RESUMO
Aim: Black rot of crucifers caused by Xanthomonas campestris pv. campestris (Pammel) Dowson (Xcc) is a major seed-borne disease. The present study aimed to develop a rapid diagnostic protocol for the specific and sensitive detection of this pathogen. Methodology: A specific primer set was designed based on rpf gene and optimization of PCR condition was done for specific detection of Xcc. Sensitivity of PCR for primer set was then determined by diluting the Xcc DNA and cells. Results: Specific primer set was able to amplify a specific band of 304 bp in all 11 isolates of Xcc but failed to amplify other Xanthomonas species and one each of Ralstonia solanacearum, Erwinia caratovora subsp. caratovora, Bacillus subtilis, Pseudomonas fluorescens and P. aeruginosa. The primer set was highly sensitive as it was able to detect 10 pg μl-1 bacterial DNA and up to 3x103 CFU ml-1 corresponding to 12 viable cells of Xcc which were used as template for PCR reaction Interpretation: The results suggest that developed PCR primers are highly specific and sensitive and it can be used to detect the pathogen at an early stage of infection for disease management.