探索微生物群的组装机制对于理解土壤生态系统功能至关重要。然而,不同生物和非生物因素在确定细菌群落中的相对重要性尚未得到适当澄清。在这项研究中,通过无菌土壤接种实验,研究了接种物和受体对土壤群落组装的影响,以评估其重要性。两种不同的土壤,常规氮肥土壤和芳香族化合物污染土壤,被消毒,交叉接种,并在不同的接种剂量和氧气条件下孵育2个月。结果表明,群落结构的最大变化出现在接种不同接种物的样品中,而不是不同土壤受体的样品中。两种接种物的系统发育多样且不相似,尽管有许多生态等效的细菌。当使用具有不同生态等效物种的接种物时,组装群落主要由接种物确定,如β多样性和变异分配分析所示。相比之下,当接种物中生态等效物种相似时,环境选择主导了这一过程,当只使用一种类型的接种物时,土壤栖息地从定义的接种池中选择了适应性最强的细菌。这些结果表明,如果接种的细菌足够不同,则它们在环境选择上占主导地位,尽管在土壤中接种相似细菌进行群落组装时,环境选择的效果更为明显。我们的发现表明,外来细菌的迁移可能是影响社区组装的主要因素。重要性土壤微生物群具有重要的生物生态系统功能,但是土壤微生物群落与环境相互作用的潜在机制尚不清楚。通过使用两种不同的土壤进行交叉接种,我们成功地模拟了无菌土壤中细菌群落的组装。因此,本研究调查了接种者和接受者在先前调查中主导社区集会的原因。我们发现,由于生态等效细菌的差异,接种细菌主持了群落聚集的环境选择,发散或收敛。在探索社区组装机制时,应强调中性对迁移到接受者体内的生态等效细菌物种的重要性。我们的发现有助于理解社区与环境的相互作用,生态学中的一个基本问题,它将揭示这个困扰科学家多年的问题。
Exploring the assembly mechanism of microbiota is critical for understanding soil ecosystem functions. However, the relative importance of different biotic and abiotic factors in determining the bacterial community has not been properly clarified. In this study, the effects of inocula and recipients on the assembly of the soil community were investigated to evaluate their importance by inoculation experiments with sterile soil. Two distinct soils, conventional nitrogen-fertilized soil and aromatic-compound-contaminated soil, were sterilized, cross inoculated, and incubated for 2 months under different inoculation doses and oxygen conditions. The results showed that the greatest variation in community structure emerged in the samples inoculated with distinct inocula rather than in the samples of different soil recipients. The phylogenies in the two inocula were diverse and dissimilar, although there were many ecologically equivalent bacteria. When the inocula with dissimilar ecologically equivalent species were used, the assembled communities were primarily determined by the inocula as indicated by the beta diversity and variation partitioning analyses. In contrast, environmental selection dominated the process when ecologically equivalent species in the inocula were similar, as when only one type of inoculum was used, where the soil habitat selected the most adaptive bacteria from the defined inoculum pool. These results indicate that inoculated bacteria are dominant over environmental selection if they are sufficiently dissimilar, although the effect of environmental selection is more obvious when similar bacteria are inoculated in the soil for community assembly. Our findings suggest that the immigration of exotic bacteria could be a primary factor impacting community assembly.IMPORTANCE The soil microbiota conducts important biological ecosystem functions, but the mechanism underlying community-environment interactions for soil microbiota remains unclear. By using two distinct soils for cross inoculation, we successfully simulated the assembly of the bacterial community in sterile soil. Thus, the reasons why inoculum and recipient have dominated community assembly in previous investigations are investigated in this study. We found that inoculated bacteria presided over environmental selection for community assembly due to the varied difference of ecological equivalent bacteria, either divergent or convergent. The significance of neutrality for the ecologically equivalent bacterial species that immigrated into the recipients should be emphasized in exploring the mechanisms of community assembly. Our finding is helpful for understanding the community-environment interaction, a basic question in ecology, and it would shed light on this issue that has perplexed scientists for many years.