Summary
The anaerobic, mesophilic and moderately halophilic strain L21‐Spi‐D4
T
was recently isolated from the suboxic zone of a hypersaline cyanobacterial mat using protein‐rich extracts of
Arthrospira
(formerly
Spirulina
)
platensis
as substrate. Phylogenetic analyses based on 16S rRNA genes indicated an affiliation of the novel strain with the
Bacteroidetes
clade MgMjR‐022, which is widely distributed and abundant in hypersaline microbial mats and heretofore comprised only sequences of uncultured bacteria. Analyses of the complete genome sequence of strain L21‐Spi‐D4
T
revealed a possible specialization on the degradation of cyanobacterial biomass. Besides genes for enzymes degrading specific cyanobacterial proteins a conspicuous transport complex for the polypeptide cyanophycin could be identified that is homologous to typical polysaccharide utilization loci of
Bacteroidetes
. A distinct and reproducible co‐occurrence pattern of environmental 16S rRNA gene sequences of the MgMjR‐022 clade and cyanobacteria in the suboxic zone of hypersaline mats points to a specific dependence of members of this clade on decaying cyanobacteria. Based on a comparative analysis of phenotypic, genomic and ecological characteristics we propose to establish the novel taxa
Salinivirga cyanobacteriivorans
gen. nov., sp. nov., represented by the type strain L21‐Spi‐D4
T
, and
Salinivirgaceae
fam. nov., comprising sequences of the MgMjR‐022 clade.