Affiliations: [a] Instituto de Ciencias de la Vid y del Vino (ICVV), Consejo Superior de Investigaciones Científicas CSIC- Universidad de La Rioja-Gobierno de La Rioja, Carretera de Burgos, Logroño, Spain
| [b] Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tuebingen, Germany
| [c] Centro Nacional de Biotecnología (CNB-CSIC), C/ Darwin, Madrid, Spain
| [d] Bodega Santiago Ruiz, O Rosal, Pontevedra, Spain
| [e] Misión Biológica de Galicia, Consejo Superior de Investigaciones Científicas CSIC, El Palacio, Salcedo, Pontevedra, Spain
Corresponding author: Mar Vilanova, Misión Biológica de Galicia, Consejo Superior de Investigaciones Científicas CSIC, El Palacio, Salcedo, 36143 Pontevedra, Spain. E-mail: [email protected].
Abstract: BACKGROUND:Monoterpenes and C13-norisoprenoids are key terpenoid compounds for wine aroma. The enzyme encoded by VviDXS1 participates in terpenoid biosynthesis in grapevine fruits and gain-of-function mutations in this gene lead to characteristic muscat aroma. OBJECTIVE:To assess for VviDXS1 contribution to aroma variation in Northwestern Iberian wine cultivars, we resequenced this gene in 111 cultivars and compared grape juice terpenic composition in 12 of them. METHODS:VviDXS1 was capture-targeted for resequencing with Illumina paired-end reads, SAMtools was used for variant calling and gene haplotypes were reconstructed with PHASE. Monoterpenes and C13-norisoprenoids were quantified in free and glycosidically-bound forms from grape juice by gas chromatography-mass spectrometry. RESULTS:Terpenic composition discriminated between muscat, terpenic and neutral profiles across cultivars. While the terpenic profile of Loureira and Albariño white cultivars was not associated with muscat-like mutations, Albariño carries a V34L substitution in VviDXS1 that is also present in other aromatic cultivars and was not reported before. Tempranillo and Cabernet Sauvignon red cultivars accumulated higher levels of C13-norisoprenoids, which was not associated with specific variation in VviDXS1. CONCLUSIONS:Apart from the uncharacterized substitution present in Albariño, findings suggest that terpenoid pathway-related genes other than VviDXS1 could contribute to the aromatic attributes of these cultivars.
Keywords: DXS, haplotype diversity, monoterpenes, C13-norisoprenoids, muscat aroma