Cloning and functional analysis of pale-green leaf (PGL10) in rice (Oryza sativa L.)

Abstract

Leaf color mutants commonly found in rice have important implications in basic research and breeding science. In this study, we isolated a pale-green leaf mutant (pgl10) from the offspring of the rice cultivar Nipponbare (Oryza sativa L. spp. japonica) through ethyl methanesulfonate mutagenesis. Compared with the wild-type Nipponbare, the pgl10 mutant had phenotypically pale-green leaves with significantly decreased chlorophyll (a and b) and carotenoid contents. Transmission electron micrographs showed that pgl10 had less grana lamellae of chloroplasts than Nipponbare. The results of tissue-specific gene expression analysis revealed that pgl10 was expressed in various rice organs, including roots, stems, leaves, sheaths, and spikes. The expression of Chl synthesis-associated gene in pgl10 was decreased. Genetic analysis suggested that PGL10 was controlled by a recessive gene. Map-based cloning and genome sequencing data showed that pgl10 was a frameshift mutation caused by a single base insertion on chromosome 10. Bioinformation analysis indicated that PGL10 encoded protochlorophyllide oxidoreductase B. Therefore, pgl10 can be a genetic material for further studies on PGL10.