基于稳定同位素探针和宏基因组学技术的根际多环芳烃微生物降解机理研究

人类活动的加剧，特别是工业化进程的提高使得环境中的多环芳烃（PAHs）污染越来越严重。微生物降解是土壤中PAHs去除的主要途径。根际是PAHs消减最为迅速的区域，在自然界PAHs降解过程中具有特殊地位。从根际环境中发掘潜在高效的PAHs降解微生物，明确其在降解过程中的作用和机制，并阐明根际效应对PAHs降解微生物的影响，对PAHs污染土壤生物修复具有重要意义。DNA-稳定同位素探针技术（DNA-SIP）克服了传统分离培养技术的局限，能够在原位条件下将未知微生物和其功能直接联系起来。本项目以DNA-SIP、宏基因组学技术和定量PCR技术为手段，开展根际和非根际土壤同步SIP实验，研究PAHs降解的动力学特征，了解根际效应对土壤PAHs降解微生物群落组成及其动态变化过程，结合功能基因分析降解机制，揭示根际效应在根际修复PAHs过程中的作用，为PAHs污染土壤的根际修复提供微生物资源和理论依据。

With the intensification of human activities, especially industrial development, the pollution of polycyclic aromatic hydrocarbons (PAHs) has become more and more serious. Microbial degradation is the major way for the removal of PAHs in soil. Rhizosphere is the most active region for PAHs biodegradation in soil, and it plays a very important role in the dissipation of PAHs. Investigating the effects of rhizosphere on the degradation of PAHs，exploring the potential high efficient PAHs-degrading microbes and clarifying the mechanism of degradation are of great significance for the bioremediation of PAHs contaminated soils. DNA-based stable isotope probing (DNA-SIP) technique is a powerful cultivation-independent technique to assess metabolic responses and provides the opportunity to link directly the identities of unknown microorganisms to their functions in their natural habitats. With the aid of in situ labeling of soils from rhizosphere and non-rhizosphere, this work a uses DNA-SIP, high-throughput sequencing and quantitative PCR as a means to identify the PAHs degraders and related degrading genes in typical PAHs contaminated soil, reveal the potential degrading mechanisms, and elaborate the rhizospheric effects on PAHs biodegradation. Potential microbial resources and theoretical basis on the rhizoremediation of PAH-contaminated soils are hoped to be provided.