Congruent phylogenies of most common small-subunit rRNA and dissimilatory sulfite reductase gene sequences retrieved from estuarine sediments

he diversity of sulfate-reducing bacteria (SRB) in brackish sediment was in vestigated using small-subunit rRNA and dissimilatory; sulfite reductase (D SR) gene clone libraries and cultivation, The phylogenetic affiliation of t he most commonly retrieved clones for both genes was strikingly similar and produced Desulfosarcina variabilis-like sequences from the inoculum but De sulfomicrobium baculatum-like sequences from a high dilution in natural med ia. Related organisms were subsequently cultivated from the site. PCR bias appear to be limited (or very similar) for the two primersets and target ge nes. However, the DSR primers showed a much higher phylogenetic specificity . DSR gene analysis is thus a promising and specific approach for investiga ting SRB diversity in complex habitats.