The copper resistance operon copAB from Xanthomonas axonopodis pathovar citri: gene inactivation results in copper sensitivity

Teixeira, Elaine Cristina; Oliveira, Júlio Cézar Franco de; Novo, Maria Teresa Marques; Bertolini, Marina

doi:10.1099/mic.0.2007/013821-0

Cited by 40 publications

(45 citation statements)

References 29 publications

(30 reference statements)

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“…citri 306 is responsive to copper amendments; however, this strain was mistakenly rated as copper resistant. This was probably due to pH adjustments made to the medium with potassium phosphate buffer (40), which has been shown to reduce the actual concentration of copper available in the medium (29). While strains harboring the copper resistance genes copLAB, which are highly similar (Ն90%) to the ones cloned in this study, can grow on MGY agar amended with up to 400 mg liter Ϫ1 of Cu, strains that have only the chromosomal copLAB genes, such as X. citri subsp.…”

Section: Discussionmentioning

confidence: 99%

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Molecular Characterization of Copper Resistance Genes from Xanthomonas citri subsp. citri and Xanthomonas alfalfae subsp. citrumelonis

Behlau

Canteros

Minsavage

et al. 2011

Appl Environ Microbiol

129

168

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Copper sprays have been widely used for control of endemic citrus canker caused by Xanthomonas citri subsp. citri in citrus-growing areas for more than 2 decades. Xanthomonas alfalfae subsp. citrumelonis populations were also exposed to frequent sprays of copper for several years as a protective measure against citrus bacterial spot (CBS) in Florida citrus nurseries. Long-term use of these bactericides has led to the development of copperresistant (Cu r ) strains in both X. citri subsp. citri and X. alfalfae subsp. citrumelonis, resulting in a reduction of disease control. The objectives of this study were to characterize for the first time the genetics of copper resistance in X. citri subsp. citri and X. alfalfae subsp. citrumelonis and to compare these organisms to other Cu r bacteria. Copper resistance determinants from X. citri subsp. citri strain A44(pXccCu2) from Argentina and X. alfalfae subsp. citrumelonis strain 1381(pXacCu2) from Florida were cloned and sequenced. Open reading frames (ORFs) related to the genes copL, copA, copB, copM, copG, copC, copD, and copF were identified in X. citri subsp. citri A44. The same ORFs, except copC and copD, were also present in X. alfalfae subsp. citrumelonis 1381. Transposon mutagenesis of the cloned copper resistance determinants in pXccCu2 revealed that copper resistance in X. citri subsp. citri strain A44 is mostly due to copL, copA, and copB, which are the genes in the cloned cluster with the highest nucleotide homology (>92%) among different Cu r bacteria.

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Section: Discussionmentioning

confidence: 99%

“…Teixeira et al (40) demonstrated that chromosomal copAB from X. citri subsp. citri 306 is responsive to copper amendments; however, this strain was mistakenly rated as copper resistant.…”

Section: Discussionmentioning

confidence: 99%

Molecular Characterization of Copper Resistance Genes from Xanthomonas citri subsp. citri and Xanthomonas alfalfae subsp. citrumelonis

Behlau

Canteros

Minsavage

et al. 2011

Appl Environ Microbiol

129

168

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“…It is likely that the two kinds of coding VNTRs in this gene, which differ by only one amino acid change, represent a source of adaptive variation, particularly because copB is involved in resistance to copper (Table 1). Copper is often used to treat phytopathogens in agricultural crops, which triggers resistance mechanisms in these pathogens (82). Therefore, the number of each type of VNTR may play a role in responding to copper in the environment, which warrants additional exploration in future studies.…”

Section: Fastidiosamentioning

confidence: 99%

“…copB functions in copper homeostasis in X. fastidiosa (68), and inactivation of the homologous copAB operon in Xanthomonas axonopodis pv. citri rendered the bacterium incapable of growing in medium containing copper (82), so this gene is probably necessary for X. fastidiosa survival. Also, copB contains a region with a 15-bp (minisatellite)-coding variable number tandem repeat (VNTR).…”

Section: Gene Selection For Mlsa-ementioning

confidence: 99%

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

Parker

Havird

Fuente

2012

Appl Environ Microbiol

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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, including geographic differentiation, and provide additional information regarding host-based isolate variation and specificity. dN/dS ratios of environmentally mediated genes, though <1 due to high sequence similarity, are significantly greater than housekeeping gene dN/dS ratios and correlate with increased sequence variability. MLSA-E can more precisely resolve relationships between closely related bacterial strains with low genetic variability, such as X. fastidiosa isolates. Discovering the genetic relationships between X. fastidiosa isolates will provide new insights into the epidemiology of populations of X. fastidiosa, allowing improved disease management in economically important crops.X ylella fastidiosa is a Gram-negative plant-pathogenic bacterium that is adapted to live inside the xylem vessels of plant hosts and the foregut of leafhopper insect vectors (8). Biofilm formed inside the xylem vessels is believed to play a key role in disease development by obstructing water passage from the root to aerial parts of the plant (8). The bacterium infects several economically important agricultural crops, including grape, citrus, almond, and peach, as well as a variety of landscape trees and plants (38). Despite this broad host range, isolates of X. fastidiosa from different plant hosts are genetically very similar. Comparative genomic analyses between the most divergent X. fastidiosa complete genome strains (the Pierce's disease of grapevine type strain Temecula and the citrus variegated chlorosis type strain 9a5c) have shown that 98% of their genes are shared, and the average amino acid identity is 96% (85). Taxonomic analyses have grouped X. fastidiosa strains into several su...

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“…However, recently, the operon cop AB of X. axonopodis pv. citri was shown to involved in the copper resistance of this species (Teixeira et al , 2008). …”

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confidence: 99%

Differential expression of pathogenicity- and virulence-related genes of Xanthomonas axonopodis pv. citri under copper stress

et al. 2010

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In this study, we used real-time quantitative PCR (RT-qPCR) to evaluate the expression of 32 genes of Xanthomonas axonopodis pv. citri related to pathogenicity and virulence that are also involved in copper detoxification. Nearly all of the genes were up-regulated, including copA and copB. Two genes homologous to members of the type II secretion system (xcsH and xcsC) and two involved in the degradation of plant cell wall components (pglA and pel) were the most expressed in response to an elevated copper concentration. The type II secretion system (xcs operon) and a few homologues of proteins putatively secreted by this system showed enhanced expression when the bacteria were exposed to a high concentration of copper sulfate. The enhanced expression of the genes of secretion II system during copper stress suggests that this pathway may have an important role in the adaptative response of X. axonopodis pv. citri to toxic compounds. These findings highlight the potential role of these genes in attenuating the toxicity of certain metals and could represent an important means of bacterial resistance against chemicals used to control diseases.

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The copper resistance operon copAB from Xanthomonas axonopodis pathovar citri: gene inactivation results in copper sensitivity

Cited by 40 publications

References 29 publications

Molecular Characterization of Copper Resistance Genes from Xanthomonas citri subsp. citri and Xanthomonas alfalfae subsp. citrumelonis

Molecular Characterization of Copper Resistance Genes from Xanthomonas citri subsp. citri and Xanthomonas alfalfae subsp. citrumelonis

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

Differential expression of pathogenicity- and virulence-related genes of Xanthomonas axonopodis pv. citri under copper stress

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