scholarly journals Phenotypic and Phylogenetic Characterization of Cu Homeostasis among Xylella fastidiosa Strains

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 495
Author(s):  
Qing Ge ◽  
Ranlin Liu ◽  
Paul A. Cobine ◽  
Neha Potnis ◽  
Leonardo De La Fuente
Keyword(s):  
Core Genome ◽  
Xylella Fastidiosa ◽  
Bacterial Pathogen ◽  
Antimicrobial Treatment ◽  
Plant Diseases ◽  
Phylogenetic Characterization ◽  
Cu Homeostasis ◽  
Geographical Locations

Xylella fastidiosa is a bacterial pathogen causing severe diseases and asymptomatic colonization in more than 600 plants worldwide. Copper (Cu) is a widely used antimicrobial treatment for various plant diseases, including those affecting X. fastidiosa hosts. Cu homeostasis among X. fastidiosa strains from different geographical locations and host species has not been characterized. Here, we assessed minimum inhibitory concentration (MIC) of Cu for 54 X. fastidiosa strains. We observed strain-level variation in MIC values within each subspecies. We hypothesized that these differences could be explained by sequence variation in Cu homeostasis genes. Phylogenies based on copA, copB, copL, and cutC were created using 74 genomes (including 43 strains used in vitro) of X. fastidiosa, showing that the phylogenetic clustering of Cu homeostasis associated with clustering was based on core genome phylogenies, rather than on pattern of MIC. No association was found among Cu MIC, subspecies classification, and host and location of isolation, probably due to uneven and limited group of strains whose genomes are available. Further analysis focused on a subgroup of isolates from Georgia’s vineyards that shared similar Cu-related phenotypes. Further research is needed to better understand the distribution of Cu homeostasis for this pathogen.

scholarly journals Identification of Xylella fastidiosa Antivirulence Genes: Hemagglutinin Adhesins Contribute to X. fastidiosa Biofilm Maturation and Colonization and Attenuate Virulence

2005 ◽  
Vol 18 (8) ◽  
pp. 856-868 ◽  
Author(s):  
Magalie R. Guilhabert ◽  
Bruce C. Kirkpatrick
Keyword(s):  
Xylella Fastidiosa ◽  
Plant Diseases ◽  
Plant Interactions ◽  
Wild Type ◽  
In Planta ◽  
Transposon Tn5 ◽  
Transposon Insertion ◽  
Transposon Mutants ◽  
Major Impediment

Xylella fastidosa, a gram-negative, xylem-limited bacterium, is the causal agent of several economically important plant diseases, including Pierce's disease (PD) and citrus variegated chlorosis (CVC). Until recently, the inability to transform or produce transposon mutants of X. fastidosa had been a major impediment to identifying X. fastidosa genes that mediate pathogen and plant interactions. A random transposon (Tn5) library of X. fastidosa was constructed and screened for mutants showing more severe symptoms and earlier grapevine death (hypervirulence) than did vines infected with the wild type. Seven hypervirulent mutants identified in this screen moved faster and reached higher populations than the wild type in grapevines. These results suggest that X. fastidosa attenuates its virulence in planta and that movement is important in X. fastidosa virulence. The mutated genes were sequenced and none had been described previously as antivirulence genes, although six of them showed similarity with genes of known functions in other organisms. One transposon insertion inactivated a hemagglutinin adhesin gene (PD2118), which we named HxfA. Another mutant in a second putative X. fastidosa hemagglutinin gene, PD1792 (HxfB), was constructed, and further characterization of these hxf mutants suggests that X. fastidosa hemagglutinins mediate contact between X. fastidosa cells, which results in colony formation and biofilm maturation within the xylem vessels.

scholarly journals Molecular characterization of differences between the tomato immune receptors Fls3 and Fls2

2020 ◽  
Author(s):  
Robyn Roberts ◽  
Alexander E. Liu ◽  
Lingwei Wan ◽  
Annie M. Geiger ◽  
Sarah R. Hind ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Molecular Mechanisms ◽  
Bacterial Pathogen ◽  
Transcript Abundance ◽  
Defense Responses ◽  
Structural Features ◽  
Host Responses ◽  
Pathogen Invasion

AbstractPlants mount defense responses by recognizing indications of pathogen invasion, including microbe-associated molecular patterns (MAMPs). Flagellin from the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) contains two MAMPs, flg22 and flgII-28, that are recognized by tomato receptors Flagellin sensing 2 (Fls2) and Flagellin sensing 3 (Fls3), respectively. It is unknown to what degree each receptor contributes to immunity and if they promote immune responses using the same molecular mechanisms. Characterization of CRISPR/Cas9-generated Fls2 and Fls3 tomato mutants revealed that the two receptors contribute equally to disease resistance both on the leaf surface and in the apoplast. However, striking differences were observed in certain host responses mediated by the two receptors. Compared to Fls2, Fls3 mediated a more sustained production of reactive oxygen species (ROS) and an increase in transcript abundance of 44 tomato genes, with two genes serving as reporters for Fls3. Fls3 had greater in vitro kinase activity and interacted differently with the Pst effector AvrPtoB as compared to Fls2. Using chimeric Fls2/Fls3 proteins, we found that no receptor domain was solely responsible for the Fls3 sustained ROS, suggesting involvement of multiple structural features. This work reveals differences in the immunity outputs between Fls2 and Fls3, suggesting they use distinct molecular mechanisms to activate pattern-triggered immunity in response to flagellin-derived MAMPs.

scholarly journals Versatile Oxidase and Dehydrogenase Activities of Bacterial Pyranose 2-Oxidase Facilitate Redox Cycling with Manganese PeroxidaseIn Vitro

2019 ◽  
Vol 85 (13) ◽  
Author(s):  
Peter L. Herzog ◽  
Leander Sützl ◽  
Beate Eisenhut ◽  
Daniel Maresch ◽  
Dietmar Haltrich ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Lignin Degradation ◽  
Evolutionary Relationship ◽  
Physiological Role ◽  
Redox Cycling ◽  
Content Type ◽  
Phylogenetic Characterization ◽  
Pyranose Oxidase

ABSTRACTPyranose 2-oxidase (POx) has long been accredited a physiological role in lignin degradation, but evidence to provide insights into the biochemical mechanisms and interactions is insufficient. There are ample data in the literature on the oxidase and dehydrogenase activities of POx, yet the biological relevance of this duality could not be established conclusively. Here we present a comprehensive biochemical and phylogenetic characterization of a novel pyranose 2-oxidase from the actinomycetous bacteriumKitasatospora aureofaciens(KaPOx) as well as a possible biomolecular synergism of this enzyme with peroxidases using phenolic model substratesin vitro. A phylogenetic analysis of both fungal and bacterial putative POx-encoding sequences revealed their close evolutionary relationship and supports a late horizontal gene transfer of ancestral POx sequences. We successfully expressed and characterized a novel bacterial POx gene fromK. aureofaciens, one of the putative POx genes closely related to well-known fungal POx genes. Its biochemical characteristics comply with most of the classical hallmarks of known fungal pyranose 2-oxidases, i.e., reactivity with a range of different monosaccharides as electron donors as well as activity with oxygen, various quinones, and complexed metal ions as electron acceptors. Thus,KaPOx shows the pronounced duality of oxidase and dehydrogenase similar to that of fungal POx. We further performed efficient redox cycling of aromatic lignin model compounds betweenKaPOx and manganese peroxidase (MnP). In addition, we found a Mn(III) reduction activity inKaPOx, which, in combination with its ability to provide H2O2, implies this and potentially other POx as complementary enzymatic tools for oxidative lignin degradation by specialized peroxidases.IMPORTANCEEstablishment of a mechanistic synergism between pyranose oxidase and (manganese) peroxidases represents a vital step in the course of elucidating microbial lignin degradation. Here, the comprehensive characterization of a bacterial pyranose 2-oxidase fromKitasatospora aureofaciensis of particular interest for several reasons. First, the phylogenetic analysis of putative pyranose oxidase genes reveals a widespread occurrence of highly similar enzymes in bacteria. Still, there is only a single report on a bacterial pyranose oxidase, stressing the need of closing this gap in the scientific literature. In addition, the relatively smallK. aureofaciensproteome supposedly supplies a limited set of enzymatic functions to realize lignocellulosic biomass degradation. Both enzyme and organism therefore present a viable model to study the mechanisms of bacterial lignin decomposition, elucidate physiologically relevant interactions with specialized peroxidases, and potentially realize biotechnological applications.

scholarly journals Effect of the Growth Regulator Paclobutrazol on Growth of the Bacterial Pathogen Xylella fastidiosa Xylella fastidiosa

2007 ◽  
Vol 33 (4) ◽  
pp. 246-252
Author(s):  
Darren DeStefano ◽  
Arv Grybauskas ◽  
James Sherald ◽  
Bahram Momen ◽  
Qi Huang ◽  
...  
Keyword(s):  
Direct Effect ◽  
Growth Regulator ◽  
Growth Regulation ◽  
Xylella Fastidiosa ◽  
Bacterial Pathogen ◽  
Colony Growth ◽  
Shade Trees ◽  
Leaf Scorch ◽  
Chronic Disorder

Xylella fastidiosa is a fastidious, xylem-limited, insect-transmitted, bacterial plant pathogen with a wide host range that causes bacterial leaf scorch (BLS) in shade trees. BLS is a chronic disorder characterized by late season leaf scorch and dieback and is common in urban and suburban areas of the mid-Atlantic and southeast United States. BLS has been recognized since the 1980s and attempted treatments have included antibiotics and plant growth regulators. Application of paclobutrazol (PBZ), a diastereomeric triazole with both fungistatic and growth regulation properties, has been observed to alleviate symptoms of BLS, but it has not been established whether PBZ has a direct effect on the organism. In this study, we investigated the effect of PBZ on in vitro growth of two X. fastidiosa isolates. Our results showed no significant effect of PBZ on colony growth of X. fastidiosa at the manufacturers recommended rate of 20 ‘ºg/mL ’àí1. However, significant reductions in bacterial growth were observed at a rate of 200 ‘ºg/mL ’àí1, indicating that high levels of PBZ may have a direct effect on the growth of X. fastidiosa. This direct effect and growth regulator effects of PBZs suggest that PBZ may provide a promising treatment for BLS in shade trees.

scholarly journals Characterization of Pseudomonas bacteria of Piper tuberculatum regarding the production of potentially bio-stimulating compounds for plant growth

2021 ◽  
Vol 51 (1) ◽  
pp. 10-19
Author(s):  
Danyllo Amaral de OLIVEIRA ◽  
Solange da Cunha FERREIRA ◽  
Daiany Larissa Ribeiro CARRERA ◽  
Cleyson Pantoja SERRÃO ◽  
Daihany Moraes CALLEGARI ◽  
...  
Keyword(s):  
Plant Growth ◽  
Black Pepper ◽  
Plant Diseases ◽  
Piper Nigrum ◽  
Soluble Phosphate ◽  
High Concentration ◽  
Molybdenum Blue ◽  
Iaa Production

ABSTRACT Despite advances in the identification and characterization of endophytic bacteria in various plant species worldwide, little is known about such microorganisms in plants from the Amazon region. Previous studies reported that Piper tuberculatum endophytic Pseudomonas (isolates Pt12 and Pt13, identified as Pseudomonas putida and Pseudomonas sp., respectively) were able to inhibit the in vitro growth of Fusarium solani f. sp. piperis, which causes root rot in black pepper (Piper nigrum), and that Pt13 promoted the growth of P. nigrum. Therefore, the aim here was to characterize these bacteria regarding their ability to produce plant growth-promoting substances [siderophores, indol acetic acid (IAA) and soluble phosphate]. Chrome azurol S assays were performed for the detection of siderophores. For qualitative and quantitative assays of IAA production and phosphate solubilization, Salkowski´s reagent and NBRIP medium with molybdenum blue reagent, respectively, were used. Results revealed that Pt12 and Pt13 were able to synthesize IAA, mainly under a high concentration of L-tryptophan, indicating that they are IAA-producing bacteria, probably through a tryptophan-dependent biosynthesis pathway. The presence of P. nigrum extract positively influenced the IAA production by Pt12 and Pt13, with highest values of 125 and 90 µg mL-1, respectively. In addition, Pt12 was positive for the production of siderophores and produced 56.56 µg mL-1 of soluble phosphate. In contrast, Pt13 showed no ability to produce siderophores or to solubilize phosphate. Besides their potential in controlling plant diseases, Pt12 and Pt13 have potential as biofertilizers, favoring sustainable agriculture.

scholarly journals Phylogenetic Characterization of Virulence and Resistance Phenotypes of Pseudomonas syringae

2005 ◽  
Vol 71 (9) ◽  
pp. 5182-5191 ◽  
Author(s):  
Michael S. H. Hwang ◽  
Robyn L. Morgan ◽  
Sara F. Sarkar ◽  
Pauline W. Wang ◽  
David S. Guttman
Keyword(s):  
Pseudomonas Syringae ◽  
Core Genome ◽  
Dominant Role ◽  
Antimicrobial Compounds ◽  
Phylogenetic Characterization ◽  
Host Interactions ◽  
Specific Pathogen ◽  
Genome Phylogeny ◽  
History Of

ABSTRACT Individual strains of the plant pathogenic bacterium Pseudomonas syringae vary in their ability to produce toxins, nucleate ice, and resist antimicrobial compounds. These phenotypes enhance virulence, but it is not clear whether they play a dominant role in specific pathogen-host interactions. To investigate the evolution of these virulence-associated phenotypes, we used functional assays to survey for the distribution of these phenotypes among a collection of 95 P. syringae strains. All of these strains were phylogenetically characterized via multilocus sequence typing (MLST). We surveyed for the production of coronatine, phaseolotoxin, syringomycin, and tabtoxin; for resistance to ampicillin, chloramphenicol, rifampin, streptomycin, tetracycline, kanamycin, and copper; and for the ability to nucleate ice at high temperatures via the ice-nucleating protein INA. We found that fewer than 50% of the strains produced toxins and significantly fewer strains than expected produced multiple toxins, leading to the speculation that there is a cost associated with the production of multiple toxins. None of these toxins was associated with host of isolation, and their distribution, relative to core genome phylogeny, indicated extensive horizontal genetic exchange. Most strains were resistant to ampicillin and copper and had the ability to nucleate ice, and yet very few strains were resistant to the other antibiotics. The distribution of the rare resistance phenotypes was also inconsistent with the clonal history of the species and did not associate with host of isolation. The present study provides a robust phylogenetic foundation for the study of these important virulence-associated phenotypes in P. syringae host colonization and pathogenesis.

Morphological, physiological, molecular and phylogenetic characterization of new environmental isolates of Acanthamoeba spp. from the region of Bratislava, Slovakia

Biologia ◽  
2010 ◽  
Vol 65 (1) ◽  
Author(s):  
Viera Nagyová ◽  
Arpád Nagy ◽  
Štefan Janeček ◽  
Jozef Timko
Keyword(s):  
Pcr Amplification ◽  
Temperature Tolerance ◽  
Environmental Isolates ◽  
Environmental Distribution ◽  
Pathogenic Potential ◽  
Phylogenetic Characterization ◽  
Group I ◽  
Genotype Identification

AbstractProtozoa of the genus Acanthamoeba are organisms that can be generally found in the environment. The focus of this study is the detection of the presence of Acanthamoeba in different water sources and samples taken from airconditioning units. The identification of Acanthamoeba isolates was based on the morphology of cysts and trophozoites as well as PCR amplification with a genus specific primer pair JDP1 and JDP2. Growth characteristics and temperature tolerance were monitored. The pathogenic potential was tested in vitro on Vero cell cultures. Genotype identification was based on the sequencing of the GTSA.B1 PCR amplimer of 18S ribosomal DNA. The data obtained revealed that the isolates belong to T3 and T4 genotypes. One T3 and one T4 isolate contain a group I intron. The 933 base pair intron found in a genotype T4 isolate is considerably larger compared to formerly described introns of Acanthamoeba griffini (genotype T3) and A. Lenticulata (genotype T5). This is the first report detailing the environmental distribution of the Acanthamoeba genotypes in the region of Bratislava, Slovakia.

scholarly journals Natural Competence and Recombination in the Plant Pathogen Xylella fastidiosa

2011 ◽  
Vol 77 (15) ◽  
pp. 5278-5284 ◽  
Author(s):  
Stephanie H. Kung ◽  
Rodrigo P. P. Almeida
Keyword(s):  
Plant Pathogen ◽  
Xylella Fastidiosa ◽  
Genetic Material ◽  
Plant Diseases ◽  
Exogenous Dna ◽  
Content Type ◽  
Genomic Studies ◽  
Different Strains ◽  
Exogenous Plasmid

ABSTRACTHomologous recombination is one of many forces contributing to the diversity, adaptation, and emergence of pathogens. For naturally competent bacteria, transformation is one possible route for the acquisition of novel genetic material. This study demonstrates thatXylella fastidiosa, a generalist bacterial plant pathogen responsible for many emerging plant diseases, is naturally competent and able to homologously recombine exogenous DNA into its genome. Several factors that affect transformation and recombination efficiencies, such as nutrient availability, growth stage, and methylation of transforming DNA, were identified. Recombination was observed in at least one out of every 106cells when exogenous plasmid DNA was supplied and one out of every 107cells when different strains were grown togetherin vitro. Based on previous genomic studies and experimental data presented here, there is mounting evidence that recombination can occur at relatively high rates and could play a large role in shaping the genetic diversity ofX. fastidiosa.

scholarly journals Characterization of the Pasteurella multocida hgbA Gene Encoding a Hemoglobin-Binding Protein

2002 ◽  
Vol 70 (11) ◽  
pp. 5955-5964 ◽  
Author(s):  
Montserrat Bosch ◽  
M. Elena Garrido ◽  
Montserrat Llagostera ◽  
Ana M. Pérez de Rozas ◽  
Ignacio Badiola ◽  
...  
Keyword(s):  
Pasteurella Multocida ◽  
Bacterial Pathogen ◽  
Open Reading Frames ◽  
Transcriptional Unit ◽  
Gene Encoding ◽  
Hemoglobin Binding ◽  
Reading Frames

ABSTRACT Reverse transcriptase PCR analyses have demonstrated that open reading frames (ORFs) PM0298, PM0299, and PM0300 of the animal pathogen Pasteurella multocida constitute a single transcriptional unit. By cloning and overexpression studies in Escherichia coli cells, the product of ORF PM0300 was shown to bind hemoglobin in vitro; this ORF was therefore designated hgbA. In vitro and in vivo quantitative assays demonstrated that the P. multocida hgbA mutant bound hemoglobin to the same extent as the wild-type strain, although the adsorption kinetics was slightly slower for the hgbA cells. In agreement with this, the virulence of P. multocida hgbA cells was not affected, suggesting that other functional hemoglobin receptor proteins must be present in this organism. On the other hand, P. multocida mutants defective in PM0298 and PM0299 could be isolated only when a plasmid containing an intact copy of the gene was present in the cells, suggesting that these genes are essential for the viability of this bacterial pathogen. By adapting the recombinase-based expression technology in vivo to P. multocida, we also demonstrated that the transcriptional PM0298-PM0299-hgbA unit is iron regulated and that its expression is triggered in the first 2 h following infection in a mouse model. Furthermore, hybridization experiments showed that the hgbA gene is widespread in P. multocida strains regardless of their serotype or the animal from which they were isolated.

The influence of copper homeostasis genes copA and copB on Xylella fastidiosa virulence is affected by sap copper concentration

2021 ◽  
Author(s):  
Qing Ge ◽  
Paul Cobine ◽  
Leonardo De La Fuente
Keyword(s):  
Disease Severity ◽  
Molecular Basis ◽  
Copper Concentration ◽  
Xylella Fastidiosa ◽  
Bacterial Species ◽  
Agricultural Practices ◽  
Plant Pathogenic Bacterium ◽  
Wild Type ◽  
Cu Homeostasis

Xylella fastidiosa is a xylem-limited plant pathogenic bacterium that causes diseases worldwide in crops such as grape, citrus, and olive. Although copper (Cu)-containing compounds are not used for management of X. fastidiosa-caused diseases, they are widely used in X. fastidiosa hosts in vineyards and orchards. The accumulation of Cu in soils, and therefore plant saps, could be a challenge for X. fastidiosa survival. Here, the molecular basis of Cu homeostasis was studied in relation to virulence. Although homologous Cu-related genes copA (X. fastidiosa loci PD0100) and copB (PD0101) have been characterized in other bacteria, their functions differ among bacterial species. In vitro, both copA and copB mutants were more sensitive to Cu than the wild-type (WT) strain. Interestingly, the copA mutant was more sensitive to Cu shock, while the copB mutant was more sensitive to chronic Cu treatments. In tobacco greenhouse experiments with normal watering, both mutants reduced virulence compared to WT. But when Cu was added as a drench treatment, both copA and copB mutants had increased disease severity ~20% and ~50% compared to mutants without Cu added, respectively, which were significantly higher than the ~5% observed for WT under the same conditions. These results indicate that the pathogen’s Cu homeostasis affects virulence and is influenced by Cu concentration in the environment. Understanding Cu homeostasis in X. fastidiosa will help discern the outcome of Cu treatments and the adaptation of this pathogen to the xylem of plants that have been exposed to high Cu concentrations due to agricultural practices.

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