Matarese Fabiola, Cuzzola Angela, Scalabrelli Giancarlo, D'Onofrio Claudio
Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy.
Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy; Nutraceuticals and Food for Health - Nutrafood, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy.
Phytochemistry. 2014 Sep;105:12-24. doi: 10.1016/j.phytochem.2014.06.007. Epub 2014 Jul 7.
Plants produce a plethora of volatile organic compounds (VOCs) which are important in determining the quality and nutraceutical properties of horticultural food products, including the taste and aroma of wine. Given that some of the most prevalent grape aroma constituents are terpenoids, we investigated the possible variations in the relative expression of terpene synthase (TPS) genes that depend on the organ. We thus analysed mature leaves, young leaves, stems, young stems, roots, rachis, tendrils, peduncles, bud flowers, flowers and berries of cv Moscato bianco in terms of their VOC content and the expression of 23 TPS genes. In terms of the volatile characterization of the organs by SPME/GC-MS analysis, flower buds and open flowers appeared to be clearly distinct from all the other organs analysed in terms of their high VOC concentration. Qualitatively detected VOCs clearly separated all the vegetative organs from flowers and berries, then the roots and rachis from other vegetative organs and flowers from berries, which confirms the specialization in volatile production among different organs. Our real-time RT-PCR results revealed that the majority of TPS genes analysed exhibited detectable transcripts in all the organs investigated, while only some were found to be expressed specifically in one or just a few organs. In most cases, we found that the known products of the in vitro assay of VvTPS enzymes corresponded well to the terpenes found in the organs in which the encoding gene was expressed, as in the case of (E)-β-caryophyllene synthases, α-terpineol synthase and α-farnesene synthase. In addition, we found groups of homologous TPS genes, such as (E)-β-caryophyllene and β-ocimene synthases, expressed distinctively in the various tissues. This thus confirmed the subfunctionalization events and a specialization on the basis of the organs in which they are mostly expressed.
植物会产生大量挥发性有机化合物（VOCs），这些化合物对于确定园艺食品的品质和营养特性非常重要，包括葡萄酒的风味和香气。鉴于一些最常见的葡萄香气成分是萜类化合物，我们研究了萜烯合酶（TPS）基因相对表达量可能因器官而异的情况。因此，我们分析了白莫斯卡托葡萄品种的成熟叶片、幼叶、茎、嫩茎、根、果轴、卷须、花柄、花蕾、花朵和浆果的VOC含量以及23个TPS基因的表达情况。通过固相微萃取/气相色谱 - 质谱联用（SPME/GC-MS）分析对各器官进行挥发性特征分析时，花芽和开放的花朵因其高VOC浓度，在所有分析的器官中显得明显不同。定性检测到的VOCs清楚地将所有营养器官与花和浆果区分开来，然后将根和果轴与其他营养器官区分开来，将花与浆果区分开来，这证实了不同器官在挥发性物质产生方面的特异性。我们的实时逆转录 - 聚合酶链反应（RT-PCR）结果显示，所分析的大多数TPS基因在所有研究的器官中都有可检测到的转录本，而只有一些被发现仅在一个或几个器官中特异性表达。在大多数情况下，我们发现体外测定的VvTPS酶的已知产物与在编码基因表达的器官中发现的萜类化合物非常吻合，如（E）-β-石竹烯合酶、α-萜品醇合酶和α-法呢烯合酶的情况。此外，我们发现了同源TPS基因组，如（E）-β-石竹烯和β-罗勒烯合酶，在不同组织中特异性表达。这从而证实了亚功能化事件以及基于它们主要表达的器官的特异性。
