WSL5, a pentatricopeptide repeat protein, is essential for chloroplast biogenesis in rice under cold stress

AbstactChloroplasts play an essential role in plant growth and development, and cold has a great effect on chloroplast development. Although many genes or regulators involved in chloroplast biogenesis and development have been isolated and characterized, identification of novel components associated with cold is still lacking. In this study, we reported the functional characterization of white stripe leaf 5 (wsl5) mutant in rice. The mutant developed white-striped leaves during early leaf development and was albinic when planted under cold stress. Genetic and molecular analysis revealed that WSL5 encodes a novel chloroplast-targeted pentatricopeptide repeat protein. RNA-seq analysis showed that expression of nuclear-encoded photosynthetic genes in the mutant was significantly repressed, and expression of many chloroplast-encoded genes was also significantly changed. Notably, the WSL5 mutation caused defects in editing of rpl2 and atpA, and in splicing of rpl2 and rps12. Chloroplast ribosome biogenesis was impaired under cold stress. We propose that WSL5 is required for normal chloroplast development in rice under cold stress.