人工微宇宙下粘细菌捕食对微生物群落结构的影响

Effects of myxobacteria predation on microbial community structure of artificial microcosm

摘要:

[目的] 人工微宇宙条件下测试粘细菌捕食对微生物群落结构的影响，模拟粘细菌捕食对微生态系统的调控作用。[方法] 采用Lawn predation法，测定粘细菌EGB对9种猎物菌的捕食直径，以确定其对猎物菌的捕食能力。通过高通量测序技术分析粘细菌捕食引起的微生物群落结构变化。[结果] 粘细菌EGB对9种不同猎物菌的捕食能力差异显著，粘细菌对热带芽孢杆菌的捕食能力显著高于其他细菌（P<0.05）。在含有9种猎物细菌的人工微宇宙系统中添加不等量粘细菌，均可显著降低细菌群落的多样性指数（Shannon）。PCoA结果表明粘细菌捕食可影响微宇宙微生物群落结构。人工微宇宙培养24 h后，7种猎物菌相对丰度显著降低（LefSe，P<0.05），但洋葱伯克霍尔德菌的相对丰度显著升高（P<0.05）。人工微宇宙实验的结果表明，粘细菌添加是造成其微生物群落结构改变的主要影响因素，且添加最小剂量的粘细菌（1 mL）也有显著的影响效果；随着培养时间的增加，洋葱伯克霍尔德菌是唯一能抵抗粘细菌捕食并具有较高丰度的猎物细菌。[结论] 粘细菌捕食能够调控微宇宙中微生物的群落结构，为其对土壤生态的调控研究奠定了理论基础。

Abstract:

[Objective] The purpose of this research is to test the effects of myxobacteria predation on the microbial community structure in microcosms and determine the role of myxobacteria predation in the regulation of artificial microecosystem.[Methods] Predation ability was determined by the predation diameters of myxobacteria EGB against nine species of prey bacteria using Lawn predation method. The microbial community structure changes caused by the predation of myxobacteria were analyzed through high-throughput sequencing technology.[Results] The predation abilities of myxobacteria EGB to 9 different species of prey bacteria were significantly different. The predation ability of myxobacteria to Bacillus tropicus was significantly higher than that of other bacteria (P<0.05). Adding different amounts of myxobacteria in an artificial microcosm system containing nine prey bacteria, the bacterial community diversity index (Shannon) was significantly reduced. The results of PCoA showed that the myxobacteria predation could affect the microcosm microbial community structure. The relative abundance of seven species of prey bacteria was reduced significantly (LefSe, P<0.05), while the relative abundance of Burkholderia cenocepacia was increased significantly (P<0.05) after 24-hour of artificial microcosm cultivation. The results of artificial microcosm experiments showed that the addition of myxobacteria EGB was the main factor influencing the microbial community structure, and the addition of the minimum dose of myxobacteria (1 mL) also had a significant effect. With the increase of tested time, Burkholderia was the only prey bacteria that could resist the predation of myxobacteria and kept its relative high abundance.[Conclusion] Myxobacteria predation could regulate the microbial community structure in the microcosm, which lays a theoretical foundation for applying in soil-ecosystem regulation in the future.