Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia.
PLoS One. 2012;7(8):e41938. doi: 10.1371/journal.pone.0041938. Epub 2012 Aug 7.
Despite the important ecosystem role played by arbuscular mycorrhizal fungi (AMF), little is known about spatial and temporal variation in soil AMF communities. We used pyrosequencing to characterise AMF communities in soil samples (n = 44) from a natural forest ecosystem. Fungal taxa were identified by BLAST matching of reads against the MaarjAM database of AMF SSU rRNA gene diversity. Sub-sampling within our dataset and experimental shortening of a set of long reads indicated that our approaches to taxonomic identification and diversity analysis were robust to variations in pyrosequencing read length and numbers of reads per sample. Different forest plots (each 10 × 10 m and separated from one another by 30 m) contained significantly different soil AMF communities, and the pairwise similarity of communities decreased with distance up to 50 m. However, there were no significant changes in community composition between different time points in the growing season (May-September). Spatial structure in soil AMF communities may be related to the heterogeneous vegetation of the natural forest study system, while the temporal stability of communities suggests that AMF in soil represent a fairly constant local species pool from which mycorrhizae form and disband during the season.
尽管丛枝菌根真菌（AMF）在生态系统中扮演着重要的角色，但我们对土壤 AMF 群落的时空变化知之甚少。我们使用焦磷酸测序技术来描述自然森林生态系统中土壤样本（n = 44）中的 AMF 群落。通过将读取序列与 MaarjAM 数据库中的 AMF SSU rRNA 基因多样性进行 BLAST 匹配来识别真菌分类群。在我们的数据集中进行的子采样和一组长读长的实验缩短表明，我们的分类鉴定和多样性分析方法对焦磷酸测序读取长度和每个样本的读取数量的变化具有稳健性。不同的森林样地（每个 10×10 m，彼此之间相隔 30 m）含有明显不同的土壤 AMF 群落，群落之间的相似性随着距离的增加而降低，最高可达 50 m。然而，在生长季节（5 月至 9 月）的不同时间点之间，群落组成没有明显变化。土壤 AMF 群落的空间结构可能与自然森林研究系统的异质植被有关，而群落的时间稳定性表明，土壤中的 AMF 代表了一个相当稳定的本地种库，在季节过程中形成和解散菌根。
