A Molecular Genetic Study of the Cryptochrome/phytochrome Co-action

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

The ability to perceive and respond to the changing light environment is a fundamental feature of land plants. Light affects many aspects of development of a young dicotyledonous seedling. In Arabidopsis, de-etiolation is regulated by two types of photosensory receptors: the red/far-red light receptors phytochromes and blue/UV-A light receptors cryptochromes. It is well known that cryptochromes and phytochromes, which are evolutionary unrelated, co-act to bring about the similar photomorphogenic responses. Although the mechanism underlying the photoreceptor co-action is not known, it has been proposed that some photoreceptor signaling molecules might be involved in the action of both cryptochromes and phytochromes. . Consistent with this hypothesis, a novel photomorphogenic mutant, sub1 (short under blue light and far-red light), and the SUB1 gene that encodes a calcium-binding protein has been isolated. The current project is aimed to (1) characterize the cellular localization of SUB1 and light-regulated expression of SUB1; (2) investigate the significance of the calcium-binding activity in the function of SUB1; and (3) characterize the additional sub loci for possible involvement of the corresponding genes in the cryptochrome/phytochrome co-action. Completion of this research will improve understanding of the molecular mechanism of light-regulated plant development.