PbMYB120 Negatively Regulates Anthocyanin Accumulation in Pear

摘要

Subgroup 4 R2R3 MYBs play vital roles in the regulation of anthocyanin biosynthesis. However, there is limited knowledge regarding the functions of MYB repressors in pear ( ). Here, PbMYB120 was identified as a potential regulator of anthocyanin biosynthesis. A phylogenetic analysis revealed that PbMYB120 was clustered into the FaMYB1-like clade of the subgroup 4 R2R3 MYBs. was expressed higher in red peels than in green peels in five pear cultivars. expression was positively correlated with anthocyanin accumulation. However, the transient overexpression of led to the inhibition of anthocyanin accumulation and expression. Promoter binding and activation assays indicated that PbMYB120 binds to the promoter of and represses the promoter’s activity. Thus, the inhibition of anthocyanin accumulation by PbMYB120 may be correlated with the repression of . Furthermore, during anthocyanin induction, the expression levels of anthocyanin activators and were upregulated. This study demonstrated that was highly expressed in pear tissues having higher anthocyanin accumulations but acted as a repressor in the regulation of anthocyanin accumulation. PbMYB120 may work coordinately with anthocyanin activators and serve as a balancer of anthocyanin accumulation.