Genetic Analysis and Fine Mapping of Yellow-Green Leaf Mutant ygl209 in Rice

Abstract

Etiolation mutants of rice play an important role in studies on the photosynthesis, chloroplast development, and chlorophyll metabolism in higher plants. A japonica rice mutant ygl209 with yellow-green leaf was identified from the BC4F3 progeny of the cross between the transgenic variety of Zhongguo 91 and Zhendao 88 with the latter as the recurrent parent. Compared with the wild-type parent Zhendao 88, the contents of chlorophyll a, chlorophyll b and carotenoid decreased dramatically in the mutant ygl209 at the seedling, tillering and heading stages, respectively. In particular, chlorophyll b decreased most significantly. However, there was no significant change in other agronomic traits, such as heading stage, plant height, number of effective panicles per plant, number of grains in main stem panicle, seed setting rate and 1000-grain weight. Genetic analysis showed that the yellow-green leaf trait of the ygl209 mutant was controlled by one pair of recessive nuclear genes. With F2 and F3 segregation populations derived from the cross between ygl209 and Zhendao 88, the YGL209 gene was mapped to the centromere region of chromosome 1, with a physical distance of 571.6 kb. We further analyzed the putative candidate genes in the target region through sequencing. A single base substitution (G1390C) was detected in the coding region of the LOC_Os01g31110 gene, which resulted in a missense mutation (A348G) in its encoded protein. Bioinformatic analysis predicted that the LOC_Os01g31110 gene is related to the chloroplast development in rice. Therefore, LOC_Os01g31110 is likely to be the candidate gene of YGL209.