Zhu Lin, Shen Yanjie, Dai Zhengyan, Miao Xuexia, Shi Zhenying
Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences Shanghai, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Rice (N Y). 2024 Sep 9;17(1):59. doi: 10.1186/s12284-024-00736-6.
Manipulating grain size demonstrates great potential for yield promotion in cereals since it is tightly associated with grain weight. Several pathways modulating grain size have been elaborated in rice, but possible crosstalk between the ingredients is rarely studied. OsmiR396 negatively regulates grain size through targeting OsGRF4 (GS2) and OsGRF8, and proves to be multi-functioning. Here we showed that expression of GS3 gene, a Gγ-protein encoding gene, that negatively regulates grain size, was greatly down-regulated in the young embryos of MIM396, GRF8OE and GS2OE plants, indicating possible regulation of GS3 gene by OsmiR396/GRF module. Meanwhile, multiple biochemical assays proved possible transcriptional regulation of OsGRF4 and OsGRF8 proteins on GS3 gene. Further genetic relation analysis revealed tight genetic association between not only OsmiR396 and GS3 gene, but also GS2 and GS3 gene. Moreover, we revealed possible regulation of GS2 on four other grain size-regulating G protein encoding genes. Thus, the OsmiR396 pathway and the G protein pathway cross talks to regulate grain size. Therefore, we established a bridge linking the miRNA-transcription factors pathway and the G-protein signaling pathway that regulates grain size in rice.
由于谷物粒重与籽粒大小密切相关，因此调控籽粒大小在提高谷物产量方面具有巨大潜力。水稻中已经阐述了几种调节籽粒大小的途径，但这些成分之间可能存在的相互作用却鲜有研究。OsmiR396通过靶向OsGRF4（GS2）和OsGRF8负向调节籽粒大小，并被证明具有多种功能。在这里，我们表明，GS3基因（一种编码Gγ蛋白的基因，负向调节籽粒大小）在MIM396、GRF8OE和GS2OE植株的幼胚中表达大幅下调，这表明OsmiR396/GRF模块可能对GS3基因有调控作用。同时，多种生化分析证明OsGRF4和OsGRF8蛋白可能对GS3基因有转录调控作用。进一步的遗传关系分析表明，不仅OsmiR396与GS3基因之间存在紧密的遗传关联；GS2与GS3基因之间也存在紧密的遗传关联。此外，我们还揭示了GS2可能对其他四个调控籽粒大小的G蛋白编码基因有调控作用。因此，OsmiR396途径与G蛋白途径相互作用以调节籽粒大小。因此，我们建立了一座桥梁，将调控水稻籽粒大小的miRNA-转录因子途径与G蛋白信号途径联系起来。
