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

真菌在生态学、农业和医学中发挥着许多重要作用。有些是分解有机物质，有些是病原体，还有一些是对植物健康或动物营养很重要的互利共生体。Epichelium物种是禾本科植物的共生体（内生菌），具有互利和致病状态。它们和相关的内生菌增强了许多用作饲料或草坪的温带草的耐旱性，抗虫性和其他适应性因素，但有些也产生毒素，对放牧动物产生负面影响。该项目的目标是对模式内生菌Epichelfestucae的基因组进行测序，以发现与宿主植物以及放牧动物互利和致病相互作用的基因。真菌基因组将被片段化并克隆到质粒中，其中大约150，000个将从插入的基因组DNA的两端进行测序。计算机分析将识别序列重叠，导致组装成大的支架，这些组装将进行其他计算机分析以识别基因。发现的基因将提示真菌有益于宿主植物的机制、向致病性的转变以及毒素的生物合成。这种模式植物共生真菌的基因组序列将是更广泛的科学界进行植物保护、植物疾病和毒素生物合成的综合遗传研究的重要资源。此外，这种真菌和相关的内生真菌在美国农业中具有重大的经济影响，无论是负面的还是正面的。一个负面影响是，有些导致牲畜中毒，每年给牛肉行业造成6亿美元的损失，对其他牲畜和野生动物造成额外影响。主要的积极影响是这些内生菌提高了牧场，草坪和保护草林的寿命和生产力。本项目将有助于阐明内生菌的有益和有害作用机制，从而促进内生菌的农业利用，以最大限度地发挥其整体效益。

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.