 The AS and SM groups represent the third group of cyanophages classified based on host range.This group of viruses is said to be the “new blue-green algae” and infects unicellular forms of cyanobacteria.The myovirus AS-1 infects "Anacystis nidulans", "Synechococcus cedrorum", "Synechococcus elongatus" and "Microcystis aeruginosa".