Symbiosis with systemic fungal endophyte promotes the escape of Lolium multiflorum from vector-borne disease

LUIS IGNACIO PÉREZ; PEDRO GUNDEL; HUGO G. MARRERO; ADELIA GONZÁLEZ ARZAC; MARINA OMACINI

Capital Federal

Simposio; 32nd New Phytologist Symposium: Plant interactions with other organisms:molecules, ecology and evolution; 2013

New Phytologist Trust

Plants interact with myriads of microorganisms that modify host interaction with other organisms within the community. A well-known example is Neotyphodium endophytes and their negative effects on host herbivores. Moreover, early researches of plant?endophyte symbiosis suggested a protective role against pathogens, mediated by endophyte-produced fungistatic compounds and the induction of host defences. In this work we explore how endophyte reduces disease caused by Claviceps purpurea, through promoting host escape. To accomplish this we established field patches dominated by symbiotic and non-symbiotic Lolium multiflorum plants to evaluate endophyte impact on: pathogen´s vectors efficiency, using net bags on spikes; volatile organic compounds (VOCs) production; and changes on soil community structure and its effect on pathogen´s resistance stage (sclerotium) during wintering. Both incidence and severity of pathogen were two-fold lower in endophyte-symbiotic plants than in non-symbiotic ones, but turned all equally low when insects were excluded from the system. The emission pattern of VOCs differed between symbiotic and non-symbiotic plants. Notwithstanding the known belowground effects of endophytes, no differences were detected between treatments on sclerotia´s survival or soil community. Although we cannot rule out the action of the other aforementioned direct mechanisms, our results suggest a VOCs-mediated mechanism of the protective role of systemic endophyte on host grasses.