{"title":"Osmoregulation is a crucial factor for methyl jasmonate to enhance chilling tolerance of Jatropha curcas L.","authors":"Shanshan Lan, Ming Gong, Shuanglong Yang","doi":"10.1093/treephys/tpaf037","DOIUrl":null,"url":null,"abstract":"<p><p>Methyl jasmonate (MeJA) is a vital regulator of plant growth and plays a crucial role in chilling tolerance. However, the mechanism through which MeJA enhances chilling tolerance in plants remains unclear. Therefore, this study conducted hydroponic experiments to evaluate the effects of exogenous MeJA (0-125 μmol·L-1) on osmoregulation and chilling tolerance of Jatropha curcas seedlings under chilling (5 °C) stress. The seedlings under chilling stress were treated with MeJA and morphological changes, physiological traits, osmoprotectants (proline, betaine, and trehalose) contents, activities of key enzymes involved in osmoprotectants metabolism, and expression of related genes were investigated. The results showed that treatment with 75 μmol·L-1 MeJA alleviated leaf wilting and growth inhibition; significantly decreased water potential, electrolyte leakage, and malondialdehyde content; and enhanced tissue vitality, water content, total chlorophyll content, net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, and transpiration rate in J. curcas seedlings, thereby improving chilling tolerance. Under chilling stress, four days of MeJA treatment remarkably increased the contents of proline, betaine, and trehalose in the leaves of J. curcas seedlings by activating their biosynthesis pathways and inhibiting the degradation pathway of proline. The substantial accumulation of osmoprotectants reduced the cellular water potential, maintained the cellular water balance, and stabilized the cell membrane. Furthermore, 1-4 d of MeJA treatment led to increased levels of jasmonic acid (JA) and ethylene and upregulation of JcMYC2 expression in J. curcas seedlings under chilling stress. This suggested that the JA/MeJA-MYC2 signaling pathway, along with ethylene signaling, may contribute to MeJA-induced chilling tolerance in J. curcas. Our findings suggested that exogenous MeJA treatment increases the capacity for osmoregulation and chilling tolerance in J. curcas seedlings under chilling stress and that osmoregulation is a crucial component of MeJA-induced chilling tolerance.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5000,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Tree physiology","FirstCategoryId":"97","ListUrlMain":"https://doi.org/10.1093/treephys/tpaf037","RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"FORESTRY","Score":null,"Total":0}
引用次数: 0
Abstract
Methyl jasmonate (MeJA) is a vital regulator of plant growth and plays a crucial role in chilling tolerance. However, the mechanism through which MeJA enhances chilling tolerance in plants remains unclear. Therefore, this study conducted hydroponic experiments to evaluate the effects of exogenous MeJA (0-125 μmol·L-1) on osmoregulation and chilling tolerance of Jatropha curcas seedlings under chilling (5 °C) stress. The seedlings under chilling stress were treated with MeJA and morphological changes, physiological traits, osmoprotectants (proline, betaine, and trehalose) contents, activities of key enzymes involved in osmoprotectants metabolism, and expression of related genes were investigated. The results showed that treatment with 75 μmol·L-1 MeJA alleviated leaf wilting and growth inhibition; significantly decreased water potential, electrolyte leakage, and malondialdehyde content; and enhanced tissue vitality, water content, total chlorophyll content, net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, and transpiration rate in J. curcas seedlings, thereby improving chilling tolerance. Under chilling stress, four days of MeJA treatment remarkably increased the contents of proline, betaine, and trehalose in the leaves of J. curcas seedlings by activating their biosynthesis pathways and inhibiting the degradation pathway of proline. The substantial accumulation of osmoprotectants reduced the cellular water potential, maintained the cellular water balance, and stabilized the cell membrane. Furthermore, 1-4 d of MeJA treatment led to increased levels of jasmonic acid (JA) and ethylene and upregulation of JcMYC2 expression in J. curcas seedlings under chilling stress. This suggested that the JA/MeJA-MYC2 signaling pathway, along with ethylene signaling, may contribute to MeJA-induced chilling tolerance in J. curcas. Our findings suggested that exogenous MeJA treatment increases the capacity for osmoregulation and chilling tolerance in J. curcas seedlings under chilling stress and that osmoregulation is a crucial component of MeJA-induced chilling tolerance.
期刊介绍：
Tree Physiology promotes research in a framework of hierarchically organized systems, measuring insight by the ability to link adjacent layers: thus, investigated tree physiology phenomenon should seek mechanistic explanation in finer-scale phenomena as well as seek significance in larger scale phenomena (Passioura 1979). A phenomenon not linked downscale is merely descriptive; an observation not linked upscale, might be trivial. Physiologists often refer qualitatively to processes at finer or coarser scale than the scale of their observation, and studies formally directed at three, or even two adjacent scales are rare. To emphasize the importance of relating mechanisms to coarser scale function, Tree Physiology will highlight papers doing so particularly well as feature papers.
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