Normal development of chloroplast is vitally important to plants, but its biological mechanism is still far from fully being understood, especially in rice.
In this study, a novel yellow-green leaf mutant, ygl138, derived from Nipponbare ( Oryza sativa L. ssp. japonica) treated by ethyl methanesulfonate (EMS), was isolated. The mutant exhibited a distinct yellow-green leaf phenotype throughout development, reduced chlorophyll level, and arrested chloroplast development. The phenotype of the ygl138 mutant was caused by a single nuclear gene, which was tentatively designed as YGL138( t). The YGL138( t) locus was mapped to chromosome 11 and isolated into a confined region of 91.8 kb by map-based cloning. Sequencing analysis revealed that, Os11g05552, which was predicted to encode a signal recognition particle 54 kDa (SRP54) protein and act as a chloroplast precursor, had 18 bp nucleotides deletion in the coding region of ygl138 and led to a frameshift. Furthermore, the identity of Os11g05552 was verified by transgenic complementation.
These results are very valuable for further study on YGL138( t) gene and illuminating the mechanism of SRP54 protein involving in chloroplast development of rice.