Research article Metabolite profiling elucidates communalities and differences in the polyphenol biosynthetic pathways of red and white Muscat genotypes Asfaw Degu a, b , Caterina Morcia c , Giorgio Tumino c , Uri Hochberg a, b , David Toubiana a, b , Fulvio Mattivi e , Anna Schneider f , Polina Bosca d , Luigi Cattivelli c , Valeria Terzi c , Aaron Fait b, * a The Albert Katz International School, Beer-Sheva, Israel b The French Associates Institute for Biotechnology and Agriculture of Dryland, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 84990, Israel c Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Genomics Research Centre, Via S. Protaso 302, 29017 Fiorenzuola d' Arda, PC, Italy d BOSCA S.p.A, Canelli, AT 14053, Italy e IASMA Research and Innovation Center, Fondazione Edmund Mach, S. Michele a/Adige, I-38010, Italy f Consiglio Nazionale delle Ricerche, Istituto di Virologia Vegetale, Sezione Grugliasco, Torino 10095, Italy article info Article history: Received 20 June 2014 Accepted 13 November 2014 Available online 15 November 2014 Keywords: Muscat Flavonoids Grapevine Metabolite-profiling abstract The chemical composition of grape berries is varietal dependent and influenced by the environment and viticulture practices. In Muscat grapes, phenolic compounds play a significant role in the organoleptic property of the wine. In the present study, we investigated the chemical diversity of berries in a Muscat collection. Metabolite profiling was performed on 18 Moscato bianco clones and 43 different red and white grape varieties of Muscat using ultra-performance liquid chromatographyequadrupole time of flightemass spectrometry (UPLC-QTOF-MS/MS) coupled with SNP genotyping. Principle component analysis and hierarchical clustering showed a separation of the genotypes into six main groups, three red and three white. Anthocyanins mainly explained the variance between the different groups. Additionally, within the white varieties mainly flavonols and flavanols contributed to the chemical diversity identified. A genotype-specific rootstock effect was identified when separately analyzing the skin of the clones, and it was attributed mainly to resveratrol, quercetin 3-O-galactoside, citrate and malate. The metabolite profile of the varieties investigated reveals the chemical diversity existing among different groups of Muscat genotypes. The distribution pattern of metabolites among the groups dictates the abundance of precursors and intermediate metabolite classes, which contribute to the organoleptic properties of Muscat berries. © 2014 Elsevier Masson SAS. All rights reserved. 1. Introduction Natural variety in fruit metabolism is a fundamental aspect of crop breeding used to develop novel strategies for fruit quality enhancement. In tomato, exotic germplasm resources are being exploited for the identification of agriculturally valuable traits or for their potential use for metabolic engineering (Schauer et al., 2005). The screening of wild or natural varieties can be later used to generate mapping populations to study the genetic regulation of complex traits (Schauer et al., 2006). This approach was used to elucidate the genetic basis of fruit metabolism in several species (Schauer et al., 2006; Harel-Beja et al., 2010). In grape, the genomic resources available have increased significantly in recent years (Grimplet et al., 2009, 2011; Cipriani et al., 2008; Vezzulli et al., 2008; Denoeud et al., 2008; Cipriani et al., 2010; Laucou et al., 2011), and research efforts are dedicated to determine the genetic variation among grape varieties and its impact on fruit quality and metabolism (This et al., 2006). Yet, while extensive research has been conducted on the metabolism of developing berries of single varieties (Deluc et al., 2007), only a few works focused on the metabolic diversity between berries of different varieties (Mattivi et al., 2006; Cantos et al., 2002; Dimitrovska et al., 2011). More- over, the distinguishing between the environmental and the * Corresponding author. E-mail address: fait@bgu.ac.il (A. Fait). Contents lists available at ScienceDirect Plant Physiology and Biochemistry journal homepage: www.elsevier.com/locate/plaphy http://dx.doi.org/10.1016/j.plaphy.2014.11.006 0981-9428/© 2014 Elsevier Masson SAS. All rights reserved. Plant Physiology and Biochemistry 86 (2015) 24e33