Global phylogeography of pelagic Polynucleobacter bacteria: Restricted geographic distribution of subgroups, isolation by distance and influence of climate

0448236 - BC 2016 RIV GB eng J - Článek v odborném periodiku
Hahn, M.W. - Koll, U. - Jezberová, Jitka - Camacho, A.
Global phylogeography of pelagic Polynucleobacter bacteria: Restricted geographic distribution of subgroups, isolation by distance and influence of climate.
Environmental Microbiology. Roč. 17, č. 3 (2015), s. 829-840. ISSN 1462-2912. E-ISSN 1462-2920
Grant CEP: GA ČR(CZ) GEEEF/10/E011
Institucionální podpora: RVO:60077344
Klíčová slova: polynucleobacter * phylogeography * microbiology * bacteria
Kód oboru RIV: EE - Mikrobiologie, virologie
Impakt faktor: 5.932, rok: 2015

The free-living planktonic freshwater bacterium Polynucleobacter necessarius subspecies asymbioticus (> 99% 16S rRNA similarity) represents a taxon with a cosmopolitan distribution and apparently ubiquitous occurrence in lentic freshwater habitats. We tested for intra-taxon biogeographic patterns by combining cultivation-independent and cultivation methods. A culture collection of 204 strains isolated from globally distributed freshwater habitats (Arctic to Antarctica) was investigated for phylogeographic patterns based on sequences of two markers, the 16S–23S internal transcribed spacers and the glutamine synthetase gene (glnA). Genetic distance between isolates showed significant geographic distance-decay patterns for both markers, suggesting that an isolation-by-distance mechanism influences the global phylogeography. Furthermore, a couple of subgroups showed restricted geographic distributions. Strains of one subgroup were exclusively obtained from tropical sites on four continents (pantropical subgroup). Cultivation-independent methods were used to confirm the restricted geographic distributions of two subgroups. The pantropical taxon could be detected in 63% of investigated tropical habitats but not in any of 121 European freshwater samples. Physiological tests indicated that almost all strains of the pantropical subgroup failed to grow at temperatures of 4°C, while strains affiliated with other subgroups showed good growth at this temperature. This suggests that thermal adaptation is involved in phylogeographic structuring of the global Polynucleobacter population.
Trvalý link: http://hdl.handle.net/11104/0249982