Why Sequence Chestnut Blight Fungus?

Cryphonectria parasitica, the chestnut blight fungus, is responsible for epidemics that caused the destruction of hundreds of millions of mature chestnut trees in forests of North America and Europe during the first part of the 20th century. The discovery of a group of RNA viruses, now classified in the family Hypoviridae (hypoviruses), that reduce the virulence (hypovirulence) of this pathogen stimulated intensive research into the potential of using fungal viruses for the biological control of fungal disease. Subsequent epidemiologic and population genetic studies have established the chestnut/C. parasitica/hypovirus pathosystem as the textbook example of both the consequences of accidental introduction of an exotic organism and of hypovirulence-mediated biological control of fungal pathogens.

Interest in C. parasitica, hypoviruses, and their interactions now extends well beyond disease control potential. The development of a robust C. parasitica transformation protocol and of hypovirus reverse genetics led to the establishment of a biologically relevant experimental system with the rare capacity for efficiently manipulating the genomes of both a eukaryotic virus and its host. Scientists studying this system have also made significant contributions to the current understanding of mycovirus/host interactions, fungal population genetics, mechanisms underlying fungal pathogenesis, and fungal signal transduction pathways. Very recent advances with this system are providing important new insights into the role of RNA silencing as an antiviral defense mechanism in fungi and the impact of viruses on cell death associated with fungal vegetative incompatibility systems and secondary metabolism. Thus, the availability of the C. parasitica genome sequence, the first for an Ascomycete tree pathogen, will greatly accelerate the efforts of an active and growing research community to address a broad range of important fundamental and applied research topics.

Principal Investigators: Donald L. Nuss (Univ. of Maryland Biotech. Inst.) and Alice Churchill and Michael Milgroom (Cornell Univ.)