Standard Article

Mycotoxins

  1. Kenneth C Ehrlich,
  2. Perng-Kuang Chang,
  3. Deepak Bhatnagar

Published Online: 15 APR 2011

DOI: 10.1002/9780470015902.a0000373.pub2

eLS

eLS

How to Cite

Ehrlich, K. C., Chang, P.-K. and Bhatnagar, D. 2011. Mycotoxins. eLS. .

Author Information

  1. Southern Regional Research Center ARS/USDA, New Orleans, Louisiana, USA

Publication History

  1. Published Online: 15 APR 2011

Abstract

Mycotoxins are a class of natural fungal metabolites that are specifically toxic to mammals and are frequent contaminants of foods and feeds. In this article we describe mycotoxins from Ascomycota or sac fungi, the largest phylum of fungi, which includes penicillia, aspergilli, fusaria, alternaria, claviceps and other non-Basidiomycota (‘higher fungi’ or mushroom-producing) genera. We discuss the toxicity and biosynthesis of the most agriculturally important mycotoxins, namely, polyketide toxins (fumonisins, aflatoxins, ochratoxins, patulin and zearalenone), nonribosomal peptide toxins (ergot alkaloids and tremorgenic toxins) and trichothecenes produced via the terpene biosynthesis pathway. The Ascomycota produce mycotoxins in crops both before harvest and during storage. The genes required for biosynthesis are usually clustered. Transcriptional regulation of biosynthesis involves a pathway-specific Cys6Zn2 type protein as well as a secondary metabolite-specific methyltransferase, LaeA. Both of these transcription factors are unique to fungi. Hypotheses about the evolution of mycotoxin biosynthesis in fungi are discussed.

Key Concepts:

  • Mycotoxins are produced by ascomycete (‘lower’) fungi in certain agriculturally important crops.

  • The most common mycotoxins exert a variety of generally nonlethal toxic effects in animals.

  • Biosynthesis of mycotoxins usually involves a co-regulated, clustered set of genes on one chromosome.

  • Co-regulation involves transcription factors of the Cys6Zn2 type and a putative methyltransferase, LaeA.

  • Mycotoxins can be of several types: polyketides, nonribosomal peptides or terpene-derived metabolites.

  • Mycotoxin biosynthesis has evolved in fungi in the absence of agriculture and is not strictly associated with fungal virulence in contaminated crops.

Keywords:

  • mycotoxin;
  • mycotoxicoses;
  • aflatoxin;
  • trichothecene;
  • fumonisin;
  • Aspergillus;
  • Fusarium;
  • Penicillium;
  • biosynthesis;
  • secondary metabolite