Mycelial Growth and Oxalate Production by Five Strains of Cryphonectria Parasitica in Selected Liquid Culture Media

ABSTRACT

In vitro mycelial growth and oxalate production by five isogenic strains of Cryphonectria parasitica were examined. One dsRNA-free strain and four containing either Michigan or Italian cytoplasmic, dsRNA hypovirulence (reduced virulence) agents, were incubated, without agitation, for 10 days at 25 C in 25 ml of defined liquid media containing either glucose, fructose, calcium polypectate or glucose + glyoxylic acid as carbon sources and either asparagine, arginine or methionine as nitrogen sources. Strains containing Italian hypovirulence agents often produced the most mycelium in these media. Media containing arginine or asparagine generally supported comparable amounts of myelium but growth was reduced in media containing methionine. Greatest oxalate production by all strains occurred in the asparagine medium containing calcium polypectate, and decreased progressively when glucose + glyoxylic acid, glucose and fructose were used respectively as carbon sources. The least oxalate accumulated in media containing methionine as the nitrogen source with intermediate levels in media containing arginine. The greatest oxalate accumulated in these media when the pH of the culture filtrates was 5.0 or above. Oxalate production in all media was independent of cytoplasmic agents for hypovirulence and was not associated with the amount of mycelium produced.

Key Words:

• oxalate
• hypovirulence
• dsRNA
• chestnut blight