Analysis of volatile compounds and their potential regulators in four high-quality peach (Prunus persica L.) cultivars with unique aromas

The significant decline of flavor in modern commercial peach (Prunus persica L.) cultivars has become a serious problem for producers and consumers; therefore, understanding peach flavor is important for improving commercial cultivars. Here we analyzed the volatiles in the Four Nationwide Traditional Famous Peach of China, ‘Bai Hua Shui Mi,’ ‘Feng Hua Yu Lu,’ ‘Fei Cheng Tao,’ and ‘Shen Zhou Mi Tao’, which are well known for their flavors and long cultivation history. We determined the major volatile groups and volatiles unique to and common among each cultivar. Eight odors were dominant in the peach aromas. We measured the expression levels of the genes encoding biosynthetic enzymes and transcription factors associated with the important volatiles. This revealed differences among cultivars in three volatile compound biosynthetic pathways: the β-oxidation pathway (epoxide hydrolase genes [Prupe.3G156700, Prupe.7G041200] and acyl-coA oxidase genes [Prupe.7G067100]); lipoxygenase pathway (lipoxygenase genes [Prupe.4G047800, Prupe.6G324100]); terpenoid pathway (phytoene synthase genes [Prupe.3G013200, Prupe.3G178500], terpene synthase genes [Prupe.4G030300, Prupe.4G030400], and ζ-carotene desaturase genes [Prupe.6G340000]). Expression of a bHLH transcription factor (Prupe.8G157500) was also associated with the important volatiles. These results provide a greater understanding of the aromas of these high-quality peach cultivars, which could contribute to efforts to improve peach fruit aroma.