Agricultural Research Journal

Citrus canker is one of the most devastating citrus diseases in the world. The Phytopathogen responsible for this disease is Xanthomonas axonopodis pv. citri (Xac). Thirty isolates of Xac were isolated from three districts of Uttarakhand state and out of which 13 isolates were selected for genetic diversity study. Pathogenicity test was conducted to identify the pathogen and various morphological and biochemical tests were conducted for characterization of bacterial isolates. PCR based asseys i.e. Repetitive DNA polymerase chain reaction (rep-PCR) fingerprinting using repetitive extragenic palindromic (rep) and enterobacterial repetitive intergenic consensus (ERIC) and BOX primers were used to study genetic diversity. All the 13 isolates differentiated into 13 distinct banding patterns (haplotypes) by rep-PCR technique. The generated banding patterns by the rep-PCR based assays were compared among all the Xac isolates. UPGMA cluster analysis of the fingerprints generated by BOX, REP AND ERIC primers revealed considerable diversity among the isolates collected from different areas of Uttarakhand. Cluster analysis grouped the isolates into two main clusters (A & B) with 28 per cent similarity. The results on molecular characterization revealed that the isolates collected from different locations of Uttarakhand were found diversified, due to different geographic location of isolates.