Integration of Transcriptome, miRNA-Omics, and Hormone Metabolism Analysis Reveals the Regulatory Network of Camellia drupifera Fruit Maturation

<i>Camellia drupifera</i> is an important woody oil crop with high economic and medicinal value. Fruit maturation is a complex process regulated by hormones and gene networks, yet its molecular basis remains unclear. Here, we integrated hormone profiling (IAA, GA₃, ABA), transcriptomics, and miRNA-omics across three key stages: nutrient synthesis (S1), lipid accumulation (S4), and maturation (S7). During early development (S1), IAA and GA₃ levels peaked, accompanied by the upregulation of growth-related genes (<i>AUX1</i>, <i>ARF</i>, <i>GID1</i>), which promote fruit growth. By maturation (S7), ABA content increased markedly, activating <i>PYR/PYL</i>, <i>PP2C</i>, and <i>ABF</i>, while IAA and GA₃ declined. Transcriptome analysis revealed 45 key differentially expressed genes correlated with hormone levels. In parallel, miRNAs such as <i>miR393-z</i> (targeting <i>TIR1</i>) and <i>novel-m0146-5p</i> (targeting <i>ARF1</i>) were identified as regulators of hormone signaling and fruit maturation. Collectively, our results highlight a coordinated "hormone-miRNA-mRNA" regulatory network underlying <i>C. drupifera</i> fruit development. These findings provide new insights into the molecular regulation of fruit maturation and lipid accumulation in woody oil crops, offering a foundation for genetic improvement and efficient utilization of this species.