Biological variants of tobacco etch virus that induce morphologically distinct nuclear inclusions

The presence of distinctive nuclear inclusions has been used for many years as a diagnostic character for tobacco etch virus (TEV). Cytological examinations of isolates of TEV in both weeds and solanaceous crops from areas widely separated geographically have demonstrated the presence of a variety of nuclear inclusions that vary considerably in form. Such inclusions can, in many cases, be related to differences in symptom expression. It is suggested that distinctive nuclear inclusions may be used to select biological variants of TEV that may be useful in the study and manipulation of closely related "strains" of this potyvirus.