Abstract: Symbioses between fungi and plants have occurred naturally and widely during long-term evolution. This relationship makes both fungi and plants more adaptable to environmental changes. Endophytes form symbiotic associations with temperate grasses including Festuca and Lolium spp. The establishment and maintenance of these mutualistic associations involves mutual communication between the endophyte and the host. The growth of these endophytes is strictly intercellular and tightly regulated, and is synchronized with the growth of the host. Using this unique growth pattern, the endophyte does not trigger the host defense response and establishes a precise communication and regulatory pathway with the host. This communication will likely involve many well-known signaling pathways. Mitogen-activated protein kinase (MAPK) cascades and second messenger signaling pathways involving cAMP and calcium are the main pathways for signal transduction. Here, we review the endophyte growth pattern in the host, and discuss research on the genes involved in signaling pathways between the endophyte and host using modern molecular technologies. The information gained so far can be used to predict the possible functions of these pathways in endophyte associations, and provides a reference for further in-depth analyses of the communication network between the endophyte and the host.