<prompt> Beta phage is seen inBacillus anthracisCorynebacterium diptheriaeClostridium botulinumPeptostreptococcus  <response>: The toxigenicity of the diphtheria bacillus depends on the intracellular presence of corynephages tox, which acts as genetic controlling toxin production. Non-toxigenic strains are rendered toxigenic by infecting them with the beta or some other phages This is known as lysogenic or phage conversion. REF:Textbook of microbiology; Ananthanarayan and panikers; 10th Edition; Pg: 240 