Integration of Metabolite Profiling and Transcriptome Analysis Reveals Genes Related to Volatile Terpenoid Metabolism in Finger Citron (C. medica var. sarcodactylis)

Xu, Yaying; Zhu, Changqing; Xu, Changjie; Sun, Jun; Grierson, Donald; Zhang, Bo; Chen, Kunsong

Abstract

Finger citron (Citrus medica var. sarcodactylis) is a popular ornamental tree and an important source of essential oils rich in terpenoids, but the mechanisms behind volatile formation are poorly understood. We investigated gene expression changes combined with volatile profiling of ten samples from three developing organs: flower, leaf, and fruit. A total of 62 volatiles were identified with limonene and γ-terpinene being the most abundant ones. Six volatiles were identified using partial least squares discriminant analysis (PLS-DA) that could be used as markers for distinguishing finger citron from other citrus species. RNA-Seq revealed 1,611,966,118 high quality clean reads that were assembled into 32,579 unigenes. From these a total of 58 terpene synthase (TPS) gene family members were identified and the spatial and temporal distribution of their transcripts was measured in developing organs. Transcript levels of transcription factor genes AP2/ERF (251), bHLH (169), bZIP (76), MYB (155), NAC (184), and WRKY (66) during finger citron development were also analyzed. From extracted subnetworks of three modules constructed by weighted gene co-expression network analysis (WGCNA), thirteen TPS genes and fifteen transcription factors were suggested to be related to volatile terpenoid formation. These results provide a framework for future investigations into the identification and regulatory network of terpenoids in finger citron.

Citation

Xu, Y., Zhu, C., Xu, C., Sun, J., Grierson, D., Zhang, B., & Chen, K. (2019). Integration of Metabolite Profiling and Transcriptome Analysis Reveals Genes Related to Volatile Terpenoid Metabolism in Finger Citron (C. medica var. sarcodactylis). Molecules, 24(14), 1-21. https://doi.org/10.3390/molecules24142564

• Journal Article Type: Article
• Acceptance Date: Jul 12, 2019
• Online Publication Date: Jul 15, 2019
• Publication Date: Jul 15, 2019
• Deposit Date: Sep 26, 2019
• Publicly Available Date: Sep 26, 2019
• Journal: Molecules
• Electronic ISSN: 1420-3049
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 24
• Issue: 14
• Article Number: 2564
• Pages: 1-21
• DOI: https://doi.org/10.3390/molecules24142564
• Keywords: citrus; limonene; γ-terpinene; WGCNA; terpene synthase gene; transcription factor; RNA-Seq
• Public URL: https://nottingham-repository.worktribe.com/output/2664263
• Publisher URL: https://www.mdpi.com/1420-3049/24/14/2564
• Contract Date: Sep 26, 2019