水稻白化转绿突变体wrg20的鉴定与基因克隆OA北大核心CSTPCD

In order to explore the molecular mechanism of chloroplast development in rice,phenotypic identification,gene mapping and functional analysis of rice wr20(white turn green 20)mutant were performed in this study.By EMS(Ethyl methylsulfone)mutagenesis of japonica rice,a stable leaf color albino mutant wrg20 was obtained.Compared with the wild type(WT),the mutant was completely white before the three-leaf stage when cultured at 30℃,while the albino leaves of the mutant partially turned green at 26℃.Genetic analysis showed that the mutant trait was controlled by a single recessive nuclear gene.By crossing the mutated with indica rice 93-11 to construct the F2 isolate population for gene mapping,the gene was mapped in the 198 kb interval of chromosome 2.Sequencing revealed a single base substitution from G to A in LOC_Os02g33610,resulting in the conversion of the encoding aspartic acid to asparagine.This gene may be a candidate gene for OsWRG20 and was allelic with GRY79,a previously reported gene that regulates chloroplast development.Further analysis showed that the chloroplast RNA splicing efficiency of the mutant was reduced compared with the WT.These results suggest that OsWRG20 may be involved in the regulation of chloroplast development in seedling stage by regulating the splicing of chloroplast RNA.This study may provide a new theoretical basis for the research of the chloroplasts development in seedling rice.