Flagella-specific bacteriophages of Agrobacterium tumefaciens: demonstration of virulence of nonmotile mutants.

Bacteriophages GS2 and GS6 for Agrobacterium tumefaciens were shown by electron microscopy to adsorb to flagella. This specificity was confirmed by the finding that phage-resistant mutants were nonmotile. Such mutants retained tumor-inducing virulence and ability to attach to plant cells, indicating that motility was not required for these properties. Both phages had contractile tails and appeared similar in the electron microscope.