Epichloe glyceriae infection affects carbon translocation in the clonal grass Glyceria striata

Systemic fungal endophytes derive resources from hosts and can affect host resource movement and integration. We examined whether infection by Epichloe glyceriae altered clonal growth of its host, Glyceria striata, through changes in physiology. Growth of severed and intact stolons was compared to examine physiological integration in infected and disinfected (fungicide-treated) plants. To assess whether infection changed carbon (C) movement, labelling with C-14 was used. We found physiological integration did not affect biomass per stolon for either infected or disinfected plants. The severed stolon to intact stolon ratio for the number of daughter ramets within a plant did not differ by infection status, although fewer daughter ramets were produced on severed stolons of disinfected plants. C-14 movement from the labelled leaf was greater for infected stolons, whereas the labelled leaf retained more assimilate for stolons of disinfected plants. Previous studies showed that Epichloe glyceriae could increase host clonal growth. In this study, infection changed host assimilate distribution, but did not lead to corresponding differences in stolon growth. The effects of endophytes on host physiology and clonal growth may depend on environmental conditions.