Development of bacteriophage phi29 in sporulating and non-sporulating cells of bacillus subtilis 168

Infection by bacteriophage phi29 of Bacillus subtilis 168 and of its asporogenous mutant spoOA-3NA has been studied in exponential and stationary phases. As first observed with phage phie infections, the burst-size decreases during the stationary phase much more rapidly in wild type than in mutant cells. In addition, the two strains are shown to differ even during growth in their response to phage phi29 infection. During a short period in the exponential phase, no phage production occurs when infected bacteria (whether spo+ or spo-) are incubated in their growth medium, but phage is produced when incubation takes place after transfer to fresh medium. From these and other unexpected findings it is concluded that any causal relation between sporulation and phage development must be considered with caution. Phage infection of spo+ cells at the end of the growth period does not affect the time required for mature spore formation.