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Charles Manceau - One of the best experts on this subject based on the ideXlab platform.
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Aggressive Emerging Pathovars of Xanthomonas arboricola Represent Widespread Epidemic Clones Distinct from Poorly Pathogenic Strains, as Revealed by Multilocus Sequence Typing.
Applied and environmental microbiology, 2015Co-Authors: Marion Fischerle Saux, Charles Manceau, Sophie Bonneau, Salwa Essakhi, Marie Agnes JacquesAbstract:Deep and comprehensive knowledge of the genetic structure of pathogenic species is the cornerstone on which the design of precise molecular diagnostic tools is built. Xanthomonas arboricola is divided into Pathovars, some of which are classified as quarantine organisms in many countries and are responsible for diseases on nut and stone fruit trees that have emerged worldwide. Recent taxonomic studies of the genus Xanthomonas showed that strains isolated from other hosts should be classified in X. arboricola, extending the host range of the species. To investigate the genetic structure of X. arboricola and the genetic relationships between highly pathogenic strains and strains apparently not relevant to plant health, we conducted multilocus sequence analyses on a collection of strains representative of the known diversity of the species. Most of the Pathovars were clustered in separate monophyletic groups. The Pathovars pruni, corylina, and juglandis, responsible for pandemics in specific hosts, were highly phylogenetically related and clustered in three distinct clonal complexes. In contrast, strains with no or uncertain pathogenicity were represented by numerous unrelated singletons scattered in the phylogenic tree. Depending on the Pathovar, intra- and interspecies recombination played contrasting roles in generating nucleotide polymorphism. This work provides a population genetics framework for molecular epidemiological surveys of emerging plant pathogens within X. arboricola. Based on our results, we propose to reclassify three former Pathovars of Xanthomonas campestris as X. arboricola pv. arracaciae comb. nov., X. arboricola pv. guizotiae comb. nov., and X. arboricola pv. zantedeschiae comb. nov. An emended description of X. arboricola Vauterin et al. 1995 is provided.
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type three effector gene distribution and sequence analysis provide new insights into the pathogenicity of plant pathogenic xanthomonas arboricola
Applied and Environmental Microbiology, 2012Co-Authors: Ahmed Hajri, Joel F Pothier, Marion Fischerle Saux, Sophie Bonneau, Stephane Poussier, Tristan Boureau, Brion Duffy, Charles ManceauAbstract:Xanthomonas arboricola is a complex bacterial species which mainly attacks fruit trees and is responsible for emerging diseases in Europe. It comprises seven Pathovars (X. arboricola pv. pruni, X. arboricola pv. corylina, X. arboricola pv. juglandis, X. arboricola pv. populi, X. arboricola pv. poinsettiicola, X. arboricola pv. celebensis, and X. arboricola pv. fragariae), each exhibiting characteristic disease symptoms and distinct host specificities. To better understand the factors underlying this ecological trait, we first assessed the phylogenetic relationships among a worldwide collection of X. arboricola strains by sequencing the housekeeping gene rpoD. This analysis revealed that strains of X. arboricola Pathovar populi are divergent from the main X. arboricola cluster formed by all other strains. Then, we investigated the distribution of 53 type III effector (T3E) genes in a collection of 57 X. arboricola strains that are representative of the main X. arboricola cluster. Our results showed that T3E repertoires vary greatly between X. arboricola Pathovars in terms of size. Indeed, X. arboricola Pathovars pruni, corylina, and juglandis, which are responsible for economically important stone fruit and nut diseases in Europe, harbored the largest T3E repertoires, whereas Pathovars poinsettiicola, celebensis, and fragariae harbored the smallest. We also identified several differences in T3E gene content between X. arboricola Pathovars pruni, corylina, and juglandis which may account for their differing host specificities. Further, we examined the allelic diversity of eight T3E genes from X. arboricola Pathovars. This analysis revealed very limited allelic variations at the different loci. Altogether, the data presented here provide new insights into the evolution of pathogenicity and host range of X. arboricola and are discussed in terms of emergence of new diseases within this bacterial species.
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Housekeeping Gene Sequencing and Multilocus Variable-Number Tandem-Repeat Analysis To Identify Subpopulations within Pseudomonas syringae pv. maculicola and Pseudomonas syringae pv. tomato That Correlate with Host Specificity
Applied and Environmental Microbiology, 2012Co-Authors: Sophie Gironde, Charles ManceauAbstract:Pseudomonas syringae pv. maculicola causes bacterial spot on Brassicaceae worldwide, and for the last 10 years severe outbreaks have been reported in the Loire Valley, France. P. syringae pv. maculicola resembles P. syringae pv. tomato in that it is also pathogenic for tomato and causes the same types of symptoms. We used a collection of 106 strains of P. syringae to characterize the relationships between P. syringae pv. maculicola and related Pathovars, paying special attention to P. syringae pv. tomato. Phylogenetic analysis of gyrB and rpoD gene sequences showed that P. syringae pv. maculicola, which causes diseases in Brassicaceae, forms six genetic lineages within genomospecies 3 of P. syringae strains as defined by L. Gardan et al. (Int. J. Syst. Bacteriol. 49[ Pt 2]: 469-478, 1999), whereas P. syringae pv. tomato forms two distinct genetic lineages. A multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) conducted with eight minisatellite loci confirmed the genetic structure obtained with rpoD and gyrB sequence analyses. These results provide promising tools for fine-scale epidemiological studies on diseases caused by P. syringae pv. maculicola and P. syringae pv. tomato. The two Pathovars had distinct host ranges; only P. syringae pv. maculicola strains were pathogenic for Brassicaceae. A subpopulation of P. syringae pv. maculicola strains that are pathogenic for Pto-expressing tomato plants were shown to lack avrPto1 and avrPtoB or to contain a disrupted avrPtoB homolog. Taking phylogenetic and pathological features into account, our data suggest that the DC3000 strain belongs to P. syringae pv. maculicola. This study shows that P. syringae pv. maculicola and P. syringae pv. tomato appear multiclonal, as they did not diverge from a single common ancestral group within the ancestral P. syringae genomospecies 3, and suggests that Pathovar specificity within P. syringae may be due to independent genetic events.
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a multilocus sequence analysis of xanthomonas campestris reveals a complex structure within crucifer attacking Pathovars of this species
Systematic and Applied Microbiology, 2011Co-Authors: E Fargier, Fischerle M Saux, Charles ManceauAbstract:Previous classification of Xanthomonas campestris has defined six Pathovars (aberrans, armoraciae, barbareae, campestris, incanae, and raphani) that cause diseases on cruciferous plants. However, pathogenicity assays with a range of strains and different hosts identifies only three types of symptom: black rot, leaf spot and bacterial blight. These findings raise the question of the genetic relatedness between strains assigned to different Pathovars or symptom phenotypes. Here we have addressed this issue by multilocus sequence analysis of 42 strains. The X. campestris species was polymorphic at the 8 loci analysed and had a high genetic diversity; 23 sequence types were identified of which 16 were unique. All strains that induce black rot (Pathovars aberrans and campestris) were genetically close but split in two groups. Only three clonal complexes were found, all within Pathovar campestris. The assignment of the genome-sequenced strain 756C to Pathovar raphani suggested from disease symptoms was confirmed, although this group of strains was particularly polymorphic. Strains belonging to Pathovars barbareae and incanae were closely related, but distinct from Pathovar campestris. There is evidence of genetic exchanges of housekeeping genes within this species as deduced from a clear incongruence between individual gene phylogenies and from network structures from SplitsTree analysis. Overall this study showed that the high genetic diversity derived equally from recombination and point mutation accumulation. However, X. campestris remains a species with a clonal evolution driven by a differential adaptation to cruciferous hosts.
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Sensing and adhesion are adaptive functions in the plant pathogenic xanthomonads
BMC Evolutionary Biology, 2011Co-Authors: Nadia Mhedbi-hajri, Charles Manceau, Armelle Darrasse, Karine Durand, Sandrine Pigné, Stéphanie Fouteau, Valérie Barbe, Christophe Lemaire, Marie Agnes JacquesAbstract:Background: Bacterial plant pathogens belonging to the Xanthomonas genus are tightly adapted to their host plants and are not known to colonise other environments. The host range of each strain is usually restricted to a few host plant species. Bacterial strains responsible for the same type of symptoms on the same host range cluster in a Pathovar. The phyllosphere is a highly stressful environment, but it provides a selective habitat and a source of substrates for these bacteria. Xanthomonads colonise host phylloplane before entering leaf tissues and engaging in an invasive pathogenic phase. Hence, these bacteria are likely to have evolved strategies to adapt to life in this environment. We hypothesised that determinants responsible for bacterial host adaptation are expressed starting from the establishment of chemotactic attraction and adhesion on host tissue. Results: We established the distribution of 70 genes coding sensors and adhesins in a large collection of xanthomonad strains. These 173 strains belong to different Pathovars of Xanthomonas spp and display different host ranges. Candidate genes are involved in chemotactic attraction (25 genes), chemical environment sensing (35 genes), and adhesion (10 genes). Our study revealed that candidate gene repertoires comprised core and variable gene suites that likely have distinct roles in host adaptation. Most Pathovars were characterized by unique repertoires of candidate genes, highlighting a correspondence between Pathovar clustering and repertoires of sensors and adhesins. To further challenge our hypothesis, we tested for molecular signatures of selection on candidate genes extracted from sequenced genomes of strains belonging to different Pathovars. We found strong evidence of adaptive divergence acting on most candidate genes. Conclusions: These data provide insight into the potential role played by sensors and adhesins in the adaptation of xanthomonads to their host plants. The correspondence between repertoires of sensor and adhesin genes and Pathovars and the rapid evolution of sensors and adhesins shows that, for plant pathogenic xanthomonads, events leading to host specificity may occur as early as chemotactic attraction by host and adhesion to tissues.
Marie Agnes Jacques - One of the best experts on this subject based on the ideXlab platform.
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Evolutionary history of the plant pathogenic bacteria Xanthomonas spp.
2015Co-Authors: Marie Agnes JacquesAbstract:Deciphering mechanisms shaping bacterial diversity should help to build tools to predict the emergence of infectious diseases. Xanthomonads are plant pathogenic bacteria responsible for major socio-economic impact worldwide. As a whole the genus Xanthomonas gather strains that are responsible for diseases on a large number of plants. However, each strain displays a narrow host range that is referred to in the Pathovar concept. We address the question of the nature of the evolutionary processes – geographical, ecological and pathological speciation – that shaped the diversity for two species of this genus, namely X. axonopodis and X. arboricola. We assembled large collections of strains that were isolated over a long period, over continents, and from various plants, some strains being pathogenic on those plants, the other being not pathogenicon their host of isolation. We performed population genetic analyses using coalescent and genealogy approaches, we studied the diversification of the pathogens, and we analyzed the evolution of the virulence-associated gene repertoires in these strains. For X. axonopodis, the suggested evolutionary scenario involves a first step of generalist diversification that spanned over the last 25 000 years. A second step of ecology-driven specialization occurred during the past two centuries. Eventually, secondary contacts between host specialized strains probably occurred as a result of agricultural development and intensification, allowing genetic exchanges of virulence-associated genes. These transfers may have favored the emergence of novel pathotypes. We showed that the species X. arboricola presents an epidemic structure. The three highly aggressive Pathovars (juglandis, pruni and corylina) represent epidemic clones, which emergence was linked to the acquisition of type three effectors. Nonpathogenic strains and strains from minor Pathovars of this species represent the recombinant network within which loss of virulence-associated factors from the common ancestor is evidenced for nonpathogenic strains. Altogether, these study highlighted that evolutionary history of xanthomonads is tightly linked to their biological environment and involved horizontal gene transfer for pathoadaptation.
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Aggressive Emerging Pathovars of Xanthomonas arboricola Represent Widespread Epidemic Clones Distinct from Poorly Pathogenic Strains, as Revealed by Multilocus Sequence Typing.
Applied and environmental microbiology, 2015Co-Authors: Marion Fischerle Saux, Charles Manceau, Sophie Bonneau, Salwa Essakhi, Marie Agnes JacquesAbstract:Deep and comprehensive knowledge of the genetic structure of pathogenic species is the cornerstone on which the design of precise molecular diagnostic tools is built. Xanthomonas arboricola is divided into Pathovars, some of which are classified as quarantine organisms in many countries and are responsible for diseases on nut and stone fruit trees that have emerged worldwide. Recent taxonomic studies of the genus Xanthomonas showed that strains isolated from other hosts should be classified in X. arboricola, extending the host range of the species. To investigate the genetic structure of X. arboricola and the genetic relationships between highly pathogenic strains and strains apparently not relevant to plant health, we conducted multilocus sequence analyses on a collection of strains representative of the known diversity of the species. Most of the Pathovars were clustered in separate monophyletic groups. The Pathovars pruni, corylina, and juglandis, responsible for pandemics in specific hosts, were highly phylogenetically related and clustered in three distinct clonal complexes. In contrast, strains with no or uncertain pathogenicity were represented by numerous unrelated singletons scattered in the phylogenic tree. Depending on the Pathovar, intra- and interspecies recombination played contrasting roles in generating nucleotide polymorphism. This work provides a population genetics framework for molecular epidemiological surveys of emerging plant pathogens within X. arboricola. Based on our results, we propose to reclassify three former Pathovars of Xanthomonas campestris as X. arboricola pv. arracaciae comb. nov., X. arboricola pv. guizotiae comb. nov., and X. arboricola pv. zantedeschiae comb. nov. An emended description of X. arboricola Vauterin et al. 1995 is provided.
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Sensing and adhesion are adaptive functions in the plant pathogenic xanthomonads
BMC Evolutionary Biology, 2011Co-Authors: Nadia Mhedbi-hajri, Charles Manceau, Armelle Darrasse, Karine Durand, Sandrine Pigné, Stéphanie Fouteau, Valérie Barbe, Christophe Lemaire, Marie Agnes JacquesAbstract:Background: Bacterial plant pathogens belonging to the Xanthomonas genus are tightly adapted to their host plants and are not known to colonise other environments. The host range of each strain is usually restricted to a few host plant species. Bacterial strains responsible for the same type of symptoms on the same host range cluster in a Pathovar. The phyllosphere is a highly stressful environment, but it provides a selective habitat and a source of substrates for these bacteria. Xanthomonads colonise host phylloplane before entering leaf tissues and engaging in an invasive pathogenic phase. Hence, these bacteria are likely to have evolved strategies to adapt to life in this environment. We hypothesised that determinants responsible for bacterial host adaptation are expressed starting from the establishment of chemotactic attraction and adhesion on host tissue. Results: We established the distribution of 70 genes coding sensors and adhesins in a large collection of xanthomonad strains. These 173 strains belong to different Pathovars of Xanthomonas spp and display different host ranges. Candidate genes are involved in chemotactic attraction (25 genes), chemical environment sensing (35 genes), and adhesion (10 genes). Our study revealed that candidate gene repertoires comprised core and variable gene suites that likely have distinct roles in host adaptation. Most Pathovars were characterized by unique repertoires of candidate genes, highlighting a correspondence between Pathovar clustering and repertoires of sensors and adhesins. To further challenge our hypothesis, we tested for molecular signatures of selection on candidate genes extracted from sequenced genomes of strains belonging to different Pathovars. We found strong evidence of adaptive divergence acting on most candidate genes. Conclusions: These data provide insight into the potential role played by sensors and adhesins in the adaptation of xanthomonads to their host plants. The correspondence between repertoires of sensor and adhesin genes and Pathovars and the rapid evolution of sensors and adhesins shows that, for plant pathogenic xanthomonads, events leading to host specificity may occur as early as chemotactic attraction by host and adhesion to tissues.
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Are bacterial virulence factors involved in initial host colonization processes responsible for host specificity?
2009Co-Authors: Nadia Mhedbi-hajri, Charles Manceau, Armelle Darrasse, Karine Durand, Marie Agnes JacquesAbstract:Bacteria belonging to the genus Xanthomonas are grouped in Pathovars defined on the basis of their host range and type of symptoms. Within a Pathovar strains are highly specialized on a restricted host range. Currently, the genetic basis of host specificity for pathogenic bacteria remains poorly understood. We hypothesize that virulence factors which are involved in the initial stages of host colonization play a role in host specificity. Candidate host specificity factors we selected are methyl accepting chemotaxis proteins (MCPs) and adhesins. Actually, nothing is known about the repertoires of MCPs and adhesins in strains of the genus Xanthomonas. We have determined the distribution of 30 MCPs and 13 adhesins among 180 strains belonging to 18 Pathovars of X. axonopodis and 3 Pathovars of X. campestris, as well as phylogenetic relationships of the strains based on polymorphism analyses of housekeeping genes. The selected strains were isolated from different host plants and various geographical origins. Some Pathovars were polyphyletic while others were monophyletic. Repertoires of MCPs and adhesins were polymorphic among strains and displayed both ubiquitous and variable genes. Among the Pathovars and genetic lineages tested, thirteen were distinguished by their distinct suites of MCPs and adhesins. The other Pathovars and genetic lineages remained difficult to differentiate: five groups with unique repertoires were constituted. Polyphyletic Pathovars displayed essentially homogeneous repertoires. These results show that events leading to host specificity occur as early as initial steps of chemotactic attraction and adhesion on host tissues.
Cayo Ramos - One of the best experts on this subject based on the ideXlab platform.
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pseudomonas savastanoi pv mandevillae pv nov a clonal pathogen causing an emerging devastating disease of the ornamental plant mandevilla spp
Phytopathology, 2021Co-Authors: Eloy Caballoponce, Adrian Pintado, Alba Morenoperez, Jesus Murillo, Kornelia Smalla, Cayo RamosAbstract:Commercial production of the ornamental plant dipladenia (Mandevilla spp.) is threatened by dipladenia leaf and stem spot disease, caused by the bacterium Pseudomonas savastanoi. P. savastanoi includes four Pathovars of woody hosts differentiated by a characteristic host range in olive, oleander, ash and broom plants. However, isolates from dipladenia have not been ascribed to any particular lineage or P. savastanoi Pathovar. Here we report that isolates from dipladenia represent a distinct, clonal lineage. First, dipladenia isolates display very similar plasmid profiles, including a plasmid encoding the iaaM gene for biosynthesis of indole-3-acetic acid. Second, multilocus sequence analysis and core-genome single-nucleotide-polymorphisms phylogenies showed a monophyletic origin for dipladenia isolates, which cluster with isolates from oleander (Pathovar nerii) in a distinct clade well separated from other P. savastanoi strains. Metabolic profiling and cross-pathogenicity tests in olive, oleander, ash, broom and dipladenia clearly distinguished dipladenia isolates from the four P. savastanoi Pathovars. Comparative genomics of the draft genome sequence of the dipladenia strain Ph3 with the other four Pathovars showed that Ph3 encodes very few strain-specific genes, and a similar set of virulence genes to pv. nerii, including its repertoire of type III secretion system effectors. However, hierarchical clustering based on the catalogue of effectors and their allelic variants clearly separated Ph3 from pv. nerii strains. Based on their distinctive pathogenicity profile, we propose a de novo Pathovar for P. savastanoi isolates from dipladenia, P. savastanoi pv. mandevillae pv. nov., for which strain Ph3 (CFBP 8832PT) has been designated as the pathotype strain.
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Host Range Determinants of Pseudomonas savastanoi Pathovars of Woody Hosts Revealed by Comparative Genomics and Cross-Pathogenicity Tests.
Frontiers in plant science, 2020Co-Authors: Alba Moreno-pérez, Adrian Pintado, Jesus Murillo, Eloy Caballo-ponce, Stefania Tegli, Chiaraluce Moretti, Pablo Rodríguez-palenzuela, Cayo RamosAbstract:The study of host range determinants within the Pseudomonas syringae complex is gaining renewed attention due to its widespread distribution in non-agricultural environments, evidence of large variability in intra-Pathovar host range, and the emergence of new epidemic diseases. This requires the establishment of appropriate model pathosystems facilitating integration of phenotypic, genomic and evolutionary data. Pseudomonas savastanoi pv. savastanoi is a model pathogen of the olive tree, and here we report a closed genome of strain NCPPB 3335, plus draft genome sequences of three strains isolated from oleander (pv. nerii), ash (pv. fraxini) and broom plants (pv. retacarpa). We then conducted a comparative genomic analysis of these four new genomes plus 16 publicly available genomes, representing 20 strains of these four P. savastanoi Pathovars of woody hosts. Despite overlapping host ranges, cross-pathogenicity tests using four plant hosts clearly separated these Pathovars and lead to Pathovar reassignment of two strains. Critically, these functional assays were pivotal to reconcile phylogeny with host range and to define Pathovar-specific genes repertoires. We report a pan-genome of 7,953 ortholog gene families and a total of 45 type III secretion system effector genes, including 24 core genes, four genes exclusive of pv. retacarpa and several genes encoding Pathovar-specific truncations. Noticeably, the four Pathovars corresponded with well-defined genetic lineages, with core genome phylogeny and hierarchical clustering of effector genes closely correlating with pathogenic specialization. Knot-inducing Pathovars encode genes absent in the canker-inducing pv. fraxini, such as those related to indole acetic acid, cytokinins, rhizobitoxine, and a bacteriophytochrome. Other Pathovar-exclusive genes encode type I, type II, type IV, and type VI secretion system proteins, the phytotoxine phevamine A, a siderophore, c-di-GMP-related proteins, methyl chemotaxis proteins, and a broad collection of transcriptional regulators and transporters of eight different superfamilies. Our combination of pathogenicity analyses and genomics tools allowed us to correctly assign strains to Pathovars and to propose a repertoire of host range-related genes in the P. syringae complex.
Sophie Bonneau - One of the best experts on this subject based on the ideXlab platform.
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Xanthomonas citri pv. viticola Affecting Grapevine in Brazil: Emergence of a Successful Monomorphic Pathogen
Frontiers in Plant Science, 2019Co-Authors: Marisa A. S. V. Ferreira, Armelle Darrasse, Sophie Bonneau, Martial Briand, Sophie Cesbron, Perrine Portier, Marco A. S. Gama, Maria Angélica G. Barbosa, Rosa De L. R. Mariano, Elineide B. SouzaAbstract:The Pathovar viticola of Xanthomonas citri causes bacterial canker of grapevine. This disease was first recorded in India in 1972, and later in Brazil in 1998, where its distribution is currently restricted to the northeastern region. A multilocus sequence analysis (MLSA) based on seven housekeeping genes and a multilocus variable number of tandem repeat analysis (MLVA) with eight loci were performed in order to assess the genetic relatedness among strains from India and Brazil. Strains isolated in India from three related Pathovars affecting Vitaceae species and pathogenic strains isolated from Amaranthus sp. found in bacterial canker-infected vineyards in Brazil were also included. MLSA revealed lack of diversity in all seven genes and grouped grapevine and Amaranthus strains in a monophyletic group in X. citri. The VNTR (variable number of tandem repeat) typing scheme conducted on 107 strains detected 101 haplotypes. The total number of alleles per locus ranged from 5 to 12. A minimum spanning tree (MST) showed that Brazilian strains were clearly separated from Indian strains, which showed unique alleles at three loci. The two strains isolated from symptomatic Amaranthus sp. presented unique alleles at two loci. STRUCTURE analyses revealed three groups congruent with MST and a fourth group with strains from India and Brazil. Admixture among populations were observed in all groups. MST, STRUCTURE and e-BURST analyses showed that the strains collected in 1998 belong to two distinct groups, with predicted founder genotypes from two different vineyards in the same region. This suggest that one introduction of grape planting materials contaminated with genetically distinct strains took place, which was followed by pathogen adaptation. Genome sequencing of one Brazilian strain confirmed typical attributes of pathogenic xanthomonads and allowed the design of a complementary VNTR typing scheme dedicated to X. citri pv. viticola that will allow further epidemiological survey of this genetically monomorphic Pathovar.
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Table_3_Xanthomonas citri pv. viticola Affecting Grapevine in Brazil: Emergence of a Successful Monomorphic Pathogen.xlsx
2019Co-Authors: Marisa A. S. V. Ferreira, Armelle Darrasse, Sophie Bonneau, Martial Briand, Sophie Cesbron, Perrine Portier, Marco A. S. Gama, Maria Angélica G. Barbosa, Rosa De L. R. Mariano, Elineide B. SouzaAbstract:The Pathovar viticola of Xanthomonas citri causes bacterial canker of grapevine. This disease was first recorded in India in 1972, and later in Brazil in 1998, where its distribution is currently restricted to the northeastern region. A multilocus sequence analysis (MLSA) based on seven housekeeping genes and a multilocus variable number of tandem repeat analysis (MLVA) with eight loci were performed in order to assess the genetic relatedness among strains from India and Brazil. Strains isolated in India from three related Pathovars affecting Vitaceae species and pathogenic strains isolated from Amaranthus sp. found in bacterial canker-infected vineyards in Brazil were also included. MLSA revealed lack of diversity in all seven genes and grouped grapevine and Amaranthus strains in a monophyletic group in X. citri. The VNTR (variable number of tandem repeat) typing scheme conducted on 107 strains detected 101 haplotypes. The total number of alleles per locus ranged from 5 to 12. A minimum spanning tree (MST) showed that Brazilian strains were clearly separated from Indian strains, which showed unique alleles at three loci. The two strains isolated from symptomatic Amaranthus sp. presented unique alleles at two loci. STRUCTURE analyses revealed three groups congruent with MST and a fourth group with strains from India and Brazil. Admixture among populations were observed in all groups. MST, STRUCTURE and e-BURST analyses showed that the strains collected in 1998 belong to two distinct groups, with predicted founder genotypes from two different vineyards in the same region. This suggest that one introduction of grape planting materials contaminated with genetically distinct strains took place, which was followed by pathogen adaptation. Genome sequencing of one Brazilian strain confirmed typical attributes of pathogenic xanthomonads and allowed the design of a complementary VNTR typing scheme dedicated to X. citri pv. viticola that will allow further epidemiological survey of this genetically monomorphic Pathovar.
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Table_1_Xanthomonas citri pv. viticola Affecting Grapevine in Brazil: Emergence of a Successful Monomorphic Pathogen.pdf
2019Co-Authors: Marisa A. S. V. Ferreira, Armelle Darrasse, Sophie Bonneau, Martial Briand, Sophie Cesbron, Perrine Portier, Marco A. S. Gama, Maria Angélica G. Barbosa, Rosa De L. R. Mariano, Elineide B. SouzaAbstract:The Pathovar viticola of Xanthomonas citri causes bacterial canker of grapevine. This disease was first recorded in India in 1972, and later in Brazil in 1998, where its distribution is currently restricted to the northeastern region. A multilocus sequence analysis (MLSA) based on seven housekeeping genes and a multilocus variable number of tandem repeat analysis (MLVA) with eight loci were performed in order to assess the genetic relatedness among strains from India and Brazil. Strains isolated in India from three related Pathovars affecting Vitaceae species and pathogenic strains isolated from Amaranthus sp. found in bacterial canker-infected vineyards in Brazil were also included. MLSA revealed lack of diversity in all seven genes and grouped grapevine and Amaranthus strains in a monophyletic group in X. citri. The VNTR (variable number of tandem repeat) typing scheme conducted on 107 strains detected 101 haplotypes. The total number of alleles per locus ranged from 5 to 12. A minimum spanning tree (MST) showed that Brazilian strains were clearly separated from Indian strains, which showed unique alleles at three loci. The two strains isolated from symptomatic Amaranthus sp. presented unique alleles at two loci. STRUCTURE analyses revealed three groups congruent with MST and a fourth group with strains from India and Brazil. Admixture among populations were observed in all groups. MST, STRUCTURE and e-BURST analyses showed that the strains collected in 1998 belong to two distinct groups, with predicted founder genotypes from two different vineyards in the same region. This suggest that one introduction of grape planting materials contaminated with genetically distinct strains took place, which was followed by pathogen adaptation. Genome sequencing of one Brazilian strain confirmed typical attributes of pathogenic xanthomonads and allowed the design of a complementary VNTR typing scheme dedicated to X. citri pv. viticola that will allow further epidemiological survey of this genetically monomorphic Pathovar.
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Aggressive Emerging Pathovars of Xanthomonas arboricola Represent Widespread Epidemic Clones Distinct from Poorly Pathogenic Strains, as Revealed by Multilocus Sequence Typing.
Applied and environmental microbiology, 2015Co-Authors: Marion Fischerle Saux, Charles Manceau, Sophie Bonneau, Salwa Essakhi, Marie Agnes JacquesAbstract:Deep and comprehensive knowledge of the genetic structure of pathogenic species is the cornerstone on which the design of precise molecular diagnostic tools is built. Xanthomonas arboricola is divided into Pathovars, some of which are classified as quarantine organisms in many countries and are responsible for diseases on nut and stone fruit trees that have emerged worldwide. Recent taxonomic studies of the genus Xanthomonas showed that strains isolated from other hosts should be classified in X. arboricola, extending the host range of the species. To investigate the genetic structure of X. arboricola and the genetic relationships between highly pathogenic strains and strains apparently not relevant to plant health, we conducted multilocus sequence analyses on a collection of strains representative of the known diversity of the species. Most of the Pathovars were clustered in separate monophyletic groups. The Pathovars pruni, corylina, and juglandis, responsible for pandemics in specific hosts, were highly phylogenetically related and clustered in three distinct clonal complexes. In contrast, strains with no or uncertain pathogenicity were represented by numerous unrelated singletons scattered in the phylogenic tree. Depending on the Pathovar, intra- and interspecies recombination played contrasting roles in generating nucleotide polymorphism. This work provides a population genetics framework for molecular epidemiological surveys of emerging plant pathogens within X. arboricola. Based on our results, we propose to reclassify three former Pathovars of Xanthomonas campestris as X. arboricola pv. arracaciae comb. nov., X. arboricola pv. guizotiae comb. nov., and X. arboricola pv. zantedeschiae comb. nov. An emended description of X. arboricola Vauterin et al. 1995 is provided.
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type three effector gene distribution and sequence analysis provide new insights into the pathogenicity of plant pathogenic xanthomonas arboricola
Applied and Environmental Microbiology, 2012Co-Authors: Ahmed Hajri, Joel F Pothier, Marion Fischerle Saux, Sophie Bonneau, Stephane Poussier, Tristan Boureau, Brion Duffy, Charles ManceauAbstract:Xanthomonas arboricola is a complex bacterial species which mainly attacks fruit trees and is responsible for emerging diseases in Europe. It comprises seven Pathovars (X. arboricola pv. pruni, X. arboricola pv. corylina, X. arboricola pv. juglandis, X. arboricola pv. populi, X. arboricola pv. poinsettiicola, X. arboricola pv. celebensis, and X. arboricola pv. fragariae), each exhibiting characteristic disease symptoms and distinct host specificities. To better understand the factors underlying this ecological trait, we first assessed the phylogenetic relationships among a worldwide collection of X. arboricola strains by sequencing the housekeeping gene rpoD. This analysis revealed that strains of X. arboricola Pathovar populi are divergent from the main X. arboricola cluster formed by all other strains. Then, we investigated the distribution of 53 type III effector (T3E) genes in a collection of 57 X. arboricola strains that are representative of the main X. arboricola cluster. Our results showed that T3E repertoires vary greatly between X. arboricola Pathovars in terms of size. Indeed, X. arboricola Pathovars pruni, corylina, and juglandis, which are responsible for economically important stone fruit and nut diseases in Europe, harbored the largest T3E repertoires, whereas Pathovars poinsettiicola, celebensis, and fragariae harbored the smallest. We also identified several differences in T3E gene content between X. arboricola Pathovars pruni, corylina, and juglandis which may account for their differing host specificities. Further, we examined the allelic diversity of eight T3E genes from X. arboricola Pathovars. This analysis revealed very limited allelic variations at the different loci. Altogether, the data presented here provide new insights into the evolution of pathogenicity and host range of X. arboricola and are discussed in terms of emergence of new diseases within this bacterial species.
J. D. Taylor - One of the best experts on this subject based on the ideXlab platform.
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Patterns of interaction between isolates of three Pathovars of Pseudomonas syringae and accessions of a range of host and nonhost legume species
Plant Pathology, 2006Co-Authors: P. J. Hunter, J. D. TaylorAbstract:Isolates of three Pathovars of Pseudomonas syringae were tested against 10 legume species. Some isolates of all Pathovars showed cultivar-specific interactions with at least one legume species outside the expected host range. Lablab purpureus and Phaseolus lunatus were found to be hosts to isolates of both P. syringae pv. glycinea and P. syringae pv. phaseolicola, while Lathyrus latifolius was host to isolates of P. syringae pv. pisi and P. syringae pv. glycinea. Lens culinaris showed patterns of interaction with isolates of all three Pathovars. Gene models based on mathematical estimates of minimum gene numbers agreed with those previously published for the interactions of P. syringae pv. pisi with Pisum sativum and P. syringae pv. phaseolicola with Phaseolus vulgaris. Two different gene-for-gene models based on five resistance/avirulence gene pairs were proposed to explain observed interactions between Glycine max and P. syringae pv. glycinea. Pathogen isolates which contained no known avirulences defined on their respective host species were found to carry cryptic avirulences recognized by other plant species. Estimates of minimum gene numbers required to explain the interactions of a plant species with all pathogen isolates or to explain the interactions of the isolates of one Pathovar with all plant accessions were consistently lower than the sum of the minimum gene numbers required to explain the interactions of each individual component.
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identification and origin of xanthomonas campestris pv campestris races and related Pathovars
Phytopathology, 2001Co-Authors: J Vicente, J Conway, S J Roberts, J. D. TaylorAbstract:One hundred sixty-four isolates of Xanthomonas campestris pv. campestris and other X. campestris Pathovars known to infect cruciferous hosts (X. campestris pvs. aberrans, raphani, armoraciae, and incanae) were inoculated onto a differential series of Brassica spp. to determine both pathogenicity to brassicas and race. Of these, 144 isolates were identified as X. campestris pv. campestris and grouped into six races, with races 1 (62%) and 4 (32%) being predominant. Other races were rare. The remaining 20 isolates from brassicas and other cruciferous hosts were either nonpathogenic or very weakly pathogenic on the differential series and could not be race-typed. Five of these isolates, from the ornamental crucifers wallflower (Cheiranthus cheiri), stock (Matthiola incana) and candytuft (Iberis sp.), showed clear evidence of Pathovar-like specificity to the hosts of origin. A gene-for-gene model based on the interaction of four avirulence genes in X. campestris pv. campestris races and four matching resistance genes in the differential hosts is proposed. Knowledge of the race structure and worldwide distribution of races is fundamental to the search for sources of resistance and for the establishment of successful resistance breeding programs.
