Association of Potato Virus Y Gene Products with Chloroplasts in Tobacco. U. B. Gunasinghe. Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow 83843. P. H. Berger. Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow 83843.. MPMI 4:452-457. Accepted 19 June 1991. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1991.

Symptom expression in potyvirus-infected plants may be due to altered plastid function. Chloroplasts from potato virus Y (PVY)-infected plants were assayed for the presence of PVY coat protein (CP), helper component protein (HC), and genomic RNA. PVY-CP, -HC, or -RNA binding to the exterior of chloroplasts was eliminated by treating plastids with thermolysin or RNase A, respectively, and by including reconstitution experiments as controls. By western and northern blotting analyses, PVY CP, HC, and RNA were found within infected leaf chloroplasts. Furthermore, the majority of CP was associated with the thylakoids rather than the stroma. These data agree with the work of others, implicating an inhibition of photosystem II in PVY pathogenesis, and suggesting an intimate relationship between PVY RNA, PVY gene products, and host cell plastids.