Genetic Profiling of Mycotoxin Production

The regulation of mycotoxin production in fungi is mainly carried out at the transcriptional level. Therefore, it is necessary to identify the genes involved in their synthesis in order to understand their regulation and establish effective control methods. The genes involved in the production of these compounds are grouped in clusters in the fungal genome and their study was very advanced in some cases such as A. flavus producing aflatoxins or Fusarium species producing trichothecenes. However, in the case of ochratoxin A, only a few genes were known until rencent years ago. Our research group pioneered the characterisation of the biosynthetic cluster of this toxin, showing that it is composed of five genes and that it appears in phylogenetically very distant producer species (Gil-Serna et al., 2018).

During the last years, we have characterised the presence of the ochratoxin A biosynthetic cluster in numerous species of Aspergillus fungi, some of them not previously described as OTA producers, demonstrating their potential to produce the toxin under certain conditions. This was a major breakthrough as it allowed us to point out that more attention should be paid to species commonly detected in food matrices such as A. subramanianii or A. pulvericola as they can produce this relevant toxin. Likewise, we have been able to rule out the ability to synthesise this toxin in species that had traditionally been considered as producers such as A. ochraceus (Gil-Serna et al., 2020) or A. tubingensis (Gil-Serna et al., 2019).