Integrated metabolome and transcriptome analysis provides insights into the mechanisms of terpenoid biosynthesis in tea plants (Camellia sinensis)

Abstract

Volatile terpenoids are major substances responsible for the floral and fruity scents of teas. However, little is known about the regulatory mechanisms of terpenoid biosynthesis pathways in tea plants. 'Zhenfeng Yesheng tea' (ZFYS), a distinctive tea tree germplasm resource in Guizhou province, is known for its unique flavor characterized by a mellow taste and a floral aroma. Here, we conducted metabolome and transcriptome analyses of 'ZFYS', 'Jinguanyin tea' (JGY), and 'Longjing 43 tea' (LJ43) leaves to obtain the global correlation of MYB TFs with terpene synthase (TPS) genes and differential accumulated metabolites. In total, 292 differentially accumulated metabolites (DAMs) were identified and chemically classified, with 26.37% of them being terpenoids. Among these, 33 key volatile terpenoids significantly accumulated in 'ZFYS', 'LJ43', and 'JGY' leaves, mainly contributing to the floral and sweet scents. In addition, a total of 6330, 7238, and 8557 unigenes were obtained in "JGY vs LJ43", "ZFYS vs JGY", and "ZFYS vs LJ43" comparisons, respectively. The results of transcriptome analysis, correlation analysis, and quantitative real-time PCR (qRT-PCR) analysis revealed significant correlations between candidate CsTPSs and CsMYBs. The expression levels of CsMYB59, CsMYB167 and CsMYB178 showed that they had a strong positive correlation with CsTPS01, -03, -15, -53, -69 and -79, suggesting their potential function in regulating sesquiterpenoid biosynthesis. In conclusion, this study provides comprehensive metabolomics and transcriptomics profiles of the germplasm of 'ZFYS' tea plants and reveals the underlying key genes involved in volatile terpenoid biosynthesis.

Keywords: Camellia sinensis; MYB transcriptional factor; Metabolome; Transcriptome; Volatile terpenoid.