International Journal of Systematic and Evolutionary Microbiology

In Australia, Stylosanthes little leaf (StLL) phytoplasma has been detected in Stylosanthes scabra Vogel, Arachis pintoi Krapov, Saccharum officinarum L., Carica papaya L., Medicago sativa L., and Solanum tuberosum L. The 16S rRNA gene sequence of StLL phytoplasma strains from S. scabra, C. papaya, S. officinarum and S. tuberosum were compared and share 99.93–100 % nucleotide sequence identity. Phylogenetic comparisons between the 16S rRNA genes of StLL phytoplasma and other ‘Candidatus Phytoplasma’ species indicate that StLL represents a distinct phytoplasma lineage. It shares its most recent known ancestry with ‘Ca. Phytoplasma luffae’ (16SrVIII-A), with which it has 97.17–97.25 % nucleotide identity. In silico RFLP analysis of the 16S rRNA amplicon using iPhyClassifier indicate that StLL phytoplasmas have a unique pattern (similarity coefficient below 0.85) that is most similar to that of ‘Ca. Phytoplasma luffae’. The unique in silico RFLP patterns were confirmed in vitro. Nucleotide sequences of genes that are more variable than the 16S rRNA gene, namely tuf (tu-elongation factor), secA (partial translocation gene), and the partial ribosomal protein (rp) gene operon (rps19-rpl22-rps3), produced phylogenetic trees with similar branching patterns to the 16S rRNA gene tree. Sequence comparisons between the StLL 16S rRNA spacer region confirmed previous reports of rrn interoperon sequence heterogeneity for StLL, where the spacer region of rrnB encodes a complete tRNA-Isoleucine gene and the rrnA spacer region does not. Together these results suggest that the Australian phytoplasma, StLL, is unique according to the International Organization for Mycoplasmology (IRPCM) recommendations. The novel taxon ‘Ca. Phytoplasma stylosanthis’ is proposed, with the most recent strain from a potato crop in Victoria, Australia, serving as the reference strain (deposited in the Victorian Plant Pathology Herbarium as VPRI 43683).

Phytoplasmas have been associated with a disease that affects trees of at least 11 species from different botanic families in Bogotá, Colombia. ‘Candidatus Phytoplasma asteris’ and ‘Candidatus Phytoplasma fraxini’ are the major groups of phytoplasma in the area of Bogotá. In this study, the genetic diversity within ‘Ca. P. asteris’ and ‘Ca. P. fraxini’ was studied in five urban tree species: Croton species (Euphorbiaceae), Fraxinus uhdei (Oleaceae), Magnolia grandiflora (Magnoliaceae), Populus nigra (Salicaceae) and Quercus humboldtii (Fagaceae). Analyses of the 16S rRNA gene using nested PCR, RFLP and sequencing showed that phytoplasmas of ‘Ca. P. asteris’ could be assigned to: subgroup 16SrI-B; a new subgroup named 16SrI-AF, with a restriction pattern similar to that of 16SrI-B; and a new subgroup named 16SrI-AG, with a restriction pattern similar to that of 16SrI-K and 16SrI-AH with a restriction pattern similar to that of 16SrI-AC. ‘Ca. P. fraxini’ isolates belonged to a new subgroup named 16SrVII-G, with a restriction pattern similar to that of 16SrVII-A. To complement the identification of the phytoplasma strains, we amplified nonribosomal genes such as leuS and secA. Unexpectedly, it was observed that in 16 trees in which 16S rRNA gene analysis showed the presence of ‘Ca. P. fraxini’ only, the leuS or secA primers amplified sequences exclusively affiliated to ‘Ca. P. asteris. In those plants, sequences belonging to ‘Ca. P. fraxini’ leuS or secA genes were not amplified. The present work contributes to the identification of novel strains of both species in Colombia, and supports previous suggestions that phytoplasmas in South America are highly variable.

To clarify the evolutionary relationships and classification of Bacillus species, comprehensive phylogenomic and comparative analyses were performed on >300 Bacillus/Bacillaceae genomes. Multiple genomic-scale phylogenetic trees were initially reconstructed to identify different monophyletic clades of Bacillus species. In parallel, detailed analyses were performed on protein sequences of genomes to identify conserved signature indels (CSIs) that are specific for each of the identified clades. We show that in different reconstructed trees, most of the Bacillus species, in addition to the Subtilis and Cereus clades, consistently formed 17 novel distinct clades. Additionally, some Bacillus species reliably grouped with the genera Alkalicoccus, Caldalkalibacillus, Caldibacillus, Salibacterium and Salisediminibacterium . The distinctness of identified Bacillus species clades is independently strongly supported by 128 identified CSIs which are unique characteristics of these clades, providing reliable means for their demarcation. Based on the strong phylogenetic and molecular evidence, we are proposing that these 17 Bacillus species clades should be recognized as novel genera, with the names Alteribacter gen. nov., Ectobacillus gen. nov., Evansella gen. nov., Ferdinandcohnia gen. nov., Gottfriedia gen. nov., Heyndrickxia gen. nov., Lederbergia gen. nov., Litchfieldia gen. nov., Margalitia gen. nov., Niallia gen. nov., Priestia gen. nov., Robertmurraya gen. nov., Rossellomorea gen. nov., Schinkia gen. nov., Siminovitchia gen. nov., Sutcliffiella gen. nov. and Weizmannia gen. nov. We also propose to transfer ‘ Bacillus kyonggiensi s’ to Robertmurraya kyonggiensis sp. nov. (type strain: NB22=JCM 17569T=DSM 26768). Additionally, we report 31 CSIs that are unique characteristics of either the members of the Subtilis clade (containing the type species B. subtilis ) or the Cereus clade (containing B. anthracis and B. cereus ). As most Bacillus species which are not part of these two clades can now be assigned to other genera, we are proposing an emended description of the genus Bacillus to restrict it to only the members of the Subtilis and Cereus clades.

The classDeltaproteobacteriacomprises an ecologically and metabolically diverse group of bacteria best known for dissimilatory sulphate reduction and predatory behaviour. Although this lineage is the fourth described class of the phylumProteobacteria, it rarely affiliates with other proteobacterial classes and is frequently not recovered as a monophyletic unit in phylogenetic analyses. Indeed, one branch of the classDeltaproteobacteriaencompassingBdellovibrio-like predators was recently reclassified into a separate proteobacterial class, theOligoflexia. Here we systematically explore the phylogeny of taxa currently assigned to these classes using 120 conserved single-copy marker genes as well as rRNA genes. The overwhelming majority of markers reject the inclusion of the classesDeltaproteobacteriaandOligoflexiain the phylumProteobacteria. Instead, the great majority of currently recognized members of the classDeltaproteobacteriaare better classified into four novel phylum-level lineages. We propose the namesDesulfobacterotaphyl. nov. andMyxococcotaphyl. nov. for two of these phyla, based on the oldest validly published names in each lineage, and retain the placeholder name SAR324 for the third phylum pending formal description of type material. Members of the classOligoflexiarepresent a separate phylum for which we propose the nameBdellovibrionotaphyl. nov. based on priority in the literature and general recognition of the genusBdellovibrio. Desulfobacterotaphyl. nov. includes the taxa previously classified in the phylumThermodesulfobacteria, and these reclassifications imply that the ability of sulphate reduction was vertically inherited in theThermodesulfobacteriarather than laterally acquired as previously inferred. Our analysis also indicates the independent acquisition of predatory behaviour in the phylaMyxococcotaandBdellovibrionota, which is consistent with their distinct modes of action. This work represents a stable reclassification of one of the most taxonomically challenging areas of the bacterial tree and provides a robust framework for future ecological and systematic studies.

A novel Gram-stain-negative, non-endospore-forming, motile, and aerobic bacterial strain, M105T, was isolated from coral Porites lutea, and was subjected to a polyphasic taxonomic study. Global alignment based on 16S rRNA gene sequences indicated that M105T shares the highest sequence identity of 94.5 % with Aliikangiella marina GYP-15T. The average nucleotide identity (ANI) and average amino acid identity (AAI) between M105T and A. marina GYP-15T was 69.8 and 71.6 %, respectively. On the basis of the results of phenotypic, chemotaxonomic, phylogenetic, phylogenomic, and comparative genomic analyses, it is concluded that M105T should represent a novel species in the genus Aliikangiella , for which the name Aliikangiella coralliicola sp. nov. is proposed. The type strain is M105T (=MCCC 1K03773T= KCTC 72442T). Furthermore, the family Kangiellaceae was classified into two families on the basis of phylogenetic, phylogenomic, polar lipid profile and motility variations. The novel family Pleioneaceae fam. nov. is proposed to accommodate the genera Aliikangiella and Pleionea .

The List of Prokaryotic names with Standing in Nomenclature (LPSN) was acquired in November 2019 by the DSMZ and was relaunched using an entirely new production system in February 2020. This article describes in detail the structure of the new site, navigation, page layout, search facilities and new features.

The members of the genusFrankiaare, with a few exceptions, a group of nitrogen-fixing symbiotic actinobacteria that nodulate mostly woody dicotyledonous plants belonging to three orders, eight families and 23 genera of pioneer dicots. These bacteria have been characterized phylogenetically and grouped into four molecular clusters. One of the clusters, cluster 1 contains strains that induce nodules onAlnusspp. (Betulaceae),Myricaspp.,Morellaspp. andComptoniaspp. (Myricaceae) that have global distributions. Some of these strains produce not only hyphae and vesicles, as other cluster 1 strains do, but also numerous sporangia in their host symbiotic tissues, hence their phenotype being described as spore-positive (Sp+). While Sp+ strains have resisted repeated attempts at cultivation, their genomes have recently been characterized and found to be different from those of all described species, being markedly smaller than their phylogenetic neighbours. We thus hereby propose to create a 'CandidatusFrankia alpina' species for some strains present in nodules ofAlnus alnobetulaandA. incanathat grow in alpine environments at high altitudes or in subarctic environments at high latitudes.

We here present annotated lists of names ofCandidatustaxa of prokaryotes with ranks between subspecies and class, proposed between the mid-1990s, when the provisional status ofCandidatustaxa was first established, and the end of 2018. Where necessary, corrected names are proposed that comply with the current provisions of the International Code of Nomenclature of Prokaryotes and its Orthography appendix. These lists, as well as updated lists of newly published names ofCandidatustaxa with additions and corrections to the current lists to be published periodically in theInternational Journal of Systematic and Evolutionary Microbiology, may serve as the basis for the valid publication of theCandidatusnames if and when the current proposals to expand the type material for naming of prokaryotes to also include gene sequences of yet-uncultivated taxa is accepted by the International Committee on Systematics of Prokaryotes.

A novel endophytic actinobacterium, designated strain EGI 650086T, was isolated from the roots of Anabasis elatior (C.A.Mey.) Schischk. collected in Xinjiang, north-west China. The taxonomic position of the strain was investigated using a polyphasic taxonomic approach. Growth occurred at 15–40 °C, pH 6.0–8.0 and in the presence of 0–6 % NaCl (w/v). Phylogenetic analysis based on 16S rRNA gene sequence and concatenation of 22 protein marker genes revealed that strain EGI 650086T formed a monophyletic clade within the genus Amycolatopsis and shared the highest sequence similarities with Amycolatopsis nigrescens JCM 14717T (97.1 %) and Amycolatopsis sacchari DSM 44468T (97.0 %). Sequence similarities with type strains of other species of the genus Amycolatopsis were less than 97.0 %. The average nucleotide identity and DNA–DNA hybridization values between strain EGI 650086T and the reference strains were 78.1–79.8 % and 22.1–23.0 %, respectively. The genome of strain EGI 650086T was 10.9 Mb, with a DNA G+C content of 70.1 mol%. The diagnostic diamino acid in the peptidoglycan was meso-diaminopimelic acid. The major whole-cell sugars contained arabinose, galactose, glucose and ribose. The predominant menaquinones were MK-9 (H4) and MK-9 (H2). Major fatty acids were iso-C16 : 0 and summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B). The polar lipid profile of strain EGI 650086T included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides, two unknown phospholipids, an unknown glycolipid and an unknown lipid. Polyphasic taxonomic characteristics indicated that strain EGI 650086T represents a novel species of the genus Amycolatopsis , for which the name Amycolatopsis anabasis sp. nov. is proposed. The type strain is EGI 650086T (=KCTC 49044T=CGMCC 4.7188T).