Abstract
A novel bacterium, designated strain MMK2T, was isolated from a surface-sterilised root nodule of a Trifolium rubens plant growing in south-eastern Poland. Cells were Gram negative, non-spore forming and rod shaped. The strain had the highest 16S rRNA gene sequence similarity with P. endophytica (99.4%), P. leporis (99.4%) P. rwandensis (98.8%) and P. rodasii (98.45%). Phylogenomic analysis clearly showed that strain MMK2T and an additional strain, MMK3, should reside in the genus Pantoea and that they were most closely related to P. endophytica and P. leporis. Genome comparisons showed that the novel strain shared 82.96–93.50% average nucleotide identity and 26.2–53. 2% digital DNA:DNA hybridization with closely related species. Both strains produced siderophores and were able to solubilise phosphates. The MMK2T strain was also able to produce indole-3-acetic acid. The tested strains differed in their antimicrobial activity, but both were able to inhibit the growth of Sclerotinia sclerotiorum 10Ss01. Based on the results of the phenotypic, phylogenomic, genomic and chemotaxonomic analyses, strains MMK2T and MMK3 belong to a novel species in the genus Pantoea for which the name Pantoea trifolii sp. nov. is proposed with the type strain MMK2T (= DSM 115063T = LMG 33049T).
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Introduction
The genus Pantoea was first described by Gavini et al. in 19891 and it belongs to the family Enterobacteriaceae, order Enterobacteriales and phylum Pseudomonatoda. The genus contains 23 validly published species2 isolated from various ecological niches including soil3, water4, clinical samples5 and plant material6. They have been isolated as plant pathogens7, endophytes6, biocontrol agents8, plant growth promoters9 and as bioremediation agents10.
Certain species of Pantoea are well-known plant pathogens. For example, P. stewartii subsp. stewartii, is responsible for the development of Stewart's vascular wilt disease in sweet corn and maize11. Pantoea agglomerans pv. gypsophilae causes crown and root gall disease in gypsophila, whereas P. agglomerans pv. betae infects beets12. Pantoea ananatis causes a range of disease symptoms in different hosts including onions, rice, maize and melon13.
Some Pantoea species have been reported as causing opportunistic infections in humans14. Infection occurs mainly through wounding of the skin by plant material. A hospital-acquired infection caused by these species has also been described, primarily in immunocompromised patients. P. agglomerans infection may lead to skin allergies, septic arthritis, or synovitis. Strains of this species also causes periostitis, endocarditis, osteomyelitis, and sepsis12,15. However, it should be noted that some reported cases of P. agglomerans infections in humans are examples of pathogen misidentification16.
Strains of some Pantoea species have been described as epi- or endophytic plant symbionts17 while others have found application in industry. For instance, antimicrobials produced by some representatives of the genus, for example, P. agglomerans, are used as biological control agents in commercial products, such as BlightBan C9-1 and Bloomtime Biological to fight fire blight in apple and pear orchards18,19. It has been shown that some strains of P. agglomerans can induce systemic acquired resistance in some plants20. P. ananatis strains have also been shown to produce antifungal and antibacterial compounds, for example, phenazines and pantocins, and can inhibit plant infections caused by such phytopathogens as Penicillium expansum and Botrytis cinerea21,22,23. Pantoea species have been shown to contribute to increased biomass production in a variety of plants through, for example, the synthesis of phytohormones such as indole-3-acetic acid, gibberellic acid, and siderophores or the production of carotenoids17.
This paper describes a new endophytic bacterium isolated from root nodules of Trifolium rubens collected in south-eastern Poland. This putative beneficial, culturable strain was characterized using a polyphasic approach which included phenotypic, chemotaxonomic and genomic analyses.
Materials and methods
Isolation of bacterial strains
Strains were isolated from root nodules of Trifolium rubens, a plant growing in the south- eastern region of Poland (51.27454 N, 23.35748 E). Nodules were harvested and surface-sterilized by rinsing them several times with sterile water and placing them in 0.1% HgCl2 for three minutes. Thereafter, they were rinsed twice with sterile water, immersed in 70% ethanol for 2 min, and finally rinsed thrice with sterile water. The nodules were crushed in 0.5 ml of sterile saline solution (0.85% NaCl in MilliQ water) with sterile forceps, the suspension was diluted tenfold and 100 µl of the dilution was streaked on to yeast extract-mannitol (YEM) agar plates and incubated at 28 °C for three to four days24. The YEM medium was composed of the following ingredients (in 1000 ml distilled water): yeast extract 1.0 g, mannitol 10.0 g, dipotassium phosphate 0.5 g, magnesium sulphate 0.2 g, sodium chloride 0.1 g, calcium carbonate 1.0 g (pH 6.8 ± 0.2). After incubation, the single bacterial colonies were picked and further purified by repeated streaking to obtain pure cultures. Purified bacterial cultures were maintained on YEM agar slants at 4 °C as well as at − 70 °C in YEM broth with 15% (v/v) glycerol.
Research involving plants
Procedures involving the collection of plant material were carried out in accordance with institutional, national and international rules and legislation. Trifolium rubens is not included in the list of protected and endangered species of wild plants in Poland. Therefore, no permissions were required for the collection of research material. The species Trifolium rubens was identified by Dr. Mykhaylo Chernetskyy from the Maria Curie-Skłodowska University Botanical Garden in Lublin. To identify Trifolium rubens, the characteristic features of the species as described in the literature was used25,26.
Phenotypic and chemotaxonomic analyses
Gram stain reaction was performed using standard methods. The slides were examined using the 100 × oil immersion objective using an Olympus CX23 microscope (Olympus, Japan). The Schaeffer–Fulton staining technique was used to determine the presence of spores in the tested strains27. The slides were observed under the same microscope as for the Gram stain method. Growth tests were performed in YEM broth at 28 °C. The growth temperature range was tested on the same medium at 15, 28, 37, 42 and 45 °C for 4–8 days. Tolerance to NaCl was determined based on the growth of the bacteria on YEM agar supplemented with 8, 9 and 10% NaCl (w/v) concentrations and incubated 28 °C for four to eight days. The pH range for growth was established by incubating the strain in YEM broth at pH levels ranging from 5.0 to 10.0 at intervals of 1 pH unit. The Biolog GEN III system (Biolog Inc. Hayward, CA, USA) and GN A + B-ID system (Microgen) were used in accordance to the manufacturer’s recommendations. Enzymatic characterization of the bacterial isolates was performed using API ZYM strips (BioMérieux, France) according to the manufacturer’s protocol. Catalase and oxidase activity was determined using standard methods. Cellular fatty acids in the form of their methyl esters were prepared according to the protocol of Wollenweber and Rietschel28 and analysed by using an Agilent Technologies (Instrument 7890) gas chromatograph connected to a mass selective detector (Agilent Technologies MSD5975C, inert XL EI/CI) (GLC-MS), using helium as a carrier. The components of fatty acid methyl ester were determined mainly by their chromatographic and mass spectral characteristics. The positions of the branching methyl group, cyclopropane ring, and the double bonds were determined by an analysis of mass spectra of fatty acid pyrrolidines29. Each fatty acid was quantified by calculating its peak area relative to the total peak area30.
In vitro assessment of plant growth promoting characteristics
Indole-3-acetic acid (IAA) production in Pantoea strains was detected using a qualitative test. The IAA production was determined using Salkowski reagent as described by Luziatelli et al.31.
The indole production was detected in M9 broth medium32 with 0.5 mM of l-tryptophan as described by Gnat et al.33.
Assessment of HCN production by Pantoea strains was carried out by using the method described by Lorck34.
The ability of Pantoea strains to solubilize phosphate was determined on Pikovskaya agar35. The bacterial strains were streaked on Pikovskaya agar and incubated at 28 °C for 10 days. Formation of a transparent halo around the colony indicates solubilisation of phosphate.
Chrome azurol S medium (CAS, Sigma-Aldrich, USA) was used to test the capability of the microorganisms to produce siderophores36. The strains were spotted on CAS medium and inoculated for three to four days at 28 °C. Formation of a coloured halo around the colony indicated siderophore production.
Cellulase activity of studied strains were detected on carboxymethylcellulose (CMC) media according to the method described by Kasana et al.37. Gram’s iodine forms a bluish-black complex with cellulose. The positive reaction for cellulase production is visible as a sharp and distinct zone around the microbial colonies37.
Proteolytic activity was evaluated in nutrient agar supplemented with 10% skim milk38. Pantoea strains were spot inoculated and incubated for 48–72 h at 28 °C. The enzymatic degradation of milk protein was visible as a clear zone around a bacterial colony. All the experiments described above were performed in triplicate.
In vitro assessment of antifungal and antibacterial activity
The antagonism test was performed against four phytopathogenic fungi listed in Table 1. Fungal strains were grown on a potato dextrose agar (PDA, Biomaxima, Poland) plates for 7 days. A 5-mm agar plug of mycelium was excised with a sterilized cork borer and was placed in the centre of a YEM agar plate inoculated with the Pantoea strain. The interactions of the tested strains with fungal pathogens were examined every day for a period of three weeks. Three biological replications were performed for each treatment. The control were plates inoculated only with the fungal pathogen. The plates were assessed as follows: (−) no effect on inhibiting the growth of the fungal phytopathogen; (+) inhibition of the growth of the fungal phytopathogen compared to the control.
The studied Pantoea strains were tested for their ability to inhibit the growth of four phytopathogenic bacteria listed in Table 1. using the agar plug diffusion method39. Pantoea strains were cultured on YEM agar for five days at 28 °C. After this time, 9 mm agar discs with the strain were cut out using a sterilized cork borer. An agar disc with the tested strain was placed at the centre of the LB agar plates (Biomaxima, Poland) inoculated with 24 h cultures of the phytopathogens in LB broth (Biomaxima, Poland) (108 CFU/ml). The plates were incubated at 28 °C and strain interactions were checked after 24, 48 and 72 h. The appearance of a zone of inhibition of the growth of phytopathogens around bacterial colonies was considered a positive result.
16S rRNA gene phylogenetic analysis
The genomic DNA was extracted using a bacterial genomic DNA extraction kit (GeneMATRIX Tissue & Bacterial DNA Purification Kit, EURx). The 16S rRNA gene was amplified and sequenced with the bacterial universal primers fD1 and rD1 described by Weisburg et al.40. PCR amplification reactions were carried out with ReadyMix™ Taq PCR Reaction Mix (Sigma) according to the manufacturer’s recommendations. The amplified products were purified with Clean-Up purification columns (A&A Biotechnology) and sequenced with BigDye Terminator Cycle sequencing kit using the 3500 Genetic Analyzer according to the manufacturer’s procedures (Life Technologies) as described elsewehere41. The 1337 bp long 16S rRNA gene sequence fragments of MMK2T and MMK3 were deposited in GenBank under the accession numbers OQ799602 and OQ799603. The sequence similarity searches were performed by using the BLAST algorithm. Phylogenetic tree based on 16S rRNA gene sequences were constructed using the software MEGA X42 and the maximum likelihood algorithm with Tamura 3-parameter model43. Bootstrap values were derived from 1000 replications.
Genome sequencing, annotation and phylogenomic analyses
The whole genome of strains MMK2T and MMK3 were sequenced on a PacBio platform by Inqaba Biotechical Industries (Pty) Ltd (Pretoria, South Africa) and assembled using the SMRTLink v. 11.0 software (PacBio). Genome sequences of the type strain MMK2T and strain MMK3 were deposited in GenBank database under the accession numbers JANIET000000000.1 and JANIES000000000.1, respectively. Genome annotation was carried out automatically with the Genome Annotation Service using the RAST tool kit44, available at BV-BRC web resources45. The antiSMASH tool was used to identify putative biosynthetic gene clusters in the analysed genomes46. The genomes of the type strains of all other Pantoea species were obtained from GenBank. To determine the relationship between MMK2T, MMK3 and closely related species, phylogenomic analyses were performed using the bacterial Phylogenetic Tree Service available at BV-BRC web resources45 and utilizing the codon tree method and the RAxML program47. The average nucleotide identity (ANI) and digital DNA:DNA hybridization (dDDH) relatedness between MMK2T, MMK3 and types strains of closely related species were calculated using the ANI Calculator48 and the Genome-to-Genome Distance Calculator49, respectively.
Results and discussion
Isolation, morphology, physiology and biochemical features of Pantoea trifolii
The root nodules of legumes are inhabited mainly by bacteria capable of fixing atmospheric nitrogen as part of a symbiotic relationship with the host plant. The nitrogen-fixing symbiotic bacteria, collectively named as rhizobia, belong to different genera of Alpha- (e.g. Bradyrhizobium, Ensifer, Mesorhizobium, Rhizobium) and Betaproteobacteria (e.g. Paraburkholderia, Cupriavidus) classes50. In addition to the typical rhizobia, many other bacteria are often isolated from sterile root nodules, some of which are unable to fix nitrogen or induce nodulation. They are called nodule endophytes or nodule-associated bacteria51. Many of these nodule endophytes may be beneficial to plants due to their plant growth promoting effects52.
In our study, we isolated bacteria from sterile root nodules of Trifolium rubens plants growing in south-eastern Poland. Most of the examined root nodules were colonized by bacteria identified as Rhizobium spp. (data not shown), but two nodules collected from two different plants were also inhabited by bacteria that formed yellow colonies and produced a blue-violet pigment on YEM agar plates. These two isolates, designated MMK2 and MMK3, were used for further analyses.
The cells of MMK2T and MMK3 are Gram negative, non-spore forming rods. The strains are able to grow at 37 °C, but not at 42 °C (optimum, 28 °C), at a pH in the range of 5.0–9.0 and in the presence of up to 9% NaCl, but not 10%. The catalase test was positive while the oxidase test was negative for both strains. Both strains form yellow colonies on the YEM agar and produce a blue-violet pigment that diffuses into the medium. To date, only a single strain of Pantoea agglomerans has been shown to produce a blue pigment53. The MMK2T strain utilized dextrin, d-maltose, d-trehalose, d-cellobiose, gentiobiose, β-methyl-d-glucoside, d-salicin, N-acetyl-d-gucosamine, N-acetyl-β-d-mannosamine, α-d-glucose, d-mannose, d-fructose, d-galactose, 3-methyl glucose, d-fucose, l-fucose, l-rhamnose, inosine, d-sorbitol, d-mannitol, d-arbitol, myo-inositol, glycerol, d-glucose-6-PO4,d-fructose-6-PO4, d-galacturonic acid, l-galactonic acid lactone, d-gluconic acid, d-glucuronic acid, glucuronamide, mucic acid and d-saccharic acid, l-lactic acid, citric acid, d-malic acid, l-malic acid, bromo-succinic acid, γ-amino-butyric acid, acetoacetic acid, acetic acid and formic acid. The strain also used glycyl-l-proline, l-alanine, l-arginine, l-apartic acid, l-glutamic acid, l-histidine and l-serine. Negative reactions were recorded for d-turanose, stachyose, d-raffinose, α-d-lactose, d-mellibiose, N-acetyl neuraminic acid, d-aspartic acid, d-serine, gelatin, l-pyroglutamic acid, pectin, quinic acid, p-hydroxy-phenylacetic acid, methyl pyruvate, d-lactic acid methyl ester, α-keto-glutaric acid, tween 40, α-hydroksy-butyric acid, α-d,l-butyric acid, propionic acid, and minocycline. Positive enzyme activities were noted for alkaline phosphatase, esterase (C4), esterase lipase (C8), acid phospatase, naphthol-AS BI-phosphohydrolase, β-galactosidase, β-glucosidase and N-acetyl-β-glucosaminidase but not for lipase (C14), leucine arylamidase, valine arylamidase, cystine arylamidase, trypsin, α-chymotripsin, α-galactosidase, β-glucuronidase, α-glucosidase, α-mannosidase or α-fucosidase. Strain MMK2T and MMK3 could be clearly distinguished from closely related Pantoea species, P. endophytica 596T, P. rodasii DSM 26611T and P. rwandensis DSM 105076T (Table 2)6,54.
The results of the analysis of cellular fatty acids in the form of their methyl esters are presented in Table 3. The major fatty acids of MMK2T and MMK3 strains were C16:0 (44%), C17:0 cyclo (17%), and C14:0 3-OH (16%). The strains were also characterised by the presence of C18:1ɷ13, C16:1 and C19:1, an unsaturated fatty acids and C14:0, C18:0, and C20:0 saturated fatty acids. The MMK3 strain produced 2% and 2.5% higher amounts of C17:0 cyclo and C19:1ɷ9, respectively, and 1.5% lower amounts of C20:0 compared to MMK2T. These strains differed from their closest relatives, P. endophytica and P. leporis, in the amounts of C16:0, C17:0 cyclo, and the presence of C14:0 3-OH, C19:1, C20:0,6,55.
16S rRNA gene phylogeny
Using the results of the phylogenetic analysis of the 16S rRNA gene encoding sequences, we were able to estimate the taxonomic position of the studied strains at the genus level. Phylogenetic analysis based on the maximum likelihood algorithm shows that strains MMK2T and MMK3 belong to the genus Pantoea and have the highest 16S rRNA gene similarity to P. endophytica (99.4%) and P. leporis (99.4%), followed by P. rwandensis (98.8%) and P. rodasii (98.4%), with which the studied strains clustered together, but on a distinct branch in the phylogenetic tree (Fig. 1).
Maximum likelihood phylogenetic tree based on 16S rDNA sequences showing the relationship between MMK2T, MMK3 and type species of Pantoea. Escherichia coli JCM1649T and Enterobacter cloacae ATCC 13047T were used as outgroups. Species names written in quotation marks are not validly published (https://lpsn.dsmz.de/genus/pantoea). Bootstrap values greater than or equal to 70% are given at the branching points. The bar, 0.02, represents the number of substitutions per nucleotide.
Phylogenomic and genomic analyses
The phylogenomic analysis based on 500 single-copy genes found in the genomes of Pantoea sp. MMK2T, Pantoea sp. MMK3 and reference strains clearly showed that MMK2T and MMK3 were members of the genus Pantoea, and were most closely related to P. endophytica and P. leporis (Fig. 2).
Phylogenomic tree based on 500 single-copy genes showing the relationship between strains MMK2T, MMK3 and Pantoea type strains. Escherichia coli JCM1649T and Enterobacter cloacae ATCC 13047T were used as outgroups. Species names written in quotation marks are not validly published (https://lpsn.dsmz.de/genus/pantoea). The branching points are labelled with bootstrap values. The bar, 0.20, represents the number of substitutions per site. The tree was generated using RAxML program.
The genome-derived ANI and dDDH values between MMK2T, and its closely related species were between 82.96 and 93.50% (Table 4) and 26.2–53.2% (Table 5), respectively, which is all below the threshold values of 95–96% ANI and 70% dDDH, i.e. recommended cut-off values for prokaryotic species delineation56.
The draft genome of strain MMK2T was 5.06 Mb long and composed of 3 contigs with a N50 of 4.16 Mb and L50 of 1 and genome coverage of 560x (Fig. 3). The genome size is above the median being 4.85 Mb for the sequenced Pantoea strains2. It has genomic DNA G + C content of 54.63 mol % which is within the G + C content range of the genus Pantoea5. The MMK2T genome contains 4721 protein coding sequences (CDS), 78 transfer RNA (tRNA) genes, and 22 ribosomal RNA (rRNA) genes. The annotation included 733 hypothetical proteins and 3988 proteins with functional assignments (Table 6). Among the proteins with functional assignments 1241 represented proteins with Enzyme Commission (EC) numbers, 1,030 belonged to proteins with Gene Ontology (GO) assignments, and 896 included proteins that were mapped to KEGG pathways57.
A circular diagram representing the genome of Pantoea MMK2T. The three contigs and their sizes are shown as the outermost ring. Coding sequences (CDS) on the forward strand, CDS on the reverse strand are represented by the second and third rings. The remaining rings represent RNA genes, CDS with homology to known antimicrobial resistance genes, CDS with homology to known virulence factors, guanine and cytosine (GC) content and GC skew.
Analysis of biosynthetic gene clusters
Analysis of the MMK2T and MMK3 genomes using the antiSMASH tool revealed the presence of two biosynthetic gene clusters (BGC) associated with the pigments production, i.e. carotenoids and aryl polyenes (APE). The aryl polyene gene cluster showed 94% similarity to the secondary metabolite BGC from Xenorhabdus doucetiae. In addition, a cluster of genes involved in the synthesis of carotenoids was found in the genomes of studied strains. This gene cluster from strains MMK2T and MMK3 has the classical organization crtEXYIBZ, having all the necessary carotenoid synthesis genes for zeaxanthin glucosides58. The role of carotenoids in bacteria is related to the protection of the cell against stress factors, such as the toxic effects of reactive oxygen species (ROS), desiccation or salinity. They also act as photoprotectants against UV radiation (especially in the range from 320 to 400 nm). It was found that carotenoids can regulate membrane fluidity and participate in the organization of membrane domains59. The ability to synthesise carotenoids has been described for both pathogenic and endophytic members of the genus Pantoea. They have been found in P. agglomerans, P. ananatis and in the strain Pantoea sp. YR34360,61,62.
No gene clusters associated with the synthesis of the blue or violet pigment were identified in the MMK2T and MMK3 genomes. The planned research on the analysis of the structure and function of the pigment may allow the identification of genes involved in its production. In addition to the gene clusters associated with pigment production, antiSMASH found BGC involved in the synthesis of frederiksenibactin, a triscatechol siderophore, in the genomes of the studied strains. Siderophores are compounds of low molecular weight and are characterized by high affinity to metal ions, mainly ferric, but also to ions, for example, aluminium, copper, cadmium or lead63. In the case of plant growth promoting bacteria (PGPB), the production of siderophores can positively influence the physiological and biochemical processes taking place in the host. In addition, through competition for iron ions, they can limit the development of phytopathogens in the environment64.
Frederiksenibactin is produced by an opportunistic human pathogen Yersinia frederiksenii65 but the BGC related to the synthesis of this siderophore was also identified by antiSMASH in the genomes of other Pantoea species, for example, P. endophytica, P. rodassi but not in the genome of P. rwandensis.
In vitro plant growth promoting and antimicrobial characteristics of Pantoea trifolii
Among the tested traits related to the promotion of plant growth, both studied strains showed the ability to solubilize phosphates and produce siderophores. Additionally, strain MMK2T was positive for the production of indole-3-acetic acid (IAA). Using the methods described, we did not detect cellulolytic or proteolytic activity of either strains. The Pantoea strains tested were also negative in indole and HCN production (Table 7). Phosphate solubilization, production of siderophores and IAA appear to be plant growth-promoting traits that are widespread among Pantoea species. For example, these activities were determined experimentally for P. agglomerans C131, P. eucalypti66, P. brenneri67, P. alhagi68 and P. phytobeneficialis MSR29.
Analysis of the in vitro antimicrobial activity of the MMK2T and MMK3 strains showed that they differ in their antifungal and antibacterial properties (Table 7). It was found that the MMK2T strain inhibits growth of X. vesicatoria NCCB 92,059 and P. syringae pv. syringae 2905. Both MMK2T and MMK3 strains have antifungal activity against the S. sclerotiorum strain 10Ss01. Some Pantoea strains are known to produce metabolites with antibacterial and antifungal activity, and biosynthetic gene clusters related to the biosynthesis of these compounds have been identified in their genomes69. No biosynthetic gene cluster associated with synthesis of antibiotics was identified in the genomes of studied Pantoea strains, suggesting another mechanism related to their antimicrobial activity. We found that the MMK2T and MMK3 genomes contain genes encoding a complete type VI secretion system (T6SS), which can play different functions in pathogenic and non-pathogenic bacteria. One such role is to deliver effectors to neighbouring bacteria, inhibiting their growth and thus playing a role in interbacterial competition70,71. It was demonstrated that T6SS is a functional antibacterial system used by P. agglomerans bv. betae to deliver a lysozyme-like effector to eliminate competitors72. Further studies are required to determine the function of the T6SS in strains MMK2T and MMK3.
Conclusion
Based on the results obtained from the study of phenotypic and chemotaxonomic features as well as phylogenetic and phylogenomic analyses, the MMK2T strain should be considered a novel species of the genus Pantoea, for which we propose the name Pantoea trifolii sp. nov. The protologue description of this novel species is presented in Table 8.
Data availability
This article includes all the data generated or analyzed as part of this study. The strain MMK2T has been deposited in two bacterial collections: BCCM/LMG (LMG 33,049) and DSMZ (DSM 115,063). The MMK2T genome sequence has been deposited in NCBI under the accession number GCA_024506435.1 (genome assembly accession) and JANIET000000000.1 (Genbank accession). The 16S rDNA gene sequences of strains MMK2T and MMK3 have been deposited in NCBI under accession numbers OQ799602 and OQ799603.
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Funding
This work was funded by a grant from the National Centre for Research and Development, Poland (Grant Number PL-RPA2/07/TRIFOMIKRO/2019) and a Grant from the National Research Foundation (Grant Number POL180702349288).
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Conceptualization: S.W.-W., M.K., M.M.-K, and T.A.C. Methodology: S.W.-W., M.K., M.P.-S., and T.A.C. Experimental work: S.W.-W., M.M.-K, M.P.-S, M.K., W.S., and T.A.C. Writing and manuscript preparation: S.W.-W, T.A.C., M.K., and M.P.-S. Funding acquisition: M.K. and T.A.C. All authors have read and agreed to the published version of the manuscript.
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Wdowiak-Wróbel, S., Kalita, M., Palusińska-Szysz, M. et al. Pantoea trifolii sp. nov., a novel bacterium isolated from Trifolium rubens root nodules. Sci Rep 14, 2698 (2024). https://doi.org/10.1038/s41598-024-53200-2
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DOI: https://doi.org/10.1038/s41598-024-53200-2
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