Cloning and Function Analysis of Rice PhytochromeA in Photomorphogenesis

Phytochrome is the first discovered phytochrome in higher plants, which is primarily involved in far-red light sensing (high irradiance response, HIR) and in responses to a pulse of very weak light (very low fluence response, VLFR). In order to investigate the functions of OsPHYA in photomorphogenesis, we cloned OsPHYA gene and did a series of experiments including expression analysis of OsPHYA gene in different organs under light and dark, seed germination rate under VLFR, coleoptile length under VLFR and HIR, and chlorophyll content in process of etiolated seedling turning green. The results showed that expression level of OsPHYA gene in root, stem and leaf under dark was higher than that under light, OsPHYA could promote rice seed germination under VLFR, OsPHYA inhibited coleoptile elongation in responses to VLFR and HIR. We further detected agronomic characters between the OsphyA mutants and WT seedlings, which showed there was no significant differences except for panicle number per plant, indicating that OsphyA has no obvious effect on agronomic characters in rice.