Expression characteristics of the transcription factorVcMYB21in blueberry fruit coloration and response to UV in seedling
VcMYB21 is a transcription factor of R2R3-MYB. In this study,VcMYB21 was cloned by RACE-PCR method in blueberry. Bioinformatics analysis showed that the full length ofVcMYB21cDNA was 1 373 bp, including the ORF 722 bp, encoding 233 amino acids. The theoretical molecular weight of VcMYB21 was 58.37 kDa, and the value of isoelectric point (pI) was 5.12. The ScanProsite online software showed that the protein contains a 2Fe-2S and a EGF-like binding sites, and it belongs to the outer membrane with unstable structure. Yeast two-hybrid experiment showed thatVcMYB21did not have autoactivation and had the ability to form homo-dimers itself. Tissue-speciifc expression showed thatVcMYB21 was mostly expressed in peel and leaves. The expression of VcMYB21was highest at the early development stage of fruit, and then decreased sharply with a slightly elevation in the period of whole red fruit. The anthocyanin content of fruit increased as the coloration of fruit, and reach the highest at the period of purple fruit of blueberry. Furthermore, the expres-sion ofVcMYB21 was signiifcantly induced under UV-B and UV-C treatment in the leaves of blueberry seed-lings. The data showed thatVcMYB21was more sensitive to UV-B treatment. The expression ofVcMYB21 was signiifcantly induced after 5 min of UV-B treatment and 10 min of UV-C treatment. The anthocyanin content rose sharply afterVcMYB21 expression declined. Both of the expression ofVcMYB21and the anthocyanin con-tent decreased after 10 min of UV-B treatment and 15 min of UV-C treatment. These results indicated that Vc-MYB21 played a negative role in fruit coloration and played roles during abiotic stress of UV.