Sorghum chlorotic spot virus binds to potyvirus cylindrical inclusions in tobacco leaf cells

Nicotiana benthamiana can be doubly infected with either potato virus Y or tobacco etch virus and sorghum chlorotic spot virus (SCSV). Immunogold labeling showed that cylindrical inclusions of either potyvirus bind virions of the unrelated rod-shaped furovirus SCSV. Not all cells in doubly infected N. benthamiana plants contained both viruses. In cells infected by the potyviruses but not by SCSV, cylindrical inclusions did not label with the antiserum to SCSV. Numbers of cells infected with SCSV did not increase in doubly infected plants compared to those in plants infected with SCSV alone. Systemic infection of N. benthamiana by either potyvirus was not prevented by SCSV infections. This provides further evidence that unrelated rod-shaped viruses can bind to potyvirus cylindrical inclusion bodies, and that this phenomenon is not limited to graminaceous hosts.