Abstract
The rice virescent-1 (v1) mutants is temperature-conditional and develops chloroplast-deficient leaves under the restrictive temperature. We previously speculated that the V1 gene functions at an early stage of leaf development (P4), and are involved in the regulation of chloroplast translation/transcription capacity. Positional cloning revealed that V1 encodes a novel 32 kDa protein, and is deduced to be localized to chloroplast. Western blot analysis indicated that V1 protein highly accumulated in the immature leaves at P4 stage, but barely accumulated in mature leaves that correspond to P5 and P6 stages. In v1 mutant leaves, normal expression of chloroplast transcription/translation apparatus are disturbed and accumulation of plastid-encoded chloroplast proteins were severely suppressed. These results suggest that V1 has important roles in the construction of the chloroplast transcription/translation apparatus that occurs exclusively at the P4 stage.
