Integrated Analysis of Basic Helix Loop Helix Transcription Factor Family and Targeted Terpenoids Reveals Candidate Genes Involved in Terpenoid Biosynthesis in .

is a valuable traditional medicinal plant in Asia. The essential oil from its leaves is rich in terpenoids and has been used to enhance health and well-being. In China, the market scale of industries related to has attained tens of billions of Chinese Yuan. The basic helix-loop-helix (bHLH) family is one of the largest transcription factors families in plants that plays crucial roles in diverse biological processes and is an essential regulatory component of terpenoid biosynthesis. However, the bHLH TFs and their regulatory roles in remain unknown. Here, 53 genes were identified from the transcriptome of and were classified into 15 subfamilies based on the classification of bHLH proteins in . The MEME analysis showed that the conserved motif 1 and motif 2 constituted the most conserved bHLH domain and distributed in most AarbHLH proteins. Additionally, integrated analysis of the expression profiles of genes and the contents of targeted terpenoids in different tissues group and JA-treated group were performed. Eleven up-regulated and one down-regulated were screened as candidate genes that may participate in the regulation of terpenoid biosynthesis (). Correlation analysis between gene expression and terpenoid contents indicated that the gene expression of these 12 was significantly correlated with the content changes of 1,8-cineole or β-caryophyllene. Protein-protein interaction networks further illustrated that these might be involved in terpenoid biosynthesis in . This finding provides a basis to further investigate the regulation mechanism of genes in terpenoid biosynthesis, and will be helpful to improve the quality of .