Lysogenic conversion
Lysogenic conversion is when a temperate phage induces a change in the phenotype of the bacteria infected that is not part of a usual phage cycle. Changes can often involve the external membrane of the cell by making it impervious to other phages or even by increasing the pathogenic capability of the bacteria for a host.As an example, Corynebacterium diphtheriae produces the toxin of diphtheria only when it is infected by the phage &beta. In this case, the gene that codes for the toxin is carried by the phage, not the bacteria.