Effects of myxobacteria predation on microbial community structure of artificial microcosm

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.

Key words:myxobacteria;predation;microcosm;high-throughput sequencing;community structure