Abstract
Cryptochromes (CRYs) are blue-light receptors found in both plants and animals. In Arabidopsis, a long-day (LD) plant, cry1 and cry2 are implicated in numerous blue light-dependent responses, including inhibition of hypocotyl elongation, pigment biosynthesis, entrainment of circadian clock, and control of flowering time. Recent studies revealed that these photoreceptors act not only in the light input to the circadian clock but also in the post-transcriptional regulation of CONSTANS (CO). To elucidate the role of the CRY genes in short-day (SD) flowering, we isolated CRY genes in Pharbitis, namely, PnCRY1 and PnCRY2. Immunoblot analyses using specific antibodies prepared against C-termini of each protein revealed that both PnCRY1 and PnCRY2 underwent rapid blue light-induced degradation. Transgenic plants overexpressing either PnCRY1 or PnCRY2 showed shorter hypocotyls when grown under white light. We are currently investigating whether PnCRY1 and PnCRY2 are involved in the photoperiodic induction of flowering in Pharbitis.
