Arita Kayo, Honma Taro, Suzuki Shunji
Laboratory of Fruit Genetic Engineering, The Institute of Enology and Viticulture, University of Yamanashi, Kofu, Yamanashi, Japan.
Laboratory of Toxicology, Faculty of Pharma-Science, Teikyo University, Kaga, Itabashi, Tokyo, Japan.
PLoS One. 2017 Oct 20;12(10):e0186952. doi: 10.1371/journal.pone.0186952. eCollection 2017.
Vitis vinifera cv. Koshu is an indigenous grape cultivar that has been cultivated for more than a thousand years in Japan and one of the most important cultivars in white winemaking. To improve Koshu wine quality, it is necessary to identify the metabolites in Koshu berry. We conducted a comprehensive and comparative lipidome analysis of Koshu and Pinot Noir berries cultivated in the same location in Japan using GC-MS/MS for fatty acids and LC-MS for glycerolipids and glycerophospholipids. Koshu skins and juices contained 22 and 19 fatty acids, respectively, whereas 23 and 20 fatty acids were detected in Pinot Noir skins and juices. C22:6n3 and C24:0 contents in Koshu skins were two and three times higher than those in Pinot Noir skins. C24:0 content in Koshu juices was also higher than that in Pinot Noir juices. Forty-nine lipid components (six digalactosyldiacylglycerols, one monogalactosyldiacylglycerol, 10 phosphatidylcholines, 12 phosphatidylethanolamines, and 20 triglycerides) were detected in Pinot Noir and Koshu skins. Strong peaks were observed for MGDG 36:6, DGDG 36:6, PC 34:2, PC 36:5, TG 54:6, TG 54:7, and TG 54:8 in Koshu skins. The contents of 36 of the 49 lipid components were significantly higher in Pinot Noir skins than Koshu skins. Pinot Noir skins contained more lipids whose alkyl chains have more than 18 carbons than Koshu skins. Further analysis of both lipid profiles revealed that the number of double bonds in a fatty acid molecule in Pinot Noir skins and juices was significantly larger than that in Koshu skins and juices. A strong relationship exists between the heat requirement of grapevine cultivars and the level of fatty acid desaturation. C18-fatty acids were the major components in Koshu and Pinot Noir berries. The expression levels of C18-fatty acid desaturases regulated the accumulation of C18-unsaturated fatty acids in berry skins. The loss of C18:3 in Koshu berries at the end of ripening was observed. Koshu might effectively convert C18:3 into (Z)-hex-3-enal for the production of C6-aroma compounds. These findings by the lipidome analysis are expected to contribute to the improvement of Koshu wine aroma and breeding strategies of cold-tolerant Koshu grapevines.
甲州葡萄（Vitis vinifera cv. Koshu）是一种本土葡萄品种，在日本已种植了一千多年，是白葡萄酒酿造中最重要的品种之一。为了提高甲州葡萄酒的品质，有必要鉴定甲州葡萄浆果中的代谢物。我们使用气相色谱 - 质谱/质谱法分析脂肪酸，液相色谱法分析甘油脂和甘油磷脂，对在日本同一地点种植的甲州葡萄和黑皮诺葡萄浆果进行了全面的比较脂质组分析。甲州葡萄的果皮和果汁分别含有22种和19种脂肪酸，而黑皮诺葡萄的果皮和果汁中分别检测到23种和20种脂肪酸。甲州葡萄果皮中C22:6n3和C24:0的含量分别是黑皮诺葡萄果皮中含量的两倍和三倍。甲州葡萄果汁中C24:0的含量也高于黑皮诺葡萄果汁。在黑皮诺和甲州葡萄的果皮中检测到49种脂质成分（六种二半乳糖基二酰基甘油、一种单半乳糖基二酰基甘油、10种磷脂酰胆碱、12种磷脂酰乙醇胺和20种甘油三酯）。在甲州葡萄果皮中，MGDG 36:6、DGDG 36:6、PC 34:2、PC 36:5、TG 54:6、TG 54:7和TG 54:8出现了强峰。49种脂质成分中的36种在黑皮诺葡萄果皮中的含量显著高于甲州葡萄果皮。黑皮诺葡萄果皮中含有比甲州葡萄果皮更多的烷基链碳原子数超过18的脂质。对两种脂质谱的进一步分析表明，黑皮诺葡萄果皮和果汁中脂肪酸分子的双键数量显著多于甲州葡萄果皮和果汁。葡萄品种的需热量与脂肪酸去饱和水平之间存在密切关系。C18脂肪酸是甲州葡萄和黑皮诺葡萄浆果中的主要成分。C18脂肪酸去饱和酶的表达水平调节了浆果果皮中C18不饱和脂肪酸的积累。观察到甲州葡萄浆果在成熟末期C18:3的损失。甲州葡萄可能有效地将C18:3转化为（Z）-己-3-烯醛以生产C6香气化合物。脂质组分析的这些发现有望有助于改善甲州葡萄酒的香气以及耐寒甲州葡萄的育种策略。
