Résumé
Citrus plants produce large amounts of polyphenols, especially flavonoids and coumarins. These compounds are involved in fruit quality as well as plant defense and therefore are a target of breeding programs. Many studies have characterized their composition in Citrus. However, few studies reported several classes of polyphenols in a single analysis. A better understanding of the biosynthetic pathway and its regulation requires more information about environmental conditions, tissue specificity and connections between competing sub-pathways. We propose a rapid method, allowing the quantification of multiclass polyphenols across contrasting tisues and cultivars. This procedure permitted a rapid reconstruction of the distribution of main classes of polyphenols in different tissues and genotypes. We evidence that the combination of datasets from contrasting tissues improved culvitar classification based on polyphenols contents. The analysis of metabolite distribution highlighted the massive accumulation of specific polyphenols in leaves and in the external part of the fruit. Drawing a map of the distribution of polyphenol across cultivars highlights potential regulatory nodes of the biosynthetic pathway such as steps catalyzed by rhamnosyltransferases. Our results suggest that three other steps are responsible for the different metabolite profiles in Clementaine and Star Ruby grapefruit. (Texte intégral)