Infection Rates and Alkaloid Patterns of Different Grass Species with Systemic Epichloë Endophytes

• Published in: Applied and environmental microbiology 2019-09, Vol.85 (17)
• Main Authors: Vikuk, Veronika, Young, Carolyn A, Lee, Stephen T, Nagabhyru, Padmaja, Krischke, Markus, Mueller, Martin J, Krauss, Jochen
• Format: Article
• Language: English
• Subjects: Alkaloids; Biodiversity; Biosynthesis; Chromatography; Dactylis glomerata; Endophytes; Epichloe; Ergot; Festuca ovina; Festuca pratensis; Festuca rubra; Gas chromatography; Grasses; High performance liquid chromatography; Indoles; Infections; Insects; Intermediates; Intoxication; Invertebrates; Liquid chromatography; Livestock; Lolium perenne; Mass spectrometry; Mass spectroscopy; Plant Microbiology; Scientific imaging; Species diversity; Spectroscopy; Spotlight; Toxicity; Vertebrates
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/AEM.00465-19

Symbiotic species are fungal endophytes of cool-season grasses that can produce alkaloids with toxicity to vertebrates and/or invertebrates. Monitoring infections and presence of alkaloids in grasses infected with species can provide an estimate of possible intoxication risks for livestock. We sampled 3,046 individuals of 13 different grass species in three regions on 150 study sites in Germany. We determined infection rates and used PCR to identify species diversity based on the presence of different alkaloid biosynthesis genes, then confirmed the possible chemotypes with high-performance liquid chromatography (HPLC)/ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) measurements. Infections of spp. were found in Huds. (81%), L. aggregate (agg.) (73%), L. (15%), L. (15%) and L. (8%). The other eight grass species did not appear to be infected. For the majority of -infected samples (98%), the alkaloids lolitrem B and peramine were present, but ergovaline was not detected, which was consistent with the genetic evaluation, as , the gene encoding the first step of the ergot alkaloid biosynthesis pathway, was absent. in produced anti-insect loline compounds. The spp. observed in the agg. samples showed the greatest level of diversity, and different intermediates of the indole-diterpene pathway could be detected. infection rates alone are insufficient to estimate intoxication risks for livestock, as other factors, like the ability of the endophyte to produce the alkaloids, also need to be assessed. Severe problems of livestock intoxication from -infected forage grasses have been reported from New Zealand, Australia, and the United States, but much less frequently from Europe, and particularly not from Germany. Nevertheless, it is important to monitor infection rates and alkaloids of grasses with fungi to estimate possible intoxication risks. Most studies focus on agricultural grass species like and , but other cool-season grass species can also be infected. We show that in Germany, infection rates and alkaloids differ between grass species and that some of the alkaloids can be toxic to livestock. Changes in grassland management due to changing climate, especially with a shift toward grasslands dominated with -infected species such as , may result in greater numbers of intoxicated livestock in the near future. We therefore suggest regular monitoring of grass species for infections and alk