Dihydrochalcones in apple: metabolite profiling of Malus germplasm collection

Apple fruits share an economic importance not only in the province Trentino but also worldwide, which is derived from their high-value nutritional foods that provide unique contributions to the dietary choices of consumers and overall human health. In general apples are particularly rich and diverse in metabolites, both primary metabolites, such as sugars, and secondary metabolites, such as volatiles and soluble substances. These compounds are also appreciated for their special flavor, taste and colour, and, more recently, for their association with a healthy lifestyle. However, the majority of metabolites are still unknown and their biological activities and biosynthesis remain to be explored. Dihydrochalcones are one of the most abundant phenolic compounds found in apple mainly in leaves but also in fruits. Long time they were considered to be specific for the genus Malus but in recent years they were also found in other Rosaceae genus (Fragaria, Rosa) and outside this plant family. Beside their proposed contribution to plant defence reactions against bacterial and fungal deseases or herbivore attacks, these compounds have been receiving attention in terms of human nutrition and health due to their activity e.g. within glucose metabolism/uptake. The germplasm collection at FEM-IASMA includes around 1100 accessions of Malus x domestica, 50 of hybrids and 270 wild species. In a first metabolite profiling trial selected wild species were analysed regarding their dihydrochalcone pattern