Department of Biological Science, University of Manitoba, Winnipeg, R3T 2N2 MB, Canada.
Department of Biological Science, University of Manitoba, Winnipeg, R3T 2N2 MB, Canada.
J Plant Physiol. 2018 Jul;226:136-144. doi: 10.1016/j.jplph.2018.04.009. Epub 2018 Apr 21.
Jasmonic acid (JA) has been mostly studied in responses to biotic stresses, such as herbivore attack and pathogenic infection. More recently, the involvement of JA in abiotic stresses including salinity was highlighted; yet, its role in salt stress remained unclear. In the current study, we compared the physiological and biochemical responses of wild-type (WT) tomato (Solanum lycopersicum) cv Castlemart and its JA-deficient mutant defenseless-1 (def-1) under salt stress to investigate the role of JA. Plant growth, photosynthetic pigment content, ion accumulation, oxidative stress-related parameters, proline accumulation and total phenolic compounds, in addition to both enzymatic and non-enzymatic antioxidant activities, were measured in both genotypes after 14 days of 100 mM NaCl treatment. Although we observed in both genotypes similar growth pattern and sodium, calcium and potassium levels in leaves under salt stress, def-1 plants exhibited a more pronounced decrease of nitrogen content in both leaves and roots and a slightly higher level of sodium in roots compared to WT plants. In addition, def-1 plants exposed to salt stress showed reactive oxygen species (ROS)-associated injury phenotypes. These oxidative stress symptoms in def-1 were associated with lower activity of both enzymatic antioxidants and non-enzymatic antioxidants. Furthermore, the levels of the non-enzymatic ROS scavengers proline and total phenolic compounds increased in both genotypes exposed to salt stress, with a higher amount of proline in the WT plants. Overall the results of this study suggest that endogenous JA mainly enhanced tomato salt tolerance by maintaining ROS homeostasis.
茉莉酸（JA）在植物应对生物胁迫，如食草动物攻击和病原感染的过程中研究得最多。最近，JA 参与非生物胁迫，包括盐胁迫的作用也被凸显出来；然而，其在盐胁迫中的作用仍不清楚。在本研究中，我们比较了野生型（WT）番茄（Solanum lycopersicum）cv Castlemart 和其茉莉酸缺陷突变体 defenseless-1（def-1）在盐胁迫下的生理生化反应，以研究茉莉酸的作用。在 100mM NaCl 处理 14 天后，测量了两种基因型的植物生长、光合色素含量、离子积累、与氧化应激相关的参数、脯氨酸积累和总酚含量，以及酶和非酶抗氧化剂的活性。尽管我们在两种基因型的叶片中观察到相似的盐胁迫下的生长模式和钠离子、钙离子和钾离子水平，但与 WT 植株相比，def-1 植株的叶片和根系的氮含量下降更为明显，根系中的钠离子水平略高。此外，暴露在盐胁迫下的 def-1 植株表现出与活性氧（ROS）相关的损伤表型。def-1 中的这些氧化应激症状与两种酶和非酶抗氧化剂的活性降低有关。此外，暴露在盐胁迫下的两种基因型的非酶 ROS 清除剂脯氨酸和总酚含量增加，WT 植株中的脯氨酸含量更高。总的来说，这项研究的结果表明，内源性 JA 主要通过维持 ROS 平衡来增强番茄的耐盐性。
