Paludisphaera borealis gen. nov., sp. nov., a hydrolytic planctomycete from northern wetlands, and proposal of Isosphaeraceae fam. nov.

Abstract

Paludisphaera borealis gen. nov., sp. nov., a hydrolytic planctomycete from northern wetlands, and proposal of Isosphaeraceae fam. nov. Two isolates of aerobic, budding, pink-pigmented bacteria, designated strains PX4 T and PT1, were isolated from a boreal Sphagnum peat bog and a forested tundra wetland. Cells of these strains were non-motile spheres that occurred singly or in short chains. Novel isolates were capable of growth at pH values between 3.5 and 6.5 (optimum at pH 5.0-5.5) and at temperatures between 6 and 30 8C (optimum at 15-25 8C). Most sugars and a number of polysaccharides including pectin, xylan, lichenin and Phytagel were used as growth substrates. The major fatty acids were C 16 : 0 , C 18 : 1 v9 and C 18 : 0 ; the major polar lipids were phosphocholine and trimethylornithine. The quinone was menaquinone-6, and the G+C content of the DNA was 66 mol%. Strains PX4 T and PT1 were members of the order Planctomycetales and displayed 93-94 % 16S rRNA gene sequence similarity to Aquisphaera giovannonii, 91-92 % to species of the genus Singulisphaera and 90-91 % to Isosphaera pallida. The two novel strains, however, differed from members of these genera by cell morphology, substrate utilization pattern and a number of physiological characteristics. Based on these data, the novel isolates should be considered as representing a novel genus and species of planctomycetes, for which the name Paludisphaera borealis gen. nov., sp. nov., is proposed. The type strain is PX4 T (5DSM 28747 T 5VKM B-2904 T ). We also suggest the establishment of a novel family, Isosphaeraceae fam. nov., to accommodate stalk-free planctomycetes with spherical cells, which can be assembled in short chains, long filaments or shapeless aggregates. This family includes the genera Isosphaera, Aquisphaera, Singulisphaera and Paludisphaera.

High Diversity of Planctomycetes in Soils of Two Lichen-Dominated Sub-Arctic Ecosystems of Northwestern Siberia

“…These isolates were represented by large (2–3 μm) spherical, non-motile cells that multiplied by budding and occurred singly or were arranged in aggregates ( Figure 7A ). 16S rRNA gene sequences from strains P12 and P515 were identical and affiliated with the family Isosphaeraceae (Kulichevskaya et al, 2016). They displayed 93–94% sequence similarity to 16S rRNA gene sequences from members of the genus Singulisphaera , 91–92% sequence similarity to members of the genera Paludisphaera , and 89% sequence similarity to Isosphaera pallida ( Figure 6 ).…”

“…The predominant planctomycete populations in northern wetlands are represented by members of the phylogenetic group defined by the genera Isosphaera and Singulisphaera (Ivanova and Dedysh, 2012; Serkebaeva et al, 2013; Moore et al, 2015). This group was recently given the status of a separate family, i.e., the family Isosphaeraceae (Kulichevskaya et al, 2016). Several taxonomically characterized representatives of this family from northern peatlands, such as Singulisphaera acidiphila , Singulisphaera rosea , and Paludisphaera borealis , are psychrotolerant bacteria that are capable of growth at low temperatures, down to 4–6°C (Kulichevskaya et al, 2008, 2012a, 2016).…”

“…This group was recently given the status of a separate family, i.e., the family Isosphaeraceae (Kulichevskaya et al, 2016). Several taxonomically characterized representatives of this family from northern peatlands, such as Singulisphaera acidiphila , Singulisphaera rosea , and Paludisphaera borealis , are psychrotolerant bacteria that are capable of growth at low temperatures, down to 4–6°C (Kulichevskaya et al, 2008, 2012a, 2016). Most currently described peat-inhabiting planctomycetes have the ability to degrade various heteropolysaccharides and appear to be involved in degradation of Sphagnum -derived litter (Kulichevskaya et al, 2007; Moore et al, 2015).…”

Diversity of sediment‐associated Planctomycetes in the Arabian Sea oxygen minimum zone

“…The class Planctomycetacia is more deeply branched with two orders such as Planctomycetales and Candidatus Brocadiales. The order Planctomycetales include the family Planctomycetaceae, which is further branched into twenty‐one genera ( Planctomyces, Blastopirellula , Gemmata, Isosphaera , Pirellula , Rhodopirellula , Schlesneria , Singulisphaera , Aquisphaera , Telmatocola , Zavarzinella , Bythopirellula , Candidatus Anamomoximicrobium , Gimesia , Paludisphaera , Planctopirus , Roseimaritima , Rubripirellula , Rubinispahera , Thermogutta , and Thermostilla ) . The Candidatus Brocadiales includes family candidatus Brocadiaceae, which is further delineated into five candidate genera such as Brocadia , Kuenenia , Scalindua , Jettenia , and Anammoxoglobus .…”

Tuwongella immobilis gen. nov., sp. nov., a novel non-motile bacterium within the phylum Planctomycetes

“…The family Planctomycetaceae is formed by the described genera Blastopirellula , Gemmata , Gimesia , Pirellul a , Planctomicrobium , Planctopirus , Rhodopirellula , Rubinisphaera , Schlesneria , Telmatocola , Thermogutta and Zavarzinella [ 3–11 ]. Previously included in the family were the genera of Isosphaera , Singulisphaera , Aquisphaera and Paludisphaera , but these genera have recently been re-classified under the family Isosphaeraceae [ 12 ]. Here, we describe an isolate from a freshwater lake that is closely related to members of the genera Gemmata , Telmatocola and Zavarzinella but has a number of distinctive molecular and phenotypic features that distinguish it from the respective type strains G. obscuriglobus , T. sphagniphila and Z. formosa .…”