ISOLATION AND CHARACTERIZATION OF 3 MONOCLONAL-ANTIBODIES SPECIFIC FOR PISTIL AND STAMEN TISSUES OF TOBACCO (NICOTIANA-TABACUM-L)

Two immunization procedures were compared for their ability to yield monoclonal antibodies that react to antigens in the different flower parts (sepals, petals, stamens and pistil) and avoid immunodominance of some pistil-specific components in the extracts. The hybridomas were screened previously by ELISA against extracts from the different flower parts and later by in situ immunolocalization on floral sections and Western blotting. Three monoclonal antibodies displaying specificity for style (5F9) and anther (8F2 and 8G1) tissues were selected and purified by affinity chromatography. The antibody 8G1 is periodate-sensitive, implying that the epitope is a carbohydrate, while the 5F9 and 8F2 were insensitive. Western blot analysis showed that the antibodies selected react to specific bands of the different organ extracts. Immunolocalization assays showed that the antibody 8F2 recognizes an antigen that is localized in the endothecium cells of the tobacco anther while the 8G1 antigen is detectable in the stomium cells. Monoclonal 5F9 recognizes an antigen localized in a very limited region of the style tube.