Department of Biological and Environmental Science, University of Jyvaskyla, PO Box 35, FI-40014, Jyvaskyla, Finland.
Mycorrhiza. 2017 Nov;27(8):801-810. doi: 10.1007/s00572-017-0796-6. Epub 2017 Aug 15.
The effects of arbuscular mycorrhizal (AM) fungi on plant-associated microbes are poorly known. We tested the hypothesis that colonization by an AM fungus affects microbial species richness and microbial community composition of host plant tissues. We grew the grass, Deschampsia flexuosa in a greenhouse with or without the native AM fungus, Claroideoglomus etunicatum. We divided clonally produced tillers into two parts: one inoculated with AM fungus spores and one without AM fungus inoculation (non-mycorrhizal, NM). We characterized bacterial (16S rRNA gene) and fungal communities (internal transcribed spacer region) in surface-sterilized leaf and root plant compartments. AM fungus inoculation did not affect microbial species richness or diversity indices in leaves or roots, but the AM fungus inoculation significantly affected bacterial community composition in leaves. A total of three OTUs in leaves belonging to the phylum Firmicutes positively responded to the presence of the AM fungus in roots. Another six OTUs belonging to the Proteobacteria (Alpha, Beta, and Gamma) and Bacteroidetes were significantly more abundant in NM plants when compared to AM fungus-inoculated plants. Further, there was a significant correlation between plant dry weight and leaf microbial community compositional shift. Also, there was a significant correlation between leaf bacterial community compositional shift and foliar nitrogen content changes due to AM fungus inoculation. The results suggest that AM fungus colonization in roots has a profound effect on plant physiology that is reflected in leaf bacterial community composition.
丛枝菌根（AM）真菌对植物相关微生物的影响知之甚少。我们检验了一个假设，即 AM 真菌的定殖会影响宿主植物组织的微生物物种丰富度和微生物群落组成。我们在温室中种植了柳枝稷（Deschampsia flexuosa），并在有或没有本地 AM 真菌（Claroideoglomus etunicatum）的情况下进行了实验。我们将克隆产生的分株分为两部分：一部分接种 AM 真菌孢子，另一部分不接种 AM 真菌（非菌根，NM）。我们对表面消毒的叶片和根部植物组织中的细菌（16S rRNA 基因）和真菌群落（内部转录间隔区）进行了特征描述。AM 真菌接种不会影响叶片或根部的微生物物种丰富度或多样性指数，但 AM 真菌接种显著影响了叶片的细菌群落组成。叶片中属于厚壁菌门的三个 OTU 对根系中 AM 真菌的存在呈正响应。另外，属于变形菌门（Alpha、Beta 和 Gamma）和拟杆菌门的六个 OTU 在 NM 植物中比在 AM 真菌接种植物中更为丰富。此外，植物干重与叶片微生物群落组成变化之间存在显著相关性。同时，由于 AM 真菌接种，叶片细菌群落组成变化与叶片氮含量变化之间也存在显著相关性。结果表明，根系中 AM 真菌的定殖对植物生理有深远影响，这反映在叶片细菌群落组成上。
