Cucumber mosaic virus Fast New York strain (CMV-Fny) containing a mutated 2b protein (CMV-FnyΔ2b) was evaluated for the ability to infect ‘Calwonder’ bell pepper (Capsicum annuum) plants in comparative tests with the parent virus, CMV-Fny. Plants inoculated with CMV-FnyΔ2b did not develop local or systemic symptoms of infection, whereas CMV-Fny-infected plants developed systemic chlorosis by 7 days post inoculation (dpi), followed by mosaic and leaf deformation. Virus accumulation, determined by enzyme-linked immunosorbent assay (ELISA), revealed that CMV-FnyΔ2b accumulated in inoculated Calwonder leaves and inconsistently infected some noninoculated leaves at a low titer but was not detected in the youngest, noninoculated leaves. Immuno-tissue blot tests did not detect CMV-FnyΔ2b in the stems of infected plants, whereas CMV-Fny accumulated throughout the length of the stems of inoculated plants. In two experiments, protoplasts were isolated from Calwonder leaves, inoculated with viral RNAs of CMV-Fny or CMV-FnyΔ2b, and tested by ELISA for infection. In both experiments, less CMV-FnyΔ2b than CMV-Fny accumulated in protoplasts. These results suggest that the CMV 2b protein is needed for systemic infection of Calwonder pepper plants and for accumulation of the virus in inoculated protoplasts.
‘Peacework’: A Cucumber mosaic virus-resistant Early Red Bell Pepper for Organic Systems