A candidate PpRPH gene of the D locus controlling fruit acidity in peach

Key message A candidate gene, designate PpRPH, in the D locus was identified to control fruit acidity in peach. Fruit acidity has a strong impact on organoleptic quality of fruit. Peach fruit acidity is controlled by a large-effect D locus on chromosome 5. In this study, the D locus was mapped to a 509-kb interval, with two markers, 5dC720 and 5C1019, co-segregating with the non-acid/acid trait of peach fruit. Within this interval, a candidate gene encoding a putative small protein, designated PpRPH, showed a consistency between gene expression and fruit acidity, with up- and down-regulation in non-acidic and acidic fruits, respectively. Transient ectopic expression of PpRPH in tobacco leaves caused an increase of pH by approximately 40% compared to the control transformed with empty vector. Whereas, the concentrations of citrate and malate decreased significantly by 22% and 37%, respectively, with respect to the empty vector control. All these results suggest that PpRPH is a strong candidate gene of the D locus. These findings contribute to our overall understanding of the complex mechanism underlying fruit acidity in peach as well as that in other fruit crops.

Automated summary

The candidate gene PpRPH in the D locus was identified as controlling fruit acidity in peach, showing consistency between gene expression and fruit acidity. Ectopic expression of PpRPH in tobacco leaves increased pH and decreased citrate and malate concentrations, suggesting its role as a strong candidate gene of the D locus controlling fruit acidity. These findings contribute to understanding the complex mechanism underlying fruit acidity in peach and other fruit crops.