Microorganisms

BackgroundStreptococcus pneumoniae is a nasopharynx coloniser that can invade sterile tissues, causing Invasive Pneumococcal Disease (IPD). Dolosigranulum pigrum and Corynebacterium pseudodiphtheriticum are commensal bacteria commonly isolated from the nasopharynx of healthy children, potentially playing a protective role. This study aims to analyse the effects of D. pigrum and C. pseudodiphtheriticum on S. pneumoniae in vitro growth. MethodsPneumococcal strains were collected from IPD patients and healthy carriers in Catalonia (2016-2023). D. pigrum and C. pseudodiphtheriticum strains were isolated from a healthy childs nasopharynx. S. pneumoniae was co-cultured with each commensal bacterium in triplicate experiments. Pneumococcal growth was quantified using a real-time PCR assay targeting the lytA gene. The effect of commensal bacteria on pneumococcal growth was evaluated using a linear mixed-effect regression model. ResultsTwenty-eight pneumococcal strains expressing 24 different serotypes and 26 clonal types were analysed (18 isolated in blood and 10 in nasopharyngeal aspirate). Pneumococcal growth was decreased by D. pigrum ({beta} = -0.763, 95% CI: -0.94 to -0.59, p < 0.0001) and C. pseudodiphtheriticum ({beta} = -0.583, 95% CI: -0.76 to -0.41, p < 0.0001). The combined presence of both had a stronger inhibitory effect ({beta} = -0.971, 95% CI: -1.15 to -0.79, p < 0.0001). No association was found between isolation site or serotype with pneumococcal growth. ConclusionD. pigrum and C. pseudodiphtheriticum significantly reduced pneumococcal growth, with a synergic effect when combined. This antagonistic effect supports the potential protective factor of healthy nasopharyngeal microbiota against IPD and the development of these microorganisms as probiotics.

IntroductionFusarium species are devastating wheat pathogens. Plant growth-promoting rhizobacteria (PGPR) offer an effective biocontrol alternative. This study investigated the capacity of a Bacillus and Paenibacillus consortium to induce systemic resistance in winter wheat. MethodsWinter wheat plants were treated with a ten-strain PGPR consortium, with or without Fusarium oxysporum and F. graminearum. Expression of five PR-gene families was quantified in roots and shoots at 7 and 14 days post-treatment via RT-qPCR. Morphometric parameters were tracked for 28 days. ResultsThe consortium elicited a potent defense response. In roots at 7 days, PR-1 and PR-6 expression surged 16-fold and 38-fold, respectively. Defense activation in shoots was delayed, peaking at 14 days. After 28 days, PGPR-treated plants exhibited an 8% increase in shoot length. DiscussionThe results confirm that the bacterial strains effectively prime the wheat immune system, modulating early defense pathways and enhancing plant growth.

The microbiota of the respiratory tract remains a relatively poorly studied subject. At the same time, like the intestinal microbiota, it is involved in modulating the immune response to infectious agents in the host organism. A causal relationship between the composition of the respiratory microbiota and the likelihood of development and the severity of COVID-19 may be hypothesized. We analyze biomaterial from nasopharyngeal smears from 336 patients with a confirmed diagnosis of COVID-19, selected during the first and second waves of the epidemic in Russia. Sequences from a similar study conducted in Spain were also included in the analysis. We investigated associations between disease severity and microbiota at the level of microbial community (community types) and individual microbes (differentially represented species). To search for associations, we performed multivariate analysis, taking into account comorbidities, type of community and lineage of the virus. We found that two out of six community types are associated with a more severe course of the disease, and one of the community types is characterized by high stability (very similar microbiota profiles in different patients) and low level of lung damage. Differential abundance analysis with respect to comorbidities and community type suggested association of Rothia and Streptococcus genera representatives with more severe lung damage, and Leptotrichia, unclassified Lachnospiraceae and Prevotella with milder forms of the disease.

Three novel bioluminescent bacterial strains, VNB-15T, VNB-16 and SChm4, were isolated from water of the Black Sea (Russia) and intestines of the Black Sea horse mackerel. Cells of the isolated strains are motile Gram negative slightly curved rods with single polar flagellum. The temperature range for growth was 10-35{degrees}C, the optimum being 20-25{degrees}C. The pH range for growth was 6.0-9.0, the optimum being 7.0-8.0. The bacteria were able to grow in the presence of 0.5 to 5.0% NaCl (w/v), the optimum being 1.0-4.0% (w/v). Phylogenetic analysis based on comparison of 16S rRNA sequences shows these strains to have kinship with the species Vibrio jasicida, Vibrio hyugaensis, Vibrio alginolyticus, Vibrio campbelli, Vibrio rotiferianus, Vibrio harveyi and Vibrio owensii with sequence similarity from 99.6 to 98.0%. Phylogenetic analysis based on comparison of the sequences of genes gyrB, recA, pyrH, gapA, rpoA, mreB, ftsZ, topA shows that the strains VNB-15T, VNB-16 and SChm4 to form a cluster within the V. harveyi clade and belong to a new species of the Vibrio genus. Comparison of the complete genomic sequence of VNB-15T with typical strains of nearby species also indicates that VNB-15T belongs to a separate species (maximum similarity 98% with V. hyugaensis and 96% with V. jasicida). VNB-15T differs from closely related species by its ability to utilize glucose, mannitol, inositol, sorbitol, rhamnose and sucrose, and to form lysine decarboxylase, ornithine decarboxylase, lipase, acid phosphatase, -glucosidase, {beta}-glucosidase and N-acetyl-{beta}-D-glucosaminidase enzymes. Based on phylogenetic analysis and phenotypic characteristics, Vibrio aquamarinus sp. nov. is proposed. The type strain is VNB-15T (= VKPM B-11245T = DSM 26054 T). RepositoriesThe GenBank accession numbers for the gapA, 16S rRNA, gyrB, pyrH, rpoA, recA, mreB, ftsZ, topA genes sequences of strain VNB-15T are JQ319116-JQ319121, KX242381, KX 242384, KX242387, respectively. The GenBank accession numbers for the gapA, gyrB, pyrH, recA, rpoA,16S rRNA, mreB, ftsZ, topA genes sequences of strain VNB-16 are KP221561-KP221566, KX242382, KX 242385, KX242388 respectively. The GenBank accession numbers for the 16S rRNA, gapA gyrB, rpoA, recA, pyrH, mreB, ftsZ, topA genes sequences of strain SChm4 are KX242375-KX242380, KX242383, KX 242386, KX242389, respectively. The GenBank/EMBL/DDBJ accession numbers for the housekeeping gene sequences used in this study are detailed in supplementary Table S1, Figures S1-S8. The genome of Vibrio aquamarinus sp. nov. VNB-15T, comprising two chromosomes and a plasmid, has been assembled and deposited in the NCBI database under the submission number SUB14585067

Haloferax volcanii harbours four putative proviruses: Halfvol1, Halfvol2, Halfvol3 and Halfvol4. In this study we successfully deleted all four provirus genomes, demonstrating, that they are not essential. Transcriptome comparison between this strain ({Delta}Halfvol1-4) and a wild type strain reveals an increase in archaella and chemotaxis gene expression, resulting in higher swarming motility in {Delta}Halfvol1-4. Furthermore, {Delta}Halfvol1-4 cells show an elongated cell shape and a higher resistance to H2O2 stress compared to the wild type. RNA-seq also revealed down-regulation of CRISPR arrays in the provirus-free strain. Circularised genomes of Halfvol1, Halfvol2 and Halfvol3 were found in the culture supernatant. This confirms excision of the proviruses from the chromosome, which seems to happen more efficiently at low temperature (30{degrees}C). Electron microscopy revealed potential viral particles in the supernatant, and mass spectrometry analysis confirmed the presence of structural viral proteins of Halfvol1 and Halfvol3 in the isolated virus sample. These observations suggest that these proviruses are active and cause a chronic infection in Hfx. volcanii.

AcetoBase is a public repository and database published in 2019, for the formyltetrahydrofolate synthetase (FTHFS) sequences. It is the first systematic collection of bacterial formyltetrahydrofolate nucleotide and protein sequences from the genomes and metagenome assembled genomes (MAGs), as well as sequences generated by clone library sequencing. In addition, AcetoBase was first to establish connection between FTHFS gene with the Wood-Ljungdahl pathway and 16S rRNA genes. Since the publication of AcetoBase, significant improvements were seen in the taxonomy of many bacterial lineages and accessibility/availability of public genomics and metagenomics data. Thus, an update to the AcetoBase database with new sequence data and taxonomy has been made along with improvements in web-functionality and user interface. The update in AcetoBase reference database version 2 was furthermore evaluated by reanalysis of publicly accessible FTHFS amplicon sequencing data previously analysed with AcetoBase version 1. The latest database update showed significant improvements in the taxonomic assignments of FTHFS sequences. AcetoBase with its enhancements in functionality and content is publicly accessible at https://acetobase.molbio.slu.se.

The yeast Komagataella phaffii is widely used as a microbial host for heterologous protein production. However, molecular tools for this yeast are basically restricted to a few integrative and replicative plasmids. Four sequences that have recently been proposed as the K. phaffii centromeres could be used to develop a new class of mitotically stable vectors. In this work we designed a color-based genetic assay to investigate genetic stability in K. phaffii. Plasmids bearing K. phaffii centromeres and the ADE3 marker were evaluated in terms of mitotic stability in an ade2/ade3 auxotrophic strain which allows plasmid screening through colony color. Plasmid copy number was verified through qPCR. Our results confirmed that the centromeric plasmids were maintained at low copy number as a result of typical chromosome-like segregation during cell division. These features, combined with high transformation efficiency and in vivo assembly possibilities, prompt these plasmids as a new addition to the K. phaffii genetic toolbox.

The telomerase RNA, TER, is an intrinsic component of the telomerase ribonucleoprotein complex. It contains the telomere template sequence copied by the enzyme during telomere elongation. This unique molecule shows divergent nucleotide sequences but a more conserved secondary structure containing domains involved with telomerase assembly and biogenesis. The present work aims to characterize the biological roles played by the Leishmania TER component (LeishTER) in parasite homeostasis. We generated double knockout (LmTER-/-) parasites, which showed a distinct growth pattern at early passages, characterized by lower density and an extended stationary phase compared to the control. Although this pattern normalized after multiple in vitro passages, ablation of LeishTER affected cell division and proliferation, with cells arrested at the G0/G1 phase. Progressive telomere shortening was also observed during continuous passages, along with a reduction in the expression of TERRA29. Complementation with the episomal expression of LeishTER did not restore telomere length to the control levels, corroborating preliminary results showing that the overexpression of TER has a dominant negative effect on parasite lifespan. LmTER-/- also presented a higher percentage of gamma-H2A phosphorylation, likely due to stalled replication forks since no DNA damage was observed. Also, no plasma membrane modifications were detected, but pro-survival autophagic signals were present. Intriguingly, LmTER-/- retained the ability to transform into metacyclic forms, although its in vitro infectivity and growth inside the host cell were compromised. Together, these results highlight the importance of TER in parasite lifespan and open a discussion about its potential as a drug target against Leishmania.

Biogas, a mix of CO2, CH4 and small proportions of other gases, is a biofuel obtained by anaerobic digestion (AD). Biogas production is often considered a black box process, as the role and dynamics of some of the microorganisms involved remain undisclosed. Previous metataxonomic studies in the frame of the MICRO4BIOGAS project (www.micro4biogas.eu) revealed that MBA03, an uncharacterised and uncultured bacterial taxon, was very prevalent and abundant in industrial full-scale AD plants. Surprisingly, no culturable specimen or genome of this taxon has ever been reported, so its role in AD has remained unclear. In the present work, thirty samples derived from anaerobic digesters were sequenced, allowing the reconstruction of 108 metagenome-assembled genomes (MAGs) potentially belonging to MBA03. According to phylogenetic analyses and genomic similarity indices, MBA03 constitutes a new bacterial order, proposed as Darwinibacteriales ord. nov., which includes Darwinibacter acetoxidans gen. nov., sp. nov. of the family Darwinibacteriaceae fam. nov., along with Wallacebacter cryptica gen. nov., sp. nov. of the Wallacebacteriaceae fam. nov. Ecotaxonomic studies determined that AD processes are the main ecological niche of Darwinibacteriales. Moreover, metabolic predictions identified Darwinibacteraceae members as putative syntrophic acetate oxidising bacteria (SAOB), as they encode for the reversed Wood-Ljungdahl (W-L) pathway coupled to the glycine cleavage system. This suggests that Darwinibacteraceae members work in collaboration with hydrogenotrophic archaea to produce methane in industrial biogas plants. Overall, our findings present Darwinibacteriales as a potential key player in anaerobic digestion and pave the way towards the complete characterisation of this newly described bacterial taxa.

BackgroundMicrobial communities in the rhizosphere are key drivers of plant immunity, mediating plant responses to stress. Under specific stresses plants are capable of recruiting beneficial microorganisms into their rhizosphere with the potential to alleviate these stresses. Among these stresses, herbivorous pests remain a major agricultural challenge. Despite this, the impact of leaf herbivory on root-associated microbiomes, and how this impact can shape plant defense phenotypes are still understudied. In this study, our main objective was to determine the extent to which leaf herbivory affects the rhizosphere microbiome, and whether and how these herbivory-induced changes modulate plant defense phenotypes through plant-soil feedback. To that end, we designed a two-phase assay in which we challenged sunflower (Helianthus annuus L.) with Spodoptera exigua and later tested the effect of the microbial legacy after infestation on sunflower defense phenotype, considering resistance and tolerance as major drivers. ResultsWe found that herbivory triggered significant changes in the bacteriome structure and dynamics, and microbiome functional profile, while effects on mycobiome were comparatively less pronounced. Under herbivory, several bacterial taxa and functional groups were enriched, the bacterial co-occurrence network was more complex and assembly processes were slightly more stochastic. Furthermore, after evaluating the plant-soil feedbacks of herbivory-induced microbiomes we observed no effect on plant resistance proxies such as herbivore growth and survival, and leaf phenolic and flavonoid content. We did observe differences on tolerance proxies, while plants grown on herbivore-challenged microbiome were overall smaller, the biomass loss to herbivory was significantly lower while the elemental nutrient content and photosynthetic pigments content was enhanced. ConclusionsOur study demonstrates that insect herbivory by S.exigua reshapes sunflower rhizosphere microbiome and generates a soil legacy that promotes herbivory tolerance on subsequent plant generations. This highlights the broader potential of microbiome-mediated plant-soil feedbacks in shaping plant adaptation to herbivory.

Phytopathogenic fungi must adapt to the different environmental conditions found during infection and avoid the immune response of the plant. For these adaptations, fungi must tightly control gene expression, allowing sequential changes in transcriptional programs. In addition to transcription factors, chromatin modification is used by eukaryotic cells as a different layer of transcriptional control. Specifically, the acetylation of histones is one of the chromatin modifications with a strong impact on gene expression. Hyperacetylated regions usually correlate with high transcription and hypoacetylated areas with low transcription. Thus, histone deacetylases (HDACs) commonly act as repressors of transcription. One member of the family of HDACs is represented by sirtuins, which are deacetylases dependent on NAD+, and, thus, their activity is considered to be related to the physiological stage of the cells. This property makes sirtuins good regulators during environmental changes. However, only a few examples exist, and with differences in the extent of the implication of the role of sirtuins during fungal phytopathogenesis. In this work, we have performed a systematic study of sirtuins in the maize pathogen Ustilago maydis, finding Sir2 to be involved in the dimorphic switch from yeast cell to filament and pathogenic development. Specifically, the deletion of sir2 promotes filamentation, whereas its overexpression highly reduces tumor formation in the plant. Moreover, transcriptomic analysis revealed that Sir2 represses genes that are expressed during biotrophism development. Interestingly, our results suggest that this repressive effect is not through histone deacetylation, indicating a different target of Sir2 in this fungus.

The spread and adaptation of fungal plant pathogens in agroecosystems are facilitated by environmental homogeneity. Metagenomic sequencing of infected tissues allows to monitor eco-evolutionary dynamics and interactions betwen host, pathogen and the plant microbiome. Exserohilum turcicum, the causal agent of northern corn leaf blight (NCLB) in maize, is distributed in multiple clonal lineages throughout Europe. To characterize regional pathogen diversity, we conducted metagenomic DNA sequencing on 241 infected leaf samples from the highly susceptible Swiss maize landrace Rheintaler Ribelmais, collected over three years (2016-2018) from an average of 14 agricultural farms within the Swiss Rhine Valley. All major European clonal lineages of E. turcicum were identified. Lineages differ by their mating types which indicates potential for sexual recombination and rapid evolution of new pathogen strains, although we found no evidence of recent recombination. The associated eukaryotic and prokaryotic leaf microbiome exhibited variation in taxonomic diversity between years and locations and is likely influenced by local weather conditions. A network analysis revealed distinct clusters of eukaryotic and prokaryotic taxa that correlates with the frequency of E. turcicum sequencing reads, suggesting causal interactions. Notably, the yeast genus Metschnikowia exhibited a strongly negative correlation, supporting its known potential as biological control agent against fungal pathogens. Our findings show that metagenomic sequencing is a useful tool for analyzing the role of environmental factors and potential pathogen-microbiome interactions in shaping pathogen dynamics and evolution, suggesting their potential for effective pathogen management strategies.

BackgroundHelicobacter pylori, a member of campylobacteria, is the leading cause of chronic gastritis and gastric cancer. Virulence and antibiotic resistance of H. pylori are of great concern to public health. However, the relationship between virulence and antibiotic resistance genes in H. pylori in relation to other campylobacteria remains unclear. Materials and MethodsBy using the virulence and comprehensive antibiotic resistance databases, we explored all available 354 complete genomes of H. pylori and compared it with 90 species of campylobacteria for virulence and antibiotic resistance genes/proteins. ResultsOn average, H. pylori had 129 virulence genes, highest among Helicobacter spp. and 71 antibiotic resistance genes, one of the lowest among campylobacteria. Just 2.6% of virulence genes were shared by all campylobacterial members, whereas 9.4% were unique to H. pylori. The cytotoxin-associated genes (cags) seemed to be exclusive to H. pylori. Majority of the isolates from Asia and South America were cag2-negative and many antibiotic resistance genes showed isolate-specific patterns of occurrence. Just 15 (8.8%) antibiotic resistance genes, but 103 (66%) virulence genes including 25 cags were proteomically identified in H. pylori. Arcobacterial members showed large variation in the number of antibiotic resistance genes and there was a positive relation with the genome size. ConclusionLarge repository of antibiotic resistance genes in campylobacteria and a unique set of virulence genes might have important implications in shaping the course of virulence and antibiotic resistance in H. pylori.

Root exudates are composed of primary and secondary metabolites known to modulate the rhizosphere microbiota. Glucosinolates are defense compounds present in the Brassicaceae family capable of deterring pathogens, herbivores and biotic stressors in the phyllosphere. In addition, traces of glucosinolates and their hydrolyzed byproducts have been found in the soil, suggesting that these secondary metabolites could play a role in the modulation and establishment of the rhizosphere microbial community associated with this family. We used Arabidopsis thaliana mutant lines with disruptions in the indole glucosinolate pathway, liquid chromatography-tandem mass spectrometry (LC-MS/MS) and 16S rRNA amplicon sequencing to evaluate how disrupting this pathway affects the root exudate profile of Arabidopsis thaliana, and in turn, impacts the rhizosphere microbial community. Chemical analysis of the root exudates from the wild-type Columbia (Col-0), a mutant plant line overexpressing the MYB transcription factor ATR1 (atr1D) which increases glucosinolate production, and the loss-of-function cyp79B2cyp79B3 double mutant line with low levels of glucosinolates confirmed that alterations to the indole glucosinolate biosynthetic pathway shifts the root exudate profile of the plant. We observed changes in the relative abundance of exuded metabolites. Moreover, 16S rRNA amplicon sequencing results provided evidence that the rhizobacterial communities associated with the plant lines used were directly impacted in diversity and community composition. This work provides further information on the involvement of secondary metabolites and their role in modulating the rhizobacterial community. Root metabolites dictate the presence of different bacterial species, including plant growth-promoting rhizobacteria (PGPR). Our results suggest that genetic alterations in the indole glucosinolate pathway cause disruptions beyond the endogenous levels of the plant, significantly changing the abundance and presence of different metabolites in the root exudates of the plants as well as the microbial rhizosphere community.

Macroalgae are found in a variety of marine vegetation ecosystems around the world, contributing significantly to global net primary production. In particular, the sea lettuce species, i.e., members of the genus Ulva (Chlorophyta), are located in many ecological niches and are characterized by excellent adaptability to environmental changes but depend on essential associated bacteria, which release algal growth and morphogenesis-promoting-factors (AGMPFs). Our work investigated the hypothesis that bacteria need to be stress-adapted to provide sufficient amounts of AGMPFs for the growth and morphogenesis of Ulva throughout its life cycle, even under severe environmental conditions. Our study thus aimed to understand which bacteria contribute to overcoming a variety of stressors in polar regions. Green macroalgae were collected from Potter Cove, King George Island (Isla 25 de Mayo), Antarctica, to study the associated microbiome and, subsequently, to identify AGMPFs releasing bacteria. Therefore, microbiome analysis was combined with morphogenetic bioassays and chemical analysis, identifying bacteria essential for algal growth under Antarctic conditions. Hereby, axenic cultures of a Mediterranean Ulva compressa (cultivar Ulva mutabilis), previously developed as a model system for bacteria-induced algal growth and morphogenesis, were inoculated with freshly isolated and cultivable Antarctic bacteria to determine their morphogenetic activity. The exploratory microbiome investigation identified numerous cold-adapted AGMPF-producing bacteria. Unlike the reference bacterial strains isolated from the Mediterranean Sea, the cold-adapted isolates Maribacter sp. BPC-D8 and Sulfitobacter sp. BPC-C4, released sufficient amounts of AGMPFs, such as thallusin, necessary for algal morphogenesis even at 2{degrees}C. Our results illustrate the role of chemical mediators provided by bacteria in cross-kingdom interactions under cold conditions within aquatic systems. The newly isolated bacteria will enable further functional studies to understand the resilience of the holobiont Ulva and might applied in algal aquaculture even under adverse conditions. The study highlights the importance of ecophysiological assays in microbiome analysis.

Soil cultivation may change the soil microbiome and alter interactions between plants and parasites. The objective of this work was to evaluate temporal changes in plant health, microbiome abundance, bacterial diversity and the plant-parasitic nematode, Meloidogyne enterolobii incidence in two soil fields with different agricultural uses. Soil samples were collected from a commercial tomato production field (agricultural soil) and a single-cultivation strawberry field (native soil). Samples for the second experiment were collected from the same fields the following year. Tomato plants cv. Yearly Girl were grown in a greenhouse and inoculated with M. enterolobii. After 45 days, plants were evaluated for the plant growth parameters, nematode reproduction, and soil bacterial assemblages were assessed using cultivation-independent sequencing methods (V3/V4 region of the rRNA 16S). Overall the average of fruit fresh weight in the second experiment was 2.4-fold to 14-fold higher than the first experiment. Moreover, there was a 80.5% decrease in eggs present per root system from the first experiment to the second. The relative abundance of bacterial assemblages from Experiment 1 to Experiment 2 changed for most of the top phyla (eg. Actinobacteria, Bacteroidetes, and Chloroflexi) and genera (eg. Bacillus, Streptomyces, and Flavisolibacter) and there was no change in microbial diversity between the two experiments. This study suggests that soil management can lead to an overall decrease in nematode reproduction and better crop yield, as well as a shift in the overall bacterial assemblages. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=142 SRC="FIGDIR/small/525929v1_ufig1.gif" ALT="Figure 1"> View larger version (58K): org.highwire.dtl.DTLVardef@2b76b2org.highwire.dtl.DTLVardef@17db6c5org.highwire.dtl.DTLVardef@6a6d69org.highwire.dtl.DTLVardef@1352fb0_HPS_FORMAT_FIGEXP M_FIG C_FIG

Endophytes are a class of non-pathogenic microorganisms that reside within a plant and contribute to their health. Here, we isolated several endophytes from cotyledon-stage tomato seedlings that inhibited the growth of Ralstonia pseudosolanacearum, the bacterial wilt pathogen of tomato. One such endophyte, Pseudomonas aeruginosa SPT08, protected tomato seedlings as well as grown-up plants from the wilt disease. SPT08 also improved the tomato plant height by 20% and root growth by 60% in weight. SPT08 colonization inside tomato seedlings as well as in grown-up plants was studied using green fluorescent protein to demonstrate its endophytic behavior. SPT08 exhibited twitching and swimming motility and produced extracellular enzymes such as pectinase, protease, and amylase. SPT08 tested positive for several plant growth-promoting features such as phosphate solubilization, production of siderophore, plant hormone auxin, hydrogen cyanide, and ammonia. These features were further corroborated with SPT08 whole genome sequence. SPT08 genome is 6265489 bp, with 66.59% G+C and 5786 coding genes, including type II, III, and VI protein secretion systems. The antiSMASH tool identified potential for several secondary metabolites, including antibiotics, in SPT08. This study underscores the utility of P. aeruginosa SPT08 bio-protection from bacterial wilt and growth promotion agent in tomato. HighlightsPseudomonas aeruginosa SPT08, an endophyte isolated from tomato seedlings that inhibits bacterial wilt pathogen R. pseudosolanacearum, can control bacterial wilt in tomato plants and enhance the height and root growth.

A highly active alkaline phosphatase (ALP) from the mollusk strain of the marine bacterium Cobetia amphilecti KMM 296 (CmAP) was found to remove phosphorus from the Escherichia coli lipopolysaccharides (LPS). Phylogenetic analysis of the amino acid sequences of ALPs found in 36 available Cobetia genomes revealed that CmAP and its homologues from nine strains clustered together with the human and squid LPS-detoxifying enzymes. Each strain of the genus Cobetia has a variety of ALPs mostly of the PhoD and PhoX families. The PhoA gene encoding for the CmAP-like ALP is characteristic for the subspecies C. amphilecti, with a complete set of four ALP families, including PafA and two PhoD structures (5 genes). However, a single strain of the species Cobetia crustatorum JO1T from fermented shrimp, phylogenetically distant from C. amphilecti and C. marina, among four ALPs contains a CmAP homologue carrying an inactive mutation. Apparently, the multiplicity of ALPs in bacteria of the genus Cobetia is a trait of incredible adaptation to a phosphorus-depleted environment and a specialty of organophosphate destructor in eco-niches to which they once emerged, including Zostera spp. roots. The ALP clusterization and an identity level of the genus-specific biosynthetic genes encoding for ectoine and polyketide cluster T1PKS, responsible for sulfated extracellular polysaccharide synthesis, coincide with a new whole genome-based taxonomic classification of the genus Cobetia. The LPS-dephosphorylating property of the PhoA family C. amphilecti ALP CmAP may be used in the development of anti-inflammatory drugs.

Non-Saccharomyces yeasts emerge as possible new probiotics with a beneficial effect equal to or greater than the reference probiotic yeast, Saccharomyces boulardii. In this work, we evaluated the immunomodulation effect caused by Candida intermedia in mice vaccinated with inactivated SARS-CoV-2. We conducted preliminary tests using murine macrophages (RAW 264.7) stimulated with viable and heat-killed yeast cells, culture supernatant, and DNA, using qPCR to detect the mRNA transcription. Next, mice were supplemented with C. intermedia before each dose of the SARS-CoV-2 vaccine, and then antibody production was measured by ELISA. The probiotic strain S. boulardii CNCM I-745 was used as a control. We also explored the differences in fecal microbiomes between the non-supplemented and supplemented groups. Live cells of C. intermedia increased the transcription of IL-4, IL-13, and STAT3 by macrophages RAW 264.7, while heat-killed cells up-regulated TNF and Bcl6, and the culture supernatant positively impacted TLR2 transcription. Concanavalin, zymosan, and lipopolysaccharide were used to stimulate splenocytes from C. intermedia-supplemented animals, which showed increased transcription of TNF, IFN{gamma}, IL-4, Bcl6, and STAT3. Sera from these animals showed enhanced levels of anti-SARS-CoV-2 IgG, as well as IgG1 and IgM isotypes, and sIgA in fecal samples. The microbiome of the C. intermedia-supplemented group showed a higher abundance of Bacteroides spp. and Clostridium spp., impacting the Bacteroidetes/Firmicutes balance. We concluded that C. intermedia and S. boulardii could stimulate and impact the gene expression of cells important for innate immunity, influence the composition of the gastrointestinal microbiome, and primarily boost the humoral response after vaccination. Statements and Declarations FundingThe present work was carried out with the support of Conselho Nacional de Desenvolvimento Cientifico (CNPq, Brazil), grant number 150538/2021-9.

Yeasts belonging to the Candida genus typically reside on the mucosal surface and within the respiratory and gastrointestinal tract as commensals. Under conditions of host vulnerability, they can act as opportunistic pathogens, leading to various forms of candidiasis, including candidemia. Such infections can be particularly problematic when caused by isolates that exhibit resistance to antifungal drugs, which is becoming more prevalent in many regions. One hundred and seven samples of Candida spp. were isolated from patients with candidemia in the hospital San Matteo in Pavia (Italy) over a period of 6 years, from 2015 to the first COVID wave in spring 2020. In order to understand the epidemiology of Candida infections in this hospital setting, the isolates were whole-genome sequenced which identified most as C. parapsilosis and C. albicans. Comparative genomics revealed that isolates of C. albicans were genomically diverse, indicating repeated introductions in the hospital from the community. C. parapsilosis isolates comprised two groups of highly similar isolates representing strains capable of long-term persistence in the hospital. All isolates of the main persistent group were resistant to fluconazole and presented variable levels of resistance to voriconazole and itraconazole, resulting from the Y132F substitution in erg11 and the N455D substitution in upc2. Interestingly, with the exception of the single isolate susceptible to both voriconazole and itraconazole, all the 61 isolates presented one unreported missense mutation in mrr1 (S1907C).