Integrated Metabolomic and Transcriptomic Analysis of Nitraria Berries Indicate the Role of Flavonoids in Adaptation to High Altitude

Plants of , belonging to the Zygophyllaceae family, are not only widely distributed at an altitude of about 1000 m but also at an altitude of about 3000 m, which is a rare phenomenon. However, little is known about the effect of altitude on the accumulation of metabolites in plants of . Furthermore, the mechanism of the high-altitude adaptation of has yet to be fully elucidated. In this study, metabolomics and transcriptomics were used to investigate the differential accumulation of metabolites of berries and the regulatory mechanisms in different altitudes. As a result, the biosynthesis of flavonoids is the most significant metabolic pathway in the process of adaptation to high altitude, and 5 Cyanidins, 1 Pelargonidin, 3 Petunidins, 1 Peonidin, and 4 Delphinidins are highly accumulated in high-altitude . The results of transcriptomics showed that the structural genes 4 (2), 3 , 4 (2), (2), (2), and (2) were highly expressed in high-altitude . A network metabolism map of flavonoids was constructed, and the accumulation of differential metabolites and the expression of structural genes were analyzed for correlation. In summary, this study preliminarily offers a new understanding of metabolic differences and regulation mechanisms in plants of from different altitudes.