Based on Transcriptomics to Reveal the Regulatory Mechanism of Lipid Biosynthesis in Kernels of Ping'ou Hybrid Hazelnut ( Corylus heterophylla Fisch. × Corylus avellana L.) and Screen for Core Genes

Hazelnuts are natural, high-quality woody oil crops that accumulate abundant oil in their kernels. To clarify the lipid biosynthesis mechanisms during hazelnut seed development, this study characterized the dynamic expression profiles of lipid biosynthesis-related genes across developmental stages and identified key genes involved in lipid biosynthesis. The results showed that mature hazelnut kernels contained 57.52% oil, with unsaturated fatty acids (UFAs) accounting for 94.22% of total fatty acids, predominantly oleic acid (88.10%) and linoleic acid (6.12%). Transcriptomic analysis yielded 109 candidate genes and 12 lipid-related transcription factors. The candidate genes included 57 involved in fatty acid biosynthesis, 34 in triacylglycerol biosynthesis, and 18 in oil body biosynthesis. For UFA biosynthesis, four stearoyl-ACP desaturase genes, eight fatty acid desaturase 2 genes, one fatty acid desaturase 3 gene, one fatty acid desaturase 6 gene, and four fatty acid desaturase 7/8 genes were identified. The research provides comprehensive transcriptomic insights into lipid accumulation during hazelnut development, establishing a foundation for improving oil quality and genetic breeding programs.