Description of the novel planctomycetal genus Bremerella, containing Bremerella volcania sp. nov., isolated from an active volcanic site, and reclassification of Blastopirellula cremea as Bremerella cremea comb. nov

Stratiformator vulcanicus gen. nov., sp. nov., a marine member of the family Planctomycetaceae isolated from a red biofilm in the Tyrrhenian Sea close to the volcanic island Panarea

A novel planctomycetal strain, designated Pan189T, was isolated from biofilm material sampled close to Panarea Island in the Tyrrhenian Sea. Cells of strain Pan189T are round grain rice-shaped, form pink colonies and display typical planctomycetal characteristics including asymmetric cell division through polar budding and presence of crateriform structures. Cells bear a stalk opposite to the division pole and fimbriae cover the cell surface. Strain Pan189T has a mesophilic (optimum at 24 °C) and neutrophilic (optimum at pH 7.5) growth profile, is aerobic and heterotrophic. Under laboratory-scale cultivation conditions, it reached a generation time of 102 h (µmax = 0.0068 h-1), which places the strain among the slowest growing members of the phylum Planctomycetota characterized so far. The genome size of the strain is with 5.23 Mb at the lower limit among the family Planctomycetaceae (5.1-8.9 Mb). Phylogenetically, the strain represents a novel genus and species in the family Planctomycetaceae, order Planctomycetales, class Planctomycetia. We propose the name Stratiformator vulcanicus gen. nov., sp. nov. for the novel taxon, that is represented by the type strain Pan189T (= DSM 101711 T = CECT 30699 T).

Spatio-temporal variation of the microbial community of the coast of Lebanon in response to petroleum hydrocarbon pollution

In this study, the coast of Lebanon was analyzed for the dynamic changes in sediment microbial communities in response to a major petroleum oil spill and tar contamination that occurred in the summer of 2021. Spatio-temporal variations in the microbial structure along the shores of Lebanon were assessed in comparison to baseline microbial structure determined in 2017. Microbial community structure and diversity were determined using Illumina MiSeq technology and DADA2 pipeline. The results show a significant diversity of microbial populations along the Lebanese shore, and a significant change in the sediment microbial structure within four years. Namely, Woeseia, Blastopirellula, and Muriicola were identified in sediment samples collected in year 2017, while a higher microbial diversity was observed in 2021 with Woeseia, Halogranum, Bacillus, and Vibrio prevailing in beach sediments. In addition, the results demonstrate a significant correlation between certain hydrocarbon degraders, such as Marinobacter and Vibrio, and measured hydrocarbon concentrations.

Blastopirellula sediminis sp. nov. a new member of Pirellulaceae isolated from the Andaman and Nicobar Islands

Two cream-coloured strains (JC732^T, JC733) of Gram-stain negative, mesophilic, catalase and oxidase positive, aerobic bacteria which divide by budding, form crateriform structures, and cell aggregates were isolated from marine habitats of Andaman and Nicobar Islands, India. Both strains had genome size of 7.1 Mb and G + C content of 58.9%. Both strains showed highest 16S rRNA gene-based similarity with Blastopirellula retiformator Enr8^T (98.7%). Strains JC732^T and JC733 shared 100% identity of 16S rRNA gene and genome sequences. The coherence of both strains with the genus Blastopirellula was supported by the 16S rRNA gene based and the phylogenomic trees. Further, the chemo-taxonomic characters and the genome relatedness indices [ANI (82.4%), AAI (80.4%) and dDDH (25.2%)] also support the delineation at the species level. Both strains have the capability to degrade chitin and genome analysis shows the ability to fix N₂. Based on the phylogenetic, phylogenomic, comparative genomic, morphological, physiological, and biochemical characteristics, strain JC732^T is described as a new species of the genus Blastopirellula for which the name Blastopirellula sediminis sp. nov. is proposed, with strain JC733 as an additional strain.

An Update on Novel Taxa and Revised Taxonomic Status of Bacteria (Including Members of the Phylum Planctomycetota) Isolated from Aquatic Host Species Described in 2018 to 2021

Increased interest in farmed aquatic species, aquatic conservation measures, and microbial metabolic end-product utilization have translated into a need for awareness and recognition of novel microbial species and revisions to bacterial taxonomy. Because this need has largely been unmet, through a 4-year literature review, we present lists of novel and revised bacterial species (including members of the phylum Planctomycetota) derived from aquatic hosts that can serve as a baseline for future biennial summaries of taxonomic revisions in this field. Most new and revised taxa were noted within oxidase-positive and/or nonglucose fermentative Gram-negative bacilli, including members of the Tenacibaculum, Flavobacterium, and Vibrio genera. Valid and effectively published novel members of the Streptococcus, Erysipelothrix, and Photobacterium genera are additionally described from disease pathogenesis perspectives.

The Planctomycetia: an overview of the currently largest class within the phylum Planctomycetes

The phylum Planctomycetes comprises bacteria with uncommon features among prokaryotes, such as cell division by budding, absence of the bacterial tubulin-homolog cell division protein FtsZ and complex cell plans with invaginations of the cytoplasmic membrane. Although planctomycetes are ubiquitous, the number of described species and isolated strains available as axenic cultures is still low compared to the diversity observed in metagenomes or environmental studies. An increasing interest in planctomycetes is reflected by the recent description of a large number of new species and their increasing accessibility in terms of pure cultures. In this review, data from all taxonomically described species belonging to Planctomycetia, the class with the currently highest number of characterized members within the phylum Planctomycetes, is summarized. Phylogeny, morphology, physiology, ecology and genomic traits of its members are discussed. This comprehensive overview will help to acknowledge several aspects of the biology of these fascinating bacteria.

Aquisphaera insulae sp. nov., a new member in the family Isosphaeraceae, isolated from the floating island of Loktak lake and emended description of the genus Aquisphaera

Strain JC669^T was isolated from a floating island of Loktak lake, Manipur, India and shares the highest 16S rRNA gene sequence identity with Aquisphaera giovannonii OJF2^T. The novel strain is aerobic, Gram negative, light pink-coloured, non-motile, NaCl intolerant and spherical to oval-shaped. It grows in the form of single cells or aggregates and possibly forms structures which appear like fruiting bodies. Strain JC669^T grows well up to pH 9.0.The isolate produces MK-6 as respiratory quinone, C_18:1ω9c, C_16:0 and C_18:0 as major fatty acids and phosphatidylcholine, an unidentified amino lipid, an unidentified choline lipid (UCL) and six additional unidentified lipids (UL1, 2, 3, 4, 5, 6) as polar lipids. Strain JC669^T has a large genome size of 10.04 Mb and the genomic G + C content was 68.5 mol%. The genome contained all genes essential for lycopene related carotenoid biosynthesis. The polyphasic analysis of its phylogenetic position, morphological, physiological and genomic features supports the classification of strain JC669^T as a novel species of the genus Aquisphaera, for which we propose the name Aquisphaera insulae sp. nov. Strain JC669^T (= KCTC 72672^T = NBRC 114306^T) is the type strain of the novel species.

Analysis of Bacterial Communities on North Sea Macroalgae and Characterization of the Isolated Planctomycetes Adhaeretor mobilis gen. nov., sp. nov., Roseimaritima multifibrata sp. nov., Rosistilla ulvae sp. nov. and Rubripirellula lacrimiformis sp. nov

Planctomycetes are bacteria that were long thought to be unculturable, of low abundance, and therefore neglectable in the environment. This view changed in recent years, after it was shown that members of the phylum Planctomycetes can be abundant in many aquatic environments, e.g., in the epiphytic communities on macroalgae surfaces. Here, we analyzed three different macroalgae from the North Sea and show that Planctomycetes is the most abundant bacterial phylum on the alga Fucus sp., while it represents a minor fraction of the surface-associated bacterial community of Ulva sp. and Laminaria sp. Especially dominant within the phylum Planctomycetes were Blastopirellula sp., followed by Rhodopirellula sp., Rubripirellula sp., as well as other Pirellulaceae and Lacipirellulaceae, but also members of the OM190 lineage. Motivated by the observed abundance, we isolated four novel planctomycetal strains to expand the collection of species available as axenic cultures since access to different strains is a prerequisite to investigate the success of planctomycetes in marine environments. The isolated strains constitute four novel species belonging to one novel and three previously described genera in the order Pirellulales, class Planctomycetia, phylum Planctomycetes.

Bacterial evolutionary precursors of eukaryotic copper-zinc superoxide dismutases

Internalization of a bacteria by an archaeal cell expedited eukaryotic evolution. An important feature of the species that diversified into the great variety of eukaryotic life visible today was the ability to combat oxidative stress with a copper–zinc superoxide dismutase (CuZnSOD) enzyme activated by a specific, high-affinity copper chaperone. Adoption of a single protein interface that facilitates homodimerization and heterodimerization was essential; however, its evolution has been difficult to rationalize given the structural differences between bacterial and eukaryotic enzymes. In contrast, no consistent strategy for the maturation of periplasmic bacterial CuZnSODs has emerged. Here, 34 CuZnSODs are described that closely resemble the eukaryotic form but originate predominantly from aquatic bacteria. Crystal structures of a Bacteroidetes bacterium CuZnSOD portray both prokaryotic and eukaryotic characteristics and propose a mechanism for self-catalyzed disulfide maturation. Unification of a bacterial but eukaryotic-like CuZnSOD along with a ferredoxin-fold MXCXXC copper-binding domain within a single polypeptide created the advanced copper delivery system for CuZnSODs exemplified by the human copper chaperone for superoxide dismutase-1. The development of this system facilitated evolution of large and compartmentalized cells following endosymbiotic eukaryogenesis.

Bremerella alba sp. nov., a novel planctomycete isolated from the surface of the macroalga Fucus spiralis

A bacterial strain, designated FF15T, was isolated from the thallus surface of the macroalga Fucus spiralis sampled on a rocky beach in Porto, Portugal. Based on the 16S rRNA gene sequence, strain FF15T was affiliated to the phylum Planctomycetes. This strain forms white colonies on modified M13 medium and the cells are pear-shaped, can form rosettes, divide by polar budding and are motile. The novel isolate is mesophilic and neutrophilic with an optimum growth temperature of about 30 °C and an optimum pH for growth between 6.5 and 7.5. It showed growth over a broad range of salinities (0-9% NaCl - optimum at 1.5%). No additional vitamins are required for growth. It is cytochrome c oxidase and catalase positive. The major respiratory quinone was menaquinone 6 (MK-6). Genome sequencing revealed a genome size of 6.37 Mbp and a DNA G + C content of 54.2%. Analysis of phylogenetic markers, including similarities of the 16S rRNA gene sequence, rpoB gene sequence, as well as Percentage of Conserved Proteins (POCP), Average Nucleotide Identity (ANI) and Average Amino Acid Identity (AAI), suggest the affiliation of strain FF15T to "Bremerella", a recently described genus in the family Pirellulaceae. Based on the genotypic, phylogenetic, chemotaxonomic, physiological and biochemical characterization, we described a new species represented by strain FF15T (=CECT 8078T = LMG 31936T), for which we propose the name Bremerella alba snov.

"Candidatus Laterigemmans baculatus" gen. nov. sp. nov., the first representative of rod shaped planctomycetes with lateral budding in the family Pirellulaceae

Two axenic cultures of Planctomycetes were isolated from distinct geographical regions of the east coast of India. The two closely related strains (JC640 and CH01) showed <93.3% 16S rRNA gene sequence identity with members of the genus Roseimaritima followed by Rhodopirellula (<91%). Both strains displayed non-canonical cell morphology of Planctomycetes, such as rod shaped cells with division by lateral budding. Both strains showed crateriform structures on their surfaces and cells lack fimbriae. The genomes have a size of about 5.76 Mb and DNA G+C content of 63.6mol%. Phylogenetic analysis based on 16S rRNA gene sequence and 92 core genes based RAxML phylogenetic tree place both the strains in the family Pirellulaceae and indicated Roseimaritima sediminicola as their closest relative. The AAI and POCP values differentiate both strains from rest of the members of the family Pirellulaceae. The axenic cultures of both strains were able to grow up to 8-10 passages and subsequently the cells became non-viable with pleomorphic shapes. Supported by genomic, phylogenetic and morphological differences, we conclude that both strains belong to a novel genus. However, since the new isolates lost their viability on passaging, we propose the novel genus as "Candidatus Laterigemmans" gen. nov. and the novel species as "Candidatus Laterigemmans baculatus" sp. nov.

Analysis of bacterial communities in a municipal duck pond during a phytoplankton bloom and isolation of Anatilimnocola aggregata gen. nov., sp. nov., Lacipirellula limnantheis sp. nov. and Urbifossiella limnaea gen. nov., sp. nov. belonging to the phylum Planctomycetes

Waterbodies such as lakes and ponds are fragile environments affected by human influences. Suitable conditions can result in massive growth of phototrophs, commonly referred to as phytoplankton blooms. Such events benefit heterotrophic bacteria able to use compounds secreted by phototrophs or their biomass as major nutrient source. One example of such bacteria are Planctomycetes, which are abundant on the surfaces of marine macroscopic phototrophs; however, less data are available on their ecological roles in limnic environments. In this study, we followed a cultivation-independent deep sequencing approach to study the bacterial community composition during a cyanobacterial bloom event in a municipal duck pond. In addition to cyanobacteria, which caused the bloom event, members of the phylum Planctomycetes were significantly enriched in the cyanobacteria-attached fraction compared to the free-living fraction. Separate datasets based on isolated DNA and RNA point towards considerable differences in the abundance and activity of planctomycetal families, indicating different activity peaks of these families during the cyanobacterial bloom. Motivated by the finding that the sampling location harbours untapped bacterial diversity, we included a complementary cultivation-dependent approach and isolated and characterized three novel limnic strains belonging to the phylum Planctomycetes.

Rosistilla oblonga gen. nov., sp. nov. and Rosistilla carotiformis sp. nov., isolated from biotic or abiotic surfaces in Northern Germany, Mallorca, Spain and California, USA

Planctomycetes are ubiquitous bacteria with fascinating cell biological features. Strains available as axenic cultures in most cases have been isolated from aquatic environments and serve as a basis to study planctomycetal cell biology and interactions in further detail. As a contribution to the current collection of axenic cultures, here we characterise three closely related strains, Poly24T, CA51T and Mal33, which were isolated from the Baltic Sea, the Pacific Ocean and the Mediterranean Sea, respectively. The strains display cell biological features typical for related Planctomycetes, such as division by polar budding, presence of crateriform structures and formation of rosettes. Optimal growth was observed at temperatures of 30-33 °C and at pH 7.5, which led to maximal growth rates of 0.065-0.079 h-1, corresponding to generation times of 9-11 h. The genomes of the novel isolates have a size of 7.3-7.5 Mb and a G + C content of 57.7-58.2%. Phylogenetic analyses place the strains in the family Pirellulaceae and suggest that Roseimaritima ulvae and Roseimaritima sediminicola are the current closest relatives. Analysis of five different phylogenetic markers, however, supports the delineation of the strains from members of the genus Roseimaritima and other characterised genera in the family. Supported by morphological and physiological differences, we conclude that the strains belong to the novel genus Rosistilla gen. nov. and constitute two novel species, for which we propose the names Rosistilla carotiformis sp. nov. and Rosistilla oblonga sp. nov. (the type species). The two novel species are represented by the type strains Poly24T (= DSM 102938T = VKM B-3434T = LMG 31347T = CECT 9848T) and CA51T (= DSM 104080T = LMG 29702T), respectively.

Description of Polystyrenella longa gen. nov., sp. nov., isolated from polystyrene particles incubated in the Baltic Sea

Planctomycetes occur in almost all aquatic ecosystems on earth. They have a remarkable cell biology, and members of the orders Planctomycetales and Pirellulales feature cell division by polar budding, perform a lifestyle switch from sessile to motile cells and have an enlarged periplasmic space. Here, we characterise a novel planctomycetal strain, Pla110T, isolated from the surface of polystyrene particles incubated in the Baltic Sea. After phylogenetic analysis, the strain could be placed in the family Planctomycetaceae. Strain Pla110T performs cell division by budding, has crateriform structures and grows in aggregates or rosettes. The strain is a chemoheterotroph, grows under mesophilic and neutrophilic conditions, and exhibited a doubling time of 21 h. Based on our phylogenetic and morphological characterisation, strain Pla110T (DSM 103387T = LMG 29693T) is concluded to represent a novel species belonging to a novel genus, for which we propose the name Polystyrenella longa gen. nov., sp. nov.

Updates to the recently introduced family Lacipirellulaceae in the phylum Planctomycetes: isolation of strains belonging to the novel genera Aeoliella, Botrimarina, Pirellulimonas and Pseudobythopirellula and the novel species Bythopirellula polymerisocia and Posidoniimonas corsicana

Eight novel strains of the phylum Planctomycetes were isolated from different aquatic habitats. Among these habitats were the hydrothermal vent system close to Panarea Island, a public beach at Mallorca Island, the shore of Costa Brava (Spain), and three sites with brackish water in the Baltic Sea. The genome sizes of the novel strains range from 4.33 to 6.29 Mb with DNA G+C contents between 52.8 and 66.7%. All strains are mesophilic (Topt 24-30 °C) and display generation times between 17 and 94 h. All eight isolates constitute novel species of either already described or novel genera within the family Lacipirellulaceae. Two of the novel species, Posidoniimonas polymericola (type strain Pla123aT = DSM 103020T = LMG 29466T) and Bythopirellula polymerisocia (type strain Pla144T = DSM 104841T = VKM B-3442T), belong to established genera, while the other strains represent the novel genera Aeoliella gen. nov., Botrimarina gen. nov., Pirellulimonas gen. nov. and Pseudobythopirellula gen. nov. Based on our polyphasic analysis, we propose the species Aeoliella mucimassa sp. nov. (type strain Pan181T = DSM 29370T = LMG 31346T = CECT 9840T = VKM B-3426T), Botrimarina colliarenosi sp. nov. (type strain Pla108T = DSM 103355T = LMG 29803T), Botrimarina hoheduenensis sp. nov. (type strain Pla111T = DSM 103485T = STH00945T, Jena Microbial Resource Collection JMRC), Botrimarina mediterranea sp. nov. (type strain Spa11T = DSM 100745T = LMG 31350T = CECT 9852T = VKM B-3431T), Pirellulimonas nuda sp. nov. (type strain Pla175T = DSM 109594T = CECT 9871T = VKM B-3448T) and Pseudobythopirellula maris sp. nov. (type strain Mal64T = DSM 100832T = LMG 29020T).

Lignipirellula cremea gen. nov., sp. nov., a planctomycete isolated from wood particles in a brackish river estuary

A novel planctomycetal strain, designated Pla85_3_4T, was isolated from the surface of wood incubated at the discharge of a wastewater treatment plant in the Warnow river near Rostock, Germany. Cells of the novel strain have a cell envelope architecture resembling that of Gram-negative bacteria, are round to pear-shaped (length: 2.2 ± 0.4 µm, width: 1.2 ± 0.3 µm), form aggregates and divide by polar budding. Colonies have a cream colour. Strain Pla85_3_4T grows at ranges of 10-30 °C (optimum 26 °C) and at pH 6.5-10.0 (optimum 7.5), and has a doubling time of 26 h. Phylogenetically, strain Pla85_3_4T (DSM 103796T = LMG 29741T) is concluded to represent a novel species of a novel genus within the family Pirellulaceae, for which we propose the name Lignipirellula cremea gen. nov., sp. nov.

Tautonia plasticadhaerens sp. nov., a novel species in the family Isosphaeraceae isolated from an alga in a hydrothermal area of the Eolian Archipelago

A novel planctomycetal strain, designated ElPT, was isolated from an alga in the shallow hydrothermal vent system close to Panarea Island in the Tyrrhenian Sea. Cells of strain ElPT are spherical, form pink colonies and display typical planctomycetal characteristics including division by budding and presence of crateriform structures. Strain ElPT has a mesophilic (optimum at 30 °C) and neutrophilic (optimum at pH 7.5) growth profile, is aerobic and heterotrophic. It reaches a generation time of 29 h (µmax = 0.024 h-1). The strain has a genome size of 9.40 Mb with a G + C content of 71.1% and harbours five plasmids, the highest number observed in the phylum Planctomycetes thus far. Phylogenetically, the strain represents a novel species of the recently described genus Tautonia in the family Isosphaeraceae. A characteristic feature of the strain is its tendency to attach strongly to a range of plastic surfaces. We thus propose the name Tautonia plasticadhaerens sp. nov. for the novel species, represented by the type strain ElPT (DSM 101012T = LMG 29141T).

Planctomycetes as Host-Associated Bacteria: A Perspective That Holds Promise for Their Future Isolations, by Mimicking Their Native Environmental Niches in Clinical Microbiology Laboratories

Traditionally recognized as environmental bacteria, Planctomycetes have just been linked recently to human pathology as opportunistic pathogens, arousing a great interest for clinical microbiologists. However, the lack of appropriate culture media limits our future investigations as no Planctomycetes have ever been isolated from patients' specimens despite several attempts. Several Planctomycetes have no cultivable members and are only recognized by 16S rRNA gene sequence detection and analysis. The cultured representatives are slow-growing fastidious bacteria and mostly difficult to culture on synthetic media. Accordingly, the provision of environmental and nutritional conditions like those existing in the natural habitat where yet uncultured/refractory bacteria can be detected might be an option for their potential isolation. Hence, we systematically reviewed the various natural habitats of Planctomycetes, to review their nutritional requirements, the physicochemical characteristics of their natural ecological niches, current methods of cultivation of the Planctomycetes and gaps, from a perspective of collecting data in order to optimize conditions and the protocols of cultivation of these fastidious bacteria. Planctomycetes are widespread in freshwater, seawater, and terrestrial environments, essentially associated to particles or organisms like macroalgae, marine sponges, and lichens, depending on the species and metabolizable polysaccharides by their sulfatases. Most Planctomycetes grow in nutrient-poor oligotrophic environments with pH ranging from 3.4 to 11, but a few strains can also grow in quite nutrient rich media like M600/M14. Also, a seasonality variation of abundance is observed, and bloom occurs in summer-early autumn, correlating with the strong growth of algae in the marine environments. Most Planctomycetes are mesophilic, but with a few Planctomycetes being thermophilic (50°C to 60°C). Commonly added nutrients are N-acetyl-glucosamine, yeast-extracts, peptone, and some oligo and macro-elements. A biphasic host-associated extract (macroalgae, sponge extract) conjugated with a diluted basal medium should provide favorable results for the success of isolation in pure culture.

Stieleria varia sp. nov., isolated from wood particles in the Baltic Sea, constitutes a novel species in the family Pirellulaceae within the phylum Planctomycetes

Species belonging to the bacterial phylum Planctomycetes are ubiquitous members of the microbial communities in aquatic environments and are frequently isolated from various biotic and abiotic surfaces in marine and limnic water bodies. Planctomycetes have large genomes of up to 12.4 Mb, follow complex lifestyles and display an uncommon cell biology; features which motivate the investigation of members of this phylum in greater detail. As a contribution to the current collection of axenic cultures of Planctomycetes, we here describe strain Pla52^T isolated from wood particles in the Baltic Sea. Phylogenetic analysis places the strain in the family Pirellulaceae and suggests two species of the recently described genus Stieleria as current closest neighbours. Strain Pla52n^T shows typical features of members of the class Planctomycetia, including division by polar budding and the presence of crateriform structures. Colonies of strain Pla52n^T have a light orange colour, which is an unusual pigmentation compared to the majority of members in the phylum, which show either a pink to red pigmentation or entirely lack pigmentation. Optimal growth of strain Pla52n^T at 33 °C and pH 7.5 indicates a mesophilic (i.e. with optimal growth between 20 and 45 °C) and neutrophilic growth profile. The strain is an aerobic heterotroph with motile daughter cells. Its genome has a size of 9.6 Mb and a G + C content of 56.0%. Polyphasic analyses justify delineation of the strain from described species within the genus Stieleria. Therefore, we conclude that strain Pla52n^T = LMG 29463^T = VKM B-3447^T should be classified as the type strain of a novel species, for which we propose the name Stieleria varia sp. nov.

Unambiguous identification of fungi: where do we stand and how accurate and precise is fungal DNA barcoding?

True fungi (Fungi) and fungus-like organisms (e.g. Mycetozoa, Oomycota) constitute the second largest group of organisms based on global richness estimates, with around 3 million predicted species. Compared to plants and animals, fungi have simple body plans with often morphologically and ecologically obscure structures. This poses challenges for accurate and precise identifications. Here we provide a conceptual framework for the identification of fungi, encouraging the approach of integrative (polyphasic) taxonomy for species delimitation, i.e. the combination of genealogy (phylogeny), phenotype (including autecology), and reproductive biology (when feasible). This allows objective evaluation of diagnostic characters, either phenotypic or molecular or both. Verification of identifications is crucial but often neglected. Because of clade-specific evolutionary histories, there is currently no single tool for the identification of fungi, although DNA barcoding using the internal transcribed spacer (ITS) remains a first diagnosis, particularly in metabarcoding studies. Secondary DNA barcodes are increasingly implemented for groups where ITS does not provide sufficient precision. Issues of pairwise sequence similarity-based identifications and OTU clustering are discussed, and multiple sequence alignment-based phylogenetic approaches with subsequent verification are recommended as more accurate alternatives. In metabarcoding approaches, the trade-off between speed and accuracy and precision of molecular identifications must be carefully considered. Intragenomic variation of the ITS and other barcoding markers should be properly documented, as phylotype diversity is not necessarily a proxy of species richness. Important strategies to improve molecular identification of fungi are: (1) broadly document intraspecific and intragenomic variation of barcoding markers; (2) substantially expand sequence repositories, focusing on undersampled clades and missing taxa; (3) improve curation of sequence labels in primary repositories and substantially increase the number of sequences based on verified material; (4) link sequence data to digital information of voucher specimens including imagery. In parallel, technological improvements to genome sequencing offer promising alternatives to DNA barcoding in the future. Despite the prevalence of DNA-based fungal taxonomy, phenotype-based approaches remain an important strategy to catalog the global diversity of fungi and establish initial species hypotheses.

Caulifigura coniformis gen. nov., sp. nov., a novel member of the family Planctomycetaceae isolated from a red biofilm sampled in a hydrothermal area

Pan44^T, a novel strain belonging to the phylum Planctomycetes, was isolated from a red biofilm in a hydrothermal area close to the island Panarea in the Tyrrhenian Sea north of Sicily, Italy. The strain forms white colonies on solid medium and displays the following characteristics: cell division by budding, formation of rosettes, presence of matrix or fimbriae and long stalks. The cell surface has an interesting and characteristic texture made up of triangles and rectangles, which leads to a pine cone-like morphology of the strain. Strain Pan44^T is mesophilic (temperature optimum 26 °C), slightly alkaliphilic (pH optimum 8.0), aerobic and heterotrophic. The strain has a genome size of 6.76 Mb with a G + C content of 63.2%. Phylogenetically, the strain is a member of the family Planctomycetaceae, order Planctomycetales, class Planctomycetia. Our analysis supports delineation of strain Pan44^T from all known genera in this family, hence, we propose to assign it to a novel species within a novel genus, for which we propose the name Caulifigura coniformis gen. nov., sp. nov., represented by Pan44^T (DSM 29405^T = LMG 29788^T) as the type strain.

Calycomorphotria hydatis gen. nov., sp. nov., a novel species in the family Planctomycetaceae with conspicuous subcellular structures

A novel strain belonging to the family Planctomycetaceae, designated V22^T, was isolated from sediment of a seawater fish tank in Braunschweig, Germany. The isolate forms pink colonies on solid medium and displays common characteristics of planctomycetal strains, such as division by budding, formation of rosettes, a condensed nucleoid and presence of crateriform structures and fimbriae. Unusual invaginations of the cytoplasmic membrane and filamentous putative cytoskeletal elements were observed in thin sections analysed by transmission electron microscopy. Strain V22^T is an aerobic heterotroph showing optimal growth at 30 °C and pH 8.5. During laboratory cultivations, strain V22^T reached generation times of 10 h (maximal growth rate of 0.069 h^-1). Its genome has a size of 5.2 Mb and a G + C content of 54.9%. Phylogenetically, the strain represents a novel genus and species in the family Planctomycetaceae, order Planctomycetales, class Planctomycetia. We propose the name Calycomorphotria hydatis gen. nov., sp. nov. for the novel taxon, represented by the type strain V22^T (DSM 29767^T = LMG 29080^T).

Aureliella helgolandensis gen. nov., sp. nov., a novel Planctomycete isolated from a jellyfish at the shore of the island Helgoland

A novel planctomycetal strain, designated Q31a^T, was isolated from a jellyfish at the shore of the island Helgoland in the North Sea. The strain forms lucid white colonies on solid medium and displays typical characteristics of planctomycetal strains, such as division by budding, formation of rosettes, presence of crateriform structures, extracellular matrix or fibre and a holdfast structure. Q31a^T is mesophilic (temperature optimum 27 °C), neutrophilic (pH optimum 7.5), aerobic and heterotrophic. A maximal growth rate of 0.017 h^- 1 (generation time of 41 h) was observed. Q31a^T has a genome size of 8.44 Mb and a G + C content of 55.3%. Phylogenetically, the strain represents a novel genus and species in the recently introduced family Pirellulaceae, order Pirellulales, class Planctomycetia. We propose the name Aureliella helgolandensis gen. nov., sp. nov. for the novel species, represented by Q31a^T (= DSM 103537^T = LMG 29700^T) as the type strain.

Blastopirellula retiformator sp. nov. isolated from the shallow-sea hydrothermal vent system close to Panarea Island

Aquatic bacteria belonging to the deep-branching phylum Planctomycetes play a major role in global carbon and nitrogen cycles. However, their uncommon morphology and physiology, and their roles and survival on biotic surfaces in marine environments, are only partially understood. Access to axenic cultures of different planctomycetal genera is key to study their complex lifestyles, uncommon cell biology and primary and secondary metabolism in more detail. Here, we describe the characterisation of strain Enr8^T isolated from a marine biotic surface in the seawater close to the shallow-sea hydrothermal vent system off Panarea Island, an area with high temperature and pH gradients, and high availability of different sulphur and nitrogen sources resulting in a great microbial diversity. Strain Enr8^T showed typical planctomycetal traits such as division by polar budding, aggregate formation and presence of fimbriae and crateriform structures. Growth was observed at ranges of 15-33 °C (optimum 30 °C), pH 6.0-8.0 (optimum 7.0) and at NaCl concentrations from 100 to 1200 mM (optimum 350-700 mM). Strain Enr8^T forms white colonies on solid medium and white flakes in liquid culture. Its genome has a size of 6.20 Mb and a G + C content of 59.2%. Phylogenetically, the strain belongs to the genus Blastopirellula. We propose the name Blastopirellula retiformator sp. nov. for the novel species, represented by the type strain Enr8^T (DSM 100415^T = LMG 29081^T).