Cell surface hydrophobicity is a property of many microorganisms. A group of small hydrophobic proteins has recently been described in filamentous fungi. These proteins, termed hydrophobins, have a number of properties in common, including: 1) accumulation on surfaces of sporulation structures, 2) accumulation on aerial hyphae, 3) presence of eight cysteines in the molecule, 4) putative hydrophobic leader sequences, and 5) hydrophobic domains in the secreted protein. Proteins, or genes encoding such proteins, have been described from a number of different unrelated filamentous fungi, including one from the chestnut blight fungus Cryphonectria parasitica. This small hydrophobic protein, cryparin, was discovered because it is down-regulated in strains which are hypovirulent and sporulate poorly. Cryparin accumulates on asexual fruiting bodies and in aerial hyphae. Unlike other hydrophobins, cryparin is also a lectin. The evolutionary conservation in different fungi of similar small cell surface hydrophobic proteins associated with fruiting bodies suggests that they play important roles in the biology of these fungi. This proposal is to investigate the role of cryparin in the biology of the chestnut blight fungus. The physical properties of cryparin at air interfaces may be important for some aspect of fruiting body formation, positioning of the fruiting body, or spore dispersal. Cryparin could also play a role in virulence as proposed for another hydrophobin. To begin addressing the role of cryparin in the biology of the chestnut blight fungus. %%% The chestnut blight fungus, Cryphonectria parasitics, has nearly eliminated the American chestnut from its original natural range. Before this disease killed them chestnut trees were one of the most important and common trees in the forests that range from New England to the Southern Appalachians. A biological control for this disease has been discovered. A virus infects the chestnut blight fungus causing it to no longer be able to attack the chestnut tree or to form normal fungal reproductive structures. We have found in previous work that the virus interferes with production of a few specific fungal proteins, one of which is the protein cryparin. We have preliminary evidence that this protein may play a role in the ability of the fungus to reproduce. There is also a possibility that the protein enhances the ability of fungus to damage infected trees. It is the purpose of the study to investigate what role this abundantly produced protein plays in the biology of the fungus. Knowledge gained by this study may lead to the development of new approaches for the control of plant diseases.
