微生物在降解有机污染物过程中具有重要作用。2,3-二氯硝基苯广泛应用于农药制造等化工产业，是一种有毒的污染物，但目前尚无微生物降解此污染物的报道，更无其代谢途径的解析。本申请的前期工作从污染环境中筛选到一株能以2,3-二氯硝基苯为唯一碳源、氮源生长的细菌Pseudomonas sp. JS3051。该菌株通过氧化途径代谢2,3-二氯硝基苯并释放亚硝酸根离子。本项目拟通过基因组／转录组测序及构建插入突变文库等方法寻找JS3051菌株2,3-二氯硝基苯的代谢基因（簇）。借助基因敲除及互补、蛋白的体外表达及酶学特性研究等方法，结合质谱分析对基因及其编码产物功能进行鉴定，最终阐明2,3-二氯硝基苯的代谢途径及其分子机理。本研究结果将会解析尚未知晓的2,3-DCNB代谢途径，揭示多氯硝基芳烃与单氯硝基芳烃微生物代谢途径的进化关系，并在2,3-二氯硝基苯环境污染的微生物修复方面将具有潜在的应用价值。

Microorganisms play an important role in the degradation of organic pollutants. Chemical 2,3-Dichloronitrobenzene (2,3-DCNB) is a toxic pollutant widely used in chemical industries such as pesticide manufacturing. So far, no microbes capable of degrading 2,3-DCNB have been reported, let alone the analysis of its catabolic pathway. As seen in previous work, a strain of Pseudomonas sp. JS3051 capable of growing on 2,3-DCNB as the sole carbon source and nitrogen source was isolated from contaminated soil. Strain JS3051 is able to metabolize 2,3-DCNB by an oxidative pathway and release nitrite ions. This project aims to find the catabolic genes (cluster) involved in 2,3-DCNB degradation by genome/transcriptome sequencing and construction of insertion mutant library. The function of key genes and enzymes involoved will then be investigated, by using methods such as gene knockout and compensation, protein expression in vitro and enzymatic characterization, together with mass spectrometry. Finally, the catabolic pathway of 2,3-DCNB by strain JS3051 will be elucidated. The outcome of this study will reveal the unknown 2,3-DCNB catabolic pathway as well as help to explore the evolutionary relationship of catabolic pathways between polychlorinated nitroaromatic compounds and monochloronitroaromatic compounds. This project will also contribute towards a potential resolution for bioremediation application in 2,3-DCNB-contaminated environments.