Sucrose participates in the flower bud differentiation regulation promoted by short pruning in blueberry

Autumn shoot pruning is a significant production measure in Highbush blueberry (<italic>Vaccinium corymbosum</italic> L.) that promotes floral differentiation, but the mechanism is still unclear. To explore the role of carbohydrates in floral induction and differentiation promoted by short pruning, carbohydrate content, and the transport and metabolic-related genes were compared and analyzed. It is found that sucrose might be an important trigger for pruning to promote floral induction. Compared with only pruning the shoots, cutting half of the leaves significantly reduces the flower bud rate and delays the flower differentiation process, while further adding 1.5% sucrose spray alleviates this phenomenon partly. During floral induction, the soluble sugar content in buds increases significantly, while the sucrose content in leaf midvein and buds increases earlier. The starch and soluble sugar content in the stem decreases significantly. At the early flower bud morphological differentiation stage, a large number of starch granules accumulate in the buds, sucrose in leaves increases, glucose in buds decreases, and then fructose decreases. There is an upregulation of <italic>VcFT</italic>, <italic>VcSOC1</italic>, <italic>VcFUL</italic>, <italic>VcSUC,</italic> and <italic>VcINV</italic> expression in the leaf midvein, as well as an upregulation of <italic>VcFT</italic>, <italic>VcSOC1</italic>, <italic>VcTPS1</italic>, <italic>VcINV, and </italic><italic>VcSWEET1</italic> expression in buds during floral induction. At the same time, interaction between <italic>VcSOC1</italic> and <italic>VcTPS1</italic> proteins exists. The level of <italic>VcSOC1 </italic>and <italic>VcAMY</italic> can also be upregulated by <italic>VcTPS1</italic>. Sucrose plays an important role in blueberry floral induction through flowering factors and sugar-related genes, especially <italic>VcFT, VcSOC1</italic>, <italic>VcTPS1</italic>, <italic>VcSUC,</italic> and <italic>VcINV</italic>. The results of this study laid a strong foundation for further research on the regulation mechanism of flower bud differentiation in blueberry and other woody plants.