A novel strategy for enhancing anthocyanins content in VdMYB56-overexpressing rabbiteyes blueberry lines

As a horticultural plant with high nutritional and commercial value, blueberries ( Vaccinium ashei ) suffer from inefficient genetic transformation systems, which highly constrain the development of biotechnology breeding in this fruit crop. The central method involved transferring VdMYB56 into Agrobacterium , thereby establishing the Agrobacterium -mediated genetic transformation system, which was started from an infection with Agrobacterium (OD _{600 =} 0.6) for a 10 min, followed by co-cultivation for three days. The main results indicated that the transformation efficiency detected in red VdMYB56 -overexpressing calli was as high as 10.95%, which was consistent with the PCR assay results. In the VdMYB56 -overexpressing calli, the expression levels of VdMYB56 and Vd3GT were higher than those of the WT; The total anthocyanin content (TAC) and VdUFGT enzymatic activity were both superior to those of the wild type (WT). Subsequently, the VdMYB56 -overexpressing adventitious buds exhibiting red were obtained, and the expression levels of VdMYB56 and Vd3GT in the VdMYB56 -overexpressing lines were 2.75–24.15 and 10.56–20.69 folds as high as those of the WT, respectively; the TAC and VdUFGT activity in three lines were 1.78–4.52 and 2.25–4.35 times also higher than those of the WT, respectively. Collectively, an efficient genetic transformation system was established, and the VdMYB56 -overexpressing rabbiteye blueberry lines with enhanced anthocyanin content was gained herein, which provided an appropriate methodology for new germplasm creation in blueberry, and the VdMYB56 -overexpressing lines may facilitate the breeding in elevating anthocyanin.