RNGR.net is sponsored by the USDA Forest Service and Southern Regional Extension Forestry and is a colloborative effort between these two agencies.

U.S. Department of Agriculture USDA Forest Service Southern Regional Extension Forestry Southern Regional Extension Forestry

Skip to content. | Skip to navigation

Home → Publications → American Chestnut Proceedings → 1992 → Characterization of Double-stranded RNA-free Hypovirulent Strains of Cryphonectria parasitica

Characterization of Double-stranded RNA-free Hypovirulent Strains of Cryphonectria parasitica

Hypovirulent strains of Cryphonectria parasitica without detectable levels of double-stranded RNA have been associated with nonlethal cankers in Michigan American chestnut stands. This indicates that transmissible hypovirulence can be induced by cytoplasmic elements other than dsRNA. A consistent feature of dsRNA-free hypovirulent strains of C. parasitica is that a large portion of the respiratory activity of the mycelium is cyanide-resistant; whereas the respiration of virulent strains is cyanidesensitive. By analogy with other fungal systems such as Neurospora, the induction of a cyanide-resistant alternative oxidase activity is symptomatic of mitochondrial mutations that affect the activity of the cytochrome-dependent mitochondrial electron transport system. These naturally occurring dsRNA-free isolates are described and compared to laboratory derived isolates with reduced virulence.


Download this file:

PDF document Download this file — PDF document, 347Kb

Details

Author(s): A. V. Ravenscroft, C. B. Monteiro Vitorello, Dennis W. Fulbright, H. Bertrand, K. Beal, N. Mahanti

Publication: American Chestnut Proceedings - 1992