Intraspecific competition of endophyte infected vs uninfected plants of two woodland grass species

Grass endophytes (Clavicipitaceae. Ascomycota) are generally considered to be mutualists Much increase the host's fitness. Infected plants are often more persistent and competitive than uninfected plants. influencing population dynamics and plant community diversity, However, most of this empirical evidence is based on studies focusing on agronomically important grass species such as tall fescue or perennial ryegrass and their implications for livestock and man-made habitats, Recent studies indicate that endophyte-plant associations may be more variable. ranging from parasitic to mutualistic In the present study. e investigated the influence of endophyte infection on two wild woodland grasses. which are naturally infected with distinct fungal endophytes: Brachypodium sylvaticum with Epichloe sylvatica and Bromus benekenii with Epichloe bromicola, An intraspecific competition experiment as conducted over two growing seasons in the greenhouse and in an experimental garden At first harvest (after 12 weeks growing), endophyte infection had a significant negative effect on above ground dry matter yield (DMY) of B sylvaticum. but a significant positive effect on DMY of Br, benekenii tinder competition, The same differential effects on DMY and on total seed number ere also observed at Final harvest (after 62 weeks growing). Results from Br. benekenii were consistent with our hypothesis of increased competitive abilities of infected plants in nature which Could explain the high infection rate observed in natural Populations, In contrast. this explanation does not hold true for B. sylvaticum. and other factors such as increased herbivore and pathogen resistance together kith frequent horizontal transmission may be responsible for the very high incidence of this association in nature. Our result, confirm previous, predictions that beneficial effects of endophyte infection in wild grasses can vary for different grass species. even in comparable habitats.