Serological detection and immunogold localization of cross-reactive antigens shared by Camellia sinensis and Exobasidium vexans.
OBJECTIVE
Pathogenicity of Exobasidium vexans, causal agent of blister blight of tea, was studied in 30 commercially cultivated tea varieties by analysing the antigenic patterns of host and pathogen using immunological techniques.


RESULTS
Whole plant inoculation of tea varieties with E. vexans showed that T-78 and T-17/1/54 were most susceptible and most resistant respectively. Antigen preparations from tea varieties, pathogen, nonpathogen (Fusarium oxysporum) and of nonhosts (Glycine max, Leucaena leucocephala and Oryza sativa) were compared by indirect enzyme-linked immunosorbent assay and dot-immunobinding assay using polyclonal antibodies raised against the pathogen, nonpathogen, susceptible and resistant tea varieties. Cross-reactive antigens (CRA) were found among susceptible varieties and E. vexans isolates but not in resistant varieties, nonhosts or nonpathogen. Indirect staining of antibodies using fluorescein isothiocyanate indicated CRA were concentrated mainly around epidermal and mesophyll cells in compatible host (T-78). This was substantiated by ultrastructural studies using gold-labelled antibodies through transmission electron microscopy which showed specific localization in the chloroplasts and host cytoplasm.


CONCLUSIONS
Pathogenicity of E. vexans to different tea varieties is therefore related to the level of antigenic similarity between host and pathogen.


CONCLUSIONS
Immunological methods proved to be valuable in screening commercially cultivated tea varieties against E. vexans.
Chakraborty
B N
BN
Department of Botany, University of North Bengal, Siliguri, Darjeeling, India. bnc_nbu@hotmail.com
Sharma
M
M
D000818:Animals; D000908:Antibodies, Fungal / Q000276:immunology / Q000302:isolation & purification; D000941:Antigens / Q000032:analysis*; D000946:Antigens, Fungal / Q000032:analysis; D052179:Antigens, Plant / Q000032:analysis; D001487:Basidiomycota / Q000276:immunology* / Q000472:pathogenicity; D028241:Camellia sinensis / Q000276:immunology*; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005455:Fluorescent Antibody Technique; D005516:Food Microbiology; D005779:Immunodiffusion; D046529:Microscopy, Electron, Transmission; D009172:Mycology / Q000379:methods; D010935:Plant Diseases / Q000382:microbiology*; D046549:Plantibodies / Q000276:immunology / Q000302:isolation & purification; D011817:Rabbits; D013662:Tea
D000908:Antibodies, Fungal; D000941:Antigens; D000946:Antigens, Fungal; D052179:Antigens, Plant; D046549:Plantibodies; D013662:Tea