Toxicity of Epichloë endophytes

Jochen Krauss, Tabea Lang

Funder: Deutsche Forschungsgemeinschaft (DFG) - Project number 467000317
Homepage: https://gepris.dfg.de/gepris/projekt/467000317?language=en

Introduction:

This project investigates the distribution and toxicity of systemic endophytic fungi of the genus Epichloë. Epichloë endophytes occur naturally in cool-temperate grasses but are also present in commercially available seed mixtures.

The first work package focuses on characterising Epichloë species and quantifying their genotypic and chemical diversity, particularly with respect to pathway alkaloids and end products. To this end, 150 sown pastures (50 cattle, 50 sheep, and 50 horse pastures), 50 semi-natural dry grasslands managed by transhumant shepherding, and 50 sown horse pastures with documented laminitis cases in Germany will be selected and sampled. In addition, the seed mixtures used for all 200 sown pastures will be analysed to detect Epichloë infections and toxic alkaloids.

The second work package involves acquiring commercially available seed mixtures for pasture and lawn cultivation from European and international markets and analysing them for Epichloë infections and alkaloid concentrations. Infected seed will be sown on experimental plots at the university; after one year, alkaloid concentrations will be measured and their toxicity assessed. Subsequently, seed companies and the German Federal Office of Plant Varieties will be contacted to enable targeted analysis of infected grass cultivars from their collections.

The project aims to provide robust scientific data for an emerging societal debate on the extent to which endosymbiont-modified grasses may be disseminated through commercial seed. It remains unclear whether European seed companies intentionally use this technology, whether Epichloë infections occur unintentionally in seed mixtures, and whether such infections exceed relevant toxicity thresholds.

Key research questions:

1. Do the occurrence of Epichloë endophytes and alkaloid concentrations differ among sown cattle, sheep, and horse pastures?

2. Do sown pastures differ from semi-natural dry grasslands managed by transhumant shepherding in terms of Epichloë species occurrence and alkaloid concentrations?

3. Can laminitis in horses be linked to the presence and toxicity of Epichloë endophytes?

4. Which European seed mixtures contain Epichloë-infected grasses, and do they exceed toxicity thresholds relevant to grazing livestock and insect herbivores?

5. Which European grass cultivars are infected with Epichloë endophytes?