Metabolomic profiling of different clones of vitis vinifera L. cv. "Glera" and "Glera lunga" grapes by high-resolution mass spectrometry.

ABSTRACT

INTRODUCTION: Prosecco wine production has been strongly extended in the last decade and several new clones have been introduced. "Glera" (minimum 85%) and "Glera lunga" are grape varieties of great economic impact used to produce Prosecco wines. Study of grape berry secondary metabolites is effective in the classification of vine varieties and clones. High-resolution mass spectrometry provides complete panorama of these metabolites in single analysis and coupling to statistical multivariate analysis is successfully applied in vine chemotaxonomy. OBJECTIVES: update and deepen the knowledge on the "Glera" and "Glera lunga" berry grapes chemotaxonomy and investigate some of the most produced and marketed clones by using the modern analytical and statistical tools. METHODS: five clones of "Glera" and two of "Glera lunga" grown in the same vineyard with same agronomical practices were studied for three vintages. Grape berry metabolomics was characterized by UHPLC/QTOF and multivariate statistical analysis was performed on the signals of main metabolites of oenological interest. RESULTS: "Glera" and "Glera lunga" showed different monoterpene profiles ("Glera" is richer in glycosidic linalool and nerol) and differences in polyphenols (catechin, epicatechin and procyanidins, trans-feruloyltartaric acid, E-ε-viniferin, isorhamnetin-glucoside, quercetin galactoside). Vintage affected the accumulation of these metabolites in berry. No statistical differentiation among the clones of each variety, was found. CONCLUSIONS: Coupling HRMS metabolomics/statistical multivariate analysis enabled clear differentiation between the two varieties. The examined clones of same variety showed similar metabolomic profiles and enological characteristics, but vineyard planting using different clones can result in more consistent final wines reducing the vintage variability linked to genotype × environment interaction.