Abstract
Phytochromes regulate various physiological light responses in plants. In Arabidopsis thaliana, the over-expression of N-terminal domain of phytochrome B linked to GFP-GUS, rescued some phyB phenotypes. To reveal the function of rice phyB molecule, transgenic rice (phyB-2) plants over-expressing OsPhyBN450 and OsPhyBN651, fused to the GFP-GUS, were examined. Rice phyB mutant showed some altered photomorphogenesis such as longer coleoptile and pale colored first leaf under red light, and increased angle of second leaf blade under blue light. Under red light, those phenotypes were partially rescued by over-expression of OsPhyBN651, but not by OsPhyBN450. Under blue light, plants with OsPhyBN450 exhibited a similar phenotype to the wild type while plants with OsPhyBN651 exhibited a drastically stronger phenotype than wild type. These results indicate that the signaling mechanism of rice phyB molecule differs from that of A. thaliana , and distinct phyB domains may be required for various physiological responses in rice.
