Covariation of Ergot Severity and Alkaloid Content Measured by HPLC and One ELISA Method in Inoculated Winter Rye across Three Isolates and Three European Countries.

Anna Kodisch,Elisabeth Zechner,Franz Wieser,Brigitta Schmiedchen,Thomas Miedaner,Bernd Rodemann,Małgorzata Niewińska,Jakob Eifler,Dörthe Siekmann,Armin Raditschnig,Marek Korbas,Andres Gordillo,Jakub Danielewicz,Franz Joachim Fromme,Michael Oberforster,Anna Tratwal,Frederik N Wuppermann

doi:10.3390/toxins12110676

Abstract

Ergot caused by Claviceps purpurea is a problem for food and feed security in rye due to the occurrence of toxic ergot alkaloids (EAs). For grain elevators and breeders, a quick, easy-to-handle, and cheap screening assay would have a high economic impact. The study was performed to reveal (1) the covariation of ergot severity (= percentage of sclerotia in harvested grain) and the content of 12 EAs determined by high performance liquid chromatography (HPLC) and (2) the covariation between these traits and results of one commercial enzyme linked immunosorbent assays (ELISA). In total, 372 winter rye samples consisting of a diverse set of genotypes, locations from Germany, Austria, and Poland over two years, and three isolates were analyzed. Ergocornine and α-ergocryptine were detected as major EAs. Ergocristinine occurred as a minor component. Claviceps isolates from different countries showed a similar EA spectrum, but different quantities of individual EAs. A moderate, positive covariation between ergot severity and EA content determined by HPLC was observed across two years (r = 0.53, p < 0.01), but large deviation from the regression was detected. ELISA values did neither correlate with the HPLC results nor with ergot severity. In conclusion, a reliable prediction of the EA content based on ergot severity is, at present, not possible.

Highlights

The plant pathogen Claviceps purpurea ((Fr.: Fr.) Tul.) is distributed worldwide and can infect more than 400 grass species including rye (Secale cereale L.) [1]
This study revealed only a moderate positive covariation between ergot severity and ergot alkaloids (EAs) content determined by high performance liquid chromatography (HPLC) for both subsets, as previously demonstrated [27,69,74,75,76]
This study indicates that the EA content cannot be predicted in a reliable way based on ergot severity

Summary

Introduction

The plant pathogen Claviceps purpurea ((Fr.: Fr.) Tul.) is distributed worldwide and can infect more than 400 grass species including rye (Secale cereale L.) [1]. Ergot is a severe fungal disease and the over-wintering bodies called sclerotia contain toxic ergot alkaloids (EAs). The EAs are a group of secondary metabolites [3] that are defined as derivatives of 4-(γ,γ-dimethylallyl)tryptophan (DMAT) [4]. EAs are known from several Ascomycetes species [5], including C. purpurea as a plant pathogen, and symbionts like Neotyphodium and Epichloë [6]. More than 80 individual EAs are known in literature [5,10], which can be grouped into Clavine alkaloids, D-lysergic acid and its derivatives, and ergopeptines [4,11,12,13]. For Claviceps spp., the main EAs are ergometrine (Em), ergotamine (Et), ergosine (Es), ergocristine (Ecr), ergocryptin (Ekr), and ergocornine (Eco) along with their corresponding

Methods

Discussion

Conclusion