Impaired Cell-to-Cell Movement of Potato Virus Y in Pepper Plants Carrying the y^a (pr2¹) Resistance Gene. R. Arroyo. CIT-INIA. Laboratorio de Biologfa Molecular y Virologfa Vegetal, Autopista A-6, km 7. 28040 Madrid, Spain. M. J. Soto, J. M. Martfnez-Zapater, and F. Ponz. CIT-INIA. Laboratorio de Biologfa Molecular y Virologfa Vegetal, Autopista A-6, km 7. 28040 Madrid, Spain. MPMI 9:314-318. Accepted 15 February 1996. Copyright 1996 The American Phytopathological Society.

The resistance mechanism to potato virus Y (PVY) in pepper plants homozygous for the recessive resistance allele y^a (pr2¹) was investigated. The results of the fluorescence immunochemical analysis of protoplasts prepared from virus-inoculated plants or virus-inoculated protoplasts indicate that this resistance is due to impaired cell-to-cell movement of the virus, rather than to an interference with virus replication.