Anthocyanin accumulation in the red-fleshed grape germplasm ZhongShan-HongYu through bulked segregant analysis and RNA-seq.

In grapes (Vitis L.), the transcription factors VvMYBA1 and VvMYBA2, located on chromosome 2 (Chr2), are the primary genetic determinants of fruit skin color. However, the specific loci responsible for anthocyanin accumulation in the flesh remain unidentified. This study utilized ZhongShan-HongYu (ZSHY, named by Tao Jianmin, Vitis vinifera L.) red-fleshed grape germplasm, which accumulates anthocyanins in both skin and flesh, along with its selfed and hybrid progeny as experimental materials. Through bulked segregant analysis and RNA sequencing, LOC100233098 (VvMYBA1), located on Chr2, was identified within the mapping region. The research found established that the red flesh phenotype is controlled by the dominant gene VvMYBA1, with the color of leaves, skin, and flesh inherited together. Through fluorescence in situ hybridization, transient transformation of grape, and stable transformation of tobacco, the study determined that the insertion of a 408-bp tandem repeat sequence within the VvMYBA1 promoter is the principal factor contributing to the significant increase in VvMYBA1 expression, ultimately leading to the red flesh phenotype in ZSHY. This mutation discovery will aid in the cultivation of new teinturier varieties, guide molecular breeding of grapes, and provide valuable resources for improving grape cross-breeding.