Effects of Epichloe sinica on Roegneria kamoji seedling physiology under PEG-6000 simulated drought stress

摘要

Some Epichloe species are beneficial to their plant hosts by improving fitness and resistance to stress. The natural, seedborne, asymptomatic symbiotic endophyte Epichloe sinica is specific for Roegneria spp., which are perennial grasses found in grasslands or meadows; many species of Roegneria are excellent forage plants. This study was designed to reveal the biological function of E. sinica via seedling assays with drought simulation using polyethylene glycol (PEG)-6000. Endophyte infected (EI) and endophyte free (EF) R. kamoji seeds (obtained by heat treatment) were germinated and grown on 0, 10, 15 and 20% PEG-6000 for 10days; seedling and root system morphologies were investigated, and reactive oxygen species (ROS), which act as signaling molecules in plant responses to abiotic stress, were detected. E. sinica enhanced both the germination potential and rate of R. kamoji seeds treated with high concentrations of PEG-6000. After PEG treatment, shoot and root morphologies differed significantly between EF and EI seedlings. Additionally, lower amounts of ROS concentration were detected in the leaves of EI seedlings treated with high concentrations of PEG-6000. In conclusion, E. sinica promoted PEG-6000 simulated drought stress resistance in R. kamoji seedlings.