Genome-Wide Identification of the RhoGAP Gene Family and Main Function of OsRhoGAP2 in Seed Germination of Rice by Transcriptome Analysis.

Rho GTPase-activating proteins (RhoGAPs) play crucial roles in regulating various biological processes. However, the functions of RhoGAP family genes in rice (Oryza sativa) remain largely unexplored. Here, we identified 19 RhoGAP genes in rice, and preliminarily analyzed the genes information, expression patterns, and evolutionary relationship with AtRhoGAPs in Arabidopsis. Using CRISPR/Cas9-mediated gene editing, we generated loss-of-function mutants of OsRhoGAP2 (rhogap2) and found that seed germination was significantly delayed compared to the wild type (WT). Further analysis revealed that α-amylase activity was reduced in rhogap2 germinating seeds. RNA-seq profiling identified 291 upregulated and 130 downregulated genes in the mutant, with differentially expressed genes (DEGs) primarily enriched in phenylpropanoid biosynthesis and other metabolic pathways. Notably, most phenylpropanoid biosynthesis-related genes exhibited increased expression in rhogap2 germinating seeds. These findings establish a foundational framework for future functional studies of RhoGAP genes in rice and provide novel insights into the molecular mechanisms by which RhoGAPs regulate seed germination in plants.