Overexpression of OsRAA1 promotes flowering and hypocotyls elongation in Arabidopsis

Previously, OsRAA1, an AtFPF1 homologue gene, was found to play an important role in modulating rice root development. In the current study, OsRAA1 was overexpressed in Arabidopsis, and the transgenic plants showed early flowering and elongated hypocotyl phenotypes as compared with the wild-type under white-light conditions. The hypocotyls of transgenic lines were twice as long as those of wild-type plants under red-light conditions but were indistinguishable from those of the wild-type under blue and far-red light and darkness. In addition, the phenotypes of AtFPF1 transgenic lines were similar to those of OsRAA1 transgenic lines. These results suggested that OsRAA1/AtFPF1 protein is involved in regulating flowering time and plays an important role in the inhibition of hypocotyl elongation under continuous red light. The functions were preserved during the evolution.