Expression dynamics of starch and proanthocyanidin biosynthesis genes during Quercus glauca fruit development

In this study, we utilized transcriptome data to investigate the expression dynamics of genes associated with starch and PA biosynthesis during Quercus glauca fruit development. Transcriptome sequencing across five developmental stages identified 2,637 differentially expressed genes (DEGs), most of which were detected during the rapid fruit growth phase (T3-T5). Functional enrichment analyses indicated that these DEGs were significantly associated with PA biosynthesis, seed germination, sugar metabolism, and DNA metabolism. WGCNA and Mfuzz clustering indicated that starch-related genes showed a continuous increase in expression throughout maturation, while PA biosynthesis genes were upregulated early but progressively downregulated toward maturity. A stage-specific MYB transcription factor was identified, suggesting a potential regulatory role in coordinating PA biosynthesis with other secondary metabolic pathways. Among the eight major starch biosynthesis gene families, the GPT family exhibited lineage-specific expansion. The expression profiles of PA and starch gene families were consistent with their assigned modules, and RT-qPCR results validated the RNA-seq data. This study elucidates the molecular regulatory mechanisms governing starch and PA accumulation during Q. glauca fruit development, laying a molecular foundation for the utilization of acorn resources and supporting the development of value-added acorn-based products.