Molecular Biology and Biotechnology Division, CSIR-National Botanical Research Institute, India.
Plant Ecology and Environmental Technology Division, CSIR-National Botanical Research Institute, India.
Ecotoxicol Environ Saf. 2020 Jun 1;195:110471. doi: 10.1016/j.ecoenv.2020.110471. Epub 2020 Mar 20.
Rice is the most consumed food crop and essential determinant in global food security program. Currently, arsenic (As) accumulation in rice is a critical concern in terms of both crop productivity and grain quality; therefore, it is an urgent need to reduce As accumulation. Here, we selected a glutaredoxin (OsGrx_C7) gene that plays an essential role in AsIII tolerance in rice. To explore the mechanism, we raised OsGrx_C7 overexpression (OE) rice lines, which showed improved plant AsIII tolerance and lowered its accumulation in grains. Arsenic accumulation in husk, unpolished, and polished rice reduced by ca. 65%, 67%, and 85%, respectively, in OE lines, compared to wild-type (WT) plants. To know the rationale, expression of AsIII transporters (aquaporins) in root and shoot tissues were examined, and revealed that OsGrx_C7 regulates the expression of these genes, which ultimately reduces root to shoot AsIII translocation. Additionally, OsGrx_C7 improves root growth by regulating the expression of oxidative stress-induced root expansion related genes, promote root growth and plant health. Overall, current study suggested that AsIII induced OsGrx_C7 markedly enhanced tolerance to AsIII with reduced accumulation in grains by regulating root expansion and controlling root to shoot As transport by altered expression of AsIII aquaporins.
水稻是最主要的食用作物，也是全球粮食安全计划中的重要决定因素。目前，水稻砷（As）积累问题是作物生产力和粮食质量方面的一个关键关注点；因此，减少 As 积累是当务之急。在这里，我们选择了一个谷胱甘肽还原酶（OsGrx_C7）基因，该基因在水稻砷 III 耐受中发挥着重要作用。为了探索其机制，我们培育了 OsGrx_C7 过表达（OE）水稻品系，这些品系表现出增强的植物砷 III 耐受能力，并降低了其在谷物中的积累。与野生型（WT）植物相比，OE 系水稻的稻壳、糙米和精米中的砷积累分别降低了约 65%、67%和 85%。为了了解其原理，我们检测了根和茎叶组织中砷 III 转运蛋白（水通道蛋白）的表达情况，结果表明 OsGrx_C7 调节这些基因的表达，从而最终减少了根到茎叶的砷 III 转运。此外，OsGrx_C7 通过调节与氧化应激诱导的根扩张相关的基因的表达来改善根系生长，促进了根系生长和植物健康。总的来说，本研究表明，砷 III 诱导 OsGrx_C7 显著增强了对 AsIII 的耐受能力，同时通过调节根扩张和控制根到茎叶的 As 转运来减少谷物中的积累，从而降低了砷的积累。
