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Pantoea

Pantoea is a genus of Gram-negative, rod-shaped bacteria belonging to the family Erwiniaceae within the order Enterobacterales, characterized by their frequent yellow pigmentation and versatile ecological roles across diverse environments.^[1]^[2] First described in 1989, the genus encompasses approximately 25 species, with P. agglomerans as the type species, and is known for its ubiquity in soil, water, plants, insects, animals, and humans, where it can act as an epiphyte, endophyte, pathogen, or beneficial microbe.^[3]^[4] Taxonomically, Pantoea species are placed in the phylum Pseudomonadota (formerly Proteobacteria), class Gammaproteobacteria, and are closely related to genera such as Erwinia and Tatumella, with emendations to the genus definition occurring in 1993 and 2010 to refine species boundaries based on phylogenetic analyses.^[1] Multilocus sequence analysis using genes like gyrB, rpoB, and others has revealed that Pantoea does not form a single monophyletic clade, leading to the reclassification of some species, such as Tatumella citrea (formerly P. citrea), T. punctata, and T. terrea, into Tatumella in 2010.^[3]^[5] Key species include P. ananatis, associated with plant diseases like bacterial fruit blotch and leaf spots; P. stewartii, the causative agent of Stewart's wilt in maize; and P. agglomerans, which is widely distributed and implicated in both plant tumors and human opportunistic infections such as septicemia in immunocompromised individuals.^[3]^[2] Ecologically, Pantoea bacteria exhibit remarkable adaptability, thriving as free-living organisms in aquatic and terrestrial habitats while forming symbiotic or pathogenic associations with hosts.^[2] In agriculture, certain strains pose significant threats as phytopathogens, causing devastating diseases in crops like rice (e.g., red stripe disease) and onions (e.g., center rot), yet others serve as biocontrol agents, such as P. agglomerans strain C9-1 (BlightBan), which inhibits fire blight in apples and pears by competing with Erwinia amylovora. Recent reports have also linked emerging leaf blight-like symptoms in rice to Pantoea species.^[2]^[6] Beneficial traits include nitrogen fixation, phosphate solubilization, and production of antimicrobial compounds, promoting plant growth and contributing to bioremediation efforts, such as degrading herbicides like 2,4-D.^[2] In human health, while generally non-pathogenic, Pantoea species have emerged as opportunistic pathogens in nosocomial infections, particularly in neonates and those with indwelling devices, highlighting their dual role in medicine.^[3]^[2] The genomic diversity of Pantoea underscores its biotechnological potential, with strains harboring genes for antibiotic biosynthesis, biofilm formation, and environmental stress resistance, making the genus a subject of ongoing research for applications in sustainable agriculture and therapeutics.^[2]

Taxonomy

History and Etymology

The genus name Pantoea derives from the Greek adjective pantoios, meaning "of all sorts and sources," which aptly captures the phenotypic and ecological diversity of its member species, encompassing strains isolated from plants, animals, humans, and environmental sources.^[7] This nomenclature highlights the genus's broad adaptability and heterogeneous characteristics, distinguishing it from more narrowly defined taxa within the Enterobacteriaceae at the time of its proposal.^[8] The genus Pantoea was first established in 1989 by Gavini et al., who proposed it as a novel taxon to accommodate the heterogeneous group previously classified as Enterobacter agglomerans, separating it from the core Enterobacter and Erwinia genera based on DNA hybridization and phenotypic data.^[9] This initial description addressed long-standing challenges in classifying these bacteria, as their phenotypic similarities—such as yellow pigmentation, motility, and lactose fermentation—often led to misidentification with Erwinia (plant pathogens) and Enterobacter (opportunistic human pathogens).^[10] Early taxonomic efforts were complicated by the lack of distinct biochemical markers, resulting in frequent reclassifications of strains from diverse sources under a single, overly broad species name.^[3] Subsequent revisions expanded and refined the genus. In 1993, Mergaert et al. emended the description of Pantoea, transferring Erwinia ananas (synonym E. uredovora) and E. stewartii into the genus as P. ananatis and P. stewartii, respectively (with the name P. ananatis corrected from P. ananas in 1997), based on fatty acid profiles, DNA:DNA hybridization, and phylogenetic analyses that confirmed their closer affinity to P. agglomerans.^[11] A major expansion occurred in 2010 with the work of Brady et al., who further emended the genus description and introduced four novel species isolated from human clinical samples—P. septica, P. eucrina, P. brenneri, and P. conspicua—using multilocus sequence analysis and phenotypic characterization to delineate them from existing taxa.^[12] In the same year, Kageyama et al. emended Tatumella and transferred P. citrea, P. punctata, and P. terrea from Pantoea to that genus as T. citrea, T. punctata, and T. terrea, respectively, based on multilocus sequence analysis revealing their closer phylogenetic affinity to Tatumella.^[13] Phylogenetic advancements prompted another significant taxonomic shift in 2016, when Adeolu et al. reclassified Pantoea from the family Enterobacteriaceae to the newly proposed Erwiniaceae, supported by whole-genome sequencing and comparative phylogenomics that revealed distinct evolutionary clades within the order Enterobacterales. This transfer underscored the genus's closer relation to plant-associated genera like Erwinia and resolved lingering ambiguities from phenotypic-based classifications.^[14]

Classification and Phylogeny

The genus Pantoea belongs to the class Gammaproteobacteria, order Enterobacterales, and family Erwiniaceae within the phylum Pseudomonadota.^[1] This placement is supported by 16S rRNA gene sequence analyses, which consistently position Pantoea as a distinct lineage closely related to genera such as Erwinia and Tatumella.^[15] Multilocus sequence analysis (MLSA) has emerged as a robust method for resolving phylogenetic relationships, employing housekeeping genes including gyrB, rpoB, atpD, and infB, which provide higher resolution than 16S rRNA alone due to their faster evolutionary rates.^[16] These markers have delineated Pantoea from neighboring genera and highlighted intraspecific diversity.^[17] Core genome phylogeny, derived from single-copy orthologs across multiple strains, reveals three main clades within Pantoea: one comprising P. stewartii subspecies (stewartii and indologenes), a second including P. agglomerans and P. vagans, and a third encompassing P. dispersa and related strains such as Pantoea sp. At_9b.^[15] This tripartite structure underscores the genus's ecological versatility, with clades reflecting adaptations to plant-associated, environmental, and potentially pathogenic niches, though further genomic sampling continues to refine these boundaries.^[18] The core genome of Pantoea typically includes around 2,185 gene families, enabling precise reconstruction of evolutionary histories that align with MLSA results.^[15] Species delineation in Pantoea relies on genomic metrics, including average nucleotide identity (ANI) thresholds of 95-96% and digital DNA-DNA hybridization (dDDH) values exceeding 70%, which have supplanted traditional phenotypic methods for accurate taxonomy.^[19] A 2019 taxogenomics study integrated MLSA with ANI, amino acid identity, tetranucleotide usage, and genomic dDDH to validate species boundaries, confirming 25 validly described species (plus two subspecies) at the time while noting reclassifications of several (e.g., to Tatumella and Mixta) for ambiguous strains.^[17] By 2023, genomic analyses had expanded this to approximately 25 validly described species, with ongoing whole-genome sequencing revealing novel lineages and supporting the genus's dynamic systematics.^[20]

Characteristics

Morphology and Cellular Features

Pantoea species are Gram-negative, straight or slightly curved rods measuring 0.5–1.0 μm in width and 1.0–3.0 μm in length.^[21] These bacteria are typically motile, propelled by peritrichous flagella, and are non-spore-forming and non-encapsulated.^[21]^[22] Most Pantoea strains exhibit yellow pigmentation attributed to carotenoid production, such as zeaxanthin, which contributes to their characteristic appearance.^[8]^[23] On nutrient agar, colonies are convex, smooth, and yellow, reaching 2–4 mm in diameter after 48 hours of incubation at 28–30°C.^[21]^[10] Electron microscopy observations confirm the cell wall structure typical of the Enterobacteriaceae family, featuring an outer membrane containing lipopolysaccharides, a thin peptidoglycan layer, and an inner cytoplasmic membrane.^[24] This morphology aligns with the genus's phylogenetic position within the Enterobacterales order, though variations exist across species.^[8]

Physiology and Biochemistry

Pantoea species are facultative anaerobes capable of growth under both aerobic and anaerobic conditions. Optimal growth occurs at temperatures between 25°C and 30°C, with some strains tolerating ranges from 4°C to 41°C, and at pH levels of 6 to 8, often peaking around 6.5 to 7.2 for processes like exopolysaccharide production.^[25]^[26]^[27] These bacteria exhibit fermentative metabolism, producing acid but no gas from glucose fermentation. They are oxidase-negative and catalase-positive, facilitating identification in clinical and environmental settings. Key biochemical tests confirm their enteric nature: positive for methyl red (indicating mixed acid fermentation), Voges-Proskauer (detecting acetoin production), and citrate utilization (via Simmons' medium); urease and H₂S production are variable across species, with many strains negative for both.^[25]^[28] Phytopathogenic strains of Pantoea produce extracellular enzymes such as pectinase and cellulase, which degrade plant cell walls and contribute to tissue maceration. For instance, pectinase activity softens pectins in host plants, while cellulase breaks down cellulose, enabling infection in species like Pantoea ananatis and Pantoea stewartii. These enzymes are induced by plant-derived substrates and are not universal across all isolates.^[29]^[30] Pantoea isolates generally show susceptibility to antibiotics like gentamicin and ampicillin, though resistance patterns vary; many are sensitive to gentamicin with minimum inhibitory concentrations below 4 μg/mL, but ampicillin resistance occurs in over 30% of clinical strains due to beta-lactamase production, including AmpC-type enzymes. Beta-lactamase-mediated resistance, often encoded by plasmids, confers variable tolerance to penicillins and cephalosporins in opportunistic pathogens.^[31]^[32]^[33]

Genomics

The genomes of Pantoea species typically range in size from 4.5 to 5.5 Mb, with G+C content varying between 54 and 60 mol%, reflecting adaptations to diverse environmental niches such as plant associations and soil habitats.^[34]^[35] These characteristics are consistent across sequenced strains, including P. ananatis and P. agglomerans, where chromosome sizes often hover around 4.8 Mb and G+C levels near 55 mol%.^[36] Plasmids are prevalent in Pantoea, contributing to genomic plasticity; for instance, the cryptic plasmid pPAGA (2,734 bp) in P. agglomerans strain EGE6 lacks known replication origins but may facilitate genetic exchange in endophytic contexts.^[37] Additionally, larger plasmids like LPP-1 (approximately 280 kb) encode traits for ecological fitness, including resistance to polymyxin and cationic antimicrobial peptides, enhancing survival in competitive environments.^[38] Pan-genome analyses of Pantoea reveal a core genome comprising approximately 3,000 genes shared among strains, essential for fundamental cellular processes and basic metabolism, while the accessory genome demonstrates high plasticity with thousands of strain-specific genes.^[39] In P. ananatis, the core genome consists of 3,153 genes, with accessory elements often involved in plant interactions, such as type III secretion systems (T3SS) that deliver effectors to modulate host responses.^[40] This open pan-genome structure, estimated at over 27,000 orthologs across the genus, underscores Pantoea's adaptability, with accessory genes comprising up to 80% of the total repertoire in some analyses.^[41] Horizontal gene transfer (HGT) has profoundly shaped Pantoea genomes, particularly through acquisition of pathogenicity islands from related genera like Erwinia.^[42] These events include the integration of T3SS loci via both vertical inheritance and HGT, enabling virulence in phytopathogenic strains while being absent or modified in non-pathogenic ones.^[43] Such transfers often occur via mobile elements like transposons and integrative conjugative elements, contributing to the genus's versatility in host colonization.^[44] As of early 2025, whole-genome sequencing efforts had characterized over 1,200 Pantoea strains deposited in GenBank, with databases like GTDB classifying hundreds of high-quality assemblies, facilitating comparative studies on ecological roles.^[45] These sequences have uncovered biotechnological potential, including gene clusters for biosurfactant production, such as the rhl operon in P. ananatis that synthesizes rhamnolipids for grazing resistance and environmental remediation.^[46] Such genes highlight Pantoea's promise in sustainable agriculture and bioremediation applications.^[39]

Ecology

Habitats and Distribution

Pantoea species are ubiquitous bacteria found in a wide array of natural environments worldwide, spanning tropical to temperate regions across the globe.^[20] They have been isolated from diverse sources, including soil, water bodies such as rivers and lakes, and plant-associated niches like the rhizosphere, phyllosphere, seeds, and decaying plant material.^[47] This broad ecological distribution reflects the genus's adaptability to various abiotic conditions, with examples reported from locations including Australia, Mexico, Russia, and South Africa.^[48] As of 2025, additional reports include isolations from rice in the Philippines, highlighting ongoing expansion in documented ranges.^[49] In agricultural settings, Pantoea exhibits high prevalence, particularly in crop ecosystems such as rice paddies and maize fields, where densities can be elevated due to the nutrient-rich interfaces of plant roots and surrounding soil.^[20] For instance, Pantoea ananatis has been detected in maize, onion fields, and sudangrass habitats.^[47] These environments provide favorable conditions for colonization, contributing to the bacteria's role in soil microbial communities. The distribution of Pantoea is influenced by key environmental factors, including moisture levels, temperature ranges, and nutrient availability. Higher moisture in aquatic and plant-adjacent habitats supports proliferation, while tolerance to varying temperatures—from refrigerated storage to frost-affected plants—enables persistence across climates.^[47] Nutrient-rich substrates, such as plant-derived carbohydrates and iron in the rhizosphere, further promote growth and dispersal.^[20] Detection of Pantoea in environmental samples typically relies on culture-dependent methods using selective media designed for Enterobacteriaceae, such as MacConkey agar or specialized differentials like Pantoea Differential Medium (PDM), which facilitate isolation by producing distinct colony morphologies.^[50] These approaches allow for the targeted recovery from complex matrices like soil and plant tissues, aiding in ecological surveys.^[20]

Interactions with Plants and Environment

Pantoea species commonly colonize plant surfaces as epiphytes, adhering to leaves and roots to form biofilms that facilitate nutrient exchange and environmental adaptation.^[51] This colonization enhances plant growth through mechanisms such as phosphate solubilization, where strains like Pantoea agglomerans and Pantoea brenneri secrete organic acids to convert insoluble soil phosphates into bioavailable forms, improving phosphorus uptake in crops like tomato and wheat.^[52]^[53] Additionally, these bacteria produce indole-3-acetic acid (IAA), a key auxin that stimulates root elongation and overall plant vigor, as observed in isolates from cereal crops.^[54]^[55] Beyond direct growth promotion, Pantoea strains exhibit biocontrol properties by antagonizing fungal pathogens, such as Fusarium species, through the production of antibiotics and competition for resources on plant surfaces.^[56] For instance, Pantoea agglomerans inhibits Fusarium graminearum growth in wheat, reducing fungal spore germination via diffusible compounds and induced plant resistance.^[57]^[58] Certain strains also contribute to nitrogen fixation, acting as diazotrophs to convert atmospheric N₂ into ammonia, thereby enriching soil nitrogen availability for associated plants like sugarcane.^[59] Complementing this, siderophore production by species such as Pantoea phytobeneficialis chelates iron from the environment, enhancing nutrient uptake and suppressing iron-limited pathogens in the rhizosphere.^[60]^[61] In environmental contexts, Pantoea bacteria aid soil remediation by degrading organic pollutants, including pesticides like quinalphos and petroleum hydrocarbons, through enzymatic pathways that break down toxic compounds into less harmful metabolites.^[62]^[63] Strains such as Pantoea ananatis demonstrate potential in lignocellulose and pesticide degradation, supporting phytoremediation efforts in contaminated agricultural soils.^[64] Quorum sensing mechanisms, mediated by N-acyl-homoserine lactones (AHLs), regulate these interactions by coordinating biofilm formation on plant surfaces, enabling collective behaviors like exopolysaccharide production for stable epiphytic communities.^[65] This AHL-based signaling in species like Pantoea ananatis optimizes colonization efficiency without invoking pathogenic responses.^[66]

Pathogenicity

Phytopathogenic Effects

Pantoea species, particularly P. ananatis and P. agglomerans, act as phytopathogens causing significant diseases in various crops through tissue degradation and necrosis.^[67] Notable examples include bacterial leaf blight in rice (Oryza sativa) induced by P. ananatis, characterized by water-soaked lesions at leaf tips that progress to drying and wilting, and center rot (soft rot) in onions (Allium cepa) caused by both P. ananatis and P. agglomerans, featuring leaf blight and bulb decay.^[68] Additional diseases encompass brown stalk rot (soft rot) in maize (Zea mays) from P. ananatis, heart rot in pineapple (Ananas comosus) leading to fruitlet discoloration and internal decay, and leaf spots in Eucalyptus species resulting in blight and dieback, primarily attributed to P. ananatis or related strains.^[67] These pathogens often originate from epiphytic colonization on plant surfaces before invading tissues.^[67] Virulence in Pantoea relies on multiple factors that facilitate host colonization and damage. Key among these are exopolysaccharides that promote biofilm formation, enhancing adhesion and persistence on plant surfaces, and quorum-sensing molecules such as N-acyl-homoserine lactones that regulate exopolysaccharide production.^[67] Extracellular enzymes, including pectate lyases and proteases, degrade plant cell walls and proteins, contributing to tissue maceration, while the type VI secretion system (T6SS) aids in injecting effectors into host cells.^[68] Toxins like indole-3-acetic acid (IAA) induce uncontrolled growth and subsequent tissue collapse, and phosphonate-based phytotoxins such as pantaphos, produced via the HiVir biosynthetic gene cluster, cause necrosis in susceptible tissues like onion scales.^[67]^[69] The infection process typically begins with entry through wounds, natural openings such as stomata, or vectors like insects and contaminated seeds, often under warm (20-35°C) and humid conditions that favor bacterial proliferation.^[67] Once inside, Pantoea forms biofilms on vascular tissues, secretes enzymes and toxins to break down cell walls, and induces necrosis, leading to symptom development such as wilting in rice or rot in onion bulbs; seed-borne transmission perpetuates the cycle in crops like rice and onions.^[68]^[70] Economically, Pantoea-induced diseases result in substantial crop losses, with center rot in onions causing up to 100% yield reduction in severe outbreaks in the United States and 30-50% in Korea, while bacterial leaf blight in rice leads to significant grain yield declines in epidemic areas of China. In maize, brown stalk rot reduces grain size and weight, impacting overall harvest quality, and heart rot in pineapple, though less severe at under 2% losses, affects marketable fruit; leaf spots in Eucalyptus plantations cause sporadic but costly dieback in forestry operations.^[67] Management of Pantoea phytopathogens emphasizes integrated approaches, including planting resistant varieties such as tolerant maize hybrids and Eucalyptus clones, which reduce disease incidence through genetic barriers to infection.^[67] Copper-based bactericides, often combined with fungicides like mancozeb, provide foliar protection against center rot in onions and leaf blight in rice, though efficacy varies with application timing. Biological controls, including antagonistic bacteria integrated with copper sprays, offer sustainable suppression of pathogen populations in field conditions for onion and maize crops. Cultural practices like mulching delay symptom onset in onions by limiting soil splash inoculum.^[67]

Infections in Humans and Animals

Pantoea species are opportunistic pathogens that rarely cause infections in humans, primarily affecting immunocompromised individuals, neonates, and those with penetrating wounds or nosocomial exposures.^[8] Infections often manifest as bacteremia, septicemia, wound infections, or device-related complications, with P. agglomerans being the most frequently implicated species.^[31] For instance, clusters of bacteremia have been reported in intravenous drug users due to contamination of needles or cotton filters with plant-derived material harboring the bacterium.^[71] Nosocomial cases are linked to contaminated intravenous fluids, catheters, or medical equipment, particularly in pediatric oncology patients or those undergoing chemotherapy.^[72] Clinical presentations typically include fever, chills, and sepsis, though symptoms can range from mild localized inflammation in wound infections to severe systemic illness in bacteremic cases.^[73] Diagnosis relies on isolation from blood, wound, or sterile site cultures, with identification confirmed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) or 16S rRNA sequencing to distinguish Pantoea from similar Enterobacteriaceae.^[74] Virulence is attributed to lipopolysaccharide (LPS) endotoxins, which contribute to inflammatory responses, and biofilm formation on medical devices such as urinary catheters, enhancing persistence and antibiotic resistance.^[75] In a retrospective study of 19 bloodstream infections in Italy (2018–2023), the 28-day mortality was low at 5.3%, reflecting the generally indolent course in treated patients, though recent reports indicate higher mortality (up to 71.4%) in neonatal cases.^[74]^[76] Treatment involves antibiotics to which Pantoea isolates show high susceptibility, including third-generation cephalosporins like ceftriaxone, carbapenems, and aminoglycosides, with over 90% susceptibility rates reported for most agents except ampicillin (63.2%).^[74] However, emerging resistance to piperacillin/tazobactam (15.8% resistant) and sporadic multidrug-resistant strains have been noted in post-2020 clinical isolates, underscoring the need for susceptibility testing.^[74] Source control, such as device removal, is critical for resolution. In animals, Pantoea infections are uncommon and often opportunistic, mirroring human cases in their environmental origins. P. agglomerans has been associated with mastitis in dairy cattle, where it acts as an environmental contaminant in bedding or water sources, leading to udder inflammation and reduced milk quality.^[77] In horses, the bacterium causes abortion and placentitis, with isolation from fetal tissues indicating ascending infection from contaminated environments.^[78] Haemorrhagic disease has been reported in dolphin fish (Coryphaena hippurus), while infections occur in brown trout (Salmo trutta).^[77]^[78] Virulence mechanisms, including endotoxin production and biofilm capabilities, likely facilitate persistence in animal hosts, though specific studies are limited.^[8] Treatment in veterinary settings typically involves broad-spectrum antibiotics, with emphasis on hygiene to prevent environmental transmission.^[79]

Species

Diversity and Evolution

The genus Pantoea currently encompasses approximately 30 validly described species as of 2025, reflecting its ecological versatility across plant-associated, environmental, and opportunistic pathogenic niches, with genomic surveys indicating substantial intraspecific and interclade variation that may warrant further species descriptions.^[80] Advances in whole-genome sequencing have revealed over 550 high-quality genomes classified within the genus as of 2023, with numbers likely higher due to ongoing research, highlighting untapped diversity and the potential for delineating additional taxa through phylogenomic approaches.^[20] The evolutionary trajectory of Pantoea traces back to its divergence from closely related genera such as Erwinia and Tatumella, though recent analyses indicate the genus is polyphyletic within the Erwiniaceae family (formerly Enterobacteriaceae), primarily propelled by adaptations to plant colonization as epiphytes and endophytes, with ongoing proposals to reclassify some species (e.g., P. citrea, P. punctata, P. terrea) to Tatumella. This association with angiosperms has shaped the genus's radiation, enabling exploitation of diverse vegetal habitats from soil and water to aerial plant surfaces, with genomic evidence underscoring ancient speciation events tied to host-specific interactions.^[3] Speciation within Pantoea is driven by mechanisms including niche adaptation to varied ecological roles—such as transitions from benign epiphytism to phytopathogenicity—and extensive horizontal gene transfer (HGT) of virulence factors, metabolic pathways, and antibiotic resistance genes.^[8]^[81] HGT, in particular, facilitates lifestyle shifts by integrating mobile genetic elements like plasmids and prophages, allowing rapid evolutionary responses to selective pressures in plant microbiomes.^[82] Intraspecific diversity is pronounced, with strains often clustered by geographic provenance; for instance, rice-pathogenic isolates of Pantoea ananatis from African regions exhibit distinct genomic profiles compared to Asian counterparts, reflecting localized adaptations to host varieties and environmental conditions.^[83] Such variation underscores ongoing evolutionary dynamics influenced by migration and selection. Looking ahead, taxonomic challenges persist due to polyphyletic assemblages within certain species clusters, prompting calls for emendations informed by multi-omics data to resolve ambiguities in classification and phylogeny.^[20]

Notable Species

Pantoea agglomerans is the most extensively studied and ubiquitous species within the genus, commonly occurring as an epiphyte on a wide range of plants, where it can act as both a commensal and an opportunistic pathogen causing issues such as galls on gypsophila and tumors on beets.^[9]^[8] It has been isolated from human infections, including septic arthritis following knee lacerations, highlighting its occasional role as an opportunistic human pathogen.^[8] Additionally, strains of P. agglomerans produce antimicrobial compounds and are commercially utilized in biocontrol products like BlightBan C9-1 to manage plant diseases such as fire blight in apples and pears, while also showing promise in bioremediation, such as arsenic degradation, and therapeutic applications like reversing immunosuppression.^[8] Pantoea ananatis is a prominent phytopathogen affecting crops like rice, where it causes stem necrosis, and onions, leading to center rot, as well as fruitlet rot in pineapples; it is also an epiphyte on these hosts and produces the antibiotic PNP-1.^[8] This species has demonstrated biocontrol potential against other pathogens and capabilities in bioremediation, such as degrading the herbicide mesotrione, though it has been linked to rare cases of human bacteremia.^[8] Pantoea stewartii, now recognized as Pantoea stewartii subsp. stewartii, is the causal agent of Stewart's wilt, a significant bacterial disease in corn transmitted by insect vectors like the corn flea beetle, utilizing a type III secretion system (T3SS) for virulence and exopolysaccharide (EPS) production for symptom development.^[8] Its quarantine status underscores its economic importance in agriculture, with research focusing on plant-insect interactions mediated by a plasmid-borne T3SS.^[8] Pantoea vagans serves primarily as a beneficial epiphyte, particularly on eucalyptus, where it produces antimicrobial agents and is employed as a commercial biocontrol agent in products like Bloomtime Biological to suppress fire blight caused by Erwinia amylovora in orchards.^[84]^[8] Among emerging species, Pantoea allii, described in 2011, is a pathogen isolated from onion plants and seeds, causing center rot in onions and posing challenges to bulb crop production.^[85] Similarly, Pantoea calida, first identified in 2010 from infant formula production environments and human clinical samples like urine and dialysate, represents a potential nosocomial pathogen, though its clinical significance remains under investigation.^[86]^[8]

References

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Taxonomy browser (Pantoea) - NCBI
name: enterobacteria Rank: genus Genetic code: Translation table 11 (Bacterial, Archaeal and Plant Plastid) Other names: heterotypic synonym
[2]
https://academic.oup.com/femsre/article/39/6/968/541478
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Phylogeny and Identification of Pantoea Species and Typing of ... - NIH
This study used multilocus gene sequencing to characterize Pantoea strains, including P. agglomerans, and to develop a method for strain typing.
[4]
Pantoea - Palmer - Major Reference Works - Wiley Online Library
Mar 9, 2022 · Pan.toe'a. Gr. masc. adj. pantoios, of all sorts and sources; N.L. fem. n. Pantoea, [bacteria] from diverse [geographical and ecological] ...
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Pantoea: insights into a highly versatile and diverse genus within the Enterobacteriaceae
### Summary of Abstract and Introduction on Pantoea Genus
[6]
Transfer of Enterobacter agglomerans (Beijerinck 1888) Ewing and ...
Jan 7, 1989 · The paper discusses the transfer of Enterobacter agglomerans to Pantoea gen. nov. as Pantoea agglomerans comb, nov. and the description of ...
[7]
Pantoea - an overview | ScienceDirect Topics
Pantoea is a genus of bacteria proposed in 1989, including the Erwinia herbicola group, and is considered to be heterogeneous.
[8]
Transfer of Erwinia ananas (synonym, Erwinia uredovora) and ...
Jan 1, 1993 · Transfer of Erwinia ananas (synonym, Erwinia uredovora) and Erwinia stewartii to the Genus Pantoea emend. as Pantoea ananas (Serrano 1928) comb. nov.
[9]
Emended description of the genus Pantoea ... - Microbiology Society
Jan 10, 2010 · Emended description of the genus Pantoea, description of four species from human clinical samples, Pantoea septica sp. nov., Pantoea eucrina sp. nov., Pantoea ...
[10]
Genomic delineation and description of species and ... - Frontiers
As the name of the genus Pantoea (“of all sorts and sources”) suggests, this genus includes bacteria with a wide range of provenances, including plants, animals ...
[11]
Examining phylogenetic relationships of Erwinia and Pantoea ...
Aug 22, 2015 · Examining phylogenetic relationships of Erwinia and Pantoea species using whole genome sequence data. Original Paper; Published: 22 August ...
[12]
Phylogeny and identification of Pantoea species ... - PubMed
MLSA uses gyrB, rpoB, atpD, and infB gene sequences to classify Pantoea strains, showing a core cluster separate from Japanese species.Missing: rRNA genome clades
[13]
Taxogenomics and Systematics of the Genus Pantoea - Frontiers
The MLSA approach based on six genes (leuS, fusA, gyrB, rpoB, and rlpB) was found to provide a more robust and reliable DNA relatedness and species delineation ...Missing: clades | Show results with:clades
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(PDF) Examining phylogenetic relationships of Erwinia and Pantoea ...
Aug 6, 2025 · different lifestyle from other species. Pantoea strains distribute into three clades. Inter-. estingly, two subspecies (stewartii and ...
[15]
Pantoea phytostimulans sp. nov., a novel strain with plant growth ...
Apr 25, 2025 · These values are all below the recommended cut-off values for prokaryotic species delineation, i.e. 95–96% for ANI and 70% for dDDH [45]. In ...
[16]
Pantoea - Grimont - Major Reference Works - Wiley Online Library
Sep 14, 2015 · Most strains are motile and are peritrichously flagellated. Gram negative. Colonies on nutrient agar are smooth, translucent, and more or less ...<|control11|><|separator|>
[17]
Pantoea - an overview | ScienceDirect Topics
Due to the different rates of evolution of different species, species for pan-genomic phylogeny need to be carefully selected and evaluated in the community.
[18]
A Carotenoid-Deficient Mutant in Pantoea sp. YR343, a Bacteria ...
Apr 18, 2016 · Microscopic observation showed that Pantoea sp. YR343 displays a rod-shaped morphology with cells averaging approximately 2 μm in length (Figure ...
[19]
Pantoea agglomerans - an overview | ScienceDirect Topics
Cultures grow well on nutrient agar at 30°C. Colonies on nutrient agar are smooth, translucent and more or less convex with entire margins. Colonies are ...
[20]
https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1254999/full
[21]
Physiologic and metabolic characterization of a new marine isolate ...
Jan 29, 2013 · The strain was identified as Pantoea sp. by 16S rRNA gene sequencing and biochemical tests. Time course of EPS production and partial chemical ...
[22]
Genomic characterization of Pantoea anthophila strain UI705 ...
Jul 13, 2023 · The genus Pantoea are Gram-negative, facultatively anaerobic, motile, and non-spore-forming bacteria that are generally isolated from ...
[23]
Pantoea agglomerans Infections in Children: Report of Two Cases
Jan 3, 2018 · Biochemical tests to differentiate P. agglomerans. Biochemicals, Interpretation. Catalase, Produced. Oxidase, Not produced. Citrate (Simmons) ...
[24]
Whole genome sequencing and characterization of Pantoea ...
Feb 7, 2024 · The phenotypic analysis focused on growth under both aerobic and anaerobic conditions, as well as traits associated with plant growth promotion.
[25]
Reconnoitering the capabilities of nodule endophytic Pantoea ...
Jan 27, 2023 · This study aimed to isolate endophytic bacteria from the root nodules of chickpea (Cicer arietinum L.) and determine their potential in improving plant growth.
[26]
Bloodstream Infections by Pantoea Species - PubMed Central - NIH
Dec 13, 2023 · Overall, Pantoea species bloodstream infection isolates displayed over 90% susceptibility to all the antibiotics except for ampicillin (63.2%), ...
[27]
Epidemiology and antibiotic resistance trends of Pantoea species in ...
Sep 1, 2019 · The highest levels of resistance were to amoxicillin–clavulanic acid and ampicillin. No extended spectrum beta-lactamase-positive isolate was ...
[28]
BlaPSZ-1, a novel AmpC gene identified from a Pantoea ... - Frontiers
Jul 16, 2023 · Results: The isolate Pantoea endophytica X85 showed some degree of resistance to penicillins as well as cephalosporins. A novel AmpC resistance ...
[29]
Draft Genome Sequence of Pantoea sp. Strain MHSD4, a Bacterial ...
Mar 13, 2024 · The average genome sizes and G+C content of Pantoea species range from 4.6 to 6.3 Mb and 52% to 55%, respectively. This is consistent with ...
[30]
Draft Genome Sequence of Pantoea sp. Strain MBLJ3, Isolated in a ...
Feb 26, 2015 · MBLJ3. The genome is 4.8 Mb in size, with a G+C content of 54.27%, and it contains 4,522 protein-coding sequences, 69 tRNA genes, and 5 rRNA ...
[31]
Complete Genome Sequence of Pantoea ananatis Strain NN08200 ...
The genome of strain NN08200 contains a single chromosome of 4,743,568 nucleotides with 53.8% G+C content and two plasmids, one of 125,402 nucleotides with ...
[32]
Characterization of a small cryptic plasmid from endophytic Pantoea ...
A circular cryptic plasmid named pPAGA (2,734 bp) was isolated from Pantoea agglomerans strain EGE6 (an endophytic bacterial isolate from eucalyptus).
[33]
The large universal Pantoea plasmid LPP-1 plays a major role in ...
Nov 15, 2012 · LPP-1 is universal to all Pantoea spp. whose genomes have been sequenced to date and is derived from an ancestral plasmid.Missing: dimensions | Show results with:dimensions
[34]
Pan-Genome-Wide Analysis of Pantoea ananatis Identified Genes ...
Pan-genome analysis revealed a large core genome of 3,153 genes and a flexible accessory genome. Pan-GWAS using the presence and absence variants (PAVs) ...Introduction · Materials and Methods · Results · Discussion
[35]
Pan-Genome-Wide Analysis of Pantoea ananatis Identified Genes ...
Pantoea ananatis, a Gram-negative and facultative anaerobic bacterium that belongs to the Erwiniaceae (previously assigned to enterobacteriaceae) is part of a ...<|control11|><|separator|>
[36]
Comparative genomics reveals the acquisition of mobile genetic ...
The Pantoea pan-genome has 27,767 gene orthologs, of which 542 are shared by the core and soft-core genomes, while 4336 and 22,889 clusters constitute the shell ...<|control11|><|separator|>
[37]
Horizontal Gene Acquisitions, Mobile Element Proliferation, and ...
Mar 18, 2016 · ... Erwinia/Pantoea phylogeny reconstructed from 731 ... pathogenicity islands were flagged by HGTector as putatively horizontally acquired.Horizontal Gene Acquisitions... · Results And Discussion · Type Iii Secretion System...
[38]
Inheritance of Pantoea type III secretion systems through both ...
Aug 6, 2025 · Thus, T3SS genes in Pantoea and Erwinia strains might have been acquired by horizontal gene transfer. Overall, our findings clarify the ...
[39]
Genetic islands in pome fruit pathogenic and non ... - Frontiers
Recent research on evolution of erwinias point out the horizontal transfer acquisition of some genomic islands that were subsequently lost in some species and ...Type Iii Secretion Systems · Type Vi Secretion Systems · Plasmids And Genetic...
[40]
A Novel Glycolipid Biosurfactant Confers Grazing Resistance upon ...
The genetic factors used for host interaction by the opportunistic human pathogen Pantoea ananatis are largely unknown. We identified two genes that are ...
[41]
Analysis of the Pantoea ananatis pan-genome reveals factors ...
May 27, 2014 · Pantoea ananatis is found in a wide range of natural environments, including water, soil, as part of the epi- and endophytic flora of various ...
[42]
Pantoea ananatis: genomic insights into a versatile pathogen - NIH
Pantoea ananatis is a Gram-negative, rod-shaped bacterium, known for its phytopathogenic characteristics, causing disease in various plants.
[43]
A semi-selective differential medium for identifying strains of ... - NIH
Oct 1, 2025 · In this study, we developed a new differential medium called “Pantoea Differential Medium (PDM)” that inhibits the growth of many Gram-positive ...
[44]
The extreme plant‐growth‐promoting properties of Pantoea ...
Feb 19, 2020 · Pantoea are found in a wide range of environments and mostly colonize and interact with plants hosts, acting as epiphytes and endophytes of ...
[45]
The phosphate solubilizing and N fixing Pantoea agglomerans ...
The selected bacteria were able to efficiently colonize tomato roots, produce plant hormones including indole acetic acid and solubilize phosphate. With the ...
[46]
Phosphate Solubilization and Plant Growth Promotion by Pantoea ...
Apr 27, 2023 · The aim of this study was to evaluate the inorganic soil phosphate solubilizing activity of phytate-hydrolyzing Pantoea brenneri soil isolates.
[47]
Phosphate solubilization and plant growth promotion by two ...
Sep 12, 2022 · In addition to phosphate solubilization, both the Pantoea isolates (HCF6 and HCF9) possess several PGP traits such as IAA and siderophores ...
[48]
Unveiling wheat growth promotion potential of phosphate ...
Sep 9, 2024 · Genetic and physiological characterizations of Pantoea sp. confirmed wheat growth promotion potential (Rasul et al., 2021) and successful ...
[49]
[PDF] Pantoea agglomerans: a mysterious bacterium of evil and good. Part ...
Pantoea agglomerans has beneficial traits for disease prevention, treatment, plant growth, and bioremediation. It produces antibiotics and has healing ...
[50]
[PDF] Gene expression profile of the plant pathogen Fusarium ...
Jul 16, 2010 · The bacterium Pantoea agglomerans has been reported to be an effective bio- logical control agent for protecting a number of crop plants from ...<|control11|><|separator|>
[51]
The plant-associated Pantoea spp. as biocontrol agents
This review addresses the current knowledge about the various types of interactions and metabolic traits of Pantoea spp. in protecting plants against pathogens.
[52]
Diazotrophic Bacteria Pantoea dispersa and Enterobacter asburiae ...
Jan 11, 2021 · A total of 350 rhizobacterial strains were isolated by using four different selective media from the sugarcane rhizosphere. Out of them ...
[53]
The extreme plant-growth-promoting properties of Pantoea ...
Nov 2, 2025 · Furthermore, genes related to siderophore production contribute to iron availability, whereas phosphate solubilization genes improve nutrient ...
[54]
Opposite Sides of Pantoea agglomerans and Its Associated ... - NIH
Oct 20, 2022 · Members of this genus contribute to plant growth mainly by increasing the supply of nitrogen, solubilizing ammonia and inorganic phosphate, and ...
[55]
Pantoea agglomerans: a mysterious bacterium of evil and good. Part ...
Jun 2, 2016 · It has been documented that the Pantoea strains show biodegradation activity on various chemical pollutants of soil and water, including ...
[56]
Biodegradation of quinalphos by gram negative bacteria Pantoea ...
May 10, 2023 · The optimal concentration of quinalphos for the growth of Pantoea agglomerans was 100 ppm, while for Acinetobacter sp. dcm5A was 200 ppm.
[57]
Identification and characterization of a novel bacterial carbohydrate ...
Mar 6, 2020 · ... Pantoea ananatis Sd-1 with potential for degradation of lignocellulose and pesticides. Original Research Paper; Published: 06 March 2020.
[58]
The Plant Pathogen Pantoea ananatis Produces N-Acylhomoserine ...
These results demonstrated that the quorum-sensing system involved the biosynthesis of EPS, biofilm formation, and infection of onion leaves in P. ananatis SK-1 ...
[59]
Cell aggregation is negatively regulated by N-acylhomoserine ...
Pantoea ananatis SK-1 produces N-acylhomoserine lactones (AHLs) and regulates expression of some virulence factors through AHL-mediated quorum sensing.
[60]
https://www.researchgate.net/publication/339380366_The_extreme_plant-growth-promoting_properties_of_Pantoea_phytobeneficialis_MSR2_revealed_by_functional_and_genomic_analysis
[61]
https://pmc.ncbi.nlm.nih.gov/articles/PMC9610544/
[62]
https://pubmed.ncbi.nlm.nih.gov/27294621/
[63]
https://journal.environcj.in/index.php/ecj/article/view/2413
[64]
Successful Treatment of Pantoea agglomerans Bacteremia Using ...
Apr 23, 2022 · agglomerans infections, and the bacteria are often found to be susceptible to amikacin, gentamicin, meropenem, ciprofloxacin, levofloxacin, ...
[65]
A Case of Nosocomial Outbreak of Pantoea agglomerans Related to ...
Jun 7, 2021 · In most cases, the clinical course of the infection is mild and the administration of the proper antibiotic leads to complete recovery.A Case Of Nosocomial... · 1. Introduction · Case Report<|control11|><|separator|>
[66]
Pantoea agglomerans Bacteremia: Is It Dangerous? - PubMed Central
Apr 3, 2020 · Pantoea agglomerans, an anaerobic Gram-negative bacillus, is a rare cause of opportunistic infections affecting premature infants to seniors.
[67]
Bloodstream Infections by Pantoea Species: Clinical and ... - MDPI
Dec 13, 2023 · Overall, Pantoea species bloodstream infection isolates displayed high susceptibility to all the antibiotics except for ampicillin (63.2 ...
[68]
Occurrence of Biofilm Formation in Serratia fonticola and Pantoea sp ...
Sep 29, 2018 · Serratia fonticola at 3 and Pantoea sp. at 4 isolates revealed to possess the ability of forming biofilm which contained SmaI and EsaI genes ...
[69]
Pantoea agglomerans - an overview | ScienceDirect Topics
1.5 Pantoea. Genus Pantoea was proposed by Gavini et al. (1989) to separate Enterobacter agglomerans/Erwinia herbicola from the genera Enterobacter and Erwinia, ...
[70]
Pantoea agglomerans : a mysterious bacterium of evil and good ...
Pantoea agglomerans, a bacterium associated with plants, is not an obligate infectious agent in humans. However, it could be a cause of opportunistic human ...
[71]
Unveiling the prevalence and antimicrobial resistance landscape of ...
Jul 7, 2025 · Susceptibility testing was performed by the standard disk diffusion method using Mueller-Hinton agar. Pantoea strains were recovered from ...
[72]
Genus: Pantoea - LPSN
Pantoea is a genus of bacteria from diverse sources, with the type species being Pantoea agglomerans. It is a feminine genus.
[73]
Inferring ancient metabolism using ancestral core metabolic models ...
Jun 11, 2013 · Catabolism of these substrates has been conserved in all free-living enterobacteria as they diverged over ~300-500 million years. Once ...
[74]
Pan-Genome of Novel Pantoea stewartii subsp. indologenes ... - NIH
Further, we conducted a horizontal gene transfer (HGT) study using Psi strains from both pathovars along with strains from other Pantoea species, namely, P.
[75]
Comparative genomics-based insights into Pantoea ananatis strains ...
May 19, 2025 · (A) Phylogenetic tree of 12 sequenced isolates and 14 other Pantoea ... ananatis pan-genome and core genome. Go to Figure Open in Viewer.
[76]
[PDF] Pantoea spp: a new bacterial threat to rice production in sub ...
Jun 16, 2020 · Description of the genus Pantoea Gavini et al. (1988) emended. Mergaert et al. ... All the details of this first report about the sequencing ...
[77]
Pantoea vagans sp. nov., Pantoea eucalypti sp. nov., Pantoea deleyi ...
Jan 9, 2009 · Bacteria isolated from eucalyptus leaves and shoots showing symptoms of blight and die-back collected in Uganda, Uruguay and Argentina and ...
[78]
Pantoea allii sp. nov., isolated from onion plants and seed
Jan 4, 2011 · Eight yellow-pigmented, Gram-negative, rod-shaped, oxidase-negative, motile, facultatively anaerobic bacteria were isolated from onion seed ...
[79]
Pantoea gaviniae sp. nov. and Pantoea calida sp. nov., isolated from ...
Jan 12, 2010 · Pantoea gaviniae sp. nov. and Pantoea calida sp. nov., isolated from infant formula and an infant formula production environment Free.