Les critères moléculaires utilisés pour classer les champignons du genre Aspergillus section flavi

Abstract

Some fungi, especially Ascomycetes, can synthesize secondary metabolites toxic to humans and vertebrates, called mycotoxins. Since the presence of these fungi in staple foods poses a potential risk to human and animal health, staple foods are eliminated when contaminated. The Flavi section is one of the most important groups of fungi from an economic and health point of view because it includes species that produce mycotoxins. Among the mycotoxins produced by this group are the aflatoxins (AFs), which are considered to be of major concern due to their deleterious effects in vertebrates. The species of the Flavi section thrive mainly in the tropics and subtropics because they benefit from optimal environmental conditions. In addition, harvesting and storage conditions are often inappropriate, thus favoring their development. In temperate regions, these species are found less frequently. However, global warming could favor their colonization. The identification of Aspergillus species from the Flavi section is a challenge, due to the inter- and intra-variability of characters. Therefore, the use of a single identification method (morphological, molecular or secondary metabolite profile characterization) is insufficient. Conversely, the development of molecular tools has made the task easier. The aim of our study was to determine the relationships between Aspergillus species of the Flavi section from different molecular markers (ITS, benA, cmdA, amdS, preA, perB, ppgA, aflP, Mat1 genes), then from identify those which allow a classification of species by phylogenetic inference. The use of phylogenetic inference in this study showed that this is a robust approach to identify Aspergillus species from the Flavi section. Indeed, the addition of molecular markers made it possible to confirm the phylogenetic placement of the species in the Flavi section.