Effects on the Synthesis and Accumulation of Triterpenes in Leaves of Cyclocarya paliurus under MeJA Treatment

Abstract

Cyclocarya paliurus (Batal.) lljinskaja, the sole and multi-functional tree species of the family Juglandaceae, grows extensively in subtropical areas of China. Species-specific triterpenoids in its leaves have validated health-promoting effects, including hypoglycemic and hypolipidemic activities. To illustrate the effect of MeJA treatment on the accumulation and biosynthesis of triterpenoids in C. paliurus leaves at different stages of maturity, the contents of total triterpenoids and six triterpene compounds, along with the relative expression of three key genes, were detected. The results showed that the contents of triterpenes and expression patterns of the genes significantly differed among the samples. Different treatment times also had diverse effects on triterpenoid accumulation and gene expression. MeJA treatment had positive effects on total triterpenoids, cyclocaric acid B, and cyclocarioside A/B, especially in young leaves. Gene expression was highest in young leaves after 10 days of treatment, indicating that they were the most sensitive to MeJA. This study provided a reference for improving the accumulation of triterpenoids in C. paliurus plantations in the future.