Multiscale responses of microbial life to spatial distance and environmental heterogeneity in a patchy ecosystem
Multiscale responses of microbial life to spatial distance and environmental heterogeneity in a patchy ecosystem
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DOI：
10.1073/pnas.0610671104
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发表时间：
2007-02-20
影响因子：
11.1
通讯作者：
Tiedje, James M.
中科院分区：
文献类型：
--
作者：
Ramette, Alban;Tiedje, James M.
空间距离（SD）和环境异质性（EH）目前被认为是影响遗传变异和种群丰度的主要因素，但它们的相对重要性仍然知之甚少。因为EH在多个空间尺度上变化，所以微生物变量也会变化。然而，在多个尺度上确定SD x EH相互作用并不是一项简单的工作，特别是当人们检查它们对微生物丰度和基因组相似性的影响时。在这里，我们评估了这些相互作用在所有尺度上可感知的已知植物物种和异质性土壤物理和化学参数组成的斑块环境。对于自由生活，土传伯克霍尔德氏菌ambifaria，基因组相似性响应的实验采样方案可以揭示的空间尺度，尽管有限的个人分散。物种丰富度和社区组成，但是，响应小得多的尺度更符合当地的响应EH。我们的研究结果表明，全基因组相似性可能反映了微生物种群中SD和EH的同时效应，但每个因子的纯效应仅占总遗传变异的< 2%。在考虑了大多数环境、空间和生物相互作用之后，仍然存在大量无法解释的变化，这被认为是由未测量的环境和空间变异性、采样效应和中性生态漂移引入的噪声的结果。
Spatial distance (SD) and environmental heterogeneity (EH) are currently thought to represent major factors shaping genetic variation and population abundance, but their relative importance is still poorly understood. Because EH varies at multiple spatial scales, so too are microbial variables expected to vary. The determination of SD x EH interactions at multiple scales is, however, not a trivial exercise, especially when one examines their effects on microbial abundance and genomic similarities. Here we assessed those interactions at all scales perceptible in a patchy environment composed of known plant species and of heterogeneous soil physical and chemical parameters. For free-living, soil-borne Burkholderia ambifaria, genomic similarities responded to most of the spatial scales that the experimental sampling scheme could reveal, despite limited dispersal of the individuals. Species abundance and community composition were, however, responding to much smaller scales more consistent with local responses to EH. Our results suggest that whole-genome similarities may reflect the simultaneous effects of both SD and EH in microbial populations, but the pure effects of each factor only contributed to < 2% of the total genetic variation. The large amount of unexplained variation that remains after considering most environmental, spatial, and biological interactions is then posited to be the result of noise introduced by unmeasured environmental and spatial variability, sampling effects, and neutral ecological drift.