RESUMO
Members of the marine genus Rhodopirellula are attached living bacteria and studies based on cultured Rhodopirellula strains suggested that three closely related species R. baltica, 'R. europaea' and 'R. islandica' have a limited geographic distribution in Europe. To address this hypothesis, we developed a nested PCR for a single gene copy detection of a partial acetyl CoA synthetase (acsA) from intertidal sediments collected all around Europe. Furthermore, we performed growth experiments in a range of temperature, salinity and light conditions. A combination of Basic Local Alignment Search Tool (BLAST) and Minimum Entropy Decomposition (MED) was used to analyze the sequences with the aim to explore the geographical distribution of the species and subspecies. MED has been mainly used for the analysis of the 16S rRNA gene and here we propose a protocol for the analysis of protein-coding genes taking into account the degeneracy of the codons and a possible overestimation of functional diversity. The high-resolution analysis revealed differences in the intraspecies community structure in different geographic regions. However, we found all three species present in all regions sampled and in agreement with growth experiments we demonstrated that Rhodopirellula species do not have a limited geographic distribution in Europe.
Assuntos
Variação Genética , Genoma Bacteriano/genética , Sedimentos Geológicos/microbiologia , Planctomycetales/classificação , Proteínas de Bactérias/genética , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Europa (Continente) , Geografia , Sequenciamento de Nucleotídeos em Larga Escala , Planctomycetales/genética , Planctomycetales/isolamento & purificação , Reação em Cadeia da Polimerase , Análise de Sequência de DNARESUMO
The planctomycete strain K833 was isolated from cold waters at the coast of Island and is tentatively named 'Rhodopirellula islandica'. It has a lower temperature range for growth than other genome-sequenced Rhodopirellula strains affiliating to Rhodopirellula baltica and 'Rhodopirellula europaea'. The permanent draft genome of strain K833 was obtained as part of a larger study on the biogeography of Rhodopirellula species in European marine waters. The genome consists of 55 contigs with a genome size of 7,433,200 bp. With an average nucleotide identity of 81% to related genomes of R. baltica and 'R. europaea' and more than 4000 common genes, it will be a valuable source for the study of temperature adaptation of planctomycete genomes.
Assuntos
Genoma Bacteriano , Planctomycetales/genética , DNA Bacteriano/genética , Planctomycetales/ultraestrutura , RNA Bacteriano/genética , TemperaturaRESUMO
Rhodopirellula is an abundant marine member of the bacterial phylum Planctomycetes. Cultivation studies revealed the presence of several closely related Rhodopirellula species in European coastal sediments. Because the 16S rRNA gene does not provide the desired taxonomic resolution to differentiate Rhodopirellula species, we performed a comparison of the genomes of nine Rhodopirellula strains and six related planctomycetes and identified carB, coding for the large subunit of carbamoylphosphate synthetase, as a suitable molecular marker. In this study, we investigated the diversity of Rhodopirellula in coastal intertidal surface sediments of Sylt island, North Sea, using the 16S rRNA and carB genes as molecular markers. The carB clone and pyrosequencing libraries revealed the presence of 12 species of Rhodopirellula and of 66 species in closely related undescribed genera, a diversity that was not detected with a 16S rRNA gene library. This study demonstrates that the carB gene is a powerful molecular marker for detecting Rhodopirellula species in the environment and may be used for the taxonomic evaluation of new strains.
