Cryphonectria parasitica is the cause of chestnut blight, a fungal disease endemic in Northern Italy. A collection of C. parasitica isolates from Pellice, Gesso, Tanaro and Mala valleys in Piedmont was evaluated for the presence or absence of dsRNA and more in particular for the presence of Cryphonectria hypovirus 1 (CHV1), a virus known to cause hypovirulence when present in the cytoplasm of its fungal host. Five isolates carrying CHV1 in their cytoplasm, and showing some phenotypic variability when cultured on PDAmb plates, were single spored. Virus free isogenic isolates were obtained from each CHV1 infected isolate through screening of conidial progeny. The effect of the presence of the virus on fungal virulence was evaluated through inoculation of 3 years old European chestnut stands (Castanea sativa). We could not observe any statistical advantage for the presence of the CHV1 viral isolates in comparison to the virus free isolates when measuring canker diameter. We are currently evaluating the molecular diversity of the CHV1 and C. parasitica isolates object of our investigation. Furthermore, we report on the phenotype of C. parasitica strains over-expressing Cpkk1, a MAPKK isolated from C. parasitica, previously shown to be affected by CHV1 viral infection.
Effect of CHV1 Virus infection in Cryphonectria parasitica isolates from Piedmont
ROSTAGNO, LAURA;TAMIETTI, Giacomo
2007-01-01
Abstract
Cryphonectria parasitica is the cause of chestnut blight, a fungal disease endemic in Northern Italy. A collection of C. parasitica isolates from Pellice, Gesso, Tanaro and Mala valleys in Piedmont was evaluated for the presence or absence of dsRNA and more in particular for the presence of Cryphonectria hypovirus 1 (CHV1), a virus known to cause hypovirulence when present in the cytoplasm of its fungal host. Five isolates carrying CHV1 in their cytoplasm, and showing some phenotypic variability when cultured on PDAmb plates, were single spored. Virus free isogenic isolates were obtained from each CHV1 infected isolate through screening of conidial progeny. The effect of the presence of the virus on fungal virulence was evaluated through inoculation of 3 years old European chestnut stands (Castanea sativa). We could not observe any statistical advantage for the presence of the CHV1 viral isolates in comparison to the virus free isolates when measuring canker diameter. We are currently evaluating the molecular diversity of the CHV1 and C. parasitica isolates object of our investigation. Furthermore, we report on the phenotype of C. parasitica strains over-expressing Cpkk1, a MAPKK isolated from C. parasitica, previously shown to be affected by CHV1 viral infection.
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