Blood peach: an unexpected genetic determinism

Plant Science, 2025, 359, pp.112572. DOI:10.1016/j.plantsci.2025.112572

Accumulation of anthocyanin pigments is a primary determinant of fruit quality in peach (Prunus persica L. Batsch). The recessive blood-flesh trait (bf), identified in French cultivars was first mapped on chromosome 4. However, the underlying gene is yet to be identified. In this study, the genetic, molecular and transcriptional bases of the bf trait were investigated. Blood-flesh cultivars showed high levels of cyanidin-3-glucoside and cyanidin-3-rutinoside in the fruit mesocarp about 45-60 days after anthesis. Fine mapping coupled to a positional cloning strategy mapped the bf locus to an 80-kb interval on peach linkage group 4. The sequence polymorphism analysis of genes present in this interval allowed the identification of only one candidate gene for bf a deletion of 21-bp in exon 3 of a PSAK-like gene (PSAK:photosystem I subunit K). A specific marker for the deletion was developed and validated in different genetic backgrounds. An expression study of PpPSAK as well as analysis of structural, regulatory and photosynthesis related genes was performed to compare cultivars with blood-flesh (‘Montarsa’) and without blood-flesh (‘S11332’) during fruit development from 60 days after blooming until fruit maturity. Overexpression of PpPSAK in the flesh of bf fruit was correlated with expression of anthocyanin biosynthesis structural genes. A protein-protein interaction study was performed and is presented with an open discussion on functional pathways in peach.