Insights into the Metabolite Profiles of Two Camellia (Theaceae) Species in Yunnan Province through Metabolomic and Transcriptomic Analysis

Tea (<i>Camellia sinensis</i>) falls into the family Theaceae, is a valuable commercial crop, and tea products made from its buds and young leaves are favored by consumers all over the world. The more common <i>Thea</i> plant is <i>Camellia sinensis</i> (<i>C. sinensis</i>), but its most important relative, <i>Camellia taliensis</i> (<i>C. taliensis</i>), is also utilized by locals in the area of cultivation to manufacture tea. In this investigation, <i>C. taliensis</i> (DL) and <i>C. sinensis</i> (QJZ) were characterized in terms of their agronomic traits, physicochemical indices, metabolomics, and transcriptomics. The leaf area of DL is larger than that of QJZ; the color of DL's buds and leaves is yellowish-green, while that of QJZ's is green. DL's buds and leaves are more densely velvety than those of QJZ. The HPLC results indicated that the physicochemical contents varied considerably between the two samples, with DL having greater concentrations of EGCG and GABA than QJZ, while QJZ had remarkably higher concentrations of C, CA, and EGC than DL. A total of 2269 metabolites and 362,190,414 genes were positively identified, with the number of DAMs and DEGs being 1001 and 34,026, respectively. The flavonoids, phenolic acids, and alkaloid metabolites were dramatically different between the two tea group plants. Bioinformatics profiling revealed that the DAMs and DEGs of the two tea group plants interacted with each other and were involved in metabolic pathways, including "biosynthesis of secondary metabolites", "biosynthesis of amino acids", "biosynthesis of cofactors", "phenylpropanoid biosynthesis", and "flavonoid biosynthesis". Overall, these results provide statistical support for germplasm conservation and production for both <i>C. taliensis</i> and <i>C. sinensis</i>.