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Review
. 2020 Feb 28;12(3):150.
doi: 10.3390/toxins12030150.

Aflatoxin Biosynthesis and Genetic Regulation: A Review

Isaura Caceres  1 , Anthony Al Khoury  1 , Rhoda El Khoury  1 , Sophie Lorber  1 , Isabelle P Oswald  1 , André El Khoury  2 , Ali Atoui  3 , Olivier Puel  1 , Jean-Denis Bailly  1
Affiliations
Review

Aflatoxin Biosynthesis and Genetic Regulation: A Review

Isaura Caceres et al. Toxins (Basel). .

Abstract

The study of fungal species evolved radically with the development of molecular techniques and produced new evidence to understand specific fungal mechanisms such as the production of toxic secondary metabolites. Taking advantage of these technologies to improve food safety, the molecular study of toxinogenic species can help elucidate the mechanisms underlying toxin production and enable the development of new effective strategies to control fungal toxicity. Numerous studies have been made on genes involved in aflatoxin B1 (AFB1) production, one of the most hazardous carcinogenic toxins for humans and animals. The current review presents the roles of these different genes and their possible impact on AFB1 production. We focus on the toxinogenic strains Aspergillus flavus and A. parasiticus, primary contaminants and major producers of AFB1 in crops. However, genetic reports on A. nidulans are also included because of the capacity of this fungus to produce sterigmatocystin, the penultimate stable metabolite during AFB1 production. The aim of this review is to provide a general overview of the AFB1 enzymatic biosynthesis pathway and its link with the genes belonging to the AFB1 cluster. It also aims to illustrate the role of global environmental factors on aflatoxin production and the recent data that demonstrate an interconnection between genes regulated by these environmental signals and aflatoxin biosynthetic pathway.

Keywords: Aspergillus; aflatoxin; biosynthesis; gene regulation.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Schematization of the different factors linked with aflatoxin production.
Figure 2
Figure 2
Organization of the aflatoxin gene cluster including the old and new cluster gene nomenclatures. This figure was adapted from the works of [24,33,37]. Red dotted lines represent the binding sites of AflR in the above pathway.
Figure 3
Figure 3
Schematization of the main intermediates produced during the AFB1 biosynthetic pathway and the confirmed or putative (indicated by?) level of intervention of the genes belonging to the AFB1 cluster. This figure is adapted from the works of [23,24,33,46,47,48,49,50,51,52,53,54,55].
Figure 4
Figure 4
Schematic representation of a putative map of genes involved in aflatoxin regulation in diverse Aspergillus species.
See this image and copyright information in PMC

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