Molecular Cloning And Functional Characterization Of UVR8 Gene In Eggplant

Eggplant（Solanum melongena L.）is one of the vegetables rich in anthocyanins.Light is a key environmental factor in regulation of anthocyanin biosynthesis.And UV-B is one of the components of natural light.As a knowed UV-B receptor,UVR8 is isolated from eggplant using homology-based cloning method,named SmUVR8.Sequence analysis showed that CDS of SmUVR8 cDNA is 1 530 bp,encoding 509 amino acids.ExPASy and SOPMA analysis show that SmUVR8 is unstable hydrophilic protein.SmUVR8 amino acid sequence compares with the UVR8 of other 5 species in GenBank,which show that UVR8 amino acid sequence homology with the potato（StUVR8 XP₀06338334.1）,wild tomato（SpUVR8 XP₀15066721.1）,pepper（CaUVR8 XP₀16561263.1）,arabidopsis thaliana（AtUVR8 NP₀01327030.1）and tobacco（NtUVR8 XP₀16442373.1）is 94 %,95 %,93 %,71 % and 92 % respectively.SmUVR8 gene is highly homologous with these species.Transferring SmUVR8 into Arabidopsis Thaliana show that the transgenic plants（SmUVR8/uvr8）restored the phenotype of hypocotyl length,the flowering time and anthocyanin accumulation,which explain SmUVR8 has the function of arabidopsis AtUVR8.Real-time fluorescent quantitation results show that the expression level of UVR8,HY5 and CHS under UV-B treatment is significantly higher than that under white light treatment in eggplant seedling,wild type arabidopsis（WT）and transgenic plants（SmUVR8/uvr8）,which show that SmUVR8 response to UV-B and affect the hypocotyl elongation and anthocyanin accumulation by SmHY5 and SmCHS.Yeast two-hybrid results show that SmUVR8 interact with SmCOP1 under UV-B,which fill in the light induced anthocyanin synthesis of eggplant regulation pathways.Under UV-B,the interaction between SmUVR8 and anthocyanin synthesis factor SmCOP1 activates SmHY5 and SmCHS promoting anthocyanin synthesis;without UV-B,SmUVR8 become homodimer form,unable to interact with SmCOP1 so that SmCOP1 degrade SmHY5,then light morphological construction is inhubited.