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.

中文翻译：

---

伊比利亚西北部葡萄酒品种的葡萄芳香类萜类成分是否与VviDXS1基因的变异有关？

背景：单萜类和C13-类异戊二烯类化合物是葡萄酒香气的重要萜类化合物。VviDXS1编码的酶参与葡萄果实中的萜类生物合成，该基因的功能获得突变导致特征性的麝香香气。目的：为评估VviDXS1对西北伊比利亚葡萄酒品种香气变化的贡献，我们在111个品种中对该基因进行了重新测序，并比较了其中12个品种的葡萄汁萜烯组成。方法：将VviDXS1靶向捕获，以Illumina的配对末端读取进行重测序，使用SAMtools进行变异调用，并使用PHASE重建基因单倍型。通过气相色谱-质谱法以葡萄汁中游离的和糖苷结合的形式对单萜和C13-类异戊二烯类化合物进行定量。结果：马斯喀特之间的萜烯成分有所区别，跨品种的萜和中性分布。虽然Loureira和Albariño白色品种的萜类特征与马斯喀特样突变无关，但Albariño在VviDXS1中带有V34L替代，而VviDXS1也存在于其他芳香品种中，以前没有报道。Tempranillo和Cabernet Sauvignon红色品种积累的C13-去甲肾上腺素水平较高，这与VviDXS1中的特定变异无关。结论：除了存在于阿尔巴里尼奥州的未表征的替代，研究结果表明，除VviDXS1外，与萜类途径相关的基因也可能有助于这些品种的芳香特性。Albariño在VviDXS1中带有V34L取代，该取代也存在于其他芳香品种中，以前没有报道。Tempranillo和Cabernet Sauvignon红色品种积累的C13-去甲肾上腺素水平较高，这与VviDXS1中的特定变异无关。结论：除了存在于阿尔巴里尼奥州的未表征的替代，研究结果表明，除VviDXS1外，与萜类途径相关的基因也可能有助于这些品种的芳香特性。Albariño在VviDXS1中带有V34L取代，该取代也存在于其他芳香品种中，以前没有报道。Tempranillo和Cabernet Sauvignon红色品种积累的C13-去甲肾上腺素水平较高，这与VviDXS1中的特定变异无关。结论：除了存在于阿尔巴里尼奥州的未表征的替代，研究结果表明，除VviDXS1外，与萜类途径相关的基因也可能有助于这些品种的芳香特性。