Martin Diane M, Toub Omid, Chiang Angela, Lo Bernard C, Ohse Sebastian, Lund Steven T, Bohlmann Jörg
Michael Smith Laboratories and Wine Research Centre, University of British Columbia, Vancouver, BC, Canada V6T 1Z4.
Proc Natl Acad Sci U S A. 2009 Apr 28;106(17):7245-50. doi: 10.1073/pnas.0901387106. Epub 2009 Apr 9.
Terpenoid volatiles are important information molecules that enable pollinators to locate flowers and may protect reproductive tissues against pathogens or herbivores. Inflorescences of grapevine (Vitis vinifera L.) are composed of tiny green flowers that produce an abundance of sesquiterpenoid volatiles. We demonstrate that male flower parts of grapevines are responsible for sesquiterpenoid floral scent formation. We describe temporal and spatial patterns of biosynthesis and release of floral volatiles throughout the blooming of V. vinifera L. cv. Cabernet Sauvignon. The biosynthesis of sesquiterpene volatiles, which are emitted with a light-dependent diurnal pattern early in the morning at prebloom and bloom, is localized to anthers and, more specifically, within the developing pollen grains. Valencene synthase (VvValCS) enzyme activity, which produces the major sesquiterpene volatiles of grapevine flowers, is present in anthers. VvValCS transcripts are most abundant in flowers at prebloom stages. Western blot analysis identified VvValCS protein in anthers, and in situ immunolabeling located VvValCS protein in pollen grains during bloom. Histochemical staining, as well as immunolabeling analysis by fluorescent microscopy and transmission electron microscopy, indicated that VvValCS localizes close to lipid bodies within the maturing microspore.
萜类挥发物是重要的信息分子，能帮助传粉者找到花朵，还可能保护生殖组织免受病原体或食草动物侵害。葡萄（Vitis vinifera L.）的花序由微小的绿色花朵组成，这些花朵会产生大量倍半萜类挥发物。我们证明葡萄的雄花部分负责倍半萜类花香的形成。我们描述了酿酒葡萄品种赤霞珠在整个花期花香挥发物生物合成和释放的时间和空间模式。倍半萜类挥发物在开花前和开花初期以光依赖的昼夜模式释放，其生物合成定位于花药，更具体地说，定位于发育中的花粉粒内。产生葡萄花主要倍半萜类挥发物的瓦伦烯合酶（VvValCS）酶活性存在于花药中。VvValCS转录本在开花前阶段的花朵中最为丰富。蛋白质免疫印迹分析在花药中鉴定出了VvValCS蛋白，原位免疫标记在开花期间在花粉粒中定位到了VvValCS蛋白。组织化学染色以及荧光显微镜和透射电子显微镜的免疫标记分析表明，VvValCS定位于成熟小孢子内靠近脂质体的位置。
