Li Ming, Feng Lianjie, Ye Huanxia, Li Meiyu, Jin Jing, Tao Li-Zhen, Liu Huili
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China.
Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.
Rice (N Y). 2024 Sep 3;17(1):57. doi: 10.1186/s12284-024-00737-5.
Cytokinins, which play crucial roles in shoot development, substantially affect grain yield. In rice, the OsRopGEF10-OsRAC3 module is associated with cytokinin signaling and crown root development. However, the effects of RopGEF-mediated cytokinin signaling on rice shoot development and grain yield remain unclear. In this study, we investigated the role of OsRopGEF10 in SAM development and the underlying mechanism. We showed that overexpression of OsRopGEF10 inhibited SAM and panicle development, leading to decreased grain yield. Intriguingly, the overexpression of a specific amino acid mutant of OsRopGEF10, designated gef10-W260S, was found to promote panicle development and grain yield. Further analysis using the BiFC assay revealed that the gef10-W260S mutation disrupted the recruitment of rice histidine phosphotransfer proteins (OsAHP1/2) to the plasma membrane (PM), thereby promoting cytokinin signaling. This effect was corroborated by a dark-induced leaf senescence assay, which revealed an increased cytokinin response in the gef10-W260S ectopic expression lines, whereas the overexpression lines presented a suppressed cytokinin response. Moreover, we revealed that the enhanced panicle development in the gef10-W260S lines was attributable to the upregulated expression of several type-B response regulators (RRs) that are crucial for panicle development. Collectively, these findings revealed the negative regulatory function of OsRopGEF10 in the development of the shoot apical meristem (SAM) via interference with cytokinin signaling. Our study highlights the promising role of OsRopGEF10 as a potential target for regulating SAM and panicle development in rice, revealing a valuable breeding strategy for increasing crop yield.
细胞分裂素在地上部发育中起关键作用，对谷物产量有重大影响。在水稻中，OsRopGEF10-OsRAC3模块与细胞分裂素信号传导和冠根发育相关。然而，RopGEF介导的细胞分裂素信号传导对水稻地上部发育和谷物产量的影响仍不清楚。在本研究中，我们研究了OsRopGEF10在茎尖分生组织（SAM）发育中的作用及其潜在机制。我们发现，OsRopGEF10的过表达抑制了SAM和穗发育，导致谷物产量下降。有趣的是，发现OsRopGEF10的一个特定氨基酸突变体（命名为gef10-W260S）的过表达促进了穗发育和谷物产量。使用双分子荧光互补（BiFC）分析的进一步分析表明，gef10-W260S突变破坏了水稻组氨酸磷酸转移蛋白（OsAHP1/2）向质膜（PM）的募集，从而促进了细胞分裂素信号传导。黑暗诱导的叶片衰老分析证实了这一效应，该分析显示gef10-W260S异位表达系中细胞分裂素反应增强，而过表达系则表现出细胞分裂素反应受到抑制。此外，我们发现gef10-W260S系中穗发育的增强归因于几种对穗发育至关重要的B型反应调节因子（RRs）的表达上调。总的来说，这些发现揭示了OsRopGEF10通过干扰细胞分裂素信号传导在茎尖分生组织（SAM）发育中的负调控功能。我们的研究突出了OsRopGEF10作为调节水稻SAM和穗发育的潜在靶点的重要作用，揭示了一种提高作物产量的有价值的育种策略。
