Biology and evolution of the ascophyllum symbiosis

该研究项目将调查一种以褐藻为基础的复杂共生关系，即紫菜。这个物种是北大西洋寒温带潮间带岩石海岸的主要光合生物，包括加拿大大西洋沿岸的大部分地区。共生包括：i)一种互惠真菌（葡萄霉），它总是存在于宿主组织中；ii)一种常见的红藻，是一种专性附生植物；iii)一种专性附生褐藻（褐藻），通常在藤蔓上丰富；iv)数量最多的海洋昆虫（Halocladius variabilis），主要局限于Elachista。该研究项目将重点关注这种共生群落的藻类和真菌成分，使用生态、生理和分子工具来了解这些物种之间相互作用的本质。此外，从整个共生群落分布的不同组成部分的分子进化研究将为北大西洋和北冰洋冰川后的生物地理学提供重要的见解。此外，由于葡萄属植物是加拿大东部主要收获和加工工业的基础，因此农业应用中使用的所得产品的特性可能来自真菌共生体。这个研究项目将通过与工业界（阿卡迪亚海洋植物有限公司）合作，并向他们提供文化，帮助解决这个基本问题。本研究将为潮间带生态学提供新的认识，并使脉藻成为海洋共生的主要模式系统。

This research program will investigate a complex symbiosis based around the brown seaweed, Ascophyllum nodosum. This species is the dominant photosynthetic organism of rocky intertidal shores of the cold-temperate North Atlantic Ocean, including large parts of coastal Atlantic Canada. The symbiosis includes: i) a mutualistic fungus (Mycophycias ascophylli), which is always present in the host tissues; ii) a common red alga that is an obligate epiphyte on Ascophyllum; iii) an obligate epiphytic brown alga (Elachista fucicola) that is often abundant on Ascophyllum; and iv) the most abundant marine insect yet described (Halocladius variabilis), that is largely restricted to Elachista. The research program will focus on the algal and fungal components of this symbiotic community using ecological, physiological and molecular tools to understand the nature of the interactions among these species. In addition, the molecular-evolutionary studies of the different components of the symbiotic community from throughout its distribution will provide important insights into the post-glacial biogeography of the North Atlantic and Arctic Oceans. Furthermore, since Ascophyllum is the basis of a major harvesting and processing industry in eastern Canada, it is possible that properties of the resulting products used in agricultural applications are derived from the fungal symbiont. This research program will help address this fundamental issue by collaborating with industry (Acadian Seaplants Ltd.) and making cultures available to them. Overall, this research program will provide new insights into intertidal ecology, and make Ascophyllum a major model system for marine symbioses.