Pantoea Ananatis Research Articles

Characterization of two LuxI/R homologs in Pantoea ananatis LMG 2665T.

Quorum sensing (QS) plays an important role in the regulation of bacteria-host interactions and ecological fitness in many bacteria. In this study, 2 luxI/R homologs, namely eanI/eanR and rhlI/rhlR, were identified in the genome sequence of Pantoea ananatis LMG 2665T. To determine a role for these luxI/R homologs in pathogenicity and biofilm formation, mutant bacterial strains lacking either eanI/R or rhlI/R and both of these homologs were generated. The results indicated that both the RhlI/R and EanI/R systems are required for pathogenicity and biofilm formation in strain LMG 2665T. This is the first study to characterize the biological significance of the RhlI/R QS system in P. ananatis.

PCR Primers for Detection of Pantoea ananatis, Burkholderia spp., and Enterobacter sp. from Onion.

Bacterial decays of onion bulbs cause sporadic and sometimes serious losses to onion (Allium cepa). In New York, three groups of bacteria were identified as problematic: Burkholderia spp., Pantoea ananatis, and Enterobacter spp. To aid in efficient detection and diagnosis of these pathogens, pairs of specific polymerase chain reaction primers were designed and validated, based on a strategy that utilized various genome sequences now available in public databases. Primer pairs were tested against numerous strains of target bacteria, closely related bacteria, and other onion-pathogenic bacteria. Each primer pair yielded a single, apparently highly specific amplicon from aqueous suspensions of the target bacteria. Minimum sensitivities were approximately 103 CFU per 25-μl reaction mixture for all three primer pairs.

Whole genome sequence of Pantoea ananatis R100, an antagonistic bacterium isolated from rice seed

Pantoea ananatis is a group of bacteria, which was first reported as plant pathogen. Recently, several papers also described its biocontrol ability. In 2003, P. ananatis R100, which showed strong antagonism against several plant pathogens, was isolated from rice seeds. In this study, whole genome sequence of this strain was determined by SMRT Cell technology. The total genome size of R100 is 4,857,861bp with 4659 coding genes (CDS), 82 tRNAs and 22 rRNAs. The genome sequence of R100 may shed a light on the research of antagonism P. ananatis.

Detection of virulence and pathogenicity genes in selected phytopathovars

Plant pathogenic organisms are known to infect host cell using various range of secretory proteins. Amongst all other secretion systems, type III secretion system (T3SS) is a key mechanism for bacterial pathogenesis for establishing and maintaining infection into the host. Expression levels of seven genes viz. avrXacE1, avrXacE2, hpaA and hrpG along with bacterial endogenous control lrp (leucine-responsive protein) were studied. The pathogenic organisms selected for the present study includes Enterobacter cloacae, Enterobacter spp., Pantoea ananatis, Xanthomonas campestris pv. Citri, Pantoea agglomerans, Ochrobactrum anthropi and Erwinia chrysanthemi. P. agglomerans and Enterobacter spp. gave high expression of above-mentioned virulence genes compared to Xanthomonas, while E. cloacae and P. ananatis showed similar expression with that of Xanthomonas. The detailed relationship of the expression profiles with respect to the selected organisms is discussed.

Draft Genome Sequence of Pantoea ananatis Strain AMG521, a Rice Plant Growth-Promoting Bacterial Endophyte Isolated from the Guadalquivir Marshes in Southern Spain

The rice endophyte Pantoea ananatis AMG521 shows several plant growth-promoting properties and promotes rice yield increases. Its draft genome was estimated at 4,891,568 bp with 4,704 coding sequences (CDS). The genome encodes genes for N-acylhomoserine lactone (AHL) synthases, AHL hydrolases, hyperadherence (yidQ, yidP, and yidR), fusaric acid resistance, and oxidation of lignin, highlighting its biotechnological potential.

Genomic and secretomic insight into lignocellulolytic system of an endophytic bacterium Pantoea ananatis Sd-1.

BackgroundExploring microorganisms especially bacteria associated with the degradation of lignocellulosic biomass shows great potentials in biofuels production. The rice endophytic bacterium Pantoea ananatis Sd-1 with strong lignocellulose degradation capacity has been reported in our previous study. However, a comprehensive analysis of its corresponding degradative system has not yet been conducted. The aim of this work is to identify and characterize the lignocellulolytic enzymes of the bacterium to understand its mechanism of lignocellulose degradation and facilitate its application in sustainable energy production.ResultsThe genomic analysis revealed that there are 154 genes encoding putative carbohydrate-active enzymes (CAZy) in P. ananatis Sd-1. This number is higher than that of compared cellulolytic and ligninolytic bacteria as well as other eight P. ananatis strains. The CAZy in P. ananatis Sd-1 contains a complete repertoire of enzymes required for cellulose and hemicellulose degradation. In addition, P. ananatis Sd-1 also possesses plenty of genes encoding potential ligninolytic relevant enzymes, such as multicopper oxidase, catalase/hydroperoxidase, glutathione S-transferase, and quinone oxidoreductase. Quantitative real-time PCR analysis of parts of genes encoding lignocellulolytic enzymes revealed that they were significantly up-regulated (at least P < 0.05) in presence of rice straw. Further identification of secretome of P. ananatis Sd-1 by nano liquid chromatography–tandem mass spectrometry confirmed that considerable amounts of proteins involved in lignocellulose degradation were only detected in rice straw cultures. Rice straw saccharification levels by the secretome of P. ananatis Sd-1 reached 129.11 ± 2.7 mg/gds. Correspondingly, the assay of several lignocellulolytic enzymes including endoglucanase, exoglucanase, β-glucosidase, xylanase-like, lignin peroxidase-like, and laccase-like activities showed that these enzymes were more active in rice straw relative to glucose substrates. The high enzymes activities were not attributed to bacterial cell densities but to the difference of secreted protein contents.ConclusionOur results indicate that P. ananatis Sd-1 can produce considerable lignocellulolytic enzymes including cellulases, hemicellulases, and ligninolytic relevant enzymes. The high activities of those enzymes could be efficiently induced by lignocellulosic biomass. This identified degradative system is valuable for the lignocellulosic bioenergy industry.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0439-8) contains supplementary material, which is available to authorized users.

First Report of Soft Rot Disease of Peach Caused by Pantoea ananatis in China

First Report of Soft Rot Disease of Peach Caused by <i>Pantoea ananatis</i> in China

ChemInform Abstract: (6E) and (6Z)‐9′‐Aporhodoxanthinone, Novel Carotenoids Produced in Zeaxanthin‐Synthesizing‐Escherichia coli by Redox Stress.

Abstract Recombinant Escherichia coli, carrying the crtE, crtB, crtI, crtY, and crtZ genes from the bacterium Pantoea ananatis in addition to the Haematococcus pluvialis idi gene, can dominantly produce zeaxanthin. Vigorous rotary-shaking culture of the recombinant cells to promote strong aeration led to the production of two structurally similar polar carotenoids [1 (3.7%) and 2 (2.9%)] and eschscholtzxanthone (2.3%), along with zeaxanthin (72.6%), β-cryptoxanthin (7.3%), β-carotene (7.1%), and rubixanthin (2.1%). Carotenoids 1 and 2 were purified, and their structures were determined as (6E)-9′-apo-rohodoxanthinone and (6Z)-9′-apo-rhodoxanthinone, respectively, based on UV–vis, MS, 1H NMR, and 13C NMR spectral data. These novel compounds were shown to exhibit excellent singlet oxygen-quenching activity by the methylene blue-sensitized photooxidation system.

A Novel Glycolipid Biosurfactant Confers Grazing Resistance upon Pantoea ananatis BRT175 against the Social Amoeba Dictyostelium discoideum.

Pantoea is a versatile genus of bacteria with both plant- and animal-pathogenic strains, some of which have been suggested to cause human infections. There is, however, limited knowledge on the potential determinants used for host association and pathogenesis in animal systems. In this study, we used the model host Dictyostelium discoideum to show that isolates of Pantoeaananatis exhibit differential grazing susceptibility, with some being resistant to grazing by the amoebae. We carried out a high-throughput genetic screen of one grazing-resistant isolate, P.ananatis BRT175, using the D.discoideum pathosystem to identify genes responsible for the resistance phenotype. Among the 26 candidate genes involved in grazing resistance, we identified rhlA and rhlB, which we show are involved in the biosynthesis of a biosurfactant that enables swarming motility in P.ananatis BRT175. Using liquid chromatography-mass spectrometry (LC-MS), the biosurfactant was shown to be a glycolipid with monohexose-C10-C10 as the primary congener. We show that this novel glycolipid biosurfactant is cytotoxic to the amoebae and is capable of compromising cellular integrity, leading to cell lysis. The production of this biosurfactant may be important for bacterial survival in the environment and could contribute to the establishment of opportunistic infections. IMPORTANCE The genetic factors used for host interaction by the opportunistic human pathogen Pantoea ananatis are largely unknown. We identified two genes that are important for the production of a biosurfactant that confers grazing resistance against the social amoeba Dictyostelium discoideum. We show that the biosurfactant, which exhibits cytotoxicity toward the amoebae, is a glycolipid that incorporates a hexose rather than rhamnose. The production of this biosurfactant may confer a competitive advantage in the environment and could potentially contribute to the establishment of opportunistic infections.

Antifungal activity of novel indole derivative from endophytic bacteria Pantoea ananatis 4G-9 against Mycosphaerella musicola

ABSTRACTAn endophytic bacterium isolated from banana G-9 (AAA genotype) leaves exhibited strong antagonistic activity against Mycosphaerella musicola. The isolate was identified as Pantoea ananatis 4G-9 by 16S rRNA sequence analysis. Secondary metabolite obtained from P. ananatis 4G-9 was found to have antifungal activity. The active compound was purified from crude extract using column chromatography. Purity of the active compound was assessed using high-performance liquid chromatography. Spectral analysis of compound using infrared, mass spectrometry and nuclear magnetic resonance indicated that the compound structure is an indole derivative. The compound showed strong and dose-dependent antifungal activity against M. musicola. This is the first report on P. ananatis isolated as an endophyte from banana leaves and its antifungal activity against M. musicola.

Identification and functional analysis of the geranylgeranyl pyrophosphate synthase gene (crtE) and phytoene synthase gene (crtB) for carotenoid biosynthesis in Euglena gracilis

BackgroundEuglena gracilis, a unicellular phytoflagellate within Euglenida, has attracted much attention as a potential feedstock for renewable energy production. In outdoor open-pond cultivation for biofuel production, excess direct sunlight can inhibit photosynthesis in this alga and decrease its productivity. Carotenoids play important roles in light harvesting during photosynthesis and offer photoprotection for certain non-photosynthetic and photosynthetic organisms including cyanobacteria, algae, and higher plants. Although, Euglenida contains β-carotene and xanthophylls (such as zeaxanthin, diatoxanthin, diadinoxanthin and 9′-cis neoxanthin), the pathway of carotenoid biosynthesis has not been elucidated.ResultsTo clarify the carotenoid biosynthetic pathway in E. gracilis, we searched for the putative E. gracilis geranylgeranyl pyrophosphate (GGPP) synthase gene (crtE) and phytoene synthase gene (crtB) by tblastn searches from RNA-seq data and obtained their cDNAs. Complementation experiments in Escherichia coli with carotenoid biosynthetic genes of Pantoea ananatis showed that E. gracilis crtE (EgcrtE) and EgcrtB cDNAs encode GGPP synthase and phytoene synthase, respectively. Phylogenetic analyses indicated that the predicted proteins of EgcrtE and EgcrtB belong to a clade distinct from a group of GGPP synthase and phytoene synthase proteins, respectively, of algae and higher plants.In addition, we investigated the effects of light stress on the expression of crtE and crtB in E. gracilis. Continuous illumination at 460 or 920 μmol m−2 s−1 at 25 °C decreased the E. gracilis cell concentration by 28–40 % and 13–91 %, respectively, relative to the control light intensity (55 μmol m−2 s−1). When grown under continuous light at 920 μmol m−2 s−1, the algal cells turned reddish-orange and showed a 1.3-fold increase in the crtB expression. In contrast, EgcrtE expression was not significantly affected by the light-stress treatments examined.ConclusionsWe identified genes encoding CrtE and CrtB in E. gracilis and found that their protein products catalyze the early steps of carotenoid biosynthesis. Further, we found that the response of the carotenoid biosynthetic pathway to light stress in E. gracilis is controlled, at least in part, by the level of crtB transcription. This is the first functional analysis of crtE and crtB in Euglena.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-015-0698-8) contains supplementary material, which is available to authorized users.

Antagonistic Effect of Bacteria Isolated from the Digestive Tract of &amp;lt;i&amp;gt;Lutzomyia evansi&amp;lt;/i&amp;gt; against Promastigotes of &amp;lt;i&amp;gt;Leishmania infantum&amp;lt;/i&amp;gt;, Antimicrobial Activities and Susceptibility to Antibiotics

Lutzomyia evansi is a phlebotomine insect endemic to Colombia’s Caribbean coast and is considered the main vector of visceral and cutaneous leishmaniasis in the region. Specific studies of the direct effects generated by bacteria in the digestive tract of the insect vectors, under Leishmania infantum using in vitro models, represent a novel alternative as a control strategy for the transmission of leishmaniasis and also provide the opportunity to detect natural products or antimicrobial peptides with different biological activities. In this study, we evaluate the leishmanicidal and antimicrobial activities of Pantoea ananatis, Ochrobactrum anthropi and Enterobacter cloacae, isolated from the digestive tract of Lutzomyia evansi and the susceptibility of these bacteria to commonly used antibiotics. The antagonistic effect of Pantoea ananatis, Ochrobactrum anthropi and Enterobacter cloacae was evaluated against six species of human pathogenic bacteria and against stationary (Metacyclic-like) and exponential promastigotes (Procyclic-like) of Leishmania infantum (BCN-GFP strain) by co-culture assays for 24 hours. The activity of the bacterial isolates on Leishmania infantum promastigotes was quantified by flow cytometry. The susceptibility of the bacterial strains to clinically used antibiotics was analyzed by antibiogram. The highest percentage of inhibition was observed against exponential promastigotes with bacterial concentrations of 108 CFU/ml of Enterobacter cloacae (77.29% ± 0.6%) and Pantoea ananatis (70.17% ± 1.1%). The extracts produced by three bacterial isolates showed similar biological activity (13 mm - 22 mm inhibition halos) against all tested bacteria; however, significant differences were observed with respect to gram-positive bacteria (P Bacillus cereus. Ochrobactrum anthropi was the isolate with the highest number of antibiotic resistance patterns while Pantoea ananatis and Enterobacter cloacae showed greater susceptibility to the evaluated antibiotics. The growth inhibitory activity of exponential Leishmania infantum promastigotes shown by extracts of Enterobacter cloacae and Pantoea ananantis suggests that the presence of these bacteria in the vector intestine may affect the parasite development to metacyclic stages, infective to human hosts. This in turn confers said bacteria, a potential in controlling the transmission of Leishmania spp. that deserves to be studied in depth.

Characterization of the inaA gene and expression of ice nucleation phenotype in Pantoea ananatis isolates from Maize White Spot disease.

Maize White Spot (MWS), a foliar disease caused by Pantoea ananatis, could cause up to 60% yield loss. Some strains of P. ananatis harboring the ice nucleation gene inaA catalyze the formation of ice nuclei, causing tissue damage at temperatures slightly below freezing. Little is known about the relationship between the presence of the ina gene in this maize pathogen and its expression during the phenomenon of ice nucleus formation. Here, we attempted to verify the presence of the inaA gene and the expression of phenotype in vitro. The identity of the isolates and the presence of the inaA gene were determined by P. ananatis species-specific primers. The expression of the inaA gene was assessed in vitro by the visualization of ice-crystal formation in water at subzero temperatures. A total of ninety P. ananatis isolates from MWS lesions were characterized. The presence of the inaA gene was confirmed by gel electrophoresis of the 350-400-bp PCR products. The inaA primers did not lead to DNA fragment amplification in three isolates. The ice nucleation phenotype was expressed in 83.34% of the isolates carrying the inaA gene. Our study showed that the ice nucleation in P. ananatis isolated from MWS lesions was dependent on the presence of a functional ina gene in the genome. We also found evidence indicating that some P. ananatis strains have a mutated form of the inaA gene, producing a non-functional ice nucleation protein. This is the first report on inaA gene characterization in P. ananatis isolates from Maize White Spot.

Colonization of Endophytic BacteriumPantoea ananatisMR5 Strain by Tagging with GFP in Wheat Tissues

The strain, Pantoea ananatis MR5 taxonomically identified using 16S ribosomal DNA sequence was isolated from roots of Cenchrus biflorus. Its endophytic colonization was investigated microscopically using green fluorescent protein introduced by vector pGLO. The strain entered wheat tissues through the root and was localized in the roots, stems & leaves.

Genomic variability of Pantoea ananatis in maize white spot lesions assessed by AFLP markers.

Measures to control maize white spot (MWS) caused by Pantoea ananatis are preferentially based on resistant cultivars. A lack of knowledge on the genetic variability of pathogens could interfere with the development and utilization of controlling strategies in this pathosystem. The main goals of this study were to investigate the genetic variability of 90 P. ananatis isolates from three different eco-geographical regions of Brazil by amplified fragment length polymorphism (AFLP), and to determine the presence of a universal P. ananatis plasmid in isolates from tropical Brazil. Analysis of genetic similarity by AFLP allowed us to categorize the 90 isolates into two groups. However, no correlation between the collecting sites and genetic groupings was observed. The polymorphism percentage found in P. ananatis ranged between 24.64 and 92.46%, and genetic diversity was calculated to be 0.07-0.09. The analysis of molecular variance showed that 99.18% of genetic variability was within the populations, providing evidence that evolutionary forces were acting on these populations. All P. ananatis isolates showed the P. ananatis universal plasmid (280 or 352 kb). This is the first report on the presence of a universal P. ananatis plasmid from MWS lesions in the tropical area.

First detection of Pantoea ananatis, the causal agent of bacterial center rot of onion in Morocco

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Ketocarotenoid Production in Soybean Seeds through Metabolic Engineering.

The pink or red ketocarotenoids, canthaxanthin and astaxanthin, are used as feed additives in the poultry and aquaculture industries as a source of egg yolk and flesh pigmentation, as farmed animals do not have access to the carotenoid sources of their wild counterparts. Because soybean is already an important component in animal feed, production of these carotenoids in soybean could be a cost-effective means of delivery. In order to characterize the ability of soybean seed to produce carotenoids, soybean cv. Jack was transformed with the crtB gene from Pantoea ananatis, which codes for phytoene synthase, an enzyme which catalyzes the first committed step in the carotenoid pathway. The crtB gene was engineered together in combinations with ketolase genes (crtW from Brevundimonas sp. strain SD212 and bkt1 from Haematococcus pluvialis) to produce ketocarotenoids; all genes were placed under the control of seed-specific promoters. HPLC results showed that canthaxanthin is present in the transgenic seeds at levels up to 52 μg/g dry weight. Transgenic seeds also accumulated other compounds in the carotenoid pathway, such as astaxanthin, lutein, β-carotene, phytoene, α-carotene, lycopene, and β-cryptoxanthin, whereas lutein was the only one of these detected in non-transgenic seeds. The accumulation of astaxanthin, which requires a β-carotene hydroxylase in addition to a β-carotene ketolase, in the transgenic seeds suggests that an endogenous soybean enzyme is able to work in combination with the ketolase transgene. Soybean seeds that accumulate ketocarotenoids could potentially be used in animal feed to reduce or eliminate the need for the costly addition of these compounds.

(6E) and (6Z)-9′-Aporhodoxanthinone, novel carotenoids produced in zeaxanthin-synthesizing-Escherichia coli by redox stress

Recombinant Escherichia coli, carrying the crtE, crtB, crtI, crtY, and crtZ genes from the bacterium Pantoea ananatis in addition to the Haematococcus pluvialis idi gene, can dominantly produce zeaxanthin. Vigorous rotary-shaking culture of the recombinant cells to promote strong aeration led to the production of two structurally similar polar carotenoids [1 (3.7%) and 2 (2.9%)] and eschscholtzxanthone (2.3%), along with zeaxanthin (72.6%), β-cryptoxanthin (7.3%), β-carotene (7.1%), and rubixanthin (2.1%). Carotenoids 1 and 2 were purified, and their structures were determined as (6E)-9′-apo-rohodoxanthinone and (6Z)-9′-apo-rhodoxanthinone, respectively, based on UV–vis, MS, 1H NMR, and 13C NMR spectral data. These novel compounds were shown to exhibit excellent singlet oxygen-quenching activity by the methylene blue-sensitized photooxidation system.

Genome Sequence of Pantoea ananatis Strain CFH 7-1, Which Is Associated with a Vector-Borne Cotton Fruit Disease.

Pantoea ananatis is a bacterium with versatile niches that vary from pathogenic to beneficial. We present the genome of strain CFH 7-1, which was recovered from a diseased greenhouse cotton boll previously caged with a field-collected cotton fleahopper (Pseudatomoscelis seriatus). These data will assist in deciphering the infection process.

Bacteria species and solution pH effect postharvest quality of cut Zinnia elegans

Bacterial growth in vase solutions can lead to stem vasculature blockage causing petal and leaf wilt, bent neck, or similar symptoms related to water stress that reduce vase life. In these studies we isolated, identified, and evaluated the effects of several bacteria species on the vase life of cut Zinnia elegans L. ‘Benary’s Giant Wine’. Nine bacterial species were isolated during postharvest testing of cut zinnia stems: Pseudomonas fulva, Serratia ficaria, Rhizobium radiobacter, Chryseobacterium sp., Pantoea ananatis, Bacillus pumilus, Chryseobacterium daejeonense, Brevundimonas sp., and Pseudomonas marginalis and pure cultures of each species were added to the vase solution of cut zinnia stems. Escherichia coli K12, a lab adapted strain, was also included. Cut flowers inoculated with P. fulva and E. coli K12 had significantly greater vase lives of 9.5 and 9.4 d, respectively, compared to P. marginalis, P. ananatis, R. radiobacter, or the nutrient broth control (7.0, 6.9, 6.8, or 7.3 d, respectively). The vase lives of the other bacteria treatments were not statistically different from the deionized (DI) water control (8.6 d). There were no significant differences in water uptake or vase water bacteria concentrations at termination among all treatments. In further studies, sterilized and non-sterilized stems of Zinnia were used to investigate the effects of solution pH and the addition of P. marginalis and E. coli K12 on number of days to drought stress (DTDS), stem hydraulic conductivity, and bacteria concentrations inside and outside the stem. The non-sterilized stems in control solution with E. coli K12 and non-sterilized stems in preservative solution with no bacteria had the most DTDS of 8.0 d. The sterilized stems in the control solution (deionized water) with E. coli K12 and sterilized stems in basic solution with no bacteria had the least DTDS of 5.5 d and 5.8 d, respectively. The concentrations of bacteria inside and outside the stems were lowest for stems in the preservative solutions. Of the stems that were sterilized, partial percent loss of conductivity (PPLC) was significantly lower in the acidic solutions (64%) compared to the preservative (87%) and control (83%). This research shows that for Zinnia the bacteria species that has a primary effect on vase life, not necessarily the concentration of bacteria in the vase solution.