College of Life Science, Hebei Normal University, No.20 Road East. 2nd Ring South, Yuhua District, Shijiazhuang 050024, Hebei, China.
College of Life Science, Hebei Normal University, No.20 Road East. 2nd Ring South, Yuhua District, Shijiazhuang 050024, Hebei, China; Boustead College, Tianjin University of Commerce, Jinjing Road 28, 300384, Tianjin, China.
Plant Sci. 2021 Jul;308:110903. doi: 10.1016/j.plantsci.2021.110903. Epub 2021 Apr 7.
In plants, auxin and ABA play significant roles in conferring tolerance to environmental abiotic stresses. Earlier studies have been shown that some Aux/IAA genes, with important signaling factors in the auxin pathway, were induced in response to drought and other abiotic stresses. However, the mechanistic links between Aux/IAA expression and general drought response remain largely unknown. In this study, OsIAA20, a rice Aux/IAA protein, shown with important roles in abiotic stress. Phenotypic analyses revealed that OsIAA20 RNAi transgenic rice reduced drought and salt tolerance; whereas, OsIAA20 overexpression plants displayed the opposite phenotype. Physiological analyses of OsIAA20 RNAi rice grown under drought or salt stress showed that proline and chlorophyll content significantly decreased, while malondialdehyde content and the ratio of Na/ K significantly increased. In addition, OsIAA20down-regulation reduced stomatal closure and increased the rate of water loss, while transgenic plants overexpressing OsIAA20 exhibited the opposite physiological responses. Furthermore, an ABA-responsive gene, OsRab21, was down-regulated in OsIAA20 RNAi rice lines and upregulated in OsIAA20 overexpression plants. Those results means OsIAA20 played an important role in plant drought and salt stress responses, by an ABA dependent mechanism, and it will be a candidate target gene used to breed abiotic stress tolerance.
在植物中，生长素和 ABA 在赋予植物对环境非生物胁迫的耐受性方面发挥着重要作用。早期的研究表明，一些 Aux/IAA 基因，作为生长素途径中的重要信号因子，在响应干旱和其他非生物胁迫时被诱导。然而，Aux/IAA 表达与一般干旱响应之间的机制联系在很大程度上仍不清楚。在这项研究中，水稻 Aux/IAA 蛋白 OsIAA20 被证明在非生物胁迫中具有重要作用。表型分析显示，OsIAA20 RNAi 转基因水稻降低了干旱和耐盐性；而 OsIAA20 过表达植株则表现出相反的表型。在干旱或盐胁迫下生长的 OsIAA20 RNAi 水稻的生理分析表明，脯氨酸和叶绿素含量显著降低，而丙二醛含量和 Na/K 比值显著增加。此外，OsIAA20 下调减少了气孔关闭并增加了水分流失率，而过表达 OsIAA20 的转基因植株则表现出相反的生理反应。此外，ABA 响应基因 OsRab21 在 OsIAA20 RNAi 水稻系中下调，而在 OsIAA20 过表达植株中上调。这些结果表明，OsIAA20 通过依赖 ABA 的机制在植物干旱和盐胁迫响应中发挥重要作用，它将成为用于培育非生物胁迫耐受性的候选靶基因。
