State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
Plant J. 2023 Jun;114(6):1369-1384. doi: 10.1111/tpj.16198. Epub 2023 Apr 10.
Hydrogen sulfide (H S) promotes plant tolerance against various environmental cues, and d-cysteine desulfhydrase (DCD) is an enzymatic source of H S to enhance abiotic stress resistance. However, the role of DCD-mediated H S production in root growth under abiotic stress remains to be further elucidated. Here, we report that DCD-mediated H S production alleviates osmotic stress-mediated root growth inhibition by promoting auxin homeostasis. Osmotic stress up-regulated DCD gene transcript and DCD protein levels and thus H S production in roots. When subjected to osmotic stress, a dcd mutant showed more severe root growth inhibition, whereas the transgenic lines DCDox overexpressing DCD exhibited less sensitivity to osmotic stress in terms of longer root compared to the wild-type. Moreover, osmotic stress inhibited root growth through repressing auxin signaling, whereas H S treatment significantly alleviated osmotic stress-mediated inhibition of auxin. Under osmotic stress, auxin accumulation was increased in DCDox but decreased in dcd mutant. H S promoted auxin biosynthesis gene expression and auxin efflux carrier PIN-FORMED 1 (PIN1) protein level under osmotic stress. Taken together, our results reveal that mannitol-induced DCD and H S in roots promote auxin homeostasis, contributing to alleviating the inhibition of root growth under osmotic stress.
硫化氢 (H S) 促进植物耐受各种环境信号，而半胱氨酸脱巯基酶 (DCD) 是 H S 的酶源，可增强非生物胁迫抗性。然而，DCD 介导的 H S 产生在非生物胁迫下对根生长的作用仍有待进一步阐明。在这里，我们报告 DCD 介导的 H S 产生通过促进生长素稳态缓解渗透胁迫介导的根生长抑制。渗透胁迫上调 DCD 基因转录物和 DCD 蛋白水平，从而在根中产生 H S。在渗透胁迫下，dcd 突变体表现出更严重的根生长抑制，而过表达 DCD 的转基因系 DCDox 表现出对渗透胁迫的敏感性较低，表现在根较长。此外，渗透胁迫通过抑制生长素信号转导抑制根生长，而 H S 处理显著缓解了渗透胁迫介导的对生长素的抑制。在渗透胁迫下，DCDox 中生长素积累增加，而 dcd 突变体中生长素积累减少。H S 在渗透胁迫下促进生长素生物合成基因表达和生长素外排载体 PIN-FORMED 1 (PIN1) 蛋白水平。总之，我们的结果表明甘露醇诱导的根中 DCD 和 H S 促进了生长素稳态，有助于缓解渗透胁迫下根生长的抑制。
