Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021, India.
National Institute of Plant Genome Research, New Delhi, 110067, India.
Plant Cell Rep. 2024 Aug 13;43(9):215. doi: 10.1007/s00299-024-03304-w.
Overexpression of rice A20/AN1 zinc-finger protein, OsSAP10, improves water-deficit stress tolerance in Arabidopsis via interaction with multiple proteins. Stress-associated proteins (SAPs) constitute a class of A20/AN1 zinc-finger domain containing proteins and their genes are induced in response to multiple abiotic stresses. The role of certain SAP genes in conferring abiotic stress tolerance is well established, but their mechanism of action is poorly understood. To improve our understanding of SAP gene functions, OsSAP10, a stress-inducible rice gene, was chosen for the functional and molecular characterization. To elucidate its role in water-deficit stress (WDS) response, we aimed to functionally characterize its roles in transgenic Arabidopsis, overexpressing OsSAP10. OsSAP10 transgenics showed improved tolerance to water-deficit stress at seed germination, seedling and mature plant stages. At physiological and biochemical levels, OsSAP10 transgenics exhibited a higher survival rate, increased relative water content, high osmolyte accumulation (proline and soluble sugar), reduced water loss, low ROS production, low MDA content and protected yield loss under WDS relative to wild type (WT). Moreover, transgenics were hypersensitive to ABA treatment with enhanced ABA signaling and stress-responsive genes expression. The protein-protein interaction studies revealed that OsSAP10 interacts with proteins involved in proteasomal pathway, such as OsRAD23, polyubiquitin and with negative and positive regulators of stress signaling, i.e., OsMBP1.2, OsDRIP2, OsSCP and OsAMTR1. The A20 domain was found to be crucial for most interactions but insufficient for all interactions tested. Overall, our investigations suggest that OsSAP10 is an important candidate for improving water-deficit stress tolerance in plants, and positively regulates ABA and WDS signaling via protein-protein interactions and modulation of endogenous genes expression in ABA-dependent manner.
过量表达水稻 A20/AN1 锌指蛋白 OsSAP10 通过与多种蛋白质相互作用提高拟南芥的水分亏缺胁迫耐受性。应激相关蛋白（SAP）构成 A20/AN1 锌指结构域包含蛋白的一类，其基因在多种非生物胁迫下被诱导。某些 SAP 基因在赋予非生物胁迫耐受性方面的作用已得到很好的证实，但它们的作用机制尚不清楚。为了提高我们对 SAP 基因功能的理解，选择了应激诱导的水稻基因 OsSAP10 进行功能和分子特征分析。为了阐明其在水分亏缺胁迫（WDS）响应中的作用，我们旨在通过过表达 OsSAP10 的转基因拟南芥对其功能进行表征。OsSAP10 转基因在种子萌发、幼苗和成熟植物阶段对水分亏缺胁迫的耐受性提高。在生理和生化水平上，与野生型（WT）相比，OsSAP10 转基因表现出更高的存活率、相对较高的水分含量、高渗透物积累（脯氨酸和可溶性糖）、较低的水分损失、较低的 ROS 产生、较低的 MDA 含量和在 WDS 下保护产量损失。此外，与 WT 相比，转基因植物对 ABA 处理更敏感，表现出增强的 ABA 信号和应激响应基因表达。蛋白-蛋白相互作用研究表明，OsSAP10 与参与蛋白酶体途径的蛋白质相互作用，如 OsRAD23、多聚泛素以及应激信号的负调控因子和正调控因子，即 OsMBP1.2、OsDRIP2、OsSCP 和 OsAMTR1。发现 A20 结构域对于大多数相互作用至关重要，但对于测试的所有相互作用都不充分。总体而言，我们的研究表明，OsSAP10 是提高植物水分亏缺胁迫耐受性的重要候选基因，通过蛋白-蛋白相互作用以及在 ABA 依赖的方式调节内源性基因表达，正向调节 ABA 和 WDS 信号。
