US-Sweden Cooperative Research: Vegetative Compatibility in Heterobasidion Annosum

该奖项将支持俄勒冈州立大学的Everett Hansen博士与瑞典乌普萨拉瑞典农业科学大学森林真菌和病理学系的Jan Stelid博士和Martin Johansson博士在系统生物学方面的合作研究。本项目的目的是研究针叶树根病真菌的群体遗传学，特别是营养磷亲和性的机制。许多真菌物种的个体通过营养体亲和(VC)系统保持其独立的身份，该系统阻止细胞核和细胞质的交换。这一现象很容易在引起林木根腐病的Anterobasidion Annosum身上表现出来。VC反应被用于研究种群遗传学和将衰弱病毒引入真菌种群。然而，由于缺乏关于VC反应的生理学和遗传调控的信息，解释受到阻碍。该项目的主要目标是：1)描述营养相容和不相容的双核菌丝体相互作用的生理和解剖反应；2)确定Vc在该真菌中的遗传控制系统。基因定义的菌丝体之间的相互作用将在微培养箱中观察到，细胞质、细胞核和线粒体的反应将用适当的组织学技术可视化。将使用同工酶和耐药标记监测细胞核和细胞质的交换。蛋白质相互作用的产物将通过电泳法测定。VC的遗传控制将通过配对和回交同胞组成的异核体来评估，目的是确定控制这一反应的基因数量。H.Annosum目前正在造成巨大的破坏，特别是在欧洲，所有迹象都表明，它在未来将造成更大的破坏。对其生物学的进一步了解将对欧洲和北美的森林病理学家具有重要的价值。

This award will support collaborative research in systematic biology between Dr. Everett Hansen, Oregon State University and Drs. Jan Stelid and Martin Johansson, Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden. The objective of the project is to study the population genetics of root disease fungi of coniferous trees, and particularly the mechanisms of vegetative P compatibility. Individuals of many fungus species maintain their separate identity by a vegetative compatibility (VC) system that prevents exchange of nuclei and cytoplasm. The phenomenon is readily demonstrated in Heterobasidion annosum, cause of annosus root rot in forest trees. VC reactions are used in studies of population genetics and the introduction of debilitating viruses into fungus populations. Interpretation is hampered, however, by lack of information on the physiology and genetic regulation of the VC reaction. The main objectives of the proposed project are: 1) to describe the physiological and anatomical reactions of interacting vegetatively compatible and incompatible dikaryotic mycelia of H.annosum; and 2) to determine the system of genetic control of VC in this fungus. Interactions between genetically defined mycelia will be observed in microculture chambers and responses of cytoplasm, nuclei, and mitochondria will be visualized with appropriate histological techniques. Exchange of nuclei and cytoplasm will be monitored using isozyme and drug resistance markers. Protein products of the interaction will be determined by electrophoresis. Genetic control of VC will be assessed by pairing and backcrossing sib-composed heterkaryons, with the goal of determining the number of genes that control this reaction. H.annosum is presently causing tremendous damage, especially in Europe, and all indications are that it will be more destructive in the future. Further understanding of its biology will be of significant value to forest pathologists in both Europe and North America.