Rice Blu-ray The Receptor Cryptochrome1 The Function And Signal Transduction Research Of The Mechanism

Cryptochromes (CRY) are blue light photoreceptors that mediate various light responses suchas inhibition of hypocotyl elongation, enhancement of cotyledon expansion, anthocyaninaccumulation, flowering and stomatal opening in Arabidopsis. The signaling mechanism ofArabidopsis CRY is mediated through direct interaction with COP1, a negative regulator ofphotomorphogenesis. CRY has now been characterized in tomato, pea, moss, and fern, but itsfunction in monocots is largely unknown. Here, we report the function and the basic signalingmechanism of rice cryptochrome 1 (OsCRY1). Overexpression of OsCRY1b resulted inblue-light dependent short hypocotyl phenotype in Arabidopsis and short coleoptile, leafsheath and leaf blade phenotype in rice, respectively. On fusion with β-glucuronidase (GUS),the C-terminal domain of either OsCRY1a (OsCCT1a) or OsCRY1b (OsCCT1b) mediated aconstitutive photomorphogenic phenotype (COP phenotype) in both Arabidopsis and rice,whereas OsCCT1b mutants corresponding to missense mutations in previously describedArabidopsis cry1 alleles failed to confer a COP phenotype. Yeast two-hybrid and subcellularcolocalization studies demonstrated that OsCRY1b physically interacted with rice COP1(OsCOP1). From these results, we conclude that OsCRY1 is implicated in blue-lightinhibition of coleoptile and leaf elongation during early seedling development in rice and thatthe signaling mechanism of OsCRY1 involves direct interaction with OsCOP1.