红球菌Rhodococcus sp. WH99降解吩嗪-1-羧酸的分子机制

吩嗪-1-羧酸(phenazine-1-carboxylic acid，PCA)是假单胞菌等分泌的广谱高效的抑菌物质，广泛应用于农业生产之中。因PCA具有强氧化还原活性，对非靶标生物有毒，破坏微生态平衡。研究PCA在环境中的代谢机制具有重要意义。微生物在PCA降解过程中起到关键作用，虽然报道了PCA降解菌株及负责其起始降解步骤的基因，但是PCA的完整降解途径和降解机制还不清楚。本项目拟以PCA降解菌Rhodococcus sp. WH99为材料，鉴定PCA降解中间产物，测定各中间产物的抑菌活性；克隆降解基因并表征酶学特性；阐明PCA降解的转录调控机制。本研究将在生化和分子水平上揭示微生物降解PCA的代谢和调控机制，为深入研究其环境归趋和毒理学提供理论依据。另外，吩嗪类化合物具有广泛的生物活性和重要的应用价值，本项目为研究吩嗪类化合物微生物代谢、转化和合成机制提供了重要依据。

Phenazine-1-carboxylic acid (PCA) is an important antimicrobial agent which mainly produced by Pseudomonas species. Owing to its high antimicrobial efficiency, PCA is widely used in agricultural processes. Despite being a promising biocide, PCA can be toxic to non-target microorganisms as well as the community by producing reactive oxygen species, thus reducing species diversity. Therefore, it is necessary to study the degradation mechanisms of PCA to prevent the potential hazards of PCA and its intermediates on the environment. Microbes play a key role in the elimination of PCA in the environment. However, how microbes metabolize PCA is a key question of interest in the field of environmental microbiology. The genetic and chemical information behind microbial degradation of PCA is almost unknown. In this project, we have already isolated an efficient PCA-degrading strain Rhodococcus sp. WH99. Based on our preliminary data, this project plans to identify the catabolic pathway, the genetic determinants and transcriptional regulation of PCA catabolism in the strain WH99. The expected findings will enhance our understanding of the microbial degradation mechanism of PCA, help us to track the fate and ecotoxicity of PCA in the natural environment and benefit the effort to eliminate PCA contamination. More importantly, phenazines compounds which are similar to PCA are valuable chemicals in applications ranging from agriculture to human health. This project will contribute to the mechanism of microbial metabolism, biotransformation and synthesis of phenazines compounds.