微生物降解芘过程中的关键细菌

Key bacteria during microbial degradation of pyrene

摘要:

[目的] 探究在渤海沉积物中参与降解芘的关键细菌及他们之间潜在的相互关系。[方法] 构建以芘为唯一碳源的微宇宙培养体系驯化来自渤海的表层沉积物，借助Illumina Hiseq 2500获取驯化过程中的细菌群落组成，基于CCLasso算法及相对丰度数据预测细菌之间的相互作用关系以构建微生物生态网络。[结果] 30 d后芘的降解率为（67.07±2.37）%，细菌群落结构也发生了明显改变：Alphaproteobacteria、Flavobacteriia、Planctomycetia等的相对丰度明显增加，而Deltaproteobacteria、Anaerolineae及Spirochaetes等则明显减少。本研究获得一个由29个点143条边构成的微生物生态网络。分类已知的属中，Erythrobacter及Planctomyces等拥有较高的点度中心度。较强的互作关系发生在Erythrobacter 与Flavobacteriaceae、Alphaproteobacteria中的未知属之间。[结论] 在芘的微生物降解过程中，关键细菌之间存在紧密互作。Erythrobacter为关键细菌的代表属。

关键词:芘;海洋沉积物;细菌群落结构;微生物生态网络;关键细菌

Abstract:

[Objective] This study aimed to identify the key bacteria during the microbial degradation of pyrene in the sediments from Bohai sea and the potential interactions among these bacteria. [Methods] We set up the microcosms system with pyrene as the sole carbon source, apllied the Illumina Hiseq 2500 to reveal the bacterial communities, and then predicted the bacterial ecological interactions using CCLasso algorithm. [Results] The concentration of pyrene decreased by (67.07±2.37)% after 30 days and meanwhile the structures of bacterial communities were distinctly changed. The significantly enriched population consisted of Alphaproteobacteria, Flavobacteriia and Planctomycetia, whereas the relative abundances of Deltaproteobacteria, Anaerolineae and Spirochaetes decreased. The microbial ecological network was constructed and composed of 29 nodes and 143 edges. The classified genera with relatively high degree values included Erythrobacter and Planctomyces. The strong associations were observed between the genus Erythrobacter and some unclassified genera affiliated to the family Flavobacteriaceae and the class Alphaproteobacteria. [Conclusion] It is possible to address scientific questions from the classic ecology to identify the key bacteria during the biodegradation of polycyclic aromatic hydrocarbons compounds by marine microbial ecological networks. Our study discovered close interactions among key bacteria represented by the genera Erythrobacter.

Key words:pyrene;marine sediments;microbial communities;microbial ecological network;key bacteria