University of Aberdeen, Institute of Biological & Environmental Sciences, Aberdeen, UK.
Mol Ecol. 2012 Oct;21(20):5110-23. doi: 10.1111/j.1365-294X.2012.05739.x. Epub 2012 Sep 13.
Microbial ecology has made large advances over the last decade, mostly because of improvements in molecular analysis techniques that have enabled the detection and identification of progressively larger numbers of microbial species. However, determining the ecological patterns and processes taking place in communities of microbes remains a significant challenge. Are communities randomly assembled through dispersal and priority effects, or do species interact with each other leading to positive and negative associations? For mycorrhizal fungi, evidence is accumulating that stochastic and competitive interactions between species may both have a role in shaping community structure. Could the methodological approach, which is often incidence based, impact the outcomes detected? Here, we applied an incidence-based Terminal Restriction Fragment Length Polymorphism (T-RFLP) database approach to examine species diversity and ecological interactions within a community of ectomycorrhizal (ECM) fungi. Co-occurrence analysis revealed that the ECM community colonizing root tips was strongly structured by competitive interactions, or ecological processes generating a similar spatial pattern, rather than neutral processes. Analysis of β-diversity indicated that community structure was significantly more similar (spatially autocorrelated) at distances equal to or <3.41 m. The eight most frequently encountered species in the root tip community of ECM fungi displayed significant competitive interactions with at least one other species, showing that the incidence-based approach was capable of detecting this sort of ecological information.
过去十年中，微生物生态学取得了重大进展，这主要得益于分子分析技术的改进，这些技术使我们能够检测和鉴定越来越多的微生物物种。然而，确定微生物群落中发生的生态模式和过程仍然是一个重大挑战。群落是通过扩散和优先效应随机组装的，还是物种之间相互作用导致正相关和负相关？对于菌根真菌，有证据表明，物种之间的随机和竞争相互作用都可能在塑造群落结构中发挥作用。通常基于事件的方法会不会影响检测到的结果？在这里，我们应用基于事件的末端限制性片段长度多态性（T-RFLP）数据库方法来研究外生菌根（ECM）真菌群落中的物种多样性和生态相互作用。共现分析表明，定殖在根尖的 ECM 群落强烈地受到竞争相互作用的结构，或者说产生相似空间模式的生态过程，而不是中性过程。β多样性分析表明，群落结构在距离等于或<3.41 m 时显著更相似（空间自相关）。在 ECM 真菌根尖群落中最常遇到的八种物种与至少一种其他物种存在显著的竞争相互作用，表明基于事件的方法能够检测到这种生态信息。
