Buitimea-Cantúa Génesis V, Magaña-Barajas Elisa, Buitimea-Cantúa Nydia E, Leija Gutiérrez Héctor Manuel, Del Refugio Rocha-Pizaña María, Rosas-Burgos Ema Carina, Hernández-Morales Alejandro, Molina-Torres Jorge
Tecnologico de Monterrey, Centro de Biotecnología-FEMSA, Escuela de Ingeniería y Ciencias, Monterrey, Nuevo León, México.
Departamento de Biotecnología y Bioquímica, CINVESTAV, Irapuato, Guanajuato, México.
J Environ Sci Health B. 2021;56(10):899-908. doi: 10.1080/03601234.2021.1974273. Epub 2021 Sep 6.
Affinin present in roots has been identified as an anti-aflatoxin molecule. However, its mechanism of action has yet to be clarified. Aflatoxins biosynthesis involves not less than 27 enzymatic reactions. In this work, the genes G, H, I, K, L, M, O, P, and Q of the aflatoxins cluster and the S gene encoding an internal regulatory factor involved in aflatoxins biosynthesis in were studied by qRT-PCR. Results demonstrated that ethanolic extract of roots and affinin inhibit aflatoxin biosynthesis and fungal growth in a dose-dependent manner. At 300 µg/mL, ethanolic extract and affinin presented the highest inhibition of radial growth (86% and 94%) and aflatoxin production (68% and 80%). The qRT-PCR analysis demonstrated that nine tested genes were down-regulated by affinin and ethanolic extract. The most down-regulated was the K, a gene that encodes an enzyme cyclase with double function during the aflatoxin biosynthesis. While no significant down-regulation was obtaining for H gene. Exposure to affinin also resulted in decreased transcript levels of the internal regulator factor S. Based on our results, a model showing the regulatory mechanism in aflatoxin biosynthesis and its role in gene expression was proposed. In conclusion, affinin modulates the expression of several aflatoxin biosynthetic genes, leading to mycotoxin biosynthesis inhibition. Therefore, roots is a suitable candidate to developed control strategies via lowering gene expressions as a future perspective in reducing aflatoxin contamination.
存在于[植物名称]根中的亲和素已被鉴定为一种抗黄曲霉毒素分子。然而，其作用机制尚未阐明。黄曲霉毒素的生物合成涉及不少于27种酶促反应。在这项工作中，通过qRT-PCR研究了黄曲霉毒素簇的基因G、H、I、K、L、M、O、P和Q以及参与[植物名称]中黄曲霉毒素生物合成的编码内部调节因子的S基因。结果表明，[植物名称]根的乙醇提取物和亲和素以剂量依赖的方式抑制黄曲霉毒素的生物合成和真菌生长。在300μg/mL时，乙醇提取物和亲和素对径向生长（分别为86%和94%）和黄曲霉毒素产生（分别为68%和80%）的抑制作用最强。qRT-PCR分析表明，9个测试基因被亲和素和乙醇提取物下调。下调最明显的是K基因，该基因在黄曲霉毒素生物合成过程中编码一种具有双重功能的环化酶。而H基因没有明显下调。暴露于亲和素还导致内部调节因子S的转录水平降低。基于我们的结果，提出了一个显示黄曲霉毒素生物合成调控机制及其在基因表达中作用的模型。总之，亲和素调节几种黄曲霉毒素生物合成基因的表达，导致霉菌毒素生物合成受到抑制。因此，作为未来减少黄曲霉毒素污染的一个前景，[植物名称]根是通过降低基因表达来制定控制策略的合适候选物。
