Overexpression of gene OsSUI1 affects floral organ development in rice (Oryza sativa L.)

Abstract

The growth of plants depends on continuous function of meristem cells. Shoot meristems are responsible for all the post-embryonic aerial organs. Despite the central importance of stem cells in plant growth and development, the molecular signatures associated with them have not been revealed in rice (Oryza sativa L.). In this article, we report a rice putative translation initiation factor SUI1 gene, OsSUI1, whose expression was mainly detected in different meristem regions and was upregulated by cold and drought stresses. The activity of the promoter of OsSUI1 was examined by GUS reporter gene technology in stably transformed rice plants. GUS activity was found to be tissue and development-specific being detected in roots, buds, and internode of seedlings, in the veins and midrib of young leaves, as well as in late developing anthers, stigmas, and developing endosperms. Overexpression of OsSUI1 in transgenic rice resulted in an increase in the number of floral organs, including the stamen, carpel, palea/lemma, and stigma. In addition, the overexpression of OsSUI1 increased the transcriptional activities of the type A RR genes OsRR1, OsRR4, and OsRR8 and reduced the expression of OsRR2 and OsRR6, OsRR7. Our data suggest that OsSUI1 may play a critical role in rice floral organ development by affecting cell proliferation.