The recognition events that lead to cell fusion are crucial steps in many important biological processes. In the Fungal Kingdom, cell recognition events are well understood for such processes as mating in Saccharomyces cerevisiae (a budding yeast.) In filamentous fungi, a recognition system is also used to control vegetative fusion (anastomosis) of the hyphae. These fusion events permit the development of large networked colonies in which the older hyphae are greatly interconnected. This allows for rapid distribution of nutrients to different parts of the colony. The benefits of cell fusion also extend to the joining of two distinct colonies of the same species. Stable colonies formed by the fusion of two partners will contain two different sets of genes, one from each partner, thus producing novel genetic combinations. In addition such fusions permit more efficient foraging, since the nutritional and metabolic resources of both colonies can be pooled. However, there are inherent risks associated with this process. Viruses that infect fungi exploit these cell fusion events in order to spread from one host to another. To counteract the inherent risk of transmitting viral infection, fungi have evolved a complex genetic mechanism, called vegetative incompatibility. This permits self-fusion but prevents the fusion of two unrelated fungal colonies. Cryphonectria parasitica, the plant pathogen responsible for the blight of the American chestnut, is a fungus that can be infected by RNA viruses that reduce the ability of the fungus to cause disease. This project will address 1) the nature of the recognition events that lead to fungal colony fusion and the transmission of the virus from one colony to another and 2) the signals that cause the fungal cells to die if the interaction is genetically incompatible.
Broader Impacts
C. parasitica is an excellent system for integrating students into research because this fungus is simple to grow and manipulate, but at the same time it can be coupled to powerful technologies. In this collaborative project there will be opportunities for the cooperative training of undergraduate and graduate students and postdoctoral fellows in a minority serving institution and a research university. The integrative nature of the project will enable a high degree of interaction between the two research teams. Contributions will be made to the fields of fungal development, plant pathology and host-virus interactions. There is potential for improving virus-based biological control strategies for chestnut blight and other fungal diseases. In addition, this project will enhance undergraduate student education by integrating the research into the classroom, and it will allow graduate and undergraduate researchers to participate in scientific meetings. The results of the project will be made available in publicly accessible databases and through distribution of the data by publication, web site dissemination, and participation in scientific meetings.
