Cytochrome P450 Monooxygenase Mediated Metabolic Utilization of Benzo(a)pyrene by Fungi. Cytochrome P450 Monooxygenase Mediated Metabolic Utilization of Benzo(a)pyrene by Fungi

Soil dwelling Aspergillus fungi possess the versatile metabolic capability to utilize complex organic compounds which are toxic to humans, yet the mechanisms they employ remain largely unknown. Benzo(a)pyrene is a common carcinogenic contaminant, posing a significant concern for human health. Here, we report that Aspergillus fungi can degrade benzo(a)pyrene effectively. In Aspergillus nidulans, exposure to benzo(a)pyrene results in transcriptomic and metabolic changes associated with cellular growth and energy generation, implying that the fungus utilizes benzo(a)pyrene as a food. Importantly, we identify and characterize the conserved bapA gene encoding a cytochrome P450 monooxygenase that exerts the first step in the degradation of benzo(a)pyrene. We further demonstrate that the fungal NF-κB-type global regulators VeA and VelB are required for benzo(a)pyrene degradation in A. nidulans, which occurs through expression control of bapA in response to nutrient limitation. Our study illuminates fundamental knowledge of fungal benzo(a)pyrene metabolism and provides novel insights into enhancing bioremediation potential. Overall design: Aspergillus nidulans hyphae were incubated in 0.1% glucose media with 200 µM benzo(a)pyrene or solvent only control (DMSO) and samples were taken at 6, 24, and 48 hours post incubation. Timepoint zero represents spore inoculation in 1% glucose media and growth for 18 hours. Transcripts were sequenced using Illumina HiSeq2500

栖息于土壤的曲霉菌属（Aspergillus）真菌拥有降解复杂有机化合物的多样代谢能力，尽管这类化合物对人类具有毒性，但其介导降解的具体机制目前仍未被充分阐明。苯并(a)芘（Benzo(a)pyrene）是一种常见的致癌污染物，对人类健康构成严重威胁。本研究证实，曲霉菌属真菌可高效降解苯并(a)芘。在构巢曲霉（Aspergillus nidulans）中，暴露于苯并(a)芘会引发与细胞生长及能量生成相关的转录组和代谢组变化，这暗示该真菌将苯并(a)芘作为营养底物加以利用。值得注意的是，本研究鉴定并表征了保守的bapA基因，其编码的细胞色素P450单加氧酶（cytochrome P450 monooxygenase）是苯并(a)芘降解途径的第一步关键酶。本研究进一步证实，真菌NF-κB型全局调控因子VeA与VelB是构巢曲霉降解苯并(a)芘所必需的，其调控机制为响应营养限制条件下对bapA基因的表达调控。本研究阐明了真菌降解苯并(a)芘的基础代谢机制，为提升生物修复潜力提供了全新的研究视角。

实验总体设计：将构巢曲霉菌丝置于添加200 μM苯并(a)芘的0.1%葡萄糖培养基中孵育，以仅添加溶剂二甲基亚砜（DMSO）的培养基作为空白对照，分别于孵育后6、24和48小时采集样本。时间点0代表将孢子接种于1%葡萄糖培养基中预生长18小时的样本。转录组测序采用Illumina HiSeq2500平台完成。