The promotion of Festuca sinensis heavy metal stress tolerance mediated by Epichloë endophyte

Background: Festuca sinensis is a perennial grass of the genus Festuca, which has strong stress tolerance and high adaptability. F. sinensis normally symbiotic with Epichloë endophyte. In order to evaluate the possibility of F. sinensis-endophyte association as bioremediation grass in heavy metal polluted soils, the effects and mechanism of the F. sinensis-endophyte interaction under heavy metal stress was investigated. Results: : The growth performance and physiology variations of F. sinensis with (E+) and without endophyte (E-) were evaluated after they were subjected to Zn2+ and Cd2+ treatments. The results showed that heavy metal treatments had significant effects on plants as the growth indices of plants under Zn2+ and Cd2+ treatments had significant differences compared with plants under control treatment (P<0.05). Zn2+ treatment had positive effects on plants whereas Cd2+ treatment had negative effects. The plants under Cd2+ treatment produced more lolitrem B (P<0.05). Endophyte increased host heavy metal stress tolerance by promoting host growth as the E+ plants had significantly higher plant height, tiller number, root length (P<0.05). Endophyte also promoted host Zn2+ ion absorbing and induced more endogenous hormone production (P<0.05). Conclusions: : These results suggested that Epichloë regulated host growth and physiology to improve association tolerance to environmental conditions.