Chemotaxonomic profiling of canadian alternaria populations using high-resolution mass spectrometry


Kelman, M.J., Renaud, J.B., Seifert, K.A., Mack, J., Yeung, K.K.C., Sumarah, M.W. (2020). Chemotaxonomic profiling of canadian alternaria populations using high-resolution mass spectrometry. Metabolites, [online] 10(6),

Plain language summary

Alternaria is a very common fungus that contaminates crops both in the field and during storage. The European Union is in the process of evaluating toxins produced by these fungi for regulation in food. In this study we examined the chemistry of strains collected from many locations in Canada. We were able to use this info to determine the exact name of some of the fungi and to assess the risk the pose to Canadian consumers.


Alternaria spp. occur as plant pathogens worldwide under field and storage conditions. They lead to food spoilage and also produce several classes of secondary metabolites that contaminate the food production chain. From a food safety perspective, the major challenge of assessing the risk of Alternaria contamination is the lack of a clear consensus on their species-level taxonomy. Furthermore, there are currently no reliable DNA sequencing methods to allow for differentiation of the toxigenic potential of these fungi. Our objective was to determine which species of Alternaria exist in Canada, and to describe the compounds they make. To address these issues, we performed metabolomic profiling using liquid chromatography high-resolution mass spectrometry (LC-HRMS) on 128 Canadian strains of Alternaria to determine their chemotaxonomy. The Alternaria strains were analyzed using principal component analysis (PCA) and unbiased k-means clustering to identify metabolites with significant differences (p < 0.001) between groups. Four populations or ‘chemotypes’ were identified within the strains studied, and several known secondary metabolites of Alternaria were identified as distinguishing metabolites, including tenuazonic acid, phomapyrones, and altenuene. Though species-level identifications could not be concluded for all groups through metabolomics alone, A. infectoria was able to be identified as a distinct population.

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