Transcriptional co-regulation of anthocyanin accumulation and acidity in fruits

Color and acidity, two important fruit quality traits, greatly influence consumer choice and market competitiveness. They result from the accumulation of anthocyanins and organic acids in the vacuole. A shift in the vacuolar pH, caused by the accumulation of organic acids, leads to a change in the absorption spectrum of anthocyanins, and thus to changes in the color of tissues, suggesting a possible relationship between these two traits. Thus, the discovery of the molecular co-mechanism responsible for these processes is one of the most challenging for improving fruit quality traits and ultimately increasing market value. Here, we review current knowledge on the relationship between anthocyanin accumulation and acidity, and highlight recent advances in the roles of TFs in regulating these quality traits via transcriptional co-regulation of different genes associated with anthocyanin accumulation and acidity for fruit quality improvement.