Data_Sheet_1_Integrated Analysis of Basic Helix Loop Helix Transcription Factor Family and Targeted Terpenoids Reveals Candidate AarbHLH Genes Involved in Terpenoid Biosynthesis in Artemisia argyi.docx

Artemisia argyi 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 A. argyi 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 A. argyi remain unknown. Here, 53 AarbHLH genes were identified from the transcriptome of A. argyi and were classified into 15 subfamilies based on the classification of bHLH proteins in Arabidopsis thaliana. 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 AarbHLH genes and the contents of targeted terpenoids in different tissues group and JA-treated group were performed. Eleven up-regulated AarbHLHs and one down-regulated AarbHLH were screened as candidate genes that may participate in the regulation of terpenoid biosynthesis (TPS-AarbHLHs). Correlation analysis between gene expression and terpenoid contents indicated that the gene expression of these 12 TPS-AarbHLHs was significantly correlated with the content changes of 1,8-cineole or β-caryophyllene. Protein–protein interaction networks further illustrated that these TPS-AarbHLHs might be involved in terpenoid biosynthesis in A. argyi. This finding provides a basis to further investigate the regulation mechanism of AarbHLH genes in terpenoid biosynthesis, and will be helpful to improve the quality of A. argyi.

艾（Artemisia argyi）是亚洲地区极具应用价值的传统药用植物。其叶片提取的精油富含萜类化合物，历来用于增进人体健康与福祉。在我国，艾草相关产业的市场规模已达数千亿元人民币。碱性螺旋-环-螺旋（basic helix-loop-helix, bHLH）家族是植物中最大的转录因子家族之一，广泛参与各类生物学过程，同时也是萜类化合物生物合成的关键调控组分。然而，艾草中的bHLH转录因子及其调控功能至今仍未得到阐明。本研究从艾草的转录组中鉴定出53个AarbHLH基因，并依据拟南芥（Arabidopsis thaliana）bHLH蛋白的分类标准，将其划分为15个亚家族。MEME保守基序分析结果显示，保守基序1与基序2构成了最为保守的bHLH结构域，且广泛分布于绝大多数AarbHLH蛋白中。此外，本研究对不同组织组与茉莉酸（jasmonic acid, JA）处理组中的AarbHLH基因表达谱以及目标萜类化合物含量开展了整合分析。研究筛选出11个上调表达的AarbHLH基因与1个下调表达的AarbHLH基因，作为可能参与萜类化合物生物合成调控的候选基因（TPS-AarbHLHs）。基因表达与萜类化合物含量的相关性分析表明，这12个TPS-AarbHLH基因的表达水平与1,8-桉叶素或β-石竹烯的含量变化呈显著相关。蛋白质相互作用网络分析进一步证实，这些TPS-AarbHLH基因可能参与艾草的萜类化合物生物合成过程。本研究结果为进一步解析AarbHLH基因在萜类化合物生物合成中的调控机制提供了理论基础，同时也可为提升艾草的品质提供参考依据。