Knowing your neighbourhood—the effects of <i>Epichloë</i> endophytes on foliar fungal assemblages in perennial ryegrass in dependence of season and land-use intensity

<i>Epichloë</i> endophytes associated with cool-season grass species can protect their hosts from herbivory and can suppress mycorrhizal colonization of the hosts' roots. However, little is known about whether or not <i>Epichloë</i> endophyte infection can also change the foliar fungal assemblages of the host. We tested 52 grassland study sites along a land-use intensity gradient in three study regions over two seasons (spring vs. summer) to determine whether <i>Epichloë</i> infection of the host grass <i>Lolium perenne</i> changes the fungal community structure in leaves. Foliar fungal communities were assessed by Next Generation Sequencing of the ITS rRNA gene region. Fungal community structure was strongly affected by study region and season in our study, while land-use intensity and infection with <i>Epichloë</i> endophytes had no significant effects. We conclude that effects on non-systemic endophytes resulting from land use practices and <i>Epichloë</i> infection reported in other studies were masked by local and seasonal variability in this study's grassland sites.