Cysteine (Cys) regulates plant growth, development, and various abiotic stress responses. However, the knowledge gained from genetic and molecular studies on the role of Cys metabolism in salinity response remains limited. Here, we introduce a sulfate metabolism-related component, Arabidopsis Halotolerance 2-like (AHL), which is involved in salt stress adaptation. AHL expression was experimentally induced under salt stress conditions using AHL promoter-β-glucuronidase transgenic plants. Phenotypic analysis revealed that the survival rate of AHL-overexpressing (AHL-OE) lines was greater than that of wild-type (WT) plants under high-salinity conditions, while ahl mutant and AHL-RNAi seedlings were more sensitive than WT seedlings. Accumulation of Cys and proline was increased in AHL-OE transgenic lines under salinity stress conditions, but malondialdehyde and hydrogen peroxide levels were lower in AHL-OE than in WT, ahl, and AHL-RNAi plants. In addition, the transcription levels of genes associated with Cys biosynthesis and sulfate metabolism were higher in AHL-OE than ahl and AHL-RNAi seedlings after salt stress treatment. Moreover, exogenous application of Cys could rescue the salt stress-induced sensitive phenotypes of ahl and AHL-RNAi lines, and return them to the WT phenotype. Taken together, our findings indicate that AHL positively regulates salinity response in Arabidopsis seedlings by modulating a Cys-dependent pathway.

半胱氨酸 (Cys) 调节植物生长、发育和各种非生物胁迫反应。然而，从遗传和分子研究中获得的关于 Cys 代谢在盐度响应中的作用的知识仍然有限。在这里，我们引入一个硫酸盐代谢相关的部件，拟南芥耐盐2 -等（AHL），其参与盐胁迫的适应。使用AHL启动子-β-葡萄糖醛酸酶转基因植物在盐胁迫条件下实验诱导AHL表达。表型分析显示，AHL 过表达（AHL-OE) 系在高盐度条件下大于野生型 (WT) 植物，而ahl突变体和AHL -RNAi 幼苗比 WT 幼苗更敏感。Cys和脯氨酸的积累增加AHL -OE转基因品系盐度胁迫条件下，但丙二醛和过氧化氢含量均在较低的AHL -OE比在WT，AHL，和AHL -RNAi植物。此外，用Cys生物合成和硫酸盐代谢相关基因的转录水平在较高AHL比-OE AHL和AHL-盐胁迫处理后的RNAi幼苗。此外，Cys 的外源应用可以挽救ahl和AHL - RNAi系的盐胁迫诱导的敏感表型，并使它们恢复到 WT 表型。总之，我们的研究结果表明，AHL通过调节 Cys 依赖性途径正调节拟南芥幼苗的盐度响应。