Molecular evidence for a close phylogenetic relationship among box-shaped halophilic bacteria, Halobacterium vallismortis, and Halobacterium marismortui

Abstract

The 5S rRNAs from Halobacterium vallismortis, Halobacterium marismortui (the Ginzburg strain), and two extremely halophilic isolates that exhibit an unusual "box-shaped" morphology were examined by ribonuclease T1 fingerprinting. The 5S rRNAs are found to be essentially identical and it is concluded that the four strains are in fact close phylogenetic relatives that should properly be assigned to a single genus. Comparison with previously available 5S rRNA sequence data from Halobacterium cutirubrum and Halococcus morrhuae indicates that the four strains examined here are quite distinct from both. It is further argued that this molecular evidence is not inconsistent with the previously proposed creation of a new genus, Haloarcula.