Ribonuclease H‐like gene SMALL GRAIN2 regulates grain size in rice through brassinosteroid signaling pathway

• DOI: 10.1111/jipb.13333
• Publication Date: 2022-07-29T08:55:04Z
• Authors: Yunshuai Huang; Hui Dong; Changling Mou; Ping Wang; Qixian Hao; Min Zhang; Hongmin Wu; Fulin Zhang; Tengfei Ma; Rong Miao; Kai Fu; Yaping Chen; Ziyan Zhu; Cheng Chen; Qikai Tong; Zhuoran Wang; Shirong Zhou; Xi Liu; Shijia Liu; Yunlu Tian; Ling Jiang; Jianmin Wan
• Keywords: Brassinosteroid

Grain size is a key agronomic trait that determines the yield in plants. Regulation of grain by brassinosteroids (BRs) rice has been widely reported. However, relationship between BR signaling pathway and still requires further study. Here, we isolated mutant, named small grain2 (sg2), which displayed smaller semi-dwarf phenotype. The decreased was caused repressed cell expansion spikelet hulls sg2 mutant. Using map-based cloning combined with MutMap approach, cloned SG2, encodes plant-specific protein ribonuclease H-like domain. SG2 positive regulator downstream GLYCOGEN SYNTHASE KINASE2 (GSK2) response to signaling, its mutation causes insensitivity exogenous treatment. Genetical biochemical analysis showed GSK2 interacts phosphorylates SG2. We found BRs enhance accumulation nucleus, subcellular distribution regulated kinase activity. In addition, Oryza sativa OVATE family 19 (OsOFP19), negative shape, plays an antagonistic role controlling gene expression size. Our results indicated new component GSK2-related regulates interacting OsOFP19.