A potyvirus in nature: indistinct populations.

Abstract

Potyviruses occur in nature as a variable population. A number of strains have been reported for many potyviruses. Two or more viruses have been separated from "one virus" isolate. Experimental isolation and/or transmission often results in atypical viral isolates. A virus may be considered as a fuzzy population. We should properly understand the range of variation in one virus. The range of variation as well as typical characteristics of a virus should be included in future descriptions.