Insight into the Genetics of a Novel White-Striped Leaf in Rice

Rice is mainly consumed by half of the world's population. The imminent climate change and population growth expected in the next 30 years will outpace the current rice production capacity, posing risks to food and nutrition security in developing nations. One simplified approach is to improve photosynthetic capacity by increasing chlorophyll content in leaves and stems.We identified a single recessive gene controlling wsl in RBR05. It is a novel missense mutation (R310H) of OsSAMHD1, a key contributor to the wsl in RBR05. The mutation, wsl310 turns Arg to His at the amino acid position 310 in exon 10, which results in abnormal chloroplast development, a lack of chlorophyll pigment and the formation of nonchlorophyllous cells in the whitened region of the leaves and leaf sheaths. The wsl310 was associated with decreased gene expression in photosynthetic machinery formation and the chlorophyll biosynthetic pathway, while upregulation of the OsRNRS1 and genes involved in the expression of plastid-encoded genes was observed. A SNP marker specific for the missense mutation was completely co-segregated with the wsl310 in the segregating population for wsl and SGL, demonstrating that the R310H is responsible for wsl in RBR05.