MdAGL29 positively regulates MdBRC1/2 and negatively controls shoot branching in apple.

The MADS-box transcription factor MdAGL29 serves as a negative regulator of branching in apple by modulating MdBRC1/2 expression. Branch number is one of the major determinants in apple tree architecture. MdAGL29, a member of the MADS-box transcription factor family, is downregulated by 6-benzylaminopurine, a synthetic cytokinin. Heterologous overexpression of MdAGL29 in poplar resulted in fewer branches and lower endogenous cytokinin content compared with the control after decapitation treatment. Yeast one-hybrid and dual-luciferase reporter assays verified that MdAGL29 positively regulates the expression of branch negative regulators MdBRC1/2. Collectively, MdAGL29 acts as a negative regulator governing branch development in apple. These findings provide a promising target for precise regulation of plant branching.