Antigen Analysis of the Polysaccharides of Xanthomonas campestris pv. oryzae

Abstract

The diffusible antigens of Xanthomonas campestris pv. oryzae were analyzed by using antisera prepared with the isolates Q7472 (serovar A), Q7502 (serovar B-I) and N5837 (serovar B-II). When these antisera were added to the slime polysaccharide and somatic polysaccharide of the isolates Q7472, Q7502 and N5837 in test tubes, precipitation of the antibody occurred showing different quantitative curves, suggesting that slime and somatic polysaccharides of these isolates were not identical serologically. In agar gel diffusion test, the suspensions of whole cells, slime polysaccharide and somatic polysaccharide of the isolate Q7472 produced a few precipitin bands with all antisera. Among these antigens, the antigen named “a” was specific for serovar A. It was extracted with distilled water, saline solution and 0.5 N trichloroacetic acid and formed thick precipitin band with both homologous and heterologous antisera in agar gel diffusion test. It was heat stable, precipitated with ethanol and not affeced by Pronase treatment. All antigens other than “a” were not specific for serovars.