Phytochrome-mediated control of COP1 gene expression in rice plants

We isolated a COP1 cDNA from rice and found that it could complement the Ar abidopsis cop1-4 mutant. The putative rice COP1 protein has the Ring-finger , coiled-coil, and WD-40 repeat domains, which are also conserved in pea, t omato, and mammalian COP1 proteins. The degree of overall identity between rice COP1 and Arabidopsis COP1 is 73%, and the similarity value is 83%. Exp ression of rice COP1 was detected in almost all plant tissues, with the lev el being relatively higher in calli and very low in etiolated leaves. The e xpression level was positively controlled by light in etiolated and green l eaves. At the end of the light period, expression of the gene in green leav es could be down-regulated by far-red light. This far-red light effect coul d be prevented by subsequent irradiation with red light. These results indi cate that phytochrome regulates rice COP1 expression.