Ambika Manirajan Binoy, Ratering Stefan, Rusch Volker, Schwiertz Andreas, Geissler-Plaum Rita, Cardinale Massimiliano, Schnell Sylvia
Institute of Applied Microbiology, Research Center for BioSystems, Land Use, and Nutrition (IFZ), Justus-Liebig-University, Giessen, Germany.
Institut für Integrative Biologie, Stiftung Old Herborn University, Herborn, Germany.
Environ Microbiol. 2016 Dec;18(12):5161-5174. doi: 10.1111/1462-2920.13524. Epub 2016 Oct 24.
Diverse microorganisms colonise the different plant-microhabitats, such as rhizosphere and phyllosphere, and play key roles for the host. However, bacteria associated with pollen are poorly investigated, despite its ecological, commercial and medical relevance. Due to structure and nutritive composition, pollen provides a unique microhabitat. Here the bacterial abundance, community structure, diversity and colonization pattern of birch, rye, rapes and autumn crocus pollens were examined, by using cultivation, high-throughput sequencing and microscopy. Cultivated bacteria belonged to Proteobacteria, Actinobacteria and Firmicutes, with remarkable differences at species level between pollen species. High-throughput sequencing of 16S rRNA gene amplicon libraries showed Proteobacteria as the dominant phylum in all pollen species, followed by Actinobacteria, Acidobacteria and Firmicutes. Both plant species and pollination type significant influenced structure and diversity of the pollen microbiota. The insect-pollinated species possessed a more similar microbiota in comparison to the wind-pollinated ones, suggesting a levelling effect by insect vectors. Scanning electron microscopy as well as fluorescent in situ hybridisation coupled with confocal laser scanning microscopy (FISH-CLSM) indicated the tectum surface as the preferred niche of bacterial colonisation. This work is the most comprehensive study of pollen microbiology, and strongly increases our knowledge on one of the less investigated plant-microhabitats.
多种微生物定殖于不同的植物微生境，如根际和叶际，并对宿主发挥关键作用。然而，尽管花粉具有生态、商业和医学相关性，但与花粉相关的细菌却鲜有研究。由于结构和营养成分的原因，花粉提供了一个独特的微生境。在此，通过培养、高通量测序和显微镜技术，研究了桦树、黑麦、油菜和番红花花粉的细菌丰度、群落结构、多样性和定殖模式。培养出的细菌属于变形菌门、放线菌门和厚壁菌门，在花粉种类之间的物种水平上存在显著差异。16S rRNA基因扩增子文库的高通量测序显示，变形菌门是所有花粉种类中的优势菌门，其次是放线菌门、酸杆菌门和厚壁菌门。植物种类和授粉类型均对花粉微生物群的结构和多样性有显著影响。与风媒授粉的物种相比，虫媒授粉的物种具有更相似的微生物群，这表明昆虫载体具有一种平衡作用。扫描电子显微镜以及荧光原位杂交结合共聚焦激光扫描显微镜（FISH-CLSM）表明，覆盖层表面是细菌定殖的首选生态位。这项工作是对花粉微生物学最全面的研究，极大地增加了我们对这个较少被研究的植物微生境之一的了解。
