Integrated Analysis of Metabolome and Transcriptome Provides Insights into Flavonoid Biosynthesis of Pear Flesh...

The flavonoids in the flesh significantly impact fruit quality and nutritional value. In this study, the flesh of 'Heqingxiaoshali' (HF) and 'Lunanhuangpingli' (LF) was analyzed by non-targeted metabolomics and transcriptomics. The results showed that the contents of reducing sugars, titratable acids and total flavonoids in HF flesh were significantly higher than those in LF. Metabolomics analysis revealed significant differences in lipids, organic acids, phenylpropanoids, and polyketides between HF and LF at each developmental stage, with Trilobatin, Cratenacin, and Betuletol 3-galactoside showing significant differences across all stages, and proanthocyanidins being the most abundant flavonoids in HF at harvest. Transcriptome analysis revealed significant differences in genes related to flavonoid biosynthesis between the two varieties, with differentially expressed genes enriched in the "phenylpropanoid biosynthesis" and "flavonoid biosynthesis" pathways across at least four developmental stages. WGCNA suggested that differences in the flavonoid accumulation were closely related to seven structural genes (PAL, CHI, FHT, FLS, DFR, ANS and ANR) and a transcription factor (MYB4), as well as genes related to auxin response and jasmonic acid metabolism. This study provides new insights into the molecular mechanisms of flavonoid accumulation in the fruit flesh of pears and offers a theoretical basis for pear fruit quality improvement.