Xiamen Key Laboratory for Plant Genetics, School of Life Sciences, Xiamen University, Xiamen, 361102, China.
School of Life Sciences, Ningxia University, Yinchuan, 750021, China.
Planta. 2024 Feb 10;259(3):68. doi: 10.1007/s00425-024-04342-0.
Overexpression and loss of function of OsGEX3 reduce seed setting rates and affect pollen fertility in rice. OsGEX3 positively regulates osmotic stress response by regulating ROS scavenging. GEX3 proteins are conserved in plants. AtGEX3 encodes a plasma membrane protein that plays a crucial role in pollen tube guidance. However, the function of its homolog in rice, OsGEX3, has not been determined. Our results demonstrate that OsGEX3 is localized in the plasma membrane and the nucleus as shown by a transiently transformed assay using Nicotiana benthamiana leaves. The up-regulation of OsGEX3 was detected in response to treatments with polyethylene glycol (PEG) 4000, hydrogen peroxide, and abscisic acid (ABA) via RT-qPCR analysis. Interestingly, we observed a significant decline in the seed setting rates of OsGEX3-OE lines and mutants, compared to the wild type. Further investigations reveal that overexpression and loss of function of OsGEX3 affect pollen maturation. TEM observation revealed a significant decrease in the fertile pollen rates of OsGEX3-OE transgenic lines and Osgex3 mutants due to a delay in pollen development at the late vacuolated stage. Overexpression of OsGEX3 improved osmotic stress and oxidative stress tolerance by enhancing reactive oxygen species (ROS) scavenging in rice seedlings, whereas Osgex3 mutants exhibited an opposite phenotype in osmotic stress. These findings highlight the multifunctional roles of OsGEX3 in pollen development and the response to abiotic stress. The functional characterization of OsGEX3 provides a fundamental basis for rice molecular breeding and can facilitate efforts to cultivate drought resistance and yield-related varieties.
OsGEX3 的过表达和功能丧失会降低结实率并影响水稻花粉育性。OsGEX3 通过调节 ROS 清除来正向调节渗透胁迫响应。GEX3 蛋白在植物中保守。AtGEX3 编码一种质膜蛋白，在花粉管导向中发挥关键作用。然而，其在水稻中的同源物 OsGEX3 的功能尚未确定。我们的结果表明，OsGEX3 定位于质膜和核内，这是通过使用烟草原生质体瞬时转化实验证明的。通过 RT-qPCR 分析检测到 OsGEX3 在上调。有趣的是，我们观察到 OsGEX3-OE 系和突变体的结实率显著下降，与野生型相比。进一步的研究表明，OsGEX3 的过表达和功能丧失会影响花粉成熟。TEM 观察表明，由于花粉在晚期液泡化阶段发育延迟，OsGEX3-OE 转基因系和 Osgex3 突变体的可育花粉率显著降低。OsGEX3 的过表达通过增强水稻幼苗中的活性氧 (ROS) 清除来提高渗透胁迫和氧化胁迫耐受性，而 Osgex3 突变体在渗透胁迫下表现出相反的表型。这些发现强调了 OsGEX3 在花粉发育和非生物胁迫响应中的多功能作用。OsGEX3 的功能表征为水稻分子育种提供了基础，并有助于培育抗旱性和产量相关品种的努力。
