MdIPT1, an adenylate isopentenyltransferase coding gene from Malus domestica, is involved in branching and flowering regulation

Flowering and shoot branching are significant agricultural traits for apple tree breeding. Cytokinin metabolism and signaling pathways play a crucial role in plant development. However, little is known about cytokinin biosynthetic molecular mechanism and function involved in apple flowering and branching. In this study, an adenylate isopentenyl transferase coding gene MdIPT1, homologous to AtIPT3/AtIPT5 in Arabidopsis thaliana, was identified. MdIPT1 was highly expressed in apple floral and axillary buds and was dramatically up-regulated during floral induction and axillary bud outgrowth. The promoter of MdIPT1 showed high activity in multiple tissues and responded to different hormone treatments. The MdIPT1-overexpressing Arabidopsis showed a multi-branching and early-flowering phenotype, with elevated endogenous cytokinin levels and altered expression of genes related to branching and flower formation. Overexpression of MdIPT1 confers the growth vigor of trans-genic apple callus on a CKs-deficient medium. Our findings suggest that MdIPT1 is a positive regulator involved in branching and flowering. The data presented herein provide extensive research results on MdIPT1 and will contribute to molecular breeding for new apple varieties.

Automated summary

This study identified a gene, MdIPT1, homologous to AtIPT3/AtIPT5 in Arabidopsis thaliana, which plays a significant role in flowering and shoot branching in apple trees. MdIPT1 was highly expressed in apple floral and axillary buds and its expression was up-regulated during floral induction and axillary bud outgrowth. Overexpression of MdIPT1 in Arabidopsis resulted in multi-branching and early-flowering phenotype, indicating its positive role in branching and flowering. This research provides valuable insight into the molecular mechanisms involved in apple flowering and branching and contributes to the development of new apple varieties.