| Sweet sorghum [Sorghum bicolor(L.)Moench] has high photosynthetic efficiency,high biological yield,and strong resistance at the same time.It has attracted more and more attention as a sugar,feed and energy crop.Light is one of the most important environmental factors that affect plant growth and development.It regulates many physiological processes in plant life cycle,such as seed germination,stem elongation,floral initiation and organ senescence.The different light spectrum play different or same roles in the regulation.Blue light regulates the deetiolation of seedling,stomatal opening and floral initiation.Cryptochrome1(CRY1)and CRY2 are two blue light receptors,first discovered in Arabidopsis thaliana,mediates a series of blue light response.In this study,The CDS of SbCRY2 from sweet sorghum was cloned into pEGAD vector driven by 35 S promoter using infusion technology.The transgenic Arabidopsis was obtained through floral dipping.The phenotype of T3 transgenic Arabidopsis was identified.The results showed that overexpression of SbCRY2 significantly inhibited the hypocotyl elongation of the transgenic Arabidopsis under blue light,and promoted the flowering of the transgenic Arabidopsis under short day conditions.Compared with the wild type,the seed germination of SbCRY2-overexpressed transgenic Arabidopsis was more sensitive to abscisic acid(ABA)and salt stress.The results of real-time fluorescent quantitative PCR(QPCR)showed that the expression of ABA signaling-related genes including ABF1,ABF2 and ABF3 in the SbCRY2 transgenic Arabidopsis were upregulated higer than that in the wild type..The results demonstrated that SbCRY2 function as a blue light receptor and may integrate blue light and stress signals to regulate plant development.BIC1(Blue-light Inhibitor of Cryptochromes 1)and BIC2,recently discovered in plants,are a kind of small molecular weight proteins and were found to interact with Arabidopsis CRY2.BIC1 and BIC2 inhibit the formation of blue light-dependent CRY2 dimerization,thereby inhibiting the physiological function of CRY2 in Arabidopsis.In our study,phylogenetic tree of BIC proteins from 12 different species was constructed.The results showed that BIC proteins formed obvious boundaries among dicotyledonous,monocotyledonous and lower plants species.Sweet sorghum BIC1 and BIC2 showed the highest homology with maize CRY1 and rice BIC2 respectively.The CDS of SbBIC1 and SbBIC2 were cloned into yeast expression vector pBridge separately,at the same time,the CDS of SbCRY2,SbCRY1 a,SbCRY1b,AtCRY1,AtCRY2 were cloned into yeast expression vector pGADT7 respectively using the technology of Infusion.The results of yeast two hybrid assay showed that SbBIC2 could interact with SbCRY2,SbCRY1 a,SbCRY1b and AtCRY2 respectively in a blue light-dependent way.This finding indicates that SbBIC2 likely participate in blue light signal transduction mediated by CRYs in sweet sorghum. |
