Figure 2: A dual role of SOS in biofilm development. For non-lysogns, cell attachment induces SOS that increases biofilm formation. For lysogens, the attachment-activated SOS and inability of CRISPR to the subsequent expression of phage-related genes lead to prophage induction and cell lysis. The lysogens are also reinfected by superinfection variants. Eventually, DNA is released to enhance biofilm formation of the nonlysogens.