Improved detection of Cucumber mosaic virus coat protein (CMV-CP) in genetically modified pepper (Capsicum annuum) using a polyclonal antibody to a synthetic CP peptide

Abstract

Enormous economic losses caused by infection of peppers with Cucumber mosaic virus (CMV) have spurred the development of CMV-resistant peppers using genetic techniques. However, growing concern from the general public over genetically modified (GM) crops has focused attention on safety and labeling issues. In this study, we developed and optimized a qualitative and quantitative enzyme-linked immunosorbent assay (ELISA) to detect CMV-resistant GM peppers. Two types of antibodies, virion-derived polyclonal antibody (VPAb) prepared from a CMV-Fny virion-immunized rabbit and peptide-based polyclonal antibody (PPAb) prepared from rabbits immunized with a peptide fragment of CMVcoat protein (CMV-CP) (LPDSVTEYDKKLVSR) predicted from the nucleotide sequence were prepared, and their affinities were compared. Optimized ELISAs using VPAb and PPAb as the primary antibodies, respectively, were carried out to measure the level of CMV-CP in GM peppers cultivated at an officially approved facility in Korea. Color development (reflecting CMV-CP levels) was 2.5-fold higher when PPAb was used as the primary antibody compared to VPAb as the primary antibody. No statistical differences were observed among GM pepper cultivars. These results imply that PPAb has higher specificity for CMV-CP than VPAb does, and that the analytical system presented in this study can be used to evaluate the level of CMV-CP in genetically modified peppers.