Mycelium Formation and Calcium Oxalate Production by dsRNA-Free Virulent and dsRNA-Containing Hypovirulent Strains of Cryphonectria parasitica

Abstract

Mycelium formation and oxalate production by two dsRNA-free, virulent strains and three dsRNA-containing, hypo virulent strains of Cryphonectria (Endothia) parasitica were evaluated after 10 days incubation on agar media containing either 0.010 M or 0.025 M calcium acetate, or no calcium acetate. The dsRNA-containing strains EP 31–2P and EP-752 consistently produced the least mycelium while the dsRNA-free strain EP-155 produced the most mycelium on these three media. Addition of 0.010 M calcium acetate did not affect the amount of growth by strain EP-155 or strain EP-752, enhanced growth of the dsRNA-free strain EP-42, and reduced growth of the dsRNA-containing strains EP 17–8B and EP 31–2P. Growth of all strains was reduced on the medium containing 0.025 M calcium acetate. Strain EP-155 produced the greatest total oxalate on these media, strains EP-42 and EP 17–8B produced significantly less, and dsRNA-containing strains, EP 31–2P and EP-752, produced the least. Formation of oxalate by C. parasitica may have a regulatory role in calcium metabolism and/or oxalic acid production.