A small predatory core genome in the divergent marine Bacteriovorax marinus SJ and the terrestrial Bdellovibrio bacteriovorus

Abstract

Bacteriovorax marinus SJ is a predatory delta-proteobacterium isolated from a marine environment. The genome sequence of this strain provides an interesting contrast to that of the terrestrial predatory bacterium Bdellovibrio bacteriovorus HD100. Based on their predatory lifestyle, Bacteriovorax were originally designated as members of the genus Bdellovibrio but subsequently were re-assigned to a new genus and family based on genetic and phenotypic differences. B. marinus attaches to Gram-negative bacteria, penetrates through the cell wall to form a bdelloplast, in which it replicates, as shown using microscopy. Bacteriovorax is distinct, as it shares only 30% of its gene products with its closest sequenced relatives. Remarkably, 34% of predicted genes over 500 nt in length were completely unique with no significant matches in the databases. As expected, Bacteriovorax shares several characteristic loci with the other delta-proteobacteria. A geneset shared between Bacteriovorax and Bdellovibrio that is not conserved among other delta-proteobacteria such as Myxobacteria (which destroy prey bacteria externally via lysis), or the non-predatory Desulfo-bacteria and Geobacter species was identified. These 291 gene orthologues common to both Bacteriovorax and Bdellovibrio may be the key indicators of host-interaction predatory-specific processes required for prey entry. The locus from Bdellovibrio bacteriovorus is implicated in the switch from predatory to prey/host-independent growth. Although the locus is conserved in B. marinus, the sequence has only limited similarity. The results of this study advance understanding of both the similarities and differences between Bdellovibrio and Bacteriovorax and confirm the distant relationship between the two and their separation into different families.

Microbial Surface Colonization and Biofilm Development in Marine Environments

“…BALOs have evolved host interaction predatory-specific genomic islands (687). As surface-associated microbiota have much higher densities than free-living communities, BALOs are more abundant on surfaces, exploiting a rich resource of prey microorganisms in marine environments (688,689).…”

Phylogenetic Diversity of NTT Nucleotide Transport Proteins in Free-Living and Parasitic Bacteria and Eukaryotes

“…2, supplementary fig. S1, Supplementary Material online), a predatory intracellular bacterial pathogen which infects other Gram-negative bacteria (Crossman et al. 2013).…”

In and out: an analysis of epibiotic vs periplasmic bacterial predators

“…Circular chromosomes were assembled, and no extra-chromosomal elements were detected. These two genomes were compared to the genomes of the periplasmic predators Bacteriovorax marinus SJ (Crossman et al, 2013), B. bacteriovorus HD100 (Rendulic et al, 2004) and of the epibiotic predator M. aeruginosavorus ARL13 (Wang et al, 2011). A detailed view of the various genomic elements is given in Table 1 and Supplementary Table S2.…”

“…A detailed metabolic annotation was performed on both the B. exovorus JSS and M. aeruginovorus EPB genomes (Table 1; Supplementary Table S2), showing that like other BALOs (Rendulic et al, 2004, Crossman et al, 2013 they possess full gene pathways for glycolysis and for the tricarboxylic acid cycle. Fatty acid elongation and the phosphogluconate pathway appear to be limited in B. exovorus JSS, but the full gene content is found in M. aeruginosavorus EPB.…”