Department of Biology, Microbial Evolution Research Group (MERG), University of Oslo, PO Box 1066 Blindern, NO-0316, Oslo, Norway.
Mol Ecol. 2014 Feb;23(3):649-59. doi: 10.1111/mec.12622.
There is growing evidence that root-associated fungi have important roles in Arctic ecosystems. Here, we assess the diversity of fungal communities associated with roots of the ectomycorrhizal perennial herb Bistorta vivipara on the Arctic archipelago of Svalbard and investigate whether spatial separation and bioclimatic variation are important structuring factors of fungal community composition. We sampled 160 plants of B. vivipara from 32 localities across Svalbard. DNA was extracted from entire root systems, and 454 pyrosequencing of ITS1 amplicons was used to profile the fungal communities. The fungal communities were predominantly composed of Basidiomycota (55% of reads) and Ascomycota (35%), with the orders Thelephorales (24%), Agaricales (13.8%), Pezizales (12.6%) and Sebacinales (11.3%) accounting for most of the reads. Plants from the same site or region had more similar fungal communities to one another than plants from other sites or regions, and sites clustered together along a weak latitudinal gradient. Furthermore, a decrease in per-plant OTU richness with increasing latitude was observed. However, no statistically significant spatial autocorrelation between sites was detected, suggesting that environmental filtering, not dispersal limitation, causes the observed patterns. Our analyses suggest that while latitudinal patterns in community composition and richness might reflect bioclimatic influences at global spatial scales, at the smaller spatial scale of the Svalbard archipelago, these changes more likely reflect varied bedrock composition and associated edaphic factors. The need for further studies focusing on identifying those specific bioclimatic and edaphic factors structuring root-associated fungal community composition at both global and local scales is emphasized.
越来越多的证据表明，根相关真菌在北极生态系统中具有重要作用。在这里，我们评估了与北极斯瓦尔巴群岛多年生草本植物活叶独活根相关的真菌群落的多样性，并研究了空间分离和生物气候变化是否是真菌群落组成的重要结构因素。我们从斯瓦尔巴群岛 32 个地点共采集了 160 株活叶独活植物。从整个根系中提取 DNA，并使用 454 焦磷酸测序对 ITS1 扩增子进行测序，以描绘真菌群落。真菌群落主要由担子菌门（55%的reads）和子囊菌门（35%）组成，其中外生菌根菌目（24%）、伞菌目（13.8%）、盘菌目（12.6%）和Sebacinales 目（11.3%）的reads 占大多数。来自同一地点或区域的植物彼此之间的真菌群落更为相似，而来自其他地点或区域的植物则不相似，而且地点沿着较弱的纬度梯度聚集在一起。此外，观察到每个植物的 OTU 丰富度随着纬度的增加而减少。然而，没有检测到地点之间存在统计学上显著的空间自相关，这表明环境过滤而不是扩散限制导致了观察到的模式。我们的分析表明，虽然群落组成和丰富度的纬度模式可能反映了全球空间尺度上的生物气候影响，但在斯瓦尔巴群岛较小的空间尺度上，这些变化更可能反映了不同的基岩组成和相关的土壤因素。强调需要进一步研究，重点确定那些在全球和局部尺度上结构根相关真菌群落组成的特定生物气候和土壤因素。
