石油污染土壤富集前后细菌群落组成和共现网络分析

为了探究石油污染土壤中细菌群落在富集过程中的演替规律，试验采用平板划线法、菌落PCR和高通量测序技术，分析了富集前后细菌群落结构、共现网络和核心菌属组成，并对富集后体系中的微生物进行分离鉴定，筛选石油降解菌.研究表明富集体系中可培养微生物隶属于34个属53个种，其中3个为潜在新种微生物，Dietzia maris OS33和Rhodococcus qingshengii OS62-1具有降解石油的能力.高通量测序结果显示，在门分类水平上，富集前后丰度较高的菌门均为Proteobacteria和Actinobacteria，富集后两菌门的丰度可达到97.98%，占据绝对优势；丰度较高菌属由Pseudomonas、Rhodococcus、Bacillus和Xanthomonas转变为Dietzia、Unspecified_Idiomarianceae和Halomonas，标志微生物转变为与石油降解有关的Dietzia.细菌群落共现网络在富集后，网络结构进一步简化且更加稳定，核心微生物转变为与石油降解有关的Pseudomonas、Lysinibacillus、Pseudochrobactrum、Agrobacterium、Lactobacillus，且非石油降解菌P.songnenensis P35可协同石油降解菌D.maris OS33降解石油.

Bacterial community composition and co-occurrence network before and after enrichment of oil-contaminated soil

Enrichment culture is one of the most important aspects of isolating petroleum degrading microorganisms, in which the microbial community undergoes corresponding succession. The bacterial community structure, co-occurrence network and core genus composition before and after the enrichment were conducted with the streak plate method, colony PCR and Illumina-MiSeq high-throughput sequencing technology to investigate the succession pattern of bacterial communities in oil-contaminated soil during the enrichment process. The microorganisms in the enriched system were isolated and identified. We observed that the culturable microorganisms in the enriched system belong to 34 genera and 53 species, among which 3 are of potential new species, and Dietzia maris OS33 and Rhodococcus qingshengii OS62-1are able to degrade oil. High-throughput sequencing results show that Proteobacteria and Actinobacteria are the main phylum, whenever it is before or after enrichment. But after enrichment, these two phylums are of absolutely dominant groups and the abundance is up to 97.98%. At the genus level, the dominant genuses are transformed from Psuedomonas, Rhodococcus,Bacillus and Xanthomonas to Dietzia, Unspecified_Idiomarianceae and Halomonas, the core genera are altered to Dietzia for degrating petroleum. The co-occurrence networks of bacterial communities are more simplified and stable after enrichment. The core microorganisms are altered to Pseudomonas, Lysinibacillus, Pseudochrobactrum, Agrobacterium and Lactobacillus which are related to petroleum degradation. The non-petroleum degrading bacteria P. songnenensis P35can cooperate with the oil degrading bacteria D. maris OS33to degrade petroleum.