Polynucleobacter asymbioticus

Polynucleobacter asymbioticus is an aerobic, catalase- and oxidase-positive, chemo-organotrophic, nonmotile, free-living bacterium of the genus Polynucleobacter. The type strain was isolated from a small pond located in the Austrian Alps in the area of Salzburg^[2] and described as a new subspecies of Polynucleobacter necessarius in 2009.^[3] The classification of the type strain was hampered by the fact that its closest described relative represented obligate endosymbionts, i.e. P. necessarius, not available as a pure culture suitable for standard tests (DNA-DNA hybridization experiments) for delineation of prokaryotic species. Therefore, the strain was preliminarily placed in the subspecies P. necessarius subsp. asymbioticus. Later sequencing of the genome of the type strain^[4] revealed that the strain represented a novel species within the genus Polynucleobacter. Therefore, its taxonomic rank was lifted from the subspecies to the species level.^[5] Strains of P. asymbioticus dwell as planktonic organisms in acidic, humic-rich freshwater systems.^[6] Comparative genome analyses revealed that P. asymbioticus represents an atypical member of the family Burkholderiaceae regarding its small genome size and its passive lifestyle.^[7] A recent study used a collection of 37 P. asymbioticus strains isolated from various ponds located in a larger region of the Austrian Alps to gain insights in the evolution of Polynucleobacter bacteria.^[8]

Polynucleobacter asymbioticus
Scientific classification
Domain:	Bacteria
Phylum:	Pseudomonadota
Class:	Betaproteobacteria
Order:	Burkholderiales
Family:	Burkholderiaceae
Genus:	Polynucleobacter
Species:	P. asymbioticus
Binomial name
Polynucleobacter asymbioticus Hahn et al. 2016
Type strain
QLW-P1DMWA-1, DSM 18221, CIP 109841[1]
Synonyms
Polynucleobacter necessarius subsp. asymbioticus, Polynucleobacter sp. QLW-P1DMWA-1, strain QLW-P1DMWA-1