|GEISER, DAVID - Pennsylvania State University|
|ALBERTS, JOHANNA - Cape Peninsula University Of Technology|
|RHEEDER, JOHN - Cape Peninsula University Of Technology|
Submitted to: Mycologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2018
Publication Date: 11/27/2018
Citation: O'Donnell, K., McCormick, S.P., Busman, M., Proctor, R.H., Ward, T.J., Doehring, G., Geiser, D.M., Alberts, J.F., Rheeder, J.P. 2018. Marasas et al. 1984 "toxigenic Fusarium species: identity and mycotoxicology" revisited. Mycologia. 110(6):1058-1080. https://doi.org/10.1080/00275514.2018.1519773.
Interpretive Summary: Fusarium is one of the most important groups of plant pathogenic molds, primarily because they produce diverse toxins that can contaminate a wide range of food and feed and result in a variety of health problems in humans and other animals. In addition to being a major food safety concern, they threaten food security worldwide because they can constrain the production of diverse crops, especially cereals, resulting in huge reductions in grain yield and quality. Due to their negative impact on human and plant health, and the global agricultural economy, the current study was initiated to determine the toxin production potential of a wide variety of Fusarium species. To obtain a broad sample, we determined the species identity and mycotoxin potential of 158 Fusarium strains that were included in the most widely used reference, Toxigenic Fusarium Species: Identity and Mycotoxicology. The results demonstrated that previously incorrect species identifications have resulted in widespread misunderstanding regarding the toxin production potential of Fusarium species. In addition, we discovered that some toxins were produced by genetically diverse Fusarium species, whereas other toxins were only produced by species in one or more closely related lineages. These findings are important to food safety and agricultural biosecurity because they accurately identify these species and their toxin potential for the first time. The results of this study will be used by a diverse set of scientists (i.e. mycotoxicologists, plant disease specialists and quarantine officials) to assess risk and develop novel strategies to prevent Fusarium and their toxins from entering the food chain.
Technical Abstract: This study was conducted to determine the species identity and mycotoxin potential of 158 Fusarium strains originally archived in the South African Medical Research Council’s Mycotoxigenic Fungal Collection (MRC) that were reported to comprise 17 morphologically distinct species in the classic 1984 compilation by Marasas et al., Toxigenic Fusarium Species: Identity and Mycotoxicology. Maximum likelihood and maximum parsimony molecular phylogenetic analyses of single and multilocus DNA sequence data indicated that the strains represented 46 genealogically exclusive phylogenetically distinct species distributed among eight species complexes. Moreover, the phylogenetic data revealed that 80/158 strains were received under a name that is not accepted today (ex F. moniliforme) or classified under a different species name. In addition, gas chromatography–mass spectrometry (GC-MS) and/or high-performance liquid chromatography–mass spectrometry (HPLC-MS)-based mycotoxin analyses were conducted to determine which toxins the strains could produce in liquid and/or solid cultures. All of the trichothecene toxin–producing fusaria were nested within the F. sambucinum (FSAMSC) or F. incarnatum-equiseti (FIESC) species complexes. Consistent with this finding, GC-MS analyses detected trichothecenes in agmatine-containing broth or rice culture extracts of all 13 FSAMSC and 10/12 FIESC species tested. Species in six and seven of the eight species complexes were able to produce moniliformin and beauvericin, respectively, whereas B-type fumonisins were only detected in extracts of cracked maize kernel cultures of three species in the F. fujikuroi (FFSC) species complex.