INSIGHTS INTO SUGAR AND AMINO ACID PATHWAYS OF CHICORY - STEM VEGETABLES BY METABOLOMIC AND RNA SEQUENCING INTEGRATED ANALYSIS

The 'Catalogna' chicory ( Cichorium intybus L.) is a typical Italian vegetable cultivated for leaves and stems ('puntarelle'); these latter are novel foods, consumed as fresh or processed, and rapidly moving to global markets. The holistic characterization of stems was carried - out by combining NMR metabolic and RNAseq profiling of 'Galatina' (Gal) and 'Molfettese' (Mol) landraces, grown in Apulia and Lazio, in order to investigat e on the nutritional quality and performance in ex situ cultivation. The content variation of thirty - two compounds was affected by the genotype (G), environment (E) and GxE interaction; PCA explained over 90% of variation, and PC1 and PC2 components neatly discriminated Gal vs Mol based on growth sites and genotypes, respectively. Focusing on carbohydrates and amino acids, the total amount of the former was higher in Gal than Mol in both areas (consistently with predicted sweetness and sensory test), whilst the opposite trend occurred for total amino acid content. The Mol vs Gal gene differential transcription was performed based on a Gal reference transcriptome ; G, E, and GxE effects were found and KEGG analysis showed the enrichment of differentially expre ssed genes within the sucrose and phenylalanine metabolisms, consistently with the metabolic profile variations. Pearson's correlation analyses of gene expression vs metabolite amount variations allowed the selection of gene sets that could explain sugar a nd amino acid content differences between Gal and Mol stems. Overall, these analyses widened knowledge on the pathways that influence nutritive quality traits and pointed at target genes useful for plant breeding.