微生物群落构建和演替对石油污染物的响应研究

发布时间：2018-03-02 18:24

本文选题：微生物演替　切入点：时间动态　出处：《西北农林科技大学》2017年博士论文　论文类型：学位论文

【摘要】：土壤生态系统是土壤中多种生物与环境通过物质、能量和信息交换,相互作用所构成的一个整体。土壤微生物是土壤中最活跃的组成部分,直接参与土壤的生物化学过程及生态功能发挥。然而石油污染土壤中微生物群落构建以及响应于石油污染物的微生物群落演替规律仍不清楚。本文针对陕西五个炼油厂附近石油污染土壤(相距46-360千米),研究长期石油污染土壤微生物的生物地理分布模式和生物多样性,探索丰富和稀有微生物的群落构建和生态地位;并对采自咸阳和靖边两个地区污染土壤样本进行10个批次共100天的连续富集培养,通过添加不同污染物,包括:菲;正十八烷;菲+正十八烷;菲+正十八烷+氯化镉,探索有机污染物连续污染和降解过程中的微生物群落的演替机制。微生物群落的分析是采用16S rRNA基因V4-V5区的MiSeq高通量测序。分析结果如下:(1)通过对石油污染土壤微生物群落构建的解析,发现pH、总石油烃、总氮、镉含量能显著影响微生物群落结构,微生物α-多样性与pH呈正相关关系而与总石油烃含量呈负相关关系。微生物群落相似度随着地理距离的增加不断减少,表现出显著的距离-衰减关系,说明微生物群落构建受空间距离和环境因子的共同驱动。通过方差分解分析,发现空间距离单独解释的微生物群落差异比环境变量大。通过共发生网络分析,确定了五个关键类群(Keystone)包括Rubrivivax、Nitrospira、Methylotenera、Methyloversatilis和Acidaminobacter,微生物共发生模式是非随机的且受微生物功能驱动。(2)石油污染土壤中,稀有和丰富微生物有不同的分布模式,稀有微生物是特殊的、瞬时存在的,而丰富微生物是普遍的、持续存在的。通过功能预测,发现丰富微生物在一些主要代谢功能表现更高的活性,而稀有微生物包含更多的代谢功能多样性。同时,丰富和稀有微生物群落都表现出显著的距离-衰减模式,但它们受不同的因子驱动;丰富微生物主要受土壤因子驱动,而稀有微生物主要受地理因子驱动。通过共发生网络分析,比较子网络水平和节点水平上的拓扑特性差异,发现丰富微生物处在核心的生态地位,而稀有微生物则没有。(3)不同污染物或组合能显著改变富集菌群微生物群落的演替方向,且菌群微生物丰富度,多样性和均匀度随着演替的进行不断降低。这些富集降解菌群主要由一些已知有降解石油烃功能的微生物组成,包括Acinetobacter、Gordonia、Sphingobium、Sphingopyxis和Castellaniella。而有一些新发现的微生物如Niabella和Naxibacter可能也参与石油烃的降解过程。不同降解菌群的共发生网络的差异,表明污染物能影响微生物之间的相互作用。(4)通过maSigPro分析,发现在降解菌群富集过程中,不同污染物处理菌群有相同的动态变化模式,即持续增多(induction),持续减少(repression)和起伏变化(fluctuation),而前两类是主要的动态变化模式。降解菌群中,物种-时间关系(STRs)和时间-衰减关系(TDRs)的指数比其他环境高如水,土壤,空气等,表明连续污染可以加快微生物群落的演替速率。不同降解菌群的条件稀有类群(CRTs)具有广泛且不同的系统发育多样性。我们的研究结果揭示了不同地区的土壤,经长时间的石油污染,会形成相似的微生物类群,群落中稀有微生物没有处于核心的生态地位,但对于生态系统功能和多样性的维持起重要的生态作用。污染物决定微生物群落的演替方向,且持续污染可以加快微生物群落演替速率。
[Abstract]:The soil ecosystem is the soil and environment through a variety of biological material, energy and information exchange, the interaction of a whole formed. Soil microbe is the most active part of soil, biological and chemical processes and ecological function of soil directly involved in the play. However, in response to the oil pollutant microbial community succession of microorganism community construction oil contaminated soil is still not clear. In this paper the petroleum contaminated soil near Shaanxi five refineries (about 46-360 km), long-term study of petroleum contaminated soil microbial biogeography distribution pattern and biodiversity, explore the rich and rare microbial community construction and ecological status; and collected from contaminated soil samples in Xianyang and Jingbian two a region of 10 batches of a total of 100 days of continuous enrichment, by adding different pollutants, including phenanthrene; are eighteen alkyl phenanthrene + is ten; The Philippines is eighteen + eight alkyl; alkane + cadmium chloride, explore the mechanism of microbial community succession and degradation of organic pollutants in the process of continuous pollution. Microbial community analysis is MiSeq high-throughput sequencing using 16S rRNA gene V4-V5 region. The results are as follows: (1) through the analysis, construction of petroleum contaminated soil microbial community the discovery of pH, total nitrogen, total petroleum hydrocarbons, the cadmium content can significantly affect the microbial community structure and microbial alpha diversity is positively correlated with pH and negatively correlated with the content of total petroleum hydrocarbons. The microbial community similarity with geographic distance increased constantly reduced, showed a significant distance decay relationship, indicating microbial community driven by the construction of common space and environmental factors. Through the analysis of variance decomposition, found differences in the microbial community space to explain the ratio of environmental variables. Through co occurrence network analysis, determine The five key groups (Keystone) including Rubrivivax, Nitrospira, Methylotenera, Methyloversatilis and Acidaminobacter, there is a non random pattern of microorganisms and microbial function driven. (2) in petroleum contaminated soil, rare and abundant microbes have different distribution patterns of rare microorganisms is special, transient existence, and abundant microorganism is common, persistent. Through function prediction, the discovery of rich microorganisms exhibited higher activity in some of the major metabolic function, and rare microorganisms including metabolic function more diversity. At the same time, rich and rare microbial communities showed significant distance decay patterns, but they are driven by different factors; rich the main driving factor is affected by soil microorganisms, and rare microorganisms mainly affected by geographical factors driving. Through network analysis were compared, and the water level of the sub network node The difference on the topological characteristics of flat, discovered the rich ecological status of microorganisms at the core, and rare microorganisms are not. (3) the direction of succession of different pollutants or combination can significantly change the bacteria in the microbial community and microbial flora, species richness, diversity and evenness decreased with succession. The enrichment of degrading bacteria the group consists of some known functional degradation of petroleum hydrocarbon components, including Acinetobacter, Gordonia, Sphingobium, Sphingopyxis and Castellaniella. and some of the newly discovered microbial degradation processes such as Niabella and Naxibacter may be involved in petroleum hydrocarbon. There were differences in different network degrading bacteria, that pollutants can affect the interaction between microorganisms. (4) through the analysis of maSigPro, found in bacteria enrichment process, different pollutant treatment bacteria have the same dynamic change model, That is increasing (induction), continued to decrease (repression) and fluctuation (fluctuation), the two is the dynamic change model. The main degradation flora, species - time relation (STRs) attenuation relationship and time index (TDRs) than other high environment such as water, soil, air, show continuous pollution can accelerate the succession of microbial community in different conditions. The rate of degradation flora of rare taxa (CRTs) system has extensive and different developmental diversity. Our results reveal the different regions of the soil, the oil pollution long time of dye, will form a similar microbial, microbial community in rare ecological status at the core, but for the ecosystem function and diversity maintenance plays an important ecological role. The microbial community succession of pollutants, and persistent pollution can accelerate the microbial community succession rate.

【学位授予单位】：西北农林科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X742;X172

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