Links Between Genetic Groups, Host Specificity, and Ergot-Alkaloid Profiles within Claviceps purpurea (Fr.) Tul. on Slovenian Grasses

Abstract

In the present study, the genetic relationships and ergot-alkaloid production of the fungus Claviceps purpurea on grasses were investigated, to determine any associations between grass host specificity, ergot-alkaloid production, and geographic origin. C. purpurea sclerotia were obtained from wild and cultivated grasses along a 300-km climatic gradient, from sub-Mediterranean to continental climates. Twenty-one infected grass samples provided 39 sclerotia for analysis of the ergot alkaloids ergometrine, ergosine, ergotamine, ergocornine, ergocryptine, and ergocristine, and their “-inine” epimers, using liquid chromatography–tandem mass spectrometry. C. purpurea ribosomal DNA underwent molecular classification to determine any grass host or geographic specificity of ergot-alkaloid composition for the different operational taxonomic units. Molecular analysis of sclerotia ribosomal DNA showed three genetic groups, with some associations with specific grass host taxonomic groups. The ergot-alkaloid composition data were in agreement with the data obtained by molecular methods. The most frequent ergot-alkaloid epimers were ergocristine, and ergosine. The total ergot-alkaloid concentrations in sclerotia varied from 59 to 4,200 mg kg–1, which corresponds to 0.059 to 4.2 mg kg–1 in animal feed (assuming ergot alkaloids at 1,000 mg kg–1 sclerotia). Therefore, grasses can be associated with significant levels of ergot alkaloids. In addition, the ergot-alkaloid compositions of C. purpurea sclerotia can be different for infections with different C. purpurea genetic groups, because these show different ergot-alkaloid compositions.