Characterization of a zebra mutant of rice with increased susceptibility to light stress

The rice zebra mutant TCM248 is a single recessive mutant. This mutant deve lops transverse-striped leaves with green and white sectors under alternate light/dark growth conditions. Mutants that were grown under a higher light intensity during the light period showed a more intense striped phenotype. The white tissues contained abnormal chloroplasts with few internal membra ne structures, while the preen tissues in the mutants contained normal chlo roplasts. The white tissue contained only trace amounts of Chls and caroten oids, and mRNA accumulation of nuclear genes encoding chloroplast proteins (rbcS, cab) was strongly suppressed compared to that in the wild type plant s. A series of growth condition shift experiments demonstrated that the mut ant displayed the striped phenotype only if it was exposed to the alternate light/dark growth conditions during a limited stage of early leaf developm ent. These data suggest that the zebra gene is involved in the acquisition of photoprotective capacity of the plants and that this gene functions at a n early stage of chloroplast differentiation.