Student Ready Project Formulation Bts 421 Project Report On Isolation, Characterization, and Antibiotic Susceptibility of Xanthomonas Strains Causing Black Rot in Cauliflower

Abstract

Xanthomonas campestris pv. Campestris is a notorious bacterial pathogen that causes black rot disease in various cruciferous crops, including cauliflower. Understanding the characteristics and behavior of this pathogen is crucial for devising effective control strategies. In this study, we aimed to isolate and characterize X. campestris pv. Campestris from cauliflower, focusing on its pathogenicity and other key traits. The isolation of X. campestris pv. Campestris was carried out from symptomatic cauliflower plants showing typical black rot symptoms. Infected tissues were surface sterilized and streaked on selective media. Colonies exhibiting characteristic features of X. campestris pv. Campestris, such as yellow mucoid appearance and circular shape, were selected for further analysis. Morphological and biochemical characterization of the isolated strains was performed. The strains displayed gram-negative characteristics, and microscopic examination revealed the presence of rod-shaped cells. Biochemical tests confirmed their ability to produce oxidase and catalase enzymes, which are typical traits of X. campestris pv. Campestris. Molecular characterization was conducted to confirm the identity of the separates. Polymerase Chain Reaction (PCR) amplification of specific genomic regions using primers targeting X. campestris pv. Campestris genes was performed. DNA sequencing of the amplicons and subsequent comparison with known X. campestris pv. Campestris sequences confirmed the identity of the isolated strains. The pathogenicity of the isolated X. campestris pv. Campestris strains was evaluated through inoculation studies. Healthy cauliflower plants were artificially inoculated with bacterial suspensions and kept under controlled conditions. Disease symptoms, such as leaf chlorosis, wilting, and blackening, appeared on the inoculated plants, confirming the pathogenic nature of the isolates. Furthermore, the virulence factors of the isolated strains were investigated. Extracellular enzymes produced by X. campestris pv. Campestris, such as cellulases and pectinases, were analyzed. Enzyme activity assays revealed significant production of these virulence factors, indicating their role in the pathogenicity of X. campestris pv. Campestris on cauliflower.