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Origins of the Xylella fastidiosa Prophage-Like Regions and Their Impact in Genome Differentiation

VARANI, Alessandro de Mello; SOUZA, Rangel Celso; NAKAYA, Helder I.; LIMA, Wanessa Cristina de; ALMEIDA, Luiz Gonzaga Paula de; KITAJIMA, Elliot Watanabe; CHEN, Jianchi; CIVEROLO, Edwin; VASCONCELOS, Ana Tereza Ribeiro; SLUYS, Marie-Anne Van
Fonte: PUBLIC LIBRARY SCIENCE Publicador: PUBLIC LIBRARY SCIENCE
Tipo: Artigo de Revista Científica
Português
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47.31%
Xylella fastidiosa is a Gram negative plant pathogen causing many economically important diseases, and analyses of completely sequenced X. fastidiosa genome strains allowed the identification of many prophage-like elements and possibly phage remnants, accounting for up to 15% of the genome composition. To better evaluate the recent evolution of the X. fastidiosa chromosome backbone among distinct pathovars, the number and location of prophage-like regions on two finished genomes (9a5c and Temecula1), and in two candidate molecules (Ann1 and Dixon) were assessed. Based on comparative best bidirectional hit analyses, the majority (51%) of the predicted genes in the X. fastidiosa prophage-like regions are related to structural phage genes belonging to the Siphoviridae family. Electron micrograph reveals the existence of putative viral particles with similar morphology to lambda phages in the bacterial cell in planta. Moreover, analysis of microarray data indicates that 9a5c strain cultivated under stress conditions presents enhanced expression of phage anti-repressor genes, suggesting switches from lysogenic to lytic cycle of phages under stress-induced situations. Furthermore, virulence-associated proteins and toxins are found within these prophage-like elements...

Transmission of Methylobacterium mesophilicum by Bucephalogonia xanthophis for Paratransgenic Control Strategy of Citrus Variegated Chlorosis

GAI, Claudia Santos; LACAVA, Paulo Teixeira; QUECINE, Maria Carolina; AURIAC, Marie-Christine; LOPES, Joao Roberto Spotti; ARAUJO, Welington Luiz; MILLER, Thomas Albert; AZEVEDO, Joao Lucia
Fonte: MICROBIOLOGICAL SOCIETY KOREA Publicador: MICROBIOLOGICAL SOCIETY KOREA
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
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Methylobacterium mesophilicum, originally isolated as an endophytic bacterium from citrus plants, was genetically transformed to express green fluorescent protein (GFP). The GFP-labeled strain of M. mesophilicum was inoculated into Catharanthus roseus (model plant) seedlings and further observed colonizing its xylem vessels. The transmission of this endophyte by Bucephalogonia xanthophis, one of the insect vectors that transmit Xylella fastidiosa subsp. pauca, was verified by insects feeding from fluids containing the GFP bacterium followed by transmission to plants and isolating the endophyte from C. roseus plants. Forty-five days after inoculation, the plants exhibited endophytic colonization by M. mesophilicum, confirming this bacterium as a nonpathogenic, xylem-associated endophyte. Our data demonstrate that M. mesophilicum not only occupy the same niche of X. fastidiosa subsp. pauca inside plants but also may be transmitted by B. xanthophis. The transmission, colonization, and genetic manipulation of M. mesophilicum is a prerequisite to examining the potential use of symbiotic control to interrupt the transmission of X. fastidiosa subsp. pauca, the bacterial pathogen causing Citrus variegated chlorosis by insect vectors.; FAPESP[06/55494-4]; CAPES; CNPq

Análise in-silico de integrases no fitopatógeno Xylella fastidiosa: diversidade, sítios de integração e associação com bacteriófagos.; In silico analysis of integrases in the phytopathogen Xylella fastidiosa: diversity, integration sites and association with bacteriophages.

Varani, Alessandro de Mello
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 03/09/2008 Português
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Os elementos genéticos móveis encontrados no genoma da bactéria Xylella fastidiosa (Xf) são representados principalmente por bacteriófagos (na forma de profagos inseridos no genoma) e ilhas genômicas. As integrases são responsáveis pelo processo de mobilização (integração e/ou excisão) destes elementos, através do mecanismo de recombinação sítio-específica. Bacteriófagos e ilhas genômicas estão associados a eventos de rearranjos genômicos e à aquisição e ou interrupção de genes importantes para bactéria, tendo implicação direta na diversidade e organização genômica e, por conseqüência, na diferenciação entre linhagens. A extensão e o impacto desses eventos é o foco deste trabalho, através da análise in-silico das integrases e sua associação com regiões de profagos e ilhas genômicas, no genoma de quatro linhagens de Xf. Os dados aqui apresentados corroboram o papel das integrases e seus elementos genéticos móveis associados como agentes chaves no processo de diversidade e evolução da organização genômica entre as quatro linhagens de Xf.; The mobile genetic elements found in the genome of the bacterium Xylella fastidiosa (Xf) are mainly represented by bacteriophages (as prophages inserted into the genome) and genomic islands. The integrases are responsible for the process of mobilization (integration and / or excision) of these elements through the mechanism of site-specific recombination. Bacteriophages and genomic islands are associated with events of genomic rearrangements and the acquisition and or interruption of important genes for bacteria...

Diversidade bacteriana endofítica associada à Citrus sinensis (L.) Osbeck com sintomas de Greening; Endophytic bacterial diversity associated to Citrus sinensis (L.) Osbeck with Huanglongbing

Bernardes, Fernanda de Sousa
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 06/12/2010 Português
Relevância na Pesquisa
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O objetivo principal do presente estudo foi avaliar a diversidade bacteriana endofítica cultivável associada a plantas de Citrus sinensis (L.) Osbeck sintomáticas e assintomáticas para a doença Greening, com destaque para Methylobacterium spp. Simultaneamente, como objetivo secundário, foi realizado o estudo da comunidade bacteriana endofítica de Methylobacterium spp. presente em plantas de laranja doce com e sem sintomas da Clorose Variegada dos Citros (CVC). Assim, em período chuvoso (novembro de 2008 e fevereiro de 2009) e seco (maio de 2009) foram amostradas dez plantas sadias e dez plantas doentes (Greening e/ou CVC), em dois municípios citrícolas da região central do estado de São Paulo. A confirmação da presença e/ou ausência dos fitopatógenos Candidatus Liberibacter americanus, Ca. L. asiaticus e Ca. L africanus, agentes causadores do Greening e, também, de Xylella fastidiosa, agente causador da CVC foram realizadas para todas as amostras pela técnica PCR a partir da utilização de iniciadores específicos para os respectivos fitopatógenos. Em relação à comunidade bacteriana estudada, foi realizado o isolamento e posterior quantificação do número de unidades formadoras de colônia (UFCs) totais e de Methylobacterium...

Microscopia de força atômica em materiais biológicos : biossensores e nanoferramentas; Atomic force microscopy on biological materials : biosensors and nanotools

Alberto Luís Dario Moreau
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/01/2011 Português
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Na primeira parte deste trabalho, nós investigamos o processo de crescimento de um biofilme de bactérias (Xylella fastidiosa) inoculadas sobre lamínulas de vidro. O tamanho e a distância entre os biofilmes foram estudados por imagens de microscopia óptica; e uma análise fractal foi realizada usando conceitos de escala e imagens de AFM. Observamos que biofilmes diferentes mostram características fractais semelhantes, embora as variações na morfologia possam ser identificadas para diferentes estádios de crescimento do biofilme. Dois tipos de padrões estruturais são identificados através da dimensão fractal (Df) sugerindo que o crescimento do biofilme pode ser entendido como o modelo de Eden nos estágios de formação e no final, enquanto para o estágio de maturação aparecem evidências do modelo DLA (diffusion-limited aggregation). Estes resultados foram correlacionados à formação da matriz do biofilme que pode dificultar a difusão dos nutrientes e por isso criar condições para um crescimento DLA. Ainda com o AFM, fizemos medidas de espectroscopia de força para estudar a interação específica entre antígeno-anticorpo relacionados ao vírus CTV (citrus tristeza virus). Para tanto foi realizado o estudo da imobilização deste material biológico nas superfícies da ponta do AFM...

Identificação de estruturas biológicas por microscopia de força atômica; Identification of biological structures by atomic force microscopy

Duber Marcel Murillo Munar
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 18/11/2011 Português
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Este trabalho tem como finalidade mostrar a importância dos diferentes modos da Microscopia de Varredura por Ponta de Prova (SPM) numa abordagem complementar para o estudo de dois diferentes sistemas biológicos. O processo de formação de biofilmes da bactéria fitopatogênica Xylella fastidiosa (Xf) foi o primeiro sistema abordado neste trabalho. Neste caso nosso objetivo é levantar informações que possam complementar o modelo mais aceito atualmente e corroborar os resultados obtidos anteriormente em nosso grupo. As amostras foram preparadas sobre substratos de silício recoberto com ouro e cultivadas durante tempos de crescimento de 7, 14 e 21 dias. O principal modo utilizado foi a Microscopia de Força Atômica por Kelvin Probe por modulação de amplitude (AM-KPFM) que fornece o potencial de superfície com resolução nanométrica. Imagens por KPFM foram adquiridas simultaneamente com as de topografia e fase obtidas por Microscopia de Força Atômica no modo não-contato (NC-AFM). Os resultados obtidos revelaram um processo de recobrimento gradual das bactérias por um filme de substância polimérica extracelular (EPS), concordando com os modelos propostos na literatura, porém ainda não comprovados. Imagens adquiridas por microscopia óptica (MO) mostram um desenvolvimento mais lento dos biofilmes (BF) em comparação aos resultados de G. S. Lorite para BF sobre substratos de silício obtidos anteriormente em nosso grupo. Isto está de acordo com a preferência das bactérias por superfícies com potenciais mais altos. Um resultado original está na observação de protuberâncias encontradas nas extremidades das bactérias...

Stable Transformation of the Xylella fastidiosa Citrus Variegated Chlorosis Strain with oriC Plasmids

Monteiro, Patrícia B.; Teixeira, Diva C.; Palma, Renê R.; Garnier, Monique; Bové, Joseph-Marie; Renaudin, Joël
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /05/2001 Português
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Xylella fastidiosa is a gram-negative, xylem-limited bacterium affecting economically important crops (e.g., grapevine, citrus, and coffee). The citrus variegated chlorosis (CVC) strain of X. fastidiosa is the causal agent of this severe disease of citrus in Brazil and represents the first plant-pathogenic bacterium for which the genome sequence was determined. Plasmids for the CVC strain of X. fastidiosa were constructed by combining the chromosomal replication origin (oriC) of X. fastidiosa with a gene which confers resistance to kanamycin (Kanr). In plasmid p16KdAori, the oriC fragment comprised the dnaA gene as well as the two flanking intergenic regions, whereas in plasmid p16Kori the oriC fragment was restricted to the dnaA-dnaN intergenic region, which contains dnaA-box like sequences and AT-rich clusters. In plasmid p16K, no oriC sequence was present. In the three constructs, the promoter region of one of the two X. fastidiosa rRNA operons was used to drive the transcription of the Kanr gene to optimize the expression of kanamycin resistance in X. fastidiosa. Five CVC X. fastidiosa strains, including strain 9a5c, the genome sequence of which was determined, and two strains isolated from coffee, were electroporated with plasmid p16KdAori or p16Kori. Two CVC isolates...

Detection and Diversity Assessment of Xylella fastidiosa in Field-Collected Plant and Insect Samples by Using 16S rRNA and gyrB Sequences

Rodrigues, Jorge L. M.; Silva-Stenico, M. E.; Gomes, J. E.; Lopes, J. R. S.; Tsai, S. M.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /07/2003 Português
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The causal agent of diseases in many economically important plants is attributed to the xylem-limited bacterium Xylella fastidiosa. The detection of this plant pathogen has been hampered due to its difficult isolation and slow growth on plates. Nearly complete nucleotide sequences of the 16S rRNA gene and partial sequences of the gyrB gene were determined for 18 strains of X. fastidiosa isolated from different plant hosts. A phylogenetic analysis, based on gyrB, grouped strains in three clusters; grape-isolated strains formed one cluster, citrus-coffee strains formed another cluster, and a third cluster resulted from all other strains. Primer pairs designed for the 16S rRNA and gyrB genes were extensively searched in databases to verify their in silico specificity. Primer pairs were certified with 30 target and 36 nontarget pure cultures of microorganisms, confirming 100% specificity. A multiplex PCR protocol was developed and its sensitivity tested. Sequencing of PCR products confirmed the validity of the multiplex PCR. Xylella fastidiosa was detected in field-collected plants, disease vector insects, and nonsymptomatic but infected plants. Specific detection of X. fastidiosa may facilitate the understanding of its ecological significance and prevention of spread of the disease.

Multilocus Sequence Type System for the Plant Pathogen Xylella fastidiosa and Relative Contributions of Recombination and Point Mutation to Clonal Diversity

Scally, Mark; Schuenzel, Erin L.; Stouthamer, Richard; Nunney, Leonard
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /12/2005 Português
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Multilocus sequence typing (MLST) identifies and groups bacterial strains based on DNA sequence data from (typically) seven housekeeping genes. MLST has also been employed to estimate the relative contributions of recombination and point mutation to clonal divergence. We applied MLST to the plant pathogen Xylella fastidiosa using an initial set of sequences for 10 loci (9.3 kb) of 25 strains from five different host plants, grapevine (PD strains), oleander (OLS strains), oak (OAK strains), almond (ALS strains), and peach (PP strains). An eBURST analysis identified six clonal complexes using the grouping criterion that each member must be identical to at least one other member at 7 or more of the 10 loci. These clonal complexes corresponded to previously identified phylogenetic clades; clonal complex 1 (CC1) (all PD strains plus two ALS strains) and CC2 (OLS strains) defined the X. fastidiosa subsp. fastidiosa and X. fastidiosa subsp. sandyi clades, while CC3 (ALS strains), CC4 (OAK strains), and CC5 (PP strains) were subclades of X. fastidiosa subsp. multiplex. CC6 (ALS strains) identified an X. fastidiosa subsp. multiplex-like group characterized by a high frequency of intersubspecific recombination. Compared to the recombination rate in other bacterial species...

Origins of the Xylella fastidiosa Prophage-Like Regions and Their Impact in Genome Differentiation

de Mello Varani, Alessandro; Souza, Rangel Celso; Nakaya, Helder I.; de Lima, Wanessa Cristina; Paula de Almeida, Luiz Gonzaga; Kitajima, Elliot Watanabe; Chen, Jianchi; Civerolo, Edwin; Vasconcelos, Ana Tereza Ribeiro; Van Sluys, Marie-Anne
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 31/12/2008 Português
Relevância na Pesquisa
47.31%
Xylella fastidiosa is a Gram negative plant pathogen causing many economically important diseases, and analyses of completely sequenced X. fastidiosa genome strains allowed the identification of many prophage-like elements and possibly phage remnants, accounting for up to 15% of the genome composition. To better evaluate the recent evolution of the X. fastidiosa chromosome backbone among distinct pathovars, the number and location of prophage-like regions on two finished genomes (9a5c and Temecula1), and in two candidate molecules (Ann1 and Dixon) were assessed. Based on comparative best bidirectional hit analyses, the majority (51%) of the predicted genes in the X. fastidiosa prophage-like regions are related to structural phage genes belonging to the Siphoviridae family. Electron micrograph reveals the existence of putative viral particles with similar morphology to lambda phages in the bacterial cell in planta. Moreover, analysis of microarray data indicates that 9a5c strain cultivated under stress conditions presents enhanced expression of phage anti-repressor genes, suggesting switches from lysogenic to lytic cycle of phages under stress-induced situations. Furthermore, virulence-associated proteins and toxins are found within these prophage-like elements...

Functional Characterization of Replication and Stability Factors of an Incompatibility Group P-1 Plasmid from Xylella fastidiosa▿

Lee, Min Woo; Rogers, Elizabeth E.; Stenger, Drake C.
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
47.27%
Xylella fastidiosa strain riv11 harbors a 25-kbp plasmid (pXF-RIV11) belonging to the IncP-1 incompatibility group. Replication and stability factors of pXF-RIV11 were identified and used to construct plasmids able to replicate in X. fastidiosa and Escherichia coli. Replication in X. fastidiosa required a 1.4-kbp region from pXF-RIV11 containing a replication initiation gene (trfA) and the adjacent origin of DNA replication (oriV). Constructs containing trfA and oriV from pVEIS01, a related IncP-1 plasmid of the earthworm symbiont Verminephrobacter eiseniae, also were competent for replication in X. fastidiosa. Constructs derived from pXF-RIV11 but not pVEIS01 replicated in Agrobacterium tumefaciens, Xanthomonas campestris, and Pseudomonas syringae. Although plasmids bearing replication elements from pXF-RIV11 or pVEIS01 could be maintained in X. fastidiosa under antibiotic selection, removal of selection resulted in plasmid extinction after 3 weekly passages. Addition of a toxin-antitoxin addiction system (pemI/pemK) from pXF-RIV11 improved plasmid stability such that >80 to 90% of X. fastidiosa cells retained plasmid after 5 weekly passages in the absence of antibiotic selection. Expression of PemK in E. coli was toxic for cell growth...

Differentiation of Xylella fastidiosa Strains via Multilocus Sequence Analysis of Environmentally Mediated Genes (MLSA-E)

Parker, Jennifer K.; Havird, Justin C.; De La Fuente, Leonardo
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /03/2012 Português
Relevância na Pesquisa
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Isolates of the plant pathogen Xylella fastidiosa are genetically very similar, but studies on their biological traits have indicated differences in virulence and infection symptomatology. Taxonomic analyses have identified several subspecies, and phylogenetic analyses of housekeeping genes have shown broad host-based genetic differences; however, results are still inconclusive for genetic differentiation of isolates within subspecies. This study employs multilocus sequence analysis of environmentally mediated genes (MLSA-E; genes influenced by environmental factors) to investigate X. fastidiosa relationships and differentiate isolates with low genetic variability. Potential environmentally mediated genes, including host colonization and survival genes related to infection establishment, were identified a priori. The ratio of the rate of nonsynonymous substitutions to the rate of synonymous substitutions (dN/dS) was calculated to select genes that may be under increased positive selection compared to previously studied housekeeping genes. Nine genes were sequenced from 54 X. fastidiosa isolates infecting different host plants across the United States. Results of maximum likelihood (ML) and Bayesian phylogenetic (BP) analyses are in agreement with known X. fastidiosa subspecies clades but show novel within-subspecies differentiation...

A Conjugative 38 kB Plasmid Is Present in Multiple Subspecies of Xylella fastidiosa

Rogers, Elizabeth E.; Stenger, Drake C.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 14/12/2012 Português
Relevância na Pesquisa
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A ∼38kB plasmid (pXF-RIV5) was present in the Riv5 strain of Xylella fastidiosa subsp. multiplex isolated from ornamental plum in southern California. The complete nucleotide sequence of pXF-RIV5 is almost identical to that of pXFAS01 from X. fastidiosa subsp. fastidiosa strain M23; the two plasmids vary at only 6 nucleotide positions. BLAST searches and phylogenetic analyses indicate pXF-RIV5 and pXFAS01 share some similarity to chromosomal and plasmid (pXF51) sequences of X. fastidiosa subsp. pauca strain 9a5c and more distant similarity to plasmids from a wide variety of bacteria. Both pXF-RIV5 and pXFAS01 encode homologues of a complete Type IV secretion system involved in conjugation and DNA transfer among bacteria. Mating pair formation proteins (Trb) from Yersinia pseudotuberculosis IP31758 are the mostly closely related non-X. fastidiosa proteins to most of the Trb proteins encoded by pXF-RIV5 and pXFAS01. Unlike many bacterial conjugative plasmids, pXF-RIV5 and pXFAS01 do not carry homologues of known accessory modules that confer selective advantage on host bacteria. However, both plasmids encode seven hypothetical proteins of unknown function and possess a small transposon-associated region encoding a putative transposase and associated factor. Vegetative replication of pXF-RIV5 and pXFAS01 appears to be under control of RepA protein and both plasmids have an origin of DNA replication (oriV) similar to that of pRP4 and pR751 from Escherichia coli. In contrast...

Diffusible Signal Factor (DSF) Synthase RpfF of Xylella fastidiosa Is a Multifunction Protein Also Required for Response to DSF

Ionescu, Michael; Baccari, Clelia; Da Silva, Aline Maria; Garcia, Angelica; Yokota, Kenji; Lindow, Steven E.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /12/2013 Português
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Xylella fastidiosa, like related Xanthomonas species, employs an Rpf cell-cell communication system consisting of a diffusible signal factor (DSF) synthase, RpfF, and a DSF sensor, RpfC, to coordinate expression of virulence genes. While phenotypes of a ΔrpfF strain in Xanthomonas campestris could be complemented by its own DSF, the DSF produced by X. fastidiosa (XfDSF) did not restore expression of the XfDSF-dependent genes hxfA and hxfB to a ΔrpfF strain of X. fastidiosa, suggesting that RpfF is involved in XfDSF sensing or XfDSF-dependent signaling. To test this conjecture, rpfC and rpfF of X. campestris were replaced by those of X. fastidiosa, and the contribution of each gene to the induction of a X. campestris DSF-dependent gene was assessed. As in X. fastidiosa, XfDSF-dependent signaling required both X. fastidiosa proteins RpfF and RpfC. RpfF repressed RpfC signaling activity, which in turn was derepressed by XfDSF. A mutated X. fastidiosa RpfF protein with two substitutions of glutamate to alanine in its active site was incapable of XfDSF production yet enabled a response to XfDSF, indicating that XfDSF production and the response to XfDSF are two separate functions in which RpfF is involved. This mutant was also hypervirulent to grape...

Intersubspecific Recombination in Xylella fastidiosa Strains Native to the United States: Infection of Novel Hosts Associated with an Unsuccessful Invasion

Nunney, Leonard; Hopkins, Donald L.; Morano, Lisa D.; Russell, Stephanie E.; Stouthamer, Richard
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /02/2014 Português
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The bacterial pathogen Xylella fastidiosa infects xylem and causes disease in many plant species in the Americas. Different subspecies of this bacterium and different genotypes within subspecies infect different plant hosts, but the genetics of host adaptation are unknown. Here we examined the hypothesis that the introduction of novel genetic variation via intersubspecific homologous recombination (IHR) facilitates host shifts. We investigated IHR in 33 X. fastidiosa subsp. multiplex isolates previously identified as recombinant based on 8 loci (7 multilocus sequence typing [MLST] loci plus 1 locus). We found significant evidence of introgression from X. fastidiosa subsp. fastidiosa in 4 of the loci and, using published data, evidence of IHR in 6 of 9 additional loci. Our data showed that IHR regions in 2 of the 4 loci were inconsistent (12 mismatches) with X. fastidiosa subsp. fastidiosa alleles found in the United States but consistent with alleles from Central America. The other two loci were consistent with alleles from both regions. We propose that the recombinant forms all originated via genomewide recombination of one X. fastidiosa subsp. multiplex ancestor with one X. fastidiosa subsp. fastidiosa donor from Central America that was introduced into the United States but subsequently disappeared. Using all of the available data...

Large-Scale Intersubspecific Recombination in the Plant-Pathogenic Bacterium Xylella fastidiosa Is Associated with the Host Shift to Mulberry

Nunney, Leonard; Schuenzel, Erin L.; Scally, Mark; Bromley, Robin E.; Stouthamer, Richard
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /05/2014 Português
Relevância na Pesquisa
47.29%
Homologous recombination plays an important role in the structuring of genetic variation of many bacteria; however, its importance in adaptive evolution is not well established. We investigated the association of intersubspecific homologous recombination (IHR) with the shift to a novel host (mulberry) by the plant-pathogenic bacterium Xylella fastidiosa. Mulberry leaf scorch was identified about 25 years ago in native red mulberry in the eastern United States and has spread to introduced white mulberry in California. Comparing a sequence of 8 genes (4,706 bp) from 21 mulberry-type isolates to published data (352 isolates representing all subspecies), we confirmed previous indications that the mulberry isolates define a group distinct from the 4 subspecies, and we propose naming the taxon X. fastidiosa subsp. morus. The ancestry of its gene sequences was mixed, with 4 derived from X. fastidiosa subsp. fastidiosa (introduced from Central America), 3 from X. fastidiosa subsp. multiplex (considered native to the United States), and 1 chimeric, demonstrating that this group originated by large-scale IHR. The very low within-type genetic variation (0.08% site polymorphism), plus the apparent inability of native X. fastidiosa subsp. multiplex to infect mulberry...

Seasonal Increase of Xylella fastidiosa in Hemiptera Collected From Central Texas Vineyards

Mitchell, Forrest L.; Brady, Jeff; Bextine, Blake; Lauzière, Isabelle
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
Português
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Yellow sticky traps were placed in six vineyards in central Texas from 2003 to 2006 and in locations outside the vineyards in 2004–2006. In total, 72 collections on 55 dates were examined. Xylem fluid-feeding insects were removed and identified to species and then analyzed by polymerase chain reaction to determine the presence or absence of Xylella fastidiosa Wells et al. Of the 1318 insects removed, 13 species were found, dominated by Homalodisca vitripennis (Germar), Clastoptera xanthocepahala Germar, and Graphocephala versuta (Say). Insects testing positive for X. fastidiosa were analyzed further using fluorescence resonance energy transfer probes to determine the genotype of the bacterium, which fell into four groups: subspecies fastidiosa, multiplex, sandyi, and unknown subspecies. Vineyards known to be affected by Pierce’s disease had more insects that were contaminated by the bacterium than those that were not as affected. X. fastidiosa subsp. fastidiosa, the causative agent of Pierce’s disease, was found more commonly in insects collected from vineyards than from insects collected outside the vineyards. Conversely, the subspecies multiplex and sandyi...

Chitin Utilization by the Insect-Transmitted Bacterium Xylella fastidiosa▿ †

Killiny, Nabil; Prado, Simone S.; Almeida, Rodrigo P. P.
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
Português
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Xylella fastidiosa is an insect-borne bacterium that colonizes xylem vessels of a large number of host plants, including several crops of economic importance. Chitin is a polysaccharide present in the cuticle of leafhopper vectors of X. fastidiosa and may serve as a carbon source for this bacterium. Biological assays showed that X. fastidiosa reached larger populations in the presence of chitin. Additionally, chitin induced phenotypic changes in this bacterium, notably increasing adhesiveness. Quantitative PCR assays indicated transcriptional changes in the presence of chitin, and an enzymatic assay demonstrated chitinolytic activity by X. fastidiosa. An ortholog of the chitinase A gene (chiA) was identified in the X. fastidiosa genome. The in silico analysis revealed that the open reading frame of chiA encodes a protein of 351 amino acids with an estimated molecular mass of 40 kDa. chiA is in a locus that consists of genes implicated in polysaccharide degradation. Moreover, this locus was also found in the genomes of closely related bacteria in the genus Xanthomonas, which are plant but not insect associated. X. fastidiosa degraded chitin when grown on a solid chitin-yeast extract-agar medium and grew in liquid medium with chitin as the sole carbon source; ChiA was also determined to be secreted. The gene encoding ChiA was cloned into Escherichia coli...

Comparative Analyses of the Complete Genome Sequences of Pierce's Disease and Citrus Variegated Chlorosis Strains of Xylella fastidiosa

Van Sluys, M. A.; de Oliveira, M. C.; Monteiro-Vitorello, C. B.; Miyaki, C. Y.; Furlan, L. R.; Camargo, L. E. A.; da Silva, A. C. R.; Moon, D. H.; Takita, M. A.; Lemos, E. G. M.; Machado, M. A.; Ferro, M. I. T.; da Silva, F. R.; Goldman, M. H. S.; Goldman
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /02/2003 Português
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Xylella fastidiosa is a xylem-dwelling, insect-transmitted, gamma-proteobacterium that causes diseases in many plants, including grapevine, citrus, periwinkle, almond, oleander, and coffee. X. fastidiosa has an unusually broad host range, has an extensive geographical distribution throughout the American continent, and induces diverse disease phenotypes. Previous molecular analyses indicated three distinct groups of X. fastidiosa isolates that were expected to be genetically divergent. Here we report the genome sequence of X. fastidiosa (Temecula strain), isolated from a naturally infected grapevine with Pierce's disease (PD) in a wine-grape-growing region of California. Comparative analyses with a previously sequenced X. fastidiosa strain responsible for citrus variegated chlorosis (CVC) revealed that 98% of the PD X. fastidiosa Temecula genes are shared with the CVC X. fastidiosa strain 9a5c genes. Furthermore, the average amino acid identity of the open reading frames in the strains is 95.7%. Genomic differences are limited to phage-associated chromosomal rearrangements and deletions that also account for the strain-specific genes present in each genome. Genomic islands, one in each genome, were identified, and their presence in other X. fastidiosa strains was analyzed. We conclude that these two organisms have identical metabolic functions and are likely to use a common set of genes in plant colonization and pathogenesis...

Asociación molecular de Xylella fastidiosa en plantas de papa (Solanum tuberosum L.) con síntomas de punta morada, en México

Gutiérrez-Ibáñez,A. T.; Laguna-Cerda,A.; Rojas-Martínez,R. I.; González-Garza,R.; Salgado-Siclán,M. L.; Aguilar-Ortigoza,C.; González-Esquivel,C.
Fonte: Universidad Autónoma Chapingo Publicador: Universidad Autónoma Chapingo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2009 Português
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La necrosis de los tubérculos de papa se asocia como parte del síndrome de punta morada (PMP). En el 2005, en Texas, EUA, a esta sintomatología se le denominó "zebra chip" o rayado de la papa y se le ha asociado con la presencia de Xylella fastidiosa. El objetivo de esta investigación fue detectar la presencia de esta bacteria en plantas de papa que presentaban punta morada. Durante el ciclo primavera-verano 2006 se hizo un muestreo dirigido en Toluca, Atlacomulco y Valle de Bravo, Estado de México. La detección de Xylella fastidiosa se realizó mediante la reacción en cadena de la polimerasa (PCR) con los iniciadores específicos RST31/RST33, resultando el 25 % de las plantas positivas para este patógeno. La comparación de las secuencias de los fragmentos amplificadas y las registradas en el GENBANK evidenciaron una homología de 97 a 99 %. Estos resultados sugieren que la necrosis y la punta morada encontrados en plantas de papa, en el Estado de México, están asociados con Xylella fastidiosa.