Microbial Genome Sequencing: Genome of Epichloe Festucae, a Model Endophyte of Grasses

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Fungi play numerous important roles in ecology, agriculture and medicine. Some decompose organic materials, others are pathogens, and others are mutualistic symbionts important for plant health or animal nutrition. The Epichloe species are symbionts (endophytes) of grass plants with both mutualistic and pathogenic states. They and the related endophytes enhance drought tolerance, insect resistance, and other fitness factors in many temperate grasses used as forage or turf, but some also produce toxins that can negatively affect grazing animals. The goal of this project is to sequence the genome of the model endophyte, Epichloe festucae, in order to discover genes involved in mutualistic and pathogenic interactions with host plants, as well as with grazing animals. The fungal genome will be fragmented and cloned into plasmids, approximately 150,000 of which will be sequenced from both ends of the inserted genomic DNA. Computer analysis will identify sequence overlaps, resulting in assembly into large scaffolds, and these assemblies will be subjected to other computer analyses to identify the genes. Discovered genes will suggest mechanisms of fungal benefits to host plants, the transition to pathogenesis, and toxin biosynthesis. The genome sequence of this model plant-symbiotic fungus will be a crucial resource to the broader scientific community for comprehensive genetic studies of plant protection, plant disease and toxin biosynthesis. Furthermore, this and related fungal endophytes have major economic impacts, both negative and positive, in U.S. agriculture. A negative impact is that some cause livestock toxicosis costing the beef industry $600 million annually, with additional impacts on other livestock and wildlife. The major positive impact is that these endophytes improve longevity and productivity of pasture, turf, and conservation grass stands. This project will help elucidate the mechanisms both of beneficial and detrimental endophyte effects, thus facilitating agricultural utilization of endophytes to maximize their overall benefits.