Molecular investigation of Tuscan sweet cherries sampled over three years: gene expression analysis coupled to metabolomics and proteomics

Sweet cherry (Prunus avium L.) is a stone fruit widely consumed and appreciated for its organoleptic properties, as well as its nutraceutical potential. We here investigated the characteristics of six non-commercial Tuscan varieties of sweet cherry maintained at the Regional Germplasm Bank of the CNR-IBE in Follonica (Italy) and sampled at maturity over three consecutive years (2016-2017-2018). We adopted an approach merging genotyping and targeted gene expression profiling with metabolomics. To complement the data, a study of the soluble proteomes was also performed on two varieties showing the highest content of phenolics. The results obtained revealed that the highest differences were observed in the expression of genes involved in the phenylpropanoid pathway during the three years and among the varieties, while metabolomics identified the presence of flavanols and proanthocyanidins in highest abundance in the varieties Morellona and Crognola. Finally, proteomics on these two varieties showed differences in proteins involved in stress response, primary metabolism, and cell wall expansion. To the best of our knowledge, this is the first multi-pronged study focused on Tuscan sweet cherry varieties providing insights into the differential abundance of genes, proteins and metabolites.