Integrate analysis of metabolome and transcriptome of three Fragaria × ananassa cultivars to stablish the non-volatile compounds of strawberry flavor

The flavor attribute of Fragaria × ananassa Duch. would decide consumers' selection of preferred strawberry commercial cultivars. The roles of volatile compounds in strawberry aroma have been well-studied while knowledge regarding the non-volatile compounds is limited. Some non-volatile compounds which are involved in consumers preference of strawberry have been reported, contributions of non-volatile compounds for strawberry flavor remain ambiguous. This study explored the strawberry flavor influences of essential non-volatile compounds by comparing biosynthesis pathways of cultivars exhibiting distinct flavor characteristics. The widely targeted metabolome generated global profiles of three cultivars including 521 known non-volatile compounds. The differential accumulation analysis and precise quantification of soluble sugars, organic acids, polyphenols and free amino acids (FAAs) predicted fructose, citric acid, kaempferol and pelargonin-3-glucoside were key compounds involved in the sweetness, acidity and astringency of strawberries. Further, the conjoint analysis of metabolites and 824 differentially expressed genes revealed that flavonoid biosynthesis, phenylpropanoid metabolism and citrate cycle pathways decided the content difference of key flavor compounds. Within these pathways, several structure genes were predicted as potential regulators of organic acids, flavonoids and umami-taste FAAs. These findings would be helpful in identification of non-volatile compounds and genes responsible for strawberry flavor.