Submitted to: Canadian Journal of Plant Pathology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/10/2005
Publication Date: 3/15/2006
Citation: Clear, R.M., Patrick, S.K., Gaba, D., Roscoe, M., Turkington, T.K., Demeke, T., Pouleur, S., Couture, L., Ward, T.J., O Donnell, K. 2006. Trichothecene and zearalenone production in culture, by isolates of Fusarium pseudograminearum from western Canada. Canadian Journal of Plant Pathology. 28:131-136. Interpretive Summary: Plant pathogenic fungi within the genus Fusarium cause a variety of diseases on cereal crops worldwide, including scab of wheat and barley, and ear and stem rots of maize. Taken together, these diseases result in billion dollar losses to agriculture each year. In addition, these fungi contaminate cereal grains with trichothecene mycotoxins that pose a serious threat to animal health and food safety. Effective disease control and monitoring efforts require detailed knowledge of the toxin potential and geographic distribution of these pathogens. The aim of the present study was to assess the toxin-producing capabilities of Canadian isolates of F. pseudograminearum collected from seed and vegetative cereal parts. We demonstrate that F. pseudograminearum in Canada produce a diverse array of toxins, including three toxin types not previously reported for this species. The unexpected toxin diversity has implications for mycotoxin risk assessments and provides further evidence that trichothecene toxin type differences are biologically significant and maintained by selection.
Technical Abstract: One hundred and twenty-seven isolates of Fusarium pseudograminearum were recovered from seed and vegetative plant parts grown in western Canada and successfully differentiated from F. graminearum by the use of Fusarium graminearum Agar. A single germinated spore was placed onto sterilized rice at 40% moisture content and incubated at 23 °C for 21 days. After 14 days, mycelium from each inoculated flask was removed and the DNA extracted for species confirmation and detection of the tri5 gene by PCR. All isolates contained the tri5 gene, and 125 of the 127 isolates were found to produce detectable levels of deoxynivalenol (DON), 122 produced 3-acetyldeoxynivalenol (3-ADON), 2 produced 15-acetyldeoxynivalenol (15-ADON), 17 produced diacetoxyscirpenol (DAS), 100 produced zearalenone, and one formed both nivalenol and fusarenon-X. There appears to be a DON/3-ADON chemotype, a DON/15-ADON chemotype, and a nivalenol chemotype. Neither of the two 15-ADON producers or the nivalenol producer formed DAS. This is the first time that DAS, and fusarenon-X has been associated with this species of Fusarium. HT-2 toxin, and T-2 toxin were not detected.