Targeted disruption of Ga and Gb genes has established the requirement of an intact G protein signaling pathway for optimal execution of several important physiological processes, including pathogenesis, in the chestnut blight fungus Cryphonectria parasitica. We now report the identification of a G protein signal transduction component, beta disruption mimic factor-1, BDM-1. Disruption of the c...

The ability to restore American chestnut (Castanea dentata) through the planting of blight-resistant (Cryphonectria parasitica) trees is currently being tested. Forest-based research on the species’ silvicultural requirements and chestnut blight development are lacking. Pure American chestnut seedlings were planted in a two-age shelterwood forest with low residual basal area and in a midstory-r...

We have determined the organization within the terminal domains of the major large double-stranded RNA genetic elements associated with the hypovirulent strain EP713 of the chestnut blight pathogen Cryphonectria (Endothia) parasitica. Only the polyadenylated strand contained long open reading frames. Furthermore, only RNA of the same polarity as the polyadenylated strand was detectable in a sin...

The recovery of chestnut from chestnut blight in Italy and Michigan largely was responsible for the resurgence in chestnut research. The observed remission of disease now has been attributed to a biological control process called hypovirulence, whereby virulent strains are debilitated as a result of infection by fungal viruses (hypoviruses). Several species of hypoviruses now are known and each...

Programmed cell death (PCD) is an essential part of the defence response in plants and animals against pathogens. Here, we report that PCD is also involved in defence against pathogens of fungi. Vegetative incompatibility is a self/non-self recognition system in fungi that results in PCD when cells of incompatible strains fuse. We quantified the frequency of cell death associated with six veget...

Viral double-stranded RNAs (dsRNAs) responsible for virulence attenuation (hypovirulence) of the chestnut blight fungus, Cryphonectria parasitica, profoundly influence a range of host functions in addition to virulence. The 5'-proximal open reading frame, A, of the prototypical hypovirulence-associated viral dsRNA, L-dsRNA, present in hypovirulent strain EP713, was recently shown by DNA-mediate...