College of Life Sciences, Northeast Agricultural University, Harbin, 150030, China.
College of Animal Sciences and Technology, Northeast Agricultural University, Harbin, 150030, China.
Plant Physiol Biochem. 2020 Sep;154:538-546. doi: 10.1016/j.plaphy.2020.07.001. Epub 2020 Jul 20.
The sulfite reductase gene in Medicago sativa L. (MsSiR) encodes sulfite reductase (SiR) and catalyses the conversion of sulfite to sulfate in the sulfite assimilation pathway. In this study, we investigated the role of MsSiR in alfalfa by generating transgenic alfalfa that ectopically expressed MsSiR under the control of the CaMV35S promoter. The differences in alkali tolerance between the MsSiR-overexpressing and wild-type (WT) plants were analyzed, and the MsSiR-overexpressing plants exhibited an improved phenotype under alkali stress. Compared to WT plants, these plants demonstrated improved antioxidant activity as well as decreased HO and O contents and increased glutathione reduced (GSH), Cysteine (Cys) and glutathione oxidized (GSSG) contents. MsSiR-overexpressing plants also exhibited high levels of adenosyl phosphosulfate reductases (APR), sulfite oxidase (SO) and MsSiR expression under alkali stress. It was speculated that MsSiR is involved in sulfur metabolism pathways, including the stabilization of sulfate and sulfite levels and the synthesis of GSH. These two processes achieve alkali tolerance by positively regulating the detoxification and antioxidant activities of alfalfa.
紫花苜蓿中的亚硫酸还原酶基因（MsSiR）编码亚硫酸还原酶（SiR），并在亚硫酸盐同化途径中催化亚硫酸盐转化为硫酸盐。在本研究中，我们通过在 CaMV35S 启动子的控制下异位表达 MsSiR 来生成转基因紫花苜蓿，从而研究 MsSiR 在紫花苜蓿中的作用。分析了 MsSiR 过表达和野生型（WT）植物之间的耐碱差异，结果表明，MsSiR 过表达植株在碱胁迫下表现出改善的表型。与 WT 植物相比，这些植物表现出更高的抗氧化活性，同时降低了 HO 和 O 的含量，增加了谷胱甘肽还原（GSH）、半胱氨酸（Cys）和谷胱甘肽氧化（GSSG）的含量。在碱胁迫下，MsSiR 过表达植株还表现出高活性的腺苷磷酸硫酸还原酶（APR）、亚硫酸氧化酶（SO）和 MsSiR 表达。推测 MsSiR 参与了硫代谢途径，包括硫酸盐和亚硫酸盐水平的稳定以及 GSH 的合成。这两个过程通过正向调节苜蓿的解毒和抗氧化活性来实现耐碱。
