Full-Length Transcriptome Sequencing Combined with RNA-Seq to Analyze Genes Related to Terpenoid Biosynthesis in Cinnamomum burmannii

Cinnamomum burmannii is a cinnamomum plant rich in natural D-borneol. Natural D-borneol is a bicycle monoterpenoid compound widely used in the food, pharmaceutical, and cosmetic industries. Therefore, analyzing the biosynthesis mechanism of natural D-borneol in C. burmannii at the molecular level is helpful for directional breeding in the future and further development and utilization of C. burmannii and its related gene resources. In our study, 76 genes related to terpene metabolism were analyzed through third-generation sequencing and second-generation sequencing. Of these genes, 57 were associated with the synthesis of the terpenoid skeleton, and 19 belonged to terpenoid synthase, including four monoterpenoid synthases, seven sesquiterpenoid synthases, and eight diterpenoid synthases. Two genes in diterpenoid synthase were differentially expressed in high D-borneol and low D-borneol plants. It was speculated that these two genes might be related to D-borneol synthesis. How these two genes participate in the synthesis of D-borneol needs further study.