Integrated Analysis of Terpenoid Profiles and Full-Length Transcriptome Reveals the Central Pathways of Sesquiterpene Biosynthesis in Atractylodes chinensis (DC.) Koidz.

Atractylodes chinensis (DC.) Koidz. is an aromatic and medicinal plant in East Asia. The primary bioactive compounds in this species are sesquiterpenes, particularly β-eudesmol, hinesol, and atractylon. Cultivation techniques require improvement to meet the medicinal demands of this species. In this study, gas chromatography-mass spectrometry analysis of an A. chinensis germplasm showed its essential oil contained various sesquiterpenes, including a high relative ratio of β-eudesmol. Full-length transcriptome profiling of A. chinensis revealed 26 genes related to terpenoid biosynthesis. These genes belonged to 13 gene families, including five in the isopentenyl pyrophosphate synthase gene family and four in the terpene synthase gene family. The functions of the four terpene synthase genes were proposed based on gene expression patterns and phylogenetic relationships: one was thought to encode monoterpene synthase and three to encode sesquiterpene synthase. Based on the results, the central biosynthesis pathways of the major sesquiterpenes in the A. chinensis rhizome were proposed, and three sesquiterpene synthase genes were identified as expressed in the rhizome for the first time. AcHMGR, AcFPPS, and the three sesquiterpene synthase genes were proposed as potential targets for molecular breeding in A. chinensis to enhance its sesquiterpene content.