XVI International Botanical Congess

Virus-like particles (VLPs) containing double-stranded (ds)RNA are found in isolates of a fungus, Alternaria alternata, which produce high levels of tentoxin, a phytotoxic peptide. Mixing purified VLPs with germinating spores of two isolates which did not produce tentoxin resulted in a stable infection, identified by the presence of dsRNA in the culture. Restriction fragment markers were used to verify the identity of the isolates. Cultures maintained their infection over four serial transfers of two weeks each. The amount of dsRNA increased over this period, but no tentoxin production was detected in either isolate.