamza Sohail, Shouyu Geng, Guangbao Luo, Dandi Xu, Bo Ouyang and Zhilong Bie.
Horticulture Research (2023)
Abstract: "Tomato (Solanum lycopersicum) is among the most important vegetables across the world, but cold stress usually affects its yield and quality. The wild tomato species Solanum habrochaites is commonly utilized as rootstock for enhancing resistance against abiotic stresses in cultivated tomato, especially cold resistance. However, the underlying molecular mechanism remains unclear. In this research, we confirmed that S. habrochaites rootstock can improve the cold tolerance of cultivated tomato scions, as revealed by growth, physiological, and biochemical indicators. Furthermore, transcriptome profiling indicated significant differences in the scion of homo- and heterografted seedlings, including substantial changes in jasmonic acid (JA) biosynthesis and signaling, which were validated by RT–qPCR analysis. S. habrochaites plants had a high basal level of jasmonate, and cold stress caused a greater amount of active JA-isoleucine in S. habrochaites heterografts. Moreover, exogenous JA enhanced while JA inhibitor decreased the cold tolerance of tomato grafts. The JA biosynthesis-defective mutant spr8 also showed increased sensitivity to cold stress. All of these results demonstrated the significance of JA in the cold tolerance of grafted tomato seedlings with S. habrochaites rootstock, suggesting a future direction for the characterization of the natural variation involved in S. habrochaites rootstock-mediated cold tolerance."
Authors: Tao Liu, Yuqing Han, Jiali Shi, Adan Liang, Dongdong Xu, Xueling Ye and Hongyan Qi.
Environmental and Experimental Botany (2022)
Highlights • Exogenous trehalose triggers endogenous ABA levels. • ABA are involved in exogenous Tre-alleviated melon oxidative stress damage. • ABA participate in the Tre-regulated maintenance of cell integrity and function under cold stress.
Abstract: "Melon is a thermophilic vegetable crop with high economic benefits. Cold stress is often encountered in the growth period of melon seedlings in early spring and limits the normal growth and development of seedlings. Exogenous trehalose (Tre) is a green and healthy sugar, known as the ‘sugar of life’, and has a significant role in regulating crop cold tolerance. In this study, we explored whether exogenous Tre induced abscisic acid (ABA) signal involved in regulating melon photosynthesis under cold tolerance and clarified the associated regulatory mechanism. Melon seedlings were pre-treated with nordihydroguaiaretic acid (NDGA), a synthetic inhibitor of the key enzyme 9-cis-epoxycarotenoid dioxygenase for ABA synthesis, followed by spraying with exogenous Tre and then treated with normal temperature or cold stress. Results showed that exogenous Tre induced the up-regulation of CmNCED3 gene expression and increase in ABA level under normal temperature conditions. Cold stress treatment significantly caused leaf membrane lipid peroxidation damage; reduced relative water content, net photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency and the spongy ratio of leaves; caused chloroplast structure damage. The use of NDGA in inhibiting the synthesis of endogenous ABA further aggravated the damages compared with cold treatment alone. Exogenous Tre treatment alleviated the inhibitory effects of cold stress and NDGA and maintained relatively normal cell morphology structure and photosynthesis. Therefore, we speculate that exogenous Tre pretreatment increases the level of endogenous ABA by up-regulating the expression of the CmNCED3 gene and triggers the defence system of melon plants. Under cold stress, cell membrane lipid peroxidation damage in the melon seedlings was significantly reduced by Tre treatment. Meanwhile, the absorption and utilisation of water maintained the relative integrity of the structure and function of mesophyll cells and chloroplasts, thereby reducing the inhibitory effect of cold stress on plant photosynthesis. In conclusion, ABA participates in exogenous Tre-enhanced melon oxidative stress tolerance and alleviation of cell morphology structure damage, which combined to improve melon cold tolerance and photosynthesis."
Authors: Fei Ding, Chuang Wang, Shuoxin Zhang and Meiling Wang.
Scientia Horticulturae (2022)
Highlights: • JA and cold promote the expression of SlGSTU24. • JA increases SlGSTU24 expression and cold tolerance. • Suppression of MYC2 reduces SlGSTU24 expression and cold tolerance. • JA-upregulated SlGSTU24 attenuates cold-triggered oxidative stress.
Abstract: "Cold stress inhibits growth, reduces productivity and deteriorates fruit quality in tomato (Solanum lycopersicum). It is thus of critical importance to elucidate the mechanisms by which tomato plants respond to cold stress. Jasmonates (JAs) are a group of phytohormones crucial for plant growth, development and stress responses. However, the role of JA and the mode of actions in the cold response in tomato plants remain largely unknown. Here, we report a JA-responsive glutathione S-transferase gene SlGSTU24 that functions to alleviate cold stress in tomato. We found that SlGSTU24 was ubiquitously expressed in all examined tissues and was responsive to both JA and cold stress. Knockdown of SlGSTU24 via an approach of VIGS (virus-induced gene silencing) aggravated cold-induced damages, as evidenced by enhanced ROS (Reactive Oxygen Species) accumulation, MDA (malondialdehyde) content and electrolyte leakage. Application of MeJA prominently increased the expression of SlGSTU24, with concomitant decreases in MDA content as well as electrolyte leakage in tomato leaves under cold conditions. In contrast, blocking JA biosynthesis using DIECA dramatically suppressed the expression of SlGSTU24 and elevated MDA content and electrolyte leakage. Furthermore, JA-regulated SlGSTU24 expression was dependent on SlMYC2, a crucial regulator of JA signaling pathway. Knockdown of SlMYC2 profoundly decreased the expression of SlGSTU24, accompanied by enhanced MDA content and electrolyte leakage under cold conditions. Dual-luciferase assay showed that SlMYC2 activates the expression of SlGSTU24 in tobacco leaves. Collectively, these results support that JA-upregulated SlGSTU24 attenuates cold-induced oxidative stress in tomato. This study uncovers a crucial module MYC2-SlGSTU24 that maintains ROS homeostasis in tomato under cold conditions."
Authors: Sheng Zheng, Min Su, Lu Wang, Tengguo Zhang, Juan Wang, Huichun Xie, Xuexia Wu, Syed Inzimam Ul Haq and Quan-Sheng Qiu.
Journal of Plant Physiology (2021)
Abstract: "Cold stress is one of the harsh environmental stresses that adversely affect plant growth and crop yields in the Qinghai-Tibet Plateau. However, plants have evolved mechanisms to overcome the impact of cold stress. Progress has been made in understanding how plants perceive and transduce low-temperature signals to tolerate cold stress. Small signaling molecules are crucial for cellular signal transduction by initiating the downstream signaling cascade that helps plants to respond to cold stress. These small signaling molecules include calcium, reactive oxygen species, nitric oxide, hydrogen sulfide, cyclic guanosine monophosphate, phosphatidic acid, and sphingolipids. The small signaling molecules are involved in many aspects of cellular and physiological functions, such as inducing gene expression and activating hormone signaling, resulting in upregulation of the antioxidant enzyme activities, protestantesimo accumulation, malondialdehyde reduction, and photosynthesis improvement. We summarize our current understanding of the roles of the small signaling molecules in cold stress in plants, and highlight their crosstalk in cold signaling transduction. These discoveries help us understand how the plateau plants adapt to the severe alpine environment as well as to develop new crops tolerating cold stress in the Qinghai-Tibet Plateau.
Authors: Amith R. Devireddy, Timothy J. Tschaplinski , Gerald A. Tuskan, Wellington Muchero and Jin-Gui Chen.
International Journal of Molecular Sciences (2021)
Abstract: "Temperature stress is one of the major abiotic stresses that adversely affect agricultural productivity worldwide. Temperatures beyond a plant’s physiological optimum can trigger significant physiological and biochemical perturbations, reducing plant growth and tolerance to stress. Improving a plant’s tolerance to these temperature fluctuations requires a deep understanding of its responses to environmental change. To adapt to temperature fluctuations, plants tailor their acclimatory signal transduction events, and specifically, cellular redox state, that are governed by plant hormones, reactive oxygen species (ROS) regulatory systems, and other molecular components. The role of ROS in plants as important signaling molecules during stress acclimation has recently been established. Here, hormone-triggered ROS produced by NADPH oxidases, feedback regulation, and integrated signaling events during temperature stress activate stress-response pathways and induce acclimation or defense mechanisms. At the other extreme, excess ROS accumulation, following temperature-induced oxidative stress, can have negative consequences on plant growth and stress acclimation. The excessive ROS is regulated by the ROS scavenging system, which subsequently promotes plant tolerance. All these signaling events, including crosstalk between hormones and ROS, modify the plant’s transcriptomic, metabolomic, and biochemical states and promote plant acclimation, tolerance, and survival. Here, we provide a comprehensive review of the ROS, hormones, and their joint role in shaping a plant’s responses to high and low temperatures, and we conclude by outlining hormone/ROS-regulated plant responsive strategies for developing stress-tolerant crops to combat temperature changes."
Authors: Hao Li, Yanliang Guo, Zhixiang Lan, Kai Xu, Jingjing Chang, Golam Jalal Ahammed, Jianxiang Ma, Chunhua Wei and Xian Zhang.
Horticultural Research (2021)
Abstract: "Root–shoot communication has a critical role in plant adaptation to environmental stress. Grafting is widely applied to enhance the abiotic stress tolerance of many horticultural crop species; however, the signal transduction mechanism involved in this tolerance remains unknown. Here, we show that pumpkin- or figleaf gourd rootstock-enhanced cold tolerance of watermelon shoots is accompanied by increases in the accumulation of melatonin, methyl jasmonate (MeJA), and hydrogen peroxide (H2O2). Increased melatonin levels in leaves were associated with both increased melatonin in rootstocks and MeJA-induced melatonin biosynthesis in leaves of plants under cold stress. Exogenous melatonin increased the accumulation of MeJA and H2O2 and enhanced cold tolerance, while inhibition of melatonin accumulation attenuated rootstock-induced MeJA and H2O2 accumulation and cold tolerance. MeJA application induced H2O2 accumulation and cold tolerance, but inhibition of JA biosynthesis abolished rootstock- or melatonin-induced H2O2 accumulation and cold tolerance. Additionally, inhibition of H2O2 production attenuated MeJA-induced tolerance to cold stress. Taken together, our results suggest that melatonin is involved in grafting-induced cold tolerance by inducing the accumulation of MeJA and H2O2. MeJA subsequently increases melatonin accumulation, forming a self-amplifying feedback loop that leads to increased H2O2 accumulation and cold tolerance. This study reveals a novel regulatory mechanism of rootstock-induced cold tolerance."
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