The content and diversity of carotenoids associated with high-altitude adaptation in Tibetan peach fruit

Carotenoids are important secondary metabolites that may participate in response to extreme environments. Fruit color changes were observed in peaches growing at altitude on the Tibetan Plateau. Here, we qualitatively and quantitatively analyzed 43 kinds of carotenoids in 96 Tibetan peach and 12 cultivated peach fruit samples. Comparative analysis revealed that 25 kinds of carotenoids accumulated at significantly different levels between Tibetan peaches and cultivated peaches. Based on a population structure analysis, the carotenoid levels of Ti-betan peaches were divided into two groups, which are mainly affected by the environmental factors light and temperature. The correlation analysis implied that the levels of 9 carotenoids were significantly correlated with altitude. qRT-PCR results showed that PSY, CCD4 and BCH were significantly differently expressed between the low and high altitude Tibetan peaches. In summary, this study showed that the abundant variation in carotenoids was highly associated with high-altitude adaptations in Tibetan peach fruit.