An Initial Study To Explore The Function Of Cryptochromes And Interacting Proteins In Rice

Cryptochrome(CRY)is a kind of blue light receptor that has been found in algae, fungi, mosses, ferns, seed plants and animals. Plant CRYs regulate many light responses, such as photomorphogenesis, flowering time, circadian clock, stomatal opening and apoptosis etc. The signal transduction mechanism of CRYs in model plant Abrbidopsis has been well studied, but the mechanism in rice is still largely unkown. This work provides a preliminary research on rice CRY signal transduction mechanisms, with the major results as follows:(1)Three Rice CRYs genes(OsCRY1a, OsCRY1 b and OsCRY2)were cloned.(2)Yeast two hybrid experiments confirmed the physical interactions between OsBICs(blue-light-dependent interaction with cryptochrome)proteins and OsCRYs. OsBIC1 interacts with OsCRY2 in a blue-light-dependent manner, while OsBIC2 interacts with OsCRYs weakly in the dark but strongly under blue light.(3)Targeted muations were generated in rice by CRISPR/Cas9 technology. The CRISPR/Cas9 vectors targeting OsCRYs, OsBICs, OsCIBs, OsSPAs and OsCOP1 genes were constructed and transformed into rice. The mutations(insertions, deletions or replacements at the target site)corresponding to OsCRY1 a, OsCRY1 b, OsCRY2 and OsBIC1 genes were detected at T0 and T1 generation. Moreover, OsCRY1 a, OsCRY1 b and Osbic1 homozygous mutants were identified.(4)Oscry1a and Oscry1 b mutants showed elogated phenotype, which is sharp contrast to the dwarf phenotype of Osbic1 mutants.(5)Overexpression of OsBIC1 and OsBIC2 conferred later flowering phenoytpe.Above results demonstrate that the protein OsBICs can interact with the protein OsCRYs, and they exhibit opposing effects in photomorphogenesis and regulation of flowering periods. Therefore, we think that OsBICs inhibits OsCRYs mediated light signal transduction functions through protein interactions. Our study provides the basis for the analysis of rice cryptochrome mediated light signal transduction mechanisms.