Isolation, Characterization, and Antibiotic Susceptibility of Xanthomonas Strains Causing Black Rot in Cauliflower

Abstract

This research aimed to isolate and characterize Xanthomonas bacteria from cauliflower leaf san1ples affected by black rot symptoms. A total of ten leaf samples were randomly collected from fields located in Modipuram, Meerut. The isolates were obtained using both select ive and general media, and their physical, morphological and biochemical characteristics were thoroughly examined. The colonies grown on nutrient agar exhibited typical features, appearing as small, yellow. translucent, and mucoid. On yeast extract-dextrose-calcium carbonate agar (YDCA), the colonies were observed to be yellow, slimy, shiny, and convex in shape. Following purification, the isolates were maintained on nutrient agar slants. Gram staining revealed that the bacteria were gram-negative and had a short rod-shaped morphology. Further biochemical tests confirmed the identity of the isolates as Xanthomonas, displaying positive react ions in sucrose, fructose, glucose, citrate utilization, and S.UVl tests. However, the urease test yielded a negative outcome. The antibiotic susceptibility profiles of the isolates were assessed using the disc diffusion technique. The results indicated that the isolates were susceptible to carbenicillin, ciprotloxacin, and cotrimoxazole. They exhibited an intermediate response to cefixin1e and erythromycin, while displaying resistance to amoxyclav, carbapenem, and tetracycline. These significant findings provide valuable insights into the isolation, characterization, and antibiotic susceptibility patterns ofXanthomonas strains responsible for black rot in cauliflower. Keywords: Xanthomonas campestris pv. Campestris, Cauliflower, Isolation, Characterization, Antibiotic, Pathogenicity.