Comparative fatty acids and nutritional components and transcriptomic analysis of fatty acids accumulation in seed oils from different tea varieties

Tea seed oil, a valuable byproduct extracted from tea plants, has gained attention as a potential edible oil. However, the composition of fatty acids and the mechanisms underlying their accumulation in tea seed oils remain largely unexplored. The study revealed significant variations in seed oil content across various tea varieties. Subsequently, the fatty acid composition, chemical properties, and the genetic basis of fatty acid differences were assessed in eleven representative tea accessions and one Camellia oleifera (YC). The results demonstrated that tea seed oils exhibited higher total polyunsaturated fatty acid content compared to YC oil, along with increased iodine and saponification values. Moreover, tea seed oils contained higher α-tocopherol, γ-tocotrienol and catechins. Importantly, gallocatechin gallate (GCG), epicatechin (EC) and catechin gallate (CG) were identified in tea seed oils, which was previously unreported in YC oil. Transcriptome analysis detected 5811 differentially expressed genes (DEGs), and correlation analysis identified 17 key genes, including fatty acid desaturase (CSS013596), crucial for regulating the fatty acid composition, particularly the accumulation of C16:1. These preliminary findings provide significant insights into the fatty acid composition and its regulation in tea seed oils, highlighting their potential as a promising alternative to traditional oil tea and other vegetable oils.