OsCRS2encoding a peptidyl-tRNA hydrolase protein is essential for chloroplast development in rice

Chloroplasts are identified as important organelles for photosynthesis, biosynthesis, and storage of metabolites. So far, the molecular regulatory mechanism of chloroplast development remains to be unclear. The chloroplast RNA splicing 2 (CRS2) protein was determined to play a key role in chloroplast development as they affect the splicing of chloroplast gene introns in maize. However, the functions ofOsCRS2in rice chloroplast development have rarely been studied. In this study,oscrs2-1andoscrs2-2mutants were obtained to gene function research using the CRISPR/Cas9 gene editing technology. Both of the mutants displayed an albino seedling phenotype. The OsCRS2 is located in the chloroplast, and is highly expressed in green tissues. OsCRS2 could affect group I and seven group II introns splicing and participate in chloroplast rRNA biogenesis. RNA sequencing analysis indicated that both nuclear-encoded photosynthesis and chloroplast development-related genes expression were significantly reduced in theoscrs2-1mutant. To conclude, these results suggested that OsCRS2 is necessary for early chloroplast development in rice.