Royal Botanic Gardens, Melbourne, VIC., 3141, Australia; Department of Biology, Duke University, Durham, NC, 27708, USA.
Mol Ecol. 2014 Jul;23(13):3356-70. doi: 10.1111/mec.12821.
Microbial communities in plant roots provide critical links between above- and belowground processes in terrestrial ecosystems. Variation in root communities has been attributed to plant host effects and microbial host preferences, as well as to factors pertaining to soil conditions, microbial biogeography and the presence of viable microbial propagules. To address hypotheses regarding the influence of plant host and soil biogeography on root fungal and bacterial communities, we designed a trap-plant bioassay experiment. Replicate Populus, Quercus and Pinus plants were grown in three soils originating from alternate field sites. Fungal and bacterial community profiles in the root of each replicate were assessed through multiplex 454 amplicon sequencing of four loci (i.e., 16S, SSU, ITS, LSU rDNA). Soil origin had a larger effect on fungal community composition than did host species, but the opposite was true for bacterial communities. Populus hosted the highest diversity of rhizospheric fungi and bacteria. Root communities on Quercus and Pinus were more similar to each other than to Populus. Overall, fungal root symbionts appear to be more constrained by dispersal and biogeography than by host availability.
根系微生物群落为陆地生态系统地上和地下过程提供了关键联系。根系群落的变化归因于植物宿主效应和微生物宿主偏好，以及与土壤条件、微生物生物地理学和可行微生物繁殖体存在有关的因素。为了解决关于植物宿主和土壤生物地理学对根真菌和细菌群落影响的假设，我们设计了一个诱捕植物生物测定实验。重复的杨树、栎树和松树植物在来自不同田间地点的三种土壤中生长。通过对四个基因座（即 16S、SSU、ITS、LSU rDNA）的多重 454 扩增子测序，评估每个重复的根系中真菌和细菌群落的特征。土壤来源对真菌群落组成的影响大于宿主种类，但对细菌群落则相反。杨树拥有最多的根际真菌和细菌多样性。栎树和松树的根群落彼此之间比与杨树的更相似。总的来说，真菌根共生体似乎受到扩散和生物地理学的限制比受到宿主可用性的限制更大。
