US-Sweden Cooperative Research: Vegetative Compatibility in Heterobasidion Annosum

该奖项将支持俄勒冈州立大学的埃弗雷特·汉森博士和俄勒冈州立大学的埃弗雷特·汉森博士在系统生物学方面的合作研究。Jan Stelid和Martin Johansson，瑞典农业科学大学森林真菌学和病理学系，瑞典乌普萨拉。本项目的目的是研究针叶树根病真菌的群体遗传学，特别是营养性磷相容性的机制。许多真菌物种的个体通过防止细胞核和细胞质交换的营养相容性（VC）系统保持其独立的身份。这一现象在引起树粪根腐病的树粪异黑霉（heterobasdion anansus）身上得到了很好的证明。VC反应用于群体遗传学和将衰弱病毒引入真菌群体的研究。然而，由于缺乏VC反应的生理和遗传调控信息，解释受到阻碍。拟建项目的主要目的是：1)描述植物相容和不相容双核菌丝体相互作用的生理和解剖反应；2)确定该真菌VC的遗传控制体系。基因定义的菌丝之间的相互作用将在微培养室中观察，细胞质、细胞核和线粒体的反应将通过适当的组织学技术可视化。用同工酶和耐药标记物监测细胞核和细胞质的交换。相互作用的蛋白质产物将通过电泳测定。VC的遗传控制将通过配对和回交兄弟姐妹组成的异核体来评估，目的是确定控制这种反应的基因数量。红蝽目前正在造成巨大的破坏，特别是在欧洲，所有迹象表明，它在未来的破坏性将更大。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.