Isolation and biochemical characterization of Xanthomonas campestris PV. Ricini from castor bean plant

Xanthomonas campestris pv. ricini is a significant bacterial pathogen affecting castor bean (Ricinus communis), leading to considerable yield losses. Accurate identification and characterization of the pathogen are essential for effective disease management. This study aimed to isolate and biochemically characterize X. campestris pv. ricini from infected castor bean plants. The bacterium was isolated from symptomatic leaf samples and subjected to a series of biochemical tests, including Gram staining, catalase test, potassium hydroxide (KOH) test, and methyl red test. Gram staining confirmed the bacterium as Gram-negative and rod-shaped. The KOH solubility test further supported its Gram-negative nature through the formation of a viscous thread. The catalase test showed a positive reaction, indicating the presence of the catalase enzyme, while the methyl red test confirmed its ability to produce stable acid end-products. These biochemical characterizations provide fundamental insights into the identity of X. campestris pv. ricini, laying the groundwork for future studies on its pathogenicity and control strategies.