The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Lin'an, Hangzhou 311300, P. R. China.
J Agric Food Chem. 2021 Aug 11;69(31):8634-8648. doi: 10.1021/acs.jafc.1c01096. Epub 2021 Aug 2.
The monocot lineage-specific miR528 was previously established as a multistress regulator. However, it remains largely unclear how miR528 participates in response to salinity stress in rice. Here, we show that miR528 positively regulates rice salt tolerance by down-regulating a gene encoding l-ascorbate oxidase (AO), thereby bolstering up the -mediated abscisic acid (ABA) synthesis and ROS scavenging. Overexpression of miR528 caused a substantial increase in ascorbic acid (AsA) and ABA contents but a significant reduction in ROS accumulation, resulting in the enhanced salt tolerance of rice plants. Conversely, knockdown of miR528 or overexpression of stimulated the expression of the gene, hence lowering the level of AsA, a critical antioxidant that promotes the ABA content but reduces the ROS level, and then compromising rice tolerance to salinity. Together, the findings reveal a novel mechanism of the miR528- module-mediated salt tolerance by modulating the processes of AsA and ABA metabolism as well as ROS detoxification, which adds a new regulatory role to the miR528- stress defense pathway in rice.
单子叶植物特异的 miR528 先前被确定为一种多应激调节剂。然而，miR528 如何参与水稻对盐胁迫的响应在很大程度上仍不清楚。在这里，我们表明 miR528 通过下调编码 l-抗坏血酸氧化酶 (AO) 的基因正向调控水稻的耐盐性，从而增强 -介导的脱落酸 (ABA) 合成和 ROS 清除。miR528 的过表达导致抗坏血酸 (AsA) 和 ABA 含量的大幅增加，但 ROS 积累的显著减少，从而增强了水稻植株的耐盐性。相反，miR528 的敲低或 的过表达刺激了 基因的表达，从而降低了作为关键抗氧化剂的 AsA 水平，促进了 ABA 含量的增加，但降低了 ROS 水平，从而损害了水稻对盐度的耐受性。总之，这些发现揭示了 miR528- 模块通过调节 AsA 和 ABA 代谢以及 ROS 解毒过程介导盐胁迫耐受性的新机制，为 miR528- 应激防御途径在水稻中的新的调控作用增添了新的内容。
