Yao Guangshan, Zhang Feng, Nie Xinyi, Wang Xiuna, Yuan Jun, Zhuang Zhenhong, Wang Shihua
Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.
Front Microbiol. 2017 Nov 20;8:2277. doi: 10.3389/fmicb.2017.02277. eCollection 2017.
Aflatoxins are a potent carcinogenic mycotoxin and has become a research model of fungal secondary metabolism (SM). Via systematically investigating the APSES transcription factors (TFs), two APSES proteins were identified: AfRafA and AfStuA. These play central roles in the synthesis of mycotoxins including aflatoxin and cyclopiazonic acid, and fungal development and are consequently central to the pathogenicity of the aflatoxigenic . Loss of AfRafA not only dramatically suppressed aflatoxin cluster expression, subsequently reducing toxin synthesis both and , but also impaired conidia and sclerotia development. More importantly, aflatoxin biosynthesis as well as conidia and sclerotia development were fully blocked in Δ. In addition, our results supported that AfStuA regulated the aflatoxin synthesis in an AflR-dependent manner. Intriguingly, it was revealed that AfRafA and AfStuA exert an antagonistic role in the regulation of biosynthesis of cyclopiazonic acid. In summary, two global transcriptional regulators for fungal development, mycotoxin production, and seed pathogenicity of the system have been established. The two novel regulators of mycotoxins are promising targets for future plant breeding and for the development of fungicides.
黄曲霉毒素是一种强效致癌性霉菌毒素，已成为真菌次级代谢（SM）的研究模型。通过系统研究APSES转录因子（TFs），鉴定出两种APSES蛋白：AfRafA和AfStuA。它们在包括黄曲霉毒素和环匹阿尼酸在内的霉菌毒素合成以及真菌发育中起核心作用，因此对于产黄曲霉毒素菌的致病性至关重要。AfRafA的缺失不仅显著抑制黄曲霉毒素簇的表达，随后降低毒素合成，还损害分生孢子和菌核的发育。更重要的是，在Δ中黄曲霉毒素生物合成以及分生孢子和菌核发育完全受阻。此外，我们的结果支持AfStuA以依赖AflR的方式调节黄曲霉毒素合成。有趣的是，研究发现AfRafA和AfStuA在环匹阿尼酸生物合成的调节中发挥拮抗作用。总之，已确定了两个参与真菌发育、霉菌毒素产生以及该系统种子致病性的全局转录调节因子。这两种新型霉菌毒素调节因子是未来植物育种和杀菌剂开发的有希望的靶点。
