The Research Center for Ornamental Plants, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China.
Department of Botany, Division of Science and Technology, University of Education, Lahore, 54770, Punjab, Pakistan.
Phytochemistry. 2020 May;173:112294. doi: 10.1016/j.phytochem.2020.112294. Epub 2020 Feb 12.
Lilies are a commercially significant cut flower worldwide due not only to their elegant shape but also to their appealing scent. Among Lilium varieties, Lilium 'Siberia' is a cultivar that is prominent and highly favored by consumers due to its snowy white color and strong floral scent. Here, two terpene synthase genes (LoTPS2 and LoTPS4) that are responsible for floral scent production in Lilium 'Siberia' were cloned and functionally characterized. Recombinant LoTPS2 specifically catalyzed the formation of (E, E)-α-farnesene from FPP. Recombinant LoTPS4 is a multiproduct enzyme that produces D-limonene and β-myrcene as major volatile compounds and β-phellandrene, (+)-4-carene and 3-carene as minor products from GPP. Furthermore, LoTPS4 generates trans-α-bergamotene as a major product and di-epi-α-cedrene, α-cubebene and (E)-β-farnesene as minor compounds from FPP. Subcellular localization analysis using GFP fusion constructs revealed that LoTPS2 was localized in the cytosol, whereas LoTPS4 was localized in plastids. Real-time PCR analysis showed that LoTPS2 was highly expressed in the petals and sepals of the flower, while LoTPS4 was highly expressed in the filament of the flower. Moreover, mechanical wounding of flowers revealed that LoTPS2 showed a strong response to wounding via a rapid increase in its mRNA transcript level. Our results will assist scientists in exploring the molecular mechanisms of terpene biosynthesis in this species and will provide new insight into the biotechnological modification of the floral bouquet in Lilium.
百合是全球范围内具有重要商业价值的切花，不仅因为其优雅的形状，还因为其吸引人的香味。在百合品种中，‘西伯利亚’百合因其雪白的颜色和浓郁的花香而成为一种突出的品种，深受消费者喜爱。在这里，我们克隆并功能表征了负责‘西伯利亚’百合花香产生的两个萜烯合酶基因（LoTPS2 和 LoTPS4）。重组 LoTPS2 特异性地催化 FPP 形成（E，E）-α-法呢烯。重组 LoTPS4 是一种多产物酶，可从 GPP 产生 D-柠檬烯和β-月桂烯作为主要挥发性化合物，以及β-水芹烯、（+）-4-蒈烯和 3-蒈烯作为次要产物。此外，LoTPS4 从 FPP 生成反式-α-柏木烯作为主要产物，以及二表-α-衣兰烯、α-古巴烯和（E）-β-法呢烯作为次要化合物。使用 GFP 融合构建体的亚细胞定位分析表明，LoTPS2 定位于细胞质中，而 LoTPS4 定位于质体中。实时 PCR 分析表明，LoTPS2 在花的花瓣和萼片中高度表达，而 LoTPS4 在花的花丝中高度表达。此外，对花朵进行机械损伤的分析表明，LoTPS2 通过其 mRNA 转录本水平的快速增加对损伤表现出强烈的反应。我们的研究结果将有助于科学家探索该物种中萜烯生物合成的分子机制，并为百合花香的生物技术修饰提供新的见解。
