Genomic basis of metabolome-mediated cultivar-specific flavor formation in juice sacs of the pomelo (Citrus grandis (L.) Osbeck) cultivars Shatian and Guanxi honey

Shatian pomelo (Citrus grandis (L.) Osbeck cv. Shatian) (ST) is one of the main cultivars of pomelo, and its flavor, aroma and mastication traits exhibit marked specificity compared to those of another major pomelo cultivar, Guanxi honey pomelo (Citrus grandis (L.) Osbeck cv. Guanxi honey) (BR). As parents, both cultivars generated many offspring cultivars with excellent quality. However, the limited study of pomelo flavor-specific metabolites and their metabolic pathways has hindered the understanding of pomelo flavor diversity. In this work, genome resequencing and metabolome analyses were performed to reveal the differences in cultivar-specific flavor metabolic pathways and cultivar-specificity formation molecular bases in taste flavor, aroma and mastication. A total of 397,056 and 427,885 SNP-InDels were found, with 53.67% and 54.76% of the SNP-InDels located in the gene intervals in ST and BR, respectively. 148 candidate genes distributed in carbohydrate, amino acid, flavonoid, lipid, terpene and lignin metabolism pathways were screened to uncover the molecular basis of flavor, aroma and mastication trait formation biological processes. Overall, revealing the origin of the cultivar-specific flavor of ST and BR may provide novel insight into the pomelo flavor formation mechanism and genetic resources for pomelo genetic breeding.