Different levels of protective alkaloids in grasses with stroma-forming and seed-transmitted Epichloë/Neotyphodium endophytes.
The three alkaloid groups - lolines, ergopeptides, and peramine - are typically associated with endophyte infection of grasses, with the main function to protect hosts against herbivores. We determined levels of N-formylloline, N-acetylloline, ergovaline, and peramine in 18 European grasses naturally infected with seed-transmitted Neotyphodium endophytes or sexual Epichloë species. Peramine was the most common alkaloid, whereas lolines and ergovaline were only detected in Festuca hosts infected with E. festucae, N. coenophialum, or N. uncinatum. Only ten of the grass species analyzed contained detectable amounts of one or more of these alkaloids. There was a clear tendency for plants associated with stroma-forming Epichloë species to be free of alkaloids, and those that did produce alkaloids contained only small levels of peramine. In contrast, plants infected with seed-transmitted Neotyphodium endophytes often contained extremely high levels of lolines. Lolines enhance host survival through increased protection from herbivores and, thus, may be particularly favored in asexual endophytes that depend on host seed-production for their dispersal.