Detection and identification of Xanthomonas axonopodis pv. phaseoli on bean seed collected in Serbia

Laboratory assays were conducted to detect and identify Xanthomonas axonopodis pv. phaseoli on bean seeds collected from naturally contaminated commercial crops. Semi-selective media, viz. Xanthomonas campestris pv. phaseoli agar and milk tween agar were used to detect the bacterium from whole bean seed extract. Colonies of the bacterium were yellow, mucoid and convex on these media and zones of hydrolysis formed around them. The pathogenicity of the strains was confirmed by stem inoculation of young bean plants. Identification of the strains was proved by using rapid methods (ELISA and PCR). The results showed the presence of seed-borne X. axonopodis pv. phaseoli in 20 out of the 23 assayed bean cultivars that are commercially grown in Serbia. These results indicate that the seed of the bean cultivars grown in our country is highly infected by the bacterium.