Abstract:In order to obtain the information of terpenoids and their synthase genes of Cymbopogon citratus, the changes in the transcriptome and metabolome of young leaves under light and shade were studied, and the expression of terpenoid synthase genes was confirmed by qRT-PCR. Metabolomic analysis showed that C. citratus contained 23 terpenes, including 4 monoterpenes, 4 sesquiterpenes, 8 diterpenes, 3 triterpenes and 4 tetraterpenes. The relative contents of ginkgolide C and astaxanthin under shade was higher than those under light. According to transcriptome sequencing, there were 24, 49 and 58 genes encoding 4, 11 and 12 synthases involved monoterpene, diterpene and sesquiterpene and triterpene biosynthesis pathway, respectively, in which the relative expression of 8 genes encoding 6 synthetases significantly increased under shade, but that of premnaspirodiene oxygenase gene was just reverse. The expression patterns of four terpenoid synthase genes with significant difference FPKM values under shading by qRT-PCR was consistent with the transcriptome sequencing results, however, the differential expression of different synthase genes were different. Therefore, it was suggested that C. citratus contains 23 terpenoids in 4 categories catalyzed by 27 synthetases, which are encoded by 131 genes, and light intensity affects the relative content of 2 terpenoids and the expression of 9 synthetase genes.