Plant & Animal Genomes XIV Conference Plant & Animal Genomes XIV ConferenceJanuary 14-18, 2006
Town & Country Convention Center
San Diego, CA
Uljana Hesse , Puram Venu-Gopal , Christopher L. Schardl
The ascomycete Epichloë festucae (anamorph Neotyphodium) lives in symbiosis with cool-season grasses. For most of its life cycle it grows benignly in meristems, vegetative and reproductive tillers, and inflorescences and seeds, facilitating vertical transmission of the symbiont. Mutualistic effects of the fungus are associated with its production of bioprotective alkaloids, and positive effects on the drought tolerance of the host. Asexual relatives of E. festucae, N. coenophialum and N. lolii, are used commercially to improve sustainability of their respective host grasses, Festuca arundinacea and Lolium perenne. Reproductive development of the host sometimes induces E. festucae to produce external hyphae and develop a stroma (a compact mycelial layer which serves as a cradle for ascogenous perithecia) enveloping the inflorescence. In more antagonistic Epichloë sp.-grass interactions host reproduction is virtually terminated and the rare seeds from escaped inflorescences are endophyte-free. Epichloë festucae is an intermediate: on each host plant some inflorescences produce viable endophyte-infected seeds, while others bear stromata. This therefore represents an interesting model for studying mutualistic and parasitic plant-fungal symbiosis. To identify plant and endophyte genes involved in the switch between benign and parasitic fungal growth we are sequencing the E. festucae genome, and have also sequenced 24131 ESTs from a normalized cDNA library from benignly infected inflorescences. Genes discovered in these studies will provide the basis for future functional genomic analyses of the mechanisms of symbiotic compatibility, pathogenesis, and mutualism.