Although pyrogenic organic matter (PyOM) generated during wildfires plays a critical role in post-fire ecosystem recovery, the specific mechanisms by which PyOM controls soil microbial community assembly after wildfire perturbation remain largely uncharacterized. Herein we characterized the effect of PyOM on soil bacterial communities at two independent wildfire-perturbed forest sites. We observed that α-diversity of bacterial communities was the highest in wildfire-perturbed soils and that bacterial communities gradually changed along a sequence of unburnt soil → burnt soil → PyOM. The microbial communities reconstructed from unburnt soil and PyOM resembled the real bacterial communities in wildfire-perturbed soils in their α-diversity and community structure. Bacterial specialists in PyOM and soils clustered in phylogenetic coherent lineages with intra-lineage pH-niche conservatism and inter-lineage pH-niche divergence. Our results suggest that PyOM mediates bacterial community assembly in wildfire-perturbed soils by a combination of environmental selection and dispersal of phylogenetic coherent specialists with habitat preference in the heterogeneous microhabitats of burnt soils with distinct PyOM patches.

尽管野火期间产生的热解有机物 (PyOM) 在火灾后生态系统恢复中起着关键作用，但在野火扰动后 PyOM 控制土壤微生物群落组装的具体机制在很大程度上仍未得到表征。在此，我们描述了 PyOM 对两个独立的野火扰动森林地点的土壤细菌群落的影响。我们观察到细菌群落的 α 多样性在野火扰动的土壤中最高，并且细菌群落沿着未燃烧土壤→燃烧土壤→PyOM 的顺序逐渐变化。从未燃烧的土壤和 PyOM 重建的微生物群落在 α 多样性和群落结构方面类似于野火扰动土壤中的真实细菌群落。PyOM 和土壤中的细菌专家聚集在具有谱系内 pH 生态位保守性和谱系间 pH 生态位分歧的系统发育连贯谱系中。我们的结果表明，在具有不同 PyOM 斑块的烧毁土壤的异质微生境中，PyOM 通过环境选择和系统发育相干专家的分散与生境偏好相结合，介导了野火扰动土壤中的细菌群落组装。