Bacteriophage 7-7-1 adsorbs to the complex flagella of Rhizobium lupini H13-3.

Bacteriophage 7-7-1 is shown to adsorb specifically to the complex flagella of its host Rhizobium lupini H13-3. Deflagellation of motile cells before the addition of phage leads to a complete inhibition of phage propagation for at least 60 min. Among phage-resistant mutants, many non-motile (mot) and non-flagellated (fla) derivatives of R. lupini H13-3 have been selected. Electron microscopic observations indicate that bacteriophage 7-7-1 attaches with its short tail fibres to the conspicuous helical filament of R. lupini flagells. This attachment is reversible; irreversible phage adsorption takes place at the flagellar base. It is postulated that phage 7-7-1 moves along the rotating flagellum towards a final receptor next to the insertion site of the flagellum, where tail contraction and injection of phage nucleic acid occurs.