Functional Characterization of a WD-Repeat Protein Gene (OsWD1) in Rice

A gene encoded WD-40 repeat protein (OsWD1) was isolated from rice cells to study the platform for protein-protein interactions in germinating seeds. The expression of OsWD1 was found to be specifically induced at 3 d of seed germination. By ectopic overexpressing (OsWD1-Ox) or RNA interference gene knockdown (OsWD1-Ri) of OsWD1, respectively. Results revealed that the rice seedlings and grain size were enhanced in OsWD1-Ox lines, but were reduced in OsWD1-Ri lines. Moreover, the expression of GA-inducible gene, OsEP3A, which was strongly induced in OsWD1-Ox lines during rice seed germination. By iodine staining in starch containing solid medium, the a-amylase activities were further enhanced in OsWD1-Ox lines regardless with or without exogenous GA in the medium. These results suggested that OsWD1 might acts as a platform for protein-protein interactions to regulate seedling and seed development in rice by a GA-dependent manner