Ergot, fungal genus Claviceps, are worldwide distributed grass pathogens known for their production of toxic ergot alkaloids (EAs) and the great agricultural impact they have on both cereal crop and farm animal production. EAs are traditionally considered as the only factor responsible for ergot toxicity. Using broad sampling covering 13 ergot species infecting wild or agricultural grasses (including cereals) across Europe, USA, New Zealand, and South Africa we showed that the content of ergochrome pigments were comparable to the content of EAs in sclerotia. While secalonic acids A-C (SAs), the main ergot ergochromes (ECs), are well known toxins, our study is the first to address the question about their contribution to overall ergot toxicity. Based on our and published data, the importance of SAs in acute intoxication seems to be negligible, but the effect of chronic exposure needs to be evaluated. Nevertheless, they have biological activities at doses corresponding to quantities found in natural conditions. Our study highlights the need for a re-evaluation of ergot toxicity mechanisms and further studies of SAs' impact on livestock production and food safety.

Department of Bioagricultural Sciences and Pest Management Colorado State University Fort Collins CO 80523 USA

Department of Cell Biology Faculty of Science Charles University Viničná 7 CZ 128 00 Prague Czech Republic

Laboratory of Fungal Genetics and Metabolism Institute of Microbiology of the Czech Academy of Sciences Vídeňská 1083 CZ 14220 Prague Czech Republic

TEVA Czech Ind CZ 74770 Opava Czech Republic

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