Zu Pengjuan, Koch Hauke, Schwery Orlando, Pironon Samuel, Phillips Charlotte, Ondo Ian, Farrell Iain W, Nes W David, Moore Elynor, Wright Geraldine A, Farman Dudley I, Stevenson Philip C
Royal Botanic Gardens, Kew, Natural Capital and Plant Health Department, Richmond, Surrey, TW9 3AB, UK.
Department Fish Ecology and Evolution, Swiss Federal Institute of Aquatic Science and Technology, Seestrasse 79, Kastanienbaum, CH-6047, Switzerland.
New Phytol. 2021 May;230(3):1169-1184. doi: 10.1111/nph.17227. Epub 2021 Feb 15.
Phytosterols are primary plant metabolites that have fundamental structural and regulatory functions. They are also essential nutrients for phytophagous insects, including pollinators, that cannot synthesize sterols. Despite the well-described composition and diversity in vegetative plant tissues, few studies have examined phytosterol diversity in pollen. We quantified 25 pollen phytosterols in 122 plant species (105 genera, 51 families) to determine their composition and diversity across plant taxa. We searched literature and databases for plant phylogeny, environmental conditions, and pollinator guilds of the species to examine the relationships with pollen sterols. 24-methylenecholesterol, sitosterol and isofucosterol were the most common and abundant pollen sterols. We found phylogenetic clustering of twelve individual sterols, total sterol content and sterol diversity, and of sterol groupings that reflect their underlying biosynthesis pathway (C-24 alkylation, ring B desaturation). Plants originating in tropical-like climates (higher mean annual temperature, lower temperature seasonality, higher precipitation in wettest quarter) were more likely to record higher pollen sterol content. However, pollen sterol composition and content showed no clear relationship with pollinator guilds. Our study is the first to show that pollen sterol diversity is phylogenetically clustered and that pollen sterol content may adapt to environmental conditions.
植物甾醇是具有基本结构和调节功能的主要植物代谢产物。它们也是包括传粉者在内的植食性昆虫必需的营养物质，这些昆虫无法合成甾醇。尽管在植物营养组织中植物甾醇的组成和多样性已有详尽描述，但很少有研究考察花粉中植物甾醇的多样性。我们对122种植物（105属，51科）中的25种花粉植物甾醇进行了定量分析，以确定它们在不同植物类群中的组成和多样性。我们在文献和数据库中搜索了这些物种的植物系统发育、环境条件和传粉者群落，以研究它们与花粉甾醇的关系。24-亚甲基胆固醇、谷甾醇和异岩藻甾醇是最常见且含量丰富的花粉甾醇。我们发现12种单个甾醇、总甾醇含量和甾醇多样性以及反映其潜在生物合成途径（C-24烷基化、B环去饱和）的甾醇分组存在系统发育聚类。起源于类似热带气候（年平均温度较高、温度季节性较低、最湿润季度降水量较高）的植物更有可能记录到较高的花粉甾醇含量。然而，花粉甾醇的组成和含量与传粉者群落没有明显关系。我们的研究首次表明花粉甾醇多样性存在系统发育聚类，且花粉甾醇含量可能适应环境条件。
