Comparative Transcriptome Analysis of Leaf, Stem, and Root Tissues of Semiliquidambar Cathayensis Hung T. Chang Reveals Candidate Genes Involved in Terpenoid Biosynthesis

Abstract

Abstract Background The roots, branches, leaves, bark, and nectar of Semiliquidambar cathayensis Hung T. Chang can treat rheumatoid arthritis, lumbar muscle strain, and other diseases. However, limited knowledge of the S. cathayensis Chang genome hampers further research on elucidating the pathways underlying active ingredient synthesis and regulation of its accumulation. In this study, we aimed to generate data to elucidate biosynthetic pathway of the active ingredient synthesis and related molecular mechanisms. Methods We conducted transcriptome sequencing of S. cathayensis Chang leaves, stem epidermis, stem xylem, root epidermis, and root xylem. Results We identified 88,582 unigenes, among which, 36,144 unigenes were annotated to the nr protein database, 21,981 to the Gene Ontology database, 11,565 to the Clusters of Orthologous Groups database, 24,209 to the Pfam database, 21,685 to the SWISS-PROT database, and 12,753 to the Kyoto Encyclopedia of Genes and Genomes (KEGG), with 5,072 unigenes common to all six databases. Of those annotated using the KEGG database, 187 unigenes were related to the terpenoid metabolism pathway, and expression analysis of the related genes indicated that the mevalonate and methylerythritol 4-phosphate pathways play different roles in terpenoid biosynthesis in different tissues of S. cathayensis Chang. Conclusions These findings greatly expand the gene resources of S. cathayensis Chang and provide basic data for the study of the biosynthetic pathways and molecular mechanisms of terpenoids.