Systematic and functional aspects of symbiotic fungi

本提案的核心部分有两个主要组成部分：开发一种有前途的新颖而强大的丛枝菌根（AM）真菌鉴定工具，以及继续探索与AM共生关系建立相关的功能方面。第三个组成部分的目的是提供一个更深入的了解负责启动外生菌根（ECM）真菌子实体形成的因素。对于AM共生，阻碍生物多样性研究的一个主要挑战是分枝菌的正确鉴定。该项目将基于孢子形态的经典鉴定与物种特异性分子探针的设计相结合。这种方法将允许AM真菌的鉴定和确定一个给定物种的遗传界限。第二个项目将研究AM真菌胚管中细胞质的流动、细胞器的运动和活性，这些细胞器表现出细分枝或流道菌丝的生长模式。遗传上不同的Glomus spp.簇的根外菌丝体的表型表达也将使用分形维数计算器程序进行表征。对于EMC共生，大多数子实体在夏末，在主树发芽后发育。这表明植物来源的光周期调节信号在触发ECM真菌原基的形成中起关键作用。一个体外系统将用于验证这一理论，并测试不同处理对子实体形成的影响。AM真菌研究的结果将是准确识别物种，提高对其多样性、生物学和生态学的认识。最后，研究人员设想，植物来源的信号作为ECM子实体的潜在引发剂的作用，将在可食用ECM真菌的培养和商业生产中得到应用。

The central part of this proposal has two principal components: the development of a promising novel and robust identification tool for arbuscular mycorrhizal (AM) fungi, and the continued exploration of the functional aspects associated with the establishment of the AM symbiosis. A third component aims to provide a greater insight into the factors responsible for initiating ectomycorrhizal (ECM) fungal fruitbody formation. For the AM symbiosis, a major challenge that hampers biodiversity studies is the correct identification of the mycobionts. The proposed project will couple classical identification, based on spore morphology, with the design of species-specific molecular probes. This approach will allow identification of AM fungi and the determination of the genetic delimitation of a given species. A second project will investigate cytoplasm streaming, and the movement and activity of organelles in AM fungal germ tubes exhibiting either the fine branching or runner hyphae growth pattern. The phenotypic expression of the extraradical mycelium of genetically distinct clusters of Glomus spp. will also be characterized using the Fractal Dimension Calculator program. For the EMC symbiosis, most fruitbodies develop at the end of summer, after bud set of the host tree. This suggests that plant-derived photoperiod-regulated signals play a key role in triggering the formation of ECM fungal primordia. An in vitro system will be used to test this theory, and to test the effect of diverse treatments on fruitbody formation. The outcome of the research on AM fungi will be the accurate identification of species and an improved understanding of their diversity, biology and ecology. Finally, it is envisaged that investigations into the role of plant-derived signal as potential initiators of ECM fruiting bodies, will have applications in the cultivation and commercial production of edible ECM fungi.