BACTERIOPHAGE SENSITIVITY AND BIOCHEMICAL GROUP IN XANTHOMONAS MALVACEARUM.

Abstract

Summary: Isolates of Xanthomonas malvacearum, of which 18 representative cultures were examined in detail, were classified into two groups differing in: capacity to oxidize lactose, colony form on first isolation, proteolytic activity, and lysis by bacteriophages. The seven group 1 isolates examined in detail gave confluent lysis at routine test dilution by 7 of 13 phages isolated from diseased cotton plant material, and were weakly proteolytic and did not oxidize lactose in common with other group 1 isolates. All but one of the 11 group 2 isolates gave confluent lysis at RTD by the 6 phages to which the group 1 isolates were resistant but not by the other 7 phages. All isolates of group 2 oxidized lactose and were relatively strongly proteolytic. Phages active against X. malvacearum were detected in 87 out of 127 collections of infected leaves examined, and there was some correlation between the presence of groups 1 or 2 xanthomonads and the group-specificity of the phage isolated from the same material. An isolate of group 2 X. malvacearum which was resistant to some of the group 2-specific phages was apparently lysogenic.