In the laboratories of Department of Molecular Mycology, Phytopathology and Entomology of Bydgoszcz UST, the process of symbiotic grass modification will be carried out. Selected isolates of Epichloë sp. will be introduced into perennial ryegrass by artificial inoculation of the tiller base. The potential ability to produce key metabolites by endophyte isolates will be determined. The profile of the chemical compounds produced by the association affecting the final nature of the association will be also characterized. The last element will be development and implementation of an innovative marketing strategy for the promotion and dissemination of cultivation and the commercialization of innovative varieties of perennial ryegrass inhabited by symbiotic endophytic fungi.