Naturally Occurring Fusarium Species and Mycotoxins in Oat Grains from Manitoba, Canada

Abstract

Fusarium head blight (FHB) can lead to dramatic yield losses and mycotoxin contamination in small grain cereals in Canada. To assess the extent and severity of FHB in oat, samples collected from 168 commercial oat fields in the province of Manitoba, Canada, during 2016–2018 were analyzed for the occurrence of Fusarium head blight and associated mycotoxins. Through morphological and molecular analysis, F. poae was found to be the predominant Fusarium species affecting oat, followed by F. graminearum, F. sporotrichioides, F. avenaceum, and F. culmorum. Deoxynivalenol (DON) and nivalenol (NIV), type B trichothecenes, were the two most abundant Fusarium mycotoxins detected in oat. Beauvericin (BEA) was also frequently detected, though at lower concentrations. Close clustering of F. poae and NIV/BEA, F. graminearum and DON, and F. sporotrichioides and HT2/T2 (type A trichothecenes) was detected in the principal component analysis. Sampling location and crop rotation significantly impacted the concentrations of Fusarium mycotoxins in oat. A phylogenetic analysis of 95 F. poae strains from Manitoba was conducted using the concatenated nucleotide sequences of Tef-1α, Tri1, and Tri8 genes. The results indicated that all F. poae strains belong to a monophyletic lineage. Four subgroups of F. poae strains were identified; however, no correlations were observed between the grouping of F. poae strains and sample locations/crop rotations.

Implications of Crop Rotation and Fungicide on Fusarium and Mycotoxin Spectra in Manitoba Barley, 2017–2019

“…Therefore, F. poae had been considered a weak pathogen on cereals. However, recent studies show F. poae has become omnipresent in Europe, South America, and North America [ 36 , 37 , 38 ], which raises concerns about the importance of this pathogen in the FHB disease complex.…”

“…These results agree with the findings of Yli-Mattila et al [ 42 ], where a similar high correlation in barley samples from Finland and Russia was observed. Islam et al [ 37 ] reported correlations between NIV content and the concentration of F. poae DNA in oat samples from Manitoba. These results suggest F. poae is a potent NIV producer in barley.…”

“…The extent of NIV contamination found in barley in this study is higher than that reported in the oat crop. Specifically, a survey of Fusarium mycotoxins in oat grains from Manitoba, collected between 2016 to 2018, found maximum concentrations of NIV ranged between 581 to 865 µg kg −1 [ 37 ]. To date, NIV contamination in wheat has been rarely reported in Western Canada and is mainly due to the predominance of F. graminearum on wheat and the absence of F. graminearum strains with the NIV chemotype in the region [ 31 ].…”

Identification and Functional Characterisation of Two Oat UDP-Glucosyltransferases Involved in Deoxynivalenol Detoxification

“…Trichothecenes are classified into groups A and B according to the presence of different substitutions at the C-8 position of the molecule’s backbone [ 7 ]. Over the last decade the most prevalent mycotoxins in oat have been deoxynivalenol (DON) (group B trichothecene) and T-2 toxin, together with its hydrolysed form HT-2 toxin (belonging to the highly toxic group A trichothecenes) [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. DON accumulating in oat is produced mostly by F. graminearum [ 15 , 16 ], while the main producers of T-2/HT-2 toxins are F. langsethiae and F. sporotrichoides [ 11 , 17 , 18 , 19 ].…”

“…Over the last decade the most prevalent mycotoxins in oat have been deoxynivalenol (DON) (group B trichothecene) and T-2 toxin, together with its hydrolysed form HT-2 toxin (belonging to the highly toxic group A trichothecenes) [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. DON accumulating in oat is produced mostly by F. graminearum [ 15 , 16 ], while the main producers of T-2/HT-2 toxins are F. langsethiae and F. sporotrichoides [ 11 , 17 , 18 , 19 ]. There is a strong tendency for the opposing occurrence of DON and T-2/HT-2 toxins in oat, depending on the weather and agricultural practices [ 20 , 21 ].…”