Epichloë Fungal Endophyte Symbiosis May Improve Tall Fescue Responses to Flooding and Oxygen-Limited Conditions

Abstract

Background and aims There is little information about the effect of grass-fungal endophyte symbiota on plant performance under oxygen-limited conditions. This study aimed to investigate the effect of Epichloë endophyte symbiosis and tall fescue genotype on plant responses to oxygen stress in a greenhouse pot experiment.Methods A greenhouse pot experiment was conducted with seven air-filled porosity levels in a sandy loam soil using two genotypes (75C and 75B) of tall fescue (Festuca arundinacea = Schedonorus arundinaceus Schreb.) infected with and without endophytic fungus Epichlöe coenophiala (E+ and E–, respectively). Some selected growth and physiological parameters were determined after nine-month application of the treatments.Results The results showed that E+ plants benefited from endophytic symbiosis and showed slightly higher root and shoot development, more leaf chlorophyll, and lower catalase and ascorbate peroxidase activity than E– plants under poor aeration. The E– plants also coped with poor aeration conditions by forming adventitious roots at the soil surface, aerenchyma formation within the root tissue, and increased alcohol dehydrogenase (ADH) activity.Conclusions The presence of endophyte improved the performance of the genotype E+ 75B under anaerobic conditions, while endophyte had an adverse effect on the performance of the genotype E+ 75C. In general, Epichloë endophyte presence decreased the flooding induced oxidative stress and prevented the formation and over-accumulation of reactive oxygen species in plant cells.