OsChlC1, a Novel Gene Encoding Magnesium-Chelating Enzyme, Affects the Content of Chlorophyll in Rice

Abstract

Leaf-color mutants in rice (Oryza sativa L.) are excellent models for studying chlorophyll biosynthesis and chloroplast development. In this study, a yellow-green-leaf mutant generated by 60Co irradiation, ygl9311, was isolated: it displayed a yellow-green leaf phenotype during the complete growth cycle. Compared with the wild type, the photosynthetic pigment contents of leaves in ygl9311 were significantly reduced, and chloroplast development was retarded. Genetic analysis indicated that the ygl9311 phenotype was controlled by a single recessive nuclear gene. Map-based cloning and transcriptome sequencing analysis suggested that the candidate gene was OsChlC1 (BGIOSGA012976), which encodes a Mg-chelatase I subunit. The results of CRISPR/Cas9 system and RNAi knockout tests show that mutation of OsChlC1 could reproduce the phenotype of yellow-green leaves of the mutant ygl9311. In conclusion, the novel rice leaf-color gene OsChlC1 affects the content of chlorophyll in rice, showing a relatively conserved function in indica and japonica rice cultivars.