Pepper Mild Mottle Virus Coat Protein Alone Can Elicit theCapsicumspp.L3Gene-Mediated Resistance

The pepper mild mottle virus (PMMoV-S) (an L3hypersensitive response [HR]-inducer strain) coat protein was expressed in Capsicum chinense (L3L3) plants with the heterologous potato virus X (PVX)-based expression system. The chimeric virus was localized in the inoculated leaves and induced the HR, thus indicating that the tobamoviral sequences that affect induction of the HR conferred by the L3resistance gene reside in the coat protein gene. Furthermore, transient expression of the PMMoV-S coat protein in C. chinense leaves by biolistic co-bombardment with a plasmid expressing the β-glucuronidase (GUS) gene leads to the induction of cell death and expression of host defense genes. Thus, the coat protein of PMMoV-S is the elicitor of the Capsicum spp. L3resistance gene-mediated HR.