State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
Sci Total Environ. 2021 Jun 15;773:145069. doi: 10.1016/j.scitotenv.2021.145069. Epub 2021 Feb 4.
Soil aggregates are integral parts of soil structure and play paramount roles in supporting microbial diversity, nutrient cycling and water retention. The formation of multispecies biofilms is a survival strategy for bacterial adaptation to the environment and help microorganisms access more complex nutrient sources via labor sharing, especially in soil aggregates. However, very little is known about the effect of species richness and composition on bacterial multispecies biofilms formation in different size soil aggregates. A random partition design strategy was used to identify the relative importance of bacterial richness and composition in driving multispecies biofilms. The strategy can separate the effects of species richness and composition from the soil aggregates occurring bacterial assemblage. Increasing species richness was found to be always positively correlated with multispecies biofilms productivity for bacteria from the same aggregate fractions. General linear model analysis revealed that species composition contributed more than species richness to forming multispecies biofilms, suggesting that "selection mechanism" plays a more important role than "complementarity mechanism". This "selection mechanism" relies mainly on culturable keystone species that can significantly enhance the formation of multispecies biofilms. The co-occurrence network was investigated to explore whether the culturable keystone species from the random partitions experiment are consistent with the keystone taxa. Four out of 10 culturable keystone species isolated from soil aggregates were matched the keystone taxa. It is concluded that the culturable keystone species determine the multispecies biofilms formation for bacteria residing in soil aggregates. This study provides insights into the role of culturable keystone species in multispecies biofilms. Understanding the formation of multispecies biofilms is fundamental to decipher how microbes interact with each other in soil aggregates. Meanwhile, it will enhance our knowledge of the quorum behavior of complex bacterial communities.
土壤团聚体是土壤结构的组成部分，在支持微生物多样性、养分循环和保持水分方面起着至关重要的作用。多物种生物膜的形成是细菌适应环境的生存策略，有助于微生物通过劳动分工获取更复杂的营养源，尤其是在土壤团聚体中。然而，对于物种丰富度和组成如何影响不同大小土壤团聚体中细菌多物种生物膜的形成，人们知之甚少。采用随机分区设计策略来确定细菌丰富度和组成对不同大小土壤团聚体中多物种生物膜形成的相对重要性。该策略可以将物种丰富度和组成的影响与土壤团聚体中发生的细菌组合分开。结果发现，对于来自同一团聚体部分的细菌，物种丰富度的增加总是与多物种生物膜的生产力呈正相关。一般线性模型分析表明，物种组成比物种丰富度对形成多物种生物膜的贡献更大，这表明“选择机制”比“互补机制”发挥更重要的作用。这种“选择机制”主要依赖于可培养的关键种，它可以显著增强多物种生物膜的形成。通过共现网络来探究随机分区实验中的可培养关键种是否与关键分类群一致。从土壤团聚体中分离出的 10 种可培养关键种中有 4 种与关键分类群相匹配。结论是，可培养的关键种决定了栖息在土壤团聚体中的细菌多物种生物膜的形成。本研究为可培养关键种在多物种生物膜形成中的作用提供了新的见解。了解多物种生物膜的形成对于揭示微生物在土壤团聚体中如何相互作用至关重要。同时，它将增强我们对复杂细菌群落群体感应行为的认识。
