Host range and particle morphology of some bacteriophages affecting pathovars of Xanthomonas campestris

Seven bacteriophages active against different pathovars of Xanthomonas campestris were isolated from naturally infected plant material. All showed polyhedral heads and could be separated into two morphological groups according to their tail structures. Phages active against X. campestris pv. cucurbitae (XCU-P1 and XCU-P3) and X. campestris pv. holcicola (XHOL-P1) were described for the first time. Ninety nine bacterial strains belonging to 5 genera (Xanthomonas, Pseudomonas, Agrobacterium, Clavibacter and Erwinia) were tested for sensitivity to the different phage suspensions. More than 60% of the Xanthomonas cultures were susceptible to one or more phages. The other genera did not react with any of the phages. The 7 phages were specific at a generic level but showed a low degree of specificity at the pathovar level.