Achieving completeness of multipartite bacterial genomes has been a difficult task, especially in rhizobia. In this study, we performed a deep bioinformatic analysis of the newly re-sequenced genome of Rhizobium favelukesii LPU83T. This strain was isolated from acid soils in Argentina and is capable of nodulating several leguminous plants, although it is unable to fix nitrogen efficiently in any of them. Oxford Nanopore sequencing allowed us to completely assemble the symbiotic plasmid of the strain, pRfaLPU83b, and we discovered that it harbors three intact prophages and a high density of insertion sequences (ISs). These characteristics show why it is often so difficult to complete the symbiotic plasmids of rhizobial strains and the importance of having long-read sequencing methods. Upon detailed analysis of this replicon, we identified a complete conjugation system with gene structure consistent with quorum sensing-associated systems that may have contributed to the genetic mosaic structure of the strain. Furthermore, we identified in the symbiotic plasmid of R. favelukesii LPU83T a large proportion of the symbiotic genes previously identified as essential for Biological Nitrogen Fixation (BNF) in symbiosis with alfalfa, with a high percentage of identity with respect to those of Sinorhizobium meliloti 2011. Among the determinants related to BNF, we found genes encoding the HrrP and SapA peptidases in the LPU83 genome, previously described and related to the degradation of nodule-specific cysteine-rich peptides. These peptides are essential for bacteroid differentiation and, therefore, efficient BNF. Our results show that despite having these genes, they are not directly responsible for the inefficient BNF phenotype of LPU83.

Pseudomonas rhodesiae is a member of the Pseudomonas genus that is ecologically adaptable but has received little research. Despite its presence in clinical, environmental, agricultural, and aquaculture contexts, there is just a small amount of genomic information available for this species. We sequenced the genome of P. rhodesiae strain SK22, which was identified after a mortality outbreak in Dicentrarchus labrax (European seabass) farming in Turkey, and conducted a thorough comparison with 32 other publicly accessible P. rhodesiae genomes sourced from different environments. Whole-genome-based core genome phylogeny and Average Nucleotide Identity (ANI) identified two misclassified strains, 26B3 and CIP104664, that grouped with P. quebecensis (> 99

Upstream open reading frames (uORFs) in the 5' leader of bacterial mRNAs can modulate gene expression, yet genome-wide identification remains limited. We combined bioinformatic prediction of ribosome-binding sites (RBSs)-a Shine-Dalgarno sequence and a start codon-with experimental validation to uncover new uORFs in Sinorhizobium meliloti 2011. From totally 1106 predicted upstream RBSs (uRBSs), we first examined 15 candidates using eGFP reporters and integrating existing RNA-seq and Ribo-seq data. Translation was detected at 13 sites, with fluorescence intensity broadly correlating with predicted initiation rates. Two uRBSs correspond to gene start sites, thereby refining gene annotations. In nine cases, uRBS mutations affected downstream gene expression in reporter fusions. Among others, the data suggests that a Type I secretion system operon, the RNA chaperone gene hfq, and metabolic genes are regulated by uORFs. Four uORFs acted through translational coupling. We also identified uRBSs that were ribosome-occupied yet (nearly) silent in eGFP assays, and closely spaced to the downstream main RBS (mRBS). These uRBSs probably mediate ribosomal occlusion downregulating lacR and SM2011_RS36230. A re-screen of the prediction set revealed 335 close uRBS/mRBS pairs. Three of them were analyzed, supporting the proposed ribosomal occlusion mechanism for SM2011_RS03630 and SM2011_RS22110, while for glnK translational coupling to an uORF was suggested. These results indicate that uORFs are more widespread in bacteria than previously recognized and suggest that direct ribosomal occlusion of the mRBS is a novel mechanism for down-regulating protein synthesis.

Escherichia coli is widely used as an indicator of faecal contamination, as it is assumed that faeces from warm-blooded animals is the primary source of E. coli in the environment. However, various studies have shown that E. coli can survive and multiply in environmental niches, including soil, sand and sediment. E. coli can be assigned to eight main phylogroups but environmental E. coli are associated primarily with phylogroups A and B1. In this study, 410 E. coli were isolated from different niches within two peri-urban catchments in the Gauteng province of South Africa. To represent the E. coli circulating within the human population, E. coli was also isolated from sewage before treatment and released into these reservoirs. To capture the diversity of E. coli among these isolates, the β-D-glucuronidase (uidA) and mismatch repair (mutS) genes were sequenced. While isolates linked to phylogroup B1 dominated as was expected, the recovery of many isolates linked to phylogroup B2, the second most dominant group, was unanticipated. To further investigate this observation, the genomes of representative phylogroup B2 isolates were sequenced and subjected to phylogenetic and functional analyses. The results showed that phylogroup B2 isolates formed a distinct phylogenetic cluster, apparently independent of niche or geographic origin. Our findings also showed that while isolates seem to be associated with environmental samples, they could have the ability to colonize the gut and cause disease as they harboured several virulence factors associated with extraintestinal E. coli.

Introduction:Elizabethkingia miricola is a gram-negative bacterium that causes life-threatening infections in vulnerable populations. Unlike other species in the Elizabethkingia genus, E. miricola also leads to meningitis-like diseases in aquatic invertebrates such as frogs, raising concerns about its zoonotic transmission potential. Management of its infection is complicated by unclear transmission pathways and multi-drug resistance. Methods:In this study, we analyzed three clinical strains (E. miricola Mich-1, Mich-2, and Mich-3) isolated from patients in Michigan using morphology observations, biochemical tests, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF/MS), and genome sequencing. Results:Average Nucleotide Identity (ANI) analysis revealed that the Michigan strains were nearly identical and shared 96.52% identity with the type strain E. miricola DSM 14571, confirming their classification as E. miricola. Comprehensive comparative genomic analyses were conducted across 28 strains, including human isolates and strains from invertebrates like frogs. The strains exhibited open pan-genome characteristics. Mich-1 shared 3,199 genes (83.2%) with human isolates but fewer genes with frog-derived isolates (ranging from 3,319 to 3,375). This phylogenetic analysis highlights regional variation and the global diversity of E. miricola isolates, revealing connections between clinical and environmental strains. Antibiotic susceptibility testing revealed that the three clinical strains were resistant to 13 out of 16 tested drugs, with susceptibility only to trimethoprim/sulfamethoxazole and ciprofloxacin. The strains carried five β-lactamase-encoding genes (BlaB-10, BlaB-39, CME-1, CME-2, and GOB-25), conferring resistance to penams, cephalosporins, and carbapenems. Several virulence-associated genes were conserved across clinical and frog isolates. These genes contribute to stress adaptation, adherence, and immune modulation. Discussion:This study underscores the evolutionary adaptability of E. miricola genomes, highlighting their capacity to acquire genetic traits that enable survival in diverse niches. This adaptability facilitates the emergence of more resistant and virulent strains, posing significant threats to both human and animal health.

Calling structural variants (SVs), i.e., genomic alterations of ≥ 50bp, from whole genome short-read data remains challenging, as existing callers are known to lack accuracy and robustness. Therefore, meta-caller approaches combining the results of multiple standalone tools in a consensus set of reported SV calls, are widely used. Here, SV-MeCa (Structural Variant Meta-Caller) is presented, the first SV meta-caller incorporating variant-specific quality metrics from individual VCF outputs, rather than relying solely on number and combination of tools supporting consensus SV calls. In addition, SV-MeCa offers a suitable score to rank obtained consensus SV calls according to evidence of representing true positive calls, i.e., real-world variants. SV-MeCa applies seven standalone SV callers and merges resulting deletion and insertion calls into a union VCF file using SURVIVOR. For each entry in the SURVIVOR-generated consensus, caller-specific quality measures are extracted from corresponding standalone VCF files, and serve as input for an either deletion- or insertion-specific XGBoost decision tree classifier, which was previously trained on the HG002 SV benchmark data provided by the Genome in a Bottle consortium. The SV-MeCa XGBoost models assign a probability to (consensus) SV calls to represent true positive calls, which can be used for ranking the final output according to evidence. Performance of SV-MeCa and four previously published meta-caller approaches were evaluated based on autosomal SV calls in samples curated by the Human Genome Structural Variation Consortium, Phase 2. With regard to F _1 scores, which were 0.58 on average for deletions and 0.42 on average for insertions, SV-MeCa outperformed the other meta-callers. With regard to precision, only ConsensuSV achieved higher values (0.97 versus 0.64 on average for deletions, 0.75 versus 0.53 on average for insertions), and with regard to recall, SV-MeCa was outperformed exclusively by Meta-SV for deletions (0.55 versus 0.53). SV-MeCa, publicly available at https://github.com/ccfboc-bioinformatics/SV-MeCa , outperforms existing SV meta-caller approaches by taking variant-specific quality measures into account. Moreover, due to the XGBoost prediction probabilities serving as scores, the output of SV-MeCa can be continuously adjusted to user needs in terms of sensitivity and precision.

Sneathia vaginalis, a fastidious pathogen of the female reproductive tract, is implicated in obstetric and gynecologic pathologies, including spontaneous preterm birth and bacterial vaginosis. Here, we report the successful cultivation and genomic sequencing of three Sneathia vaginalis isolates collected via a vaginal swab from a patient with bacterial vaginosis.

By investigating wet and dry age-related ripening of beef, Pseudomonas strains V3/3/4/13T and V3/K/3/5T were isolated. Strain V3/3/4/13T exhibited more than 99 % 16S rRNA gene-based similarity to Pseudomonas fragi and other members of this group, while isolate V3/K/3/5T was very close to Pseudomonas veronii and a number of relatives within the Pseudomonas fluorescens group. Additional comparisons of complete rpoB sequences and draft genomes allowed us to place isolate V3/3/4/13T close to Pseudomonas deceptionensis DSM 26521T. In the case of V3/K/3/5T the closest relative was P. veronii DSM 11331T. Average nucleotide identity (ANIb) and digital DNA–DNA hybridization (dDDH) values calculated from the draft genomes of V3/3/4/13T and P. deceptionensis DSM 26521T were 88.5 and 39.8 %, respectively. For V3/K/3/5T and its closest relative P. veronii DSM 11331T, the ANIb value was 95.1 % and the dDDH value was 60.7 %. The DNA G+C contents of V3/3/4/13T and V3/K/3/5T were 57.4 and 60.8 mol%, respectively. Predominant fatty acids were C16 : 0, C18 : 1 ω7c, C17 : 0 cyclo and summed feature C16 : 1 ω7ct/C15 : 0 iso 2OH. The main respiratory quinones were Q9, with minor proportions of Q8 and, in the case of V3/K/3/5T, additional Q10. The main polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and, in the case of V3/K/3/5T, additional phosphatidylcholine. Based on the combined data, isolates V3/3/4/13T and V3/K/3/5T should be considered as representatives of two novel Pseudomonas species. The type strain of the newly proposed Pseudomonas kulmbachensis sp. nov. is V3/3/4/13T (=DSM 113654T=LMG 32520T), a second strain belonging to the same species is FLM 004-28 (=DSM 113604=LMG 32521); the type strain for the newly proposed Pseudomonas paraveronii sp. nov. is V3/K/3/5T (=DSM 113573T=LMG 32518T) with a second isolate FLM 11 (=DSM 113572=LMG 32519).

Coriariaceae are a small plant family of 14-17 species and subspecies that currently have a global but disjunct distribution. All species can form root nodules in symbiosis with diazotrophic Frankia cluster-2 strains, which form the earliest divergent symbiotic clade within this bacterial genus. Studies on Frankia cluster-2 mostly have focused on strains occurring in the northern hemisphere. Except for one strain from Papua New Guinea, namely Candidatus Frankia meridionalis Cppng1, no complete genome of Frankia associated with Coriaria occurring in the southern hemisphere has been published thus far, yet the majority of the Coriariaceae species occur here. We present field sampling data of novel Frankia cluster-2 strains, representing two novel species, which are associated with Coriaria arborea and Coriaria sarmentosa in New Zealand, and with Coriaria ruscifolia in Patagonia (Argentina), in addition to identifying Ca. F. meridionalis present in New Zealand. The novel Frankia species were found to be closely related to both Ca. F. meridionalis, and a Frankia species occurring in the Philippines, Taiwan, and Japan. Our data suggest that the different Frankia cluster-2 species diverged early after becoming symbiotic circa 100 million years ago.

Elizabethkingia anophelis MSU001, isolated from Anopheles stephensi in the laboratory, was characterized by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-ToF/MS), biochemical testing, and genome sequencing. Average nucleotide identity analysis revealed 99% identity with the type species E. anophelis R26. Phylogenetic placement showed that it formed a clade with other mosquito-associated strains and departed from a clade of clinical isolates. Comparative genome analyses further showed that it shared at least 98.6% of genes with mosquito-associated isolates (except E. anophelis As1), while it shared at most 88.8% of common genes with clinical isolates. Metabolites from MSU001 significantly inhibited growth of E. coli but not the mosquito gut symbionts Serratia marcescens and Asaia sp. W12. Insect-associated E. anophelis carried unique glycoside hydrolase (GH) and auxiliary activities (AAs) encoding genes distinct from those of clinical isolates, indicating their potential role in reshaping chitin structure and other components involved in larval development or formation of the peritrophic matrix. Like other Elizabethkingia, MSU001 also carried abundant genes encoding two-component system proteins (51), transcription factor proteins (188), and DNA-binding proteins (13). E. anophelis MSU001 contains a repertoire of antibiotic resistance genes and several virulence factors. Its potential for opportunistic infections in humans should be further evaluated prior to implementation as a paratransgenesis agent (by transgenesis of a symbiont of the vector).

Uptake hydrogenase (Hup) recycles H2 formed by nitrogenase during nitrogen fixation, thereby preserving energy. Among root nodule bacteria, most rhizobial strains examined are Hup-, while only one Hup- Frankia inoculum had been identified. Previous analyses had led to the identification of two different [NiFe] hydrogenase syntons. We analysed the distribution of different types of [NiFe] hydrogenase in the genomes of different Frankia species. Our results show that Frankia strains can contain four different [NiFe] hydrogenase syntons representing groups 1f, 1h, 2a, and 3b according to S & oslash;ndergaard, Pedersen, and Greening (HydDB: a web tool for hydrogenase classification and analysis. Sci Rep 2016;6:34212. https://doi.org/10.1038/srep34212.); no more than three types were found in any individual genome. The phylogeny of the structural proteins of groups 1f, 1h, and 2a follows Frankia phylogeny; the phylogeny of the accessory proteins does not consistently. An analysis of different [NiFe] hydrogenase types in Actinomycetia shows that under the most parsimonious assumption, all four types were present in the ancestral Frankia strain. Based on Hup activities analysed and the losses of syntons in different lineages of genome reduction, we can conclude that groups 1f and 2a are involved in recycling H2 formed by nitrogenase while group 1 h and group 3b are not. Different types of [NiFe] hydrogenases in the genus Frankia and their roles in nitrogen fixation deduced from losses in lineages of genome erosion.

Type IV pili (T4P) are versatile proteinaceous protrusions that mediate diverse bacterial processes, including adhesion, motility, and biofilm formation. Aeromonas hydrophila, a Gram-negative facultative anaerobe, causes disease in a wide range of hosts. Previously, we reported the presence of a unique Type IV class C pilus, known as tight adherence (Tad), in virulent Aeromonas hydrophila (vAh). In the present study, we sought to functionalize the role of Tad pili in the pathogenicity of A. hydrophila ML09-119. Through a comprehensive comparative genomics analysis of 170 A. hydrophila genomes, the conserved presence of the Tad operon in vAh isolates was confirmed, suggesting its potential contribution to pathogenicity. Herein, the entire Tad operon was knocked out from A. hydrophila ML09-119 to elucidate its specific role in A. hydrophila virulence. The absence of the Tad operon did not affect growth kinetics but significantly reduced virulence in catfish fingerlings, highlighting the essential role of the Tad operon during infection. Biofilm formation of A. hydrophila ML09-119 was significantly decreased in the Tad operon deletant. Absence of the Tad operon had no effect on sensitivity to other environmental stressors, including hydrogen peroxide, osmolarity, alkalinity, and temperature; however, it was more sensitive to low pH conditions. Scanning electron microscopy revealed that the Tad mutant had a rougher surface structure during log phase growth than the wildtype strain, indicating the absence of Tad impacts the outer surface of vAh during cell division, of which the biological consequences are unknown. These findings highlight the role of Tad in vAh pathogenesis and biofilm formation, signifying the importance of T4P in bacterial infections.

Lettuce is an economically major leafy vegetable that is affected by numerous diseases. One of the most devastating diseases of lettuce is white mold caused by Sclerotinia sclerotiorum. Control methods for this fungus are limited due to the development of genetic resistance to commonly used fungicides, the large number of hosts and the long-term survival of sclerotia in soil. To elaborate a new and more sustainable approach to contain this pathogen, 1,210 Pseudomonas strains previously isolated from agricultural soils in Canada were screened for their antagonistic activity against S. sclerotiorum. Nine Pseudomonas strains showed strong in vitro inhibition in dual-culture confrontational assays. Whole genome sequencing of these strains revealed their affiliation with four phylogenomic subgroups within the Pseudomonas fluorescens group, namely Pseudomonas corrugata, Pseudomonas asplenii, Pseudomonas mandelii, and Pseudomonas protegens. The antagonistic strains harbor several genes and gene clusters involved in the production of secondary metabolites, including mycin-type and peptin-type lipopeptides, and antibiotics such as brabantamide, which may be involved in the inhibitory activity observed against S. sclerotiorum. Three strains also demonstrated significant in planta biocontrol abilities against the pathogen when either inoculated on lettuce leaves or in the growing substrate of lettuce plants grown in pots. They however did not impact S. sclerotiorum populations in the rhizosphere, suggesting that they protect lettuce plants by altering the fitness and the virulence of the pathogen rather than by directly impeding its growth. These results mark a step forward in the development of biocontrol products against S. sclerotiorum.

BACKGROUND:Extreme weather events induced by climate change, particularly droughts, have detrimental consequences for crop yields and food security. Concurrently, these conditions provoke substantial changes in the soil bacterial microbiota and affect plant health. Early recognition of soil affected by drought enables farmers to implement appropriate agricultural management practices. In this context, interpretable machine learning holds immense potential for drought stress classification of soil based on marker taxa.RESULTS:This study demonstrates that the 16S rRNA-based metagenomic approach of Differential Abundance Analysis methods and machine learning-based Shapley Additive Explanation values provide similar information. They exhibit their potential as complementary approaches for identifying marker taxa and investigating their enrichment or depletion under drought stress in grass lineages. Additionally, the Random Forest Classifier trained on a diverse range of relative abundance data from the soil bacterial micobiome of various plant species achieves a high accuracy of 92.3 % at the genus rank for drought stress prediction. It demonstrates its generalization capacity for the lineages tested.CONCLUSIONS:In the detection of drought stress in soil bacterial microbiota, this study emphasizes the potential of an optimized and generalized location-based ML classifier. By identifying marker taxa, this approach holds promising implications for microbe-assisted plant breeding programs and contributes to the development of sustainable agriculture practices. These findings are crucial for preserving global food security in the face of climate change.

Potato common scab is an important bacterial disease afflicting potatoes around the world. Better knowledge of the local Streptomyces spp. populations causing this disease is key to developing durable control strategies. In this study, we isolated 230 Streptomyces strains from scab-infected potato tubers harvested from commercial potato fields located across the province of Quebec, Canada. The genetic diversity of this collection was first studied using repetitive element-based PCR fingerprinting, and the genomes of 36 representative strains were sequenced using PacBio's sequencing technology. This enabled us to identify the strains to the species level, to study the distribution of previously characterized virulence-associated genes and clusters, and to explore the repertoires of putative plant cell wall-degrading enzymes. In parallel, the virulence of the 36 strains was evaluated using a potato tuber slice assay. The diversity was higher than previously reported, as 11 phytopathogenic species were found across the province. Among them, S. scabiei and S. acidiscabies were the most abundant as well as the most virulent. Strains belonging to these two species harbored numerous virulence determinants, including the thaxtomin biosynthetic gene cluster. By contrast, most weakly virulent strains lacked this cluster but harbored at least one known virulence determinant. The results obtained suggest that a higher number of virulence-associated genes and clusters in the genome of phytopathogenic Streptomyces spp. are associated with greater virulence. This study contributes to increasing the publicly available genomic resources of scab-causing Streptomyces spp. and expands our knowledge on the diversity and virulence of this important bacterial pathogen.

Microbes – bacteria, archaea, unicellular eukaryotes, and viruses – play an important role in human and environmental health. Growing awareness of this fact has led to a huge increase in microbiological research and applications in a variety of fields. Driven by technological advances that allow high-throughput molecular characterization of microbial species and communities, microbiological research now offers unparalleled opportunities to address current and emerging needs. As well as helping to address global health threats such as antimicrobial resistance and viral pandemics, it also has a key role to play in areas such as agriculture, waste management, water treatment, ecosystems remediation, and the diagnosis, treatment and prevention of various diseases. Reflecting this broad potential, billions of euros have been invested in microbiota research programs worldwide. Though run independently, many of these projects are closely related. However, Germany currently has no infrastructure to connect such projects or even compare their results. Thus, the potential synergy of data and expertise is being squandered. The goal of the NFDI4Microbiota consortium is to serve and connect this broad and heterogeneous research community by elevating the availability and quality of research results through dedicated training, and by facilitating the generation, management, interpretation, sharing, and reuse of microbial data. In doing so, we will also foster interdisciplinary interactions between researchers. NFDI4Microbiota will achieve this by creating a German microbial research network through training and community-building activities, and by creating a cloud-based system that will make the storage, integration and analysis of microbial data, especially omics data, consistent, reproducible, and accessible across all areas of life sciences. In addition to increasing the quality of microbial research in Germany, our training program will support widespread and proper usage of these services. Through this dual emphasis on education and services, NFDI4Microbiota will ensure that microbial research in Germany is synergistic and efficient, and thus excellent. By creating a central resource for German microbial research, NDFDI4Microbiota will establish a connecting hub for all NFDI consortia that work with microbiological data, including GHGA, NFDI4Biodiversity, NFDI4Agri and several others. NFDI4Microbiota will provide non-microbial specialists from these consortia with direct and easy access to the necessary expertise and infrastructure in microbial research in order to facilitate their daily work and enhance their research. The links forged through NFDI4Microbiota will not only increase the synergy between NFDI consortia, but also elevate the overall quality and relevance of microbial research in Germany.

Elimination of chemically synthesized pesticides, such as fungicides and nematicides, in agricultural products is a key to successful practice of the Vietnamese agriculture. We describe here the route for developing successful biostimulants based on members of the Bacillus subtilis species complex. A number of endospore-forming Gram-positive bacterial strains with antagonistic action against plant pathogens were isolated from Vietnamese crop plants. Based on their draft genome sequence, thirty of them were assigned to the Bacillus subtilis species complex. Most of them were assigned to the species Bacillus velezensis. Whole genome sequencing of strains BT2.4 and BP1.2A corroborated their close relatedness to B. velezensis FZB42, the model strain for Gram-positive plant growth-promoting bacteria. Genome mining revealed that at least 15 natural product biosynthesis gene clusters (BGCs) are well conserved in all B. velezensis strains. In total, 36 different BGCs were identified in the genomes of the strains representing B. velezensis, B. subtilis, Bacillus tequilensis, and Bacillus. altitudinis. In vitro and in vivo assays demonstrated the potential of the B. velezensis strains to enhance plant growth and to suppress phytopathogenic fungi and nematodes. Due to their promising potential to stimulate plant growth and to support plant health, the B. velezensis strains TL7 and S1 were selected as starting material for the development of novel biostimulants, and biocontrol agents efficient in protecting the important Vietnamese crop plants black pepper and coffee against phytopathogens. The results of the large-scale field trials performed in the Central Highlands in Vietnam corroborated that TL7 and S1 are efficient in stimulating plant growth and protecting plant health in large-scale applications. It was shown that treatment with both bioformulations resulted in prevention of the pathogenic pressure exerted by nematodes, fungi, and oomycetes, and increased harvest yield in coffee, and pepper.

Abstract Background For a sustainable production of food, research on agricultural soil microbial communities is inevitable. Due to its immense complexity, soil is still some kind of black box. Soil study designs for identifying microbiome members of relevance have various scopes and focus on particular environmental factors. To identify common features of soil microbiomes, data from multiple studies should be compiled and processed. Taxonomic compositions and functional capabilities of microbial communities associated with soils and plants have been identified and characterized in the past few decades. From a fertile Loess–Chernozem-type soil located in Germany, metagenomically assembled genomes (MAGs) classified as members of the phylum Thaumarchaeota/Thermoproteota were obtained. These possibly represent keystone agricultural soil community members encoding functions of relevance for soil fertility and plant health. Their importance for the analyzed microbiomes is corroborated by the fact that they were predicted to contribute to the cycling of nitrogen, feature the genetic potential to fix carbon dioxide and possess genes with predicted functions in plant-growth-promotion (PGP). To expand the knowledge on soil community members belonging to the phylum Thaumarchaeota, we conducted a meta-analysis integrating primary studies on European agricultural soil microbiomes. Results Taxonomic classification of the selected soil metagenomes revealed the shared agricultural soil core microbiome of European soils from 19 locations. Metadata reporting was heterogeneous between the different studies. According to the available metadata, we separated the data into 68 treatments. The phylum Thaumarchaeota is part of the core microbiome and represents a major constituent of the archaeal subcommunities in all European agricultural soils. At a higher taxonomic resolution, 2074 genera constituted the core microbiome. We observed that viral genera strongly contribute to variation in taxonomic profiles. By binning of metagenomically assembled contigs, Thaumarchaeota MAGs could be recovered from several European soil metagenomes. Notably, many of them were classified as members of the family Nitrososphaeraceae, highlighting the importance of this family for agricultural soils. The specific Loess-Chernozem Thaumarchaeota MAGs were most abundant in their original soil, but also seem to be of importance in other agricultural soil microbial communities. Metabolic reconstruction of Switzerland_1_MAG_2 revealed its genetic potential i.a. regarding carbon dioxide (CO $$_2$$ 2 ) fixation, ammonia oxidation, exopolysaccharide production and a beneficial effect on plant growth. Similar genetic features were also present in other reconstructed MAGs. Three Nitrososphaeraceae MAGs are all most likely members of a so far unknown genus. Conclusions On a broad view, European agricultural soil microbiomes are similarly structured. Differences in community structure were observable, although analysis was complicated by heterogeneity in metadata recording. Our study highlights the need for standardized metadata reporting and the benefits of networking open data. Future soil sequencing studies should also consider high sequencing depths in order to enable reconstruction of genome bins. Intriguingly, the family Nitrososphaeraceae commonly seems to be of importance in agricultural microbiomes.

We have previously reported the draft genome sequences of 59 endospore-forming Gram-positive bacterial strains isolated from Vietnamese crop plants due to their ability to suppress plant pathogens. Based on their draft genome sequence, eleven of them were assigned to the Brevibacillus and one to the Lysinibacillus genus. Further analysis including full genome sequencing revealed that several of these strains represent novel genomospecies. In vitro and in vivo assays demonstrated their ability to promote plant growth, as well as the strong biocontrol potential of Brevibacilli directed against phytopathogenic bacteria, fungi, and nematodes. Genome mining identified 157 natural product biosynthesis gene clusters (BGCs), including 36 novel BGCs not present in the MIBiG data bank. Our findings indicate that plant-associated Brevibacilli are a rich source of putative antimicrobial compounds and might serve as a valuable starting point for the development of novel biocontrol agents.