Integrative Analysis of Metabolome and Transcriptome Reveals New Insights into Major Quality Formation and Regulation in Two Strawberry Cultivars with Different Fruit Flavor

Soluble sugars, organic acids, and vitamin C (AsA) are the major metabolites contributing to strawberry fruit quality. To date, the metabolomics and genetic information for the above metabolites are still limited. In this study, we integrated the metabolome and transcriptome in two cultivars with remarkably different fruit quality. The significant difference of fructose, sucrose, and malic acid contents illustrated the flavor discrepancy in two cultivars, in addition, the recycling pathway showed vital role in AsA accumulation. Conjoint analysis implied the key metabolizing enzymes related to soluble sugars, organic acids and AsA, respectively, further construction of co-expression regulatory networks identified the transcription factors for the above structural genes. Specifically, a high potential was suggested that the accumulation of soluble sugars and AsA were synchronously regulated by MYB, bHLH, NAC, AP2 and bZIP family members during fruit ripening. This work provided new insights into the accumulation and regulation of core metabolites in strawberry fruits, and the identified gene resources are promising for further improvement of strawberry fruit quality with molecular breeding.