DEGs expression in sour orange across developmental stages
This study investigates the transcriptional regulatory network underlying dynamic flavonoid biosynthesis in sour orange (Citrus aurantium L.) peel across eight developmental stages. Fruit samples were collected at biweekly intervals from May 5 to August 18, 2023, covering stages S1 through S8, with five independent biological replicates per stage. Each replicate consisted of pooled peel samples from five randomly selected trees. Transcriptome sequencing was performed using the Illumina HiSeq X Ten platform, generating 150-bp paired-end reads. A total of 23,002 annotated genes and 1,903 novel genes were identified, among which 9,691 differentially expressed genes were detected across developmental stages. Integrated with widely-targeted metabolomics and weighted gene co-expression network analysis (WGCNA), this dataset enables the reconstruction of a high-resolution transcriptional regulatory network governing flavonoid class switching from glycosylated flavonoids (early stages) to polymethoxylated flavonoids (later stages). Key transcription factors, including MYB11, MYBH, and ANT, were experimentally validated as direct binders of the CHS2 promoter via yeast one-hybrid assays. This comprehensive transcriptomic resource provides a foundation for understanding developmentally programmed secondary metabolism in citrus and offers valuable genetic targets for metabolic engineering of flavonoid profiles.