The Single Origin of Mycorrhizas Among the Amanita: A Model for Elucidating the Genetic Architecture of Symbiosis

菌根菌是植物和根相关真菌之间普遍存在的共生体；作为碳的交换，真菌为植物提供磷或氮。不同植物和真菌物种之间的相互作用控制着当地生物多样性的格局，物种范围往往由当地合作伙伴的可用性决定。真菌属Amanita是一种新兴的模式，用于探索在专性共生中相关的生物体如何在不断变化的世界中分布和建立。Amanita是一个常见的，广泛分布和多样化的属，包括菌根和分解物种，并提供了一个难得的机会来比较密切相关的共生和自由生活真菌的遗传结构。提出的研究的中心问题包括：(1)哪些基因或基因家族定义共生？(2)、共生进化后，通常独立生长所需的基因发生了什么变化？方法包括比较分析来自不同种类的毒舌菌的遗传数据，这些菌株要么与活的植物共生，要么与死的植物共生。数据将阐明共生物种是否保持独立生长的能力，以及这如何影响响应全球变化的物种范围。变化可能随后影响相关植物物种的生物地理。研究结果将与新兴的生物燃料产业直接相关；植物材料的分解是生物燃料生产中的一个限制速度的步骤，而直接负责分解的基因的鉴定将为开发更有效的降解酶提供信息。拓展活动包括在哈佛自然历史博物馆开发新的、永久性的关于共生关系的展览。每年有超过179,000人参观，其中包括约25,000名学童和他们的老师，并作为波士顿？美国主要的自然历史博物馆。发达的传播媒介也将广泛分发，供其他博物馆和教室使用。

Mycorrhizas are ubiquitous symbioses between plants and root-associated fungi; in exchange for carbon, the fungi provide plants with either phosphorus or nitrogen. Interactions among different species of plants and fungi control local patterns of biodiversity, and species ranges are often shaped by the availability of local partners. The fungal genus Amanita is an emerging model for exploring how organisms associated in obligate symbioses are distributed and established in a changing world. Amanita is a common, widely-distributed and diverse genus encompassing both mycorrhizal and decomposer species and provides a rare opportunity to compare the genetic architecture of closely related symbiotic and free-living fungi. The central questions of proposed research include: (1) what genes or gene families define symbiosis? (2), after the evolution of symbiosis, what happens to genes normally required for independent growth? Methods involve comparative analyses of genetic data taken from different Amanita species grown either in symbiosis with a live plant, or with dead plant materials. Data will elucidate whether or not symbiotic species maintain the capacity for independent growth, and how this affects species ranges in response to global change. Shifts may subsequently influence the biogeography of associated plant species. The results will be directly relevant to the nascent biofuels industry; the decomposition of plant materials is a rate-limiting step in biofuels production, and the identification of genes directly responsible for decomposition will inform the development of more effective degradative enzymes. Outreach includes the development of new, permanent exhibits about symbiosis at the Harvard Museum of Natural History. The HMNH is visited by more than 179,000 persons annually, including approximately 25,000 schoolchildren and their teachers, and serves as Boston?s major natural history museum. Developed media will also be widely distributed for use by other museums and in classrooms.