Significance of Aspergillus niger aggregate species as contaminants of food products in Spain regarding their occurrence and their ability to produce mycotoxins

Food Microbiol. 2019 Sep;82:240-248. doi: 10.1016/j.fm.2019.02.013. Epub 2019 Feb 26.

Abstract

The Aspergillus niger aggregate contains 15 morphologically indistinguishable species which presence is related to ochratoxin A (OTA) and fumonisin B2 (FB2) contamination of foodstuffs. The taxonomy of this group was recently reevaluated and there is a need of new studies regarding the risk that these species might pose to food security. 258 isolates of A. niger aggregate obtained from a variety of products from Spain were classified by molecular methods being A. tubingensis the most frequently occurring (67.5%) followed by A. welwitschiae (19.4%) and A. niger (11.7%). Their potential ability to produce mycotoxins was evaluated by PCR protocols which allow a rapid detection of OTA and FB2 biosynthetic genes in their genomes. OTA production is not widespread in A. niger aggregate since only 17% of A. niger and 6% of A. welwitschiae isolates presented the complete biosynthetic cluster whereas the lack of the cluster was confirmed in all A. tubingensis isolates. On the other hand, A. niger and A. welwitschiae seem to be important FB2 producers with 97% and 29% of the isolates, respectively, presenting the complete cluster. The genes involved in OTA and FB2 were overexpressed in producing isolates and their expression was related to mycotoxin synthesis.

Keywords: Food safety; Fumonisins; Ochratoxin A; Section Nigri.

MeSH terms

  • Aspergillus / classification
  • Aspergillus / genetics
  • Aspergillus / isolation & purification*
  • Aspergillus / metabolism*
  • Aspergillus niger / classification
  • Aspergillus niger / genetics
  • Aspergillus niger / isolation & purification
  • Aspergillus niger / metabolism
  • DNA, Fungal / genetics
  • Food Contamination / analysis
  • Food Microbiology*
  • Fumonisins / metabolism
  • Gene Expression
  • Genome, Fungal / genetics
  • Multigene Family
  • Mycotoxins / genetics
  • Mycotoxins / metabolism*
  • Ochratoxins / metabolism
  • Phylogeny
  • Sequence Analysis, DNA
  • Spain

Substances

  • DNA, Fungal
  • Fumonisins
  • Mycotoxins
  • Ochratoxins
  • ochratoxin A