Gene regulation of anthocyanin biosynthesis in two blood-flesh peach (Prunus persica (L.) Batsch) cultivars during fruit development.

The blood-flesh peach has become popular in China due to its attractive anthocyanin-induced pigmentation and antioxidant properties. In this study, we investigated the molecular mechanisms underlying anthocyanin accumulation by examining the expression of nine genes of the anthocyanin biosynthesis pathway found in the peach mesocarp. Expression was measured at six developmental stages in fruit of two blood-flesh and one white-flesh peach cultivars, using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results show that the expression of the chalcone synthase (CHS) gene was closely related to anthocyanin accumulation in both of the blood-flesh peaches. In the white-flesh peach, we found that the transcription level of phenylalanine ammonia-lyase (PAL) during fruit development was much lower than that in the blood-flesh peach, even though all other genes of the anthocyanin biosynthesis pathway were highly expressed, suggesting that the PAL gene may be limiting in anthocyanin production in the white-flesh peach. Moreover, the transcription levels of the CHS and UDP-glucose-flavonoid 3-O-glucosyltransferase (UFGT) genes were markedly up-regulated at three days after bag removal (DABR) in the blood-flesh peach, suggesting that CHS and UFGT are the key genes in the process of anthocyanin biosynthesis for both of the blood-flesh peaches. The present study will be of great help in improving understanding of the molecular mechanisms involved in anthocyanin accumulation in blood-flesh peaches.