Effect of pre-flowering gibberellic acid applications on tartaric acid content in grape berries

Abstract

Tartaric acid (TA) is a characteristic acid in grapes (Vitis vinifera L.), capable of increasing the acidity of wine, providing a fresh and lively taste, and contributing to the stability of wine while reducing the risk of microbial contamination. However, the transcriptional regulatory mechanisms underlying TA synthesis remain not clear. Here, we found that gibberellic acid (GA3) treatment can increase the content of TA with the upregulation of TA synthesis-related gene, which was confirmed by RNA-seq results. Yeast one-hybrid and electrophoretic mobility shift assay (EMSA) validated that transcription factor VvbZIP60 can interact with the promoter of VvL-IdnDH and activate its expression to promote TA synthesis. In summary, exogenous application of GA3 can elongate fruit clusters, improve fruit quality, and especially increase the TA content in fruit. This study provides a theoretical basis for the purposeful regulation of fruit TA content in grape production.