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.

中文翻译：

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使用高分辨率质谱法对加拿大链格孢菌种群进行化学分类分析。

链格孢属 在田间和储存条件下会以植物病原体的形式出现。它们导致食物变质，还产生污染食物生产链的几类次级代谢产物。从食品安全的角度来看，评估链格孢菌污染风险的主要挑战是在其菌种分类上缺乏明确的共识。此外，目前还没有可靠的DNA测序方法来区分这些真菌的产毒潜力。我们的目标是确定哪种链格孢菌在加拿大存在，并描述它们制造的化合物。为了解决这些问题，我们使用液相色谱高分辨率质谱法（LC-HRMS）对128个加拿大链格孢属菌株进行了代谢组学分析，以确定其化学分类学。的链格孢采用主成分分析（PCA）和无偏的菌株进行分析ķ -means聚类，以识别与显著差异（代谢物p组之间<0.001）。在研究的菌株中鉴定出四个种群或“化学型”，以及几种已知的链格孢属次生代谢产物被鉴定为可区分的代谢产物，包括tenuazonic acid，phomapyrones和altenuene。虽然不能仅通过代谢组学就所有组进行物种级别的鉴定，但仍可以将感染农杆菌鉴定为不同的种群。