Genotypic identification and investigation of intra-species diversity of Xanthomonas pathogenic isolates from bean and alfalfa hosts in East and West Azerbaijan provinces

In order to isolate pathogenic bacteria from the hosts of bean and alfalfa, 140 bacterial isolates were cultured and purified on NA medium in East and West Azerbaijan provinces. Based on the color and appearance of the colonies, the isolates that were close to the desired Xanthomonas bacteria were selected. After re-cultivation and purification, a total of 62 isolates were obtained. To perform the pathogenicity test of the isolates, each of them was inoculated individually to its host and kept in greenhouse conditions for two weeks. 33 strains were able to cause pathogenicity on the host. The strains were able to amplify the 239 bp fragment of Xanthomonas specific gene, which is part of the ITS gene. Therefore, these strains were considered as Xanthomonas bacteria. Based on genetic fingerprinting by rep-PCR method, the strains isolated from bean and alfalfa was divided into four and three groups, respectively, which results indicated genetic diversity between the strains. Based on the sequencing of 16S rRNA, gyrB and rpoD genes, the strains isolated from alfalfa were identified as X. alfalfae subsp. alfalfae and bean strains were identified as X. phaseoli pv. pahseoli. By reviewing the available sources, the present research is the first report of the isolation, identification and genetic diversity of these strains from bean and alfalfa hosts in East and West Azerbaijan provinces.