The Impact of Photosynthetic Characteristics and Metabolomics on the Fatty Acid Biosynthesis in Tea Seeds

The synthesis of tea fatty acids plays a crucial role in determining the oil content of tea seeds and selecting tea tree varieties suitable for harvesting both leaves and fruits. However, there is limited research on fatty acid synthesis in tea trees, and the precise mechanisms influencing tea seed oil content remain elusive. To reveal the fatty acid biosynthesis mechanism, we conducted a photosynthetic characteristic and targeted metabolomics analysis in comparison between Jincha 2 and Wuniuzao cultivars. Our findings revealed that Jincha 2 exhibited significantly higher net photosynthetic rates (Pn), stomatal conductance (Gs), and transpiration rate (Tr) compared with Wuniuzao, indicating the superior photosynthetic capabilities of Jincha 2. Totally, we identified 94 metabolites with significant changes, including key hormone regulators such as gibberellin A1 (GA1) and indole 3-acetic acid (IAA). Additionally, linolenic acid, methyl dihydrojasmonate, and methylthiobutyric acid, precursors required for fatty acid synthesis, were significantly more abundant in Jincha 2 compared with Wuniuzao. In summary, our research suggests that photosynthetic rates and metabolites contribute to the increased yield, fatty acid synthesis, and oil content observed in Jincha 2 when compared with Wuniuzao.