Ren Yaoyao, Jin Jing, Zheng Mumin, Yang Qingli, Xing Fuguo
College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China.
Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China.
Front Microbiol. 2020 Jan 17;10:2946. doi: 10.3389/fmicb.2019.02946. eCollection 2019.
As the most carcinogenic, toxic, and economically costly mycotoxins, aflatoxin B (AFB) is primarily biosynthesized by and . Aflatoxin biosynthesis is related to oxidative stress and functions as a second line of defense from excessive reactive oxygen species. Here, we find that ethanol can inhibit fungal growth and AFB production by in a dose-dependent manner. Then, the ethanol's molecular mechanism of action on AFB biosynthesis was revealed using a comparative transcriptomic analysis. RNA-Seq data indicated that all the genes except for in the aflatoxin gene cluster were down-regulated by 3.5% ethanol. The drastic repression of aflatoxin structural genes including the complete inhibition of and may be correlated with the down-regulation of the transcription regulator genes and in the cluster. This may be due to the repression of several global regulator genes and the subsequent overexpression of some oxidative stress-related genes. The suppression of several key aflatoxin genes including , , , and may also be associated with the decreased expression of the global regulator gene . In particular, ethanol exposure caused the decreased expression of stress response transcription factor and the overexpression of bZIP transcription factor , CH transcription factors and , together with the enhanced levels of anti-oxidant enzymatic genes including , , , , and Cu, Zn superoxide dismutase gene . Taken together, these RNA-Seq data strongly suggest that ethanol inhibits AFB biosynthesis by via enhancing fungal oxidative stress response. In conclusion, this study served to reveal the anti-aflatoxigenic mechanisms of ethanol in and to provide solid evidence for its use in controlling AFB contamination.
作为最具致癌性、毒性且经济成本高昂的霉菌毒素，黄曲霉毒素B（AFB）主要由……生物合成。黄曲霉毒素生物合成与氧化应激相关，并作为抵御过量活性氧的第二道防线发挥作用。在此，我们发现乙醇能以剂量依赖的方式抑制……的真菌生长和AFB产生。然后，通过比较转录组分析揭示了乙醇对AFB生物合成的分子作用机制。RNA测序数据表明，黄曲霉毒素基因簇中除……外的所有基因在3.5%乙醇作用下均下调。包括……完全抑制在内的黄曲霉毒素结构基因的大幅抑制可能与该基因簇中转录调节基因……的下调有关。这可能是由于几个全局调节基因受到抑制以及随后一些氧化应激相关基因的过表达所致。包括……等几个关键黄曲霉毒素基因的抑制也可能与全局调节基因……表达降低有关。特别是，乙醇暴露导致应激反应转录因子……表达降低以及bZIP转录因子……、CH转录因子……和……过表达，同时抗氧化酶基因包括……以及铜锌超氧化物歧化酶基因……水平升高。综上所述，这些RNA测序数据有力地表明乙醇通过增强真菌氧化应激反应来抑制……的AFB生物合成。总之，本研究旨在揭示乙醇在……中的抗黄曲霉毒素生成机制，并为其用于控制AFB污染提供确凿证据。
