Analysis of the molecular basis of Xanthomonas axonopodis pv. citri pathogenesis in Citrus limon

Siciliano, Florencia; Torres, Pablo; Sendín, Lorena Noelia; Bermejo, Carolina; Filippone, Paula; Vellice, Gabriel; Ramallo, Jackie; Castagnaro, Atilio Pedro; Vojnov, Adrián Alberto; Maraño, María Rosa

doi:10.2225/vol9-issue3-fulltext-20

Cited by 47 publications

(59 citation statements)

References 8 publications

(19 reference statements)

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“…the rpfC mutant of Xanthomonas albilineans are consistent with findings in a number of other Xanthomonas species and in Xylella fastidiosa (Barber et al, 1997;Chatterjee et al, 2008c;Dow, 2008;Newman et al, 2004;Siciliano et al, 2006). However, mutation of rpfG in Xanthomonas albilineans also led to an overproduction of DSF, which is not seen in other Xanthomonas species Slater et al, 2000;Sun et al, 2010).…”

Section: Quorum Sensing In Xanthomonas Albilineanssupporting

confidence: 83%

“…However, mutation of rpfG in Xanthomonas albilineans also led to an overproduction of DSF, which is not seen in other Xanthomonas species Slater et al, 2000;Sun et al, 2010). Secondly, the rpfF (DSF-deficient) mutant of Xanthomonas albilineans was only slightly affected in its capacity to colonize the host plant and to cause disease symptoms, in contrast to other species of Xanthomonas lacking DSF, which are generally severely affected in their capacity to cause symptoms (Dow, 2008;Siciliano et al, 2006;Thowthampitak et al, 2008). Thirdly, mutations in rpfG and rpfC of Xanthomonas albilineans had no effect on severity of disease symptoms but led to an enhanced ability to colonize sugar cane plants.…”

Section: Quorum Sensing In Xanthomonas Albilineansmentioning

confidence: 99%

“…Phenotypes due to mutation in different rpf genes vary according to the bacterial pathogen, from deficiency in virulence to hypervirulence, thus suggesting that members of the Xanthomonadaceae family have adapted their signalling system to fit specific needs for colonization of different hosts (Dow, 2008). In Xanthomonas species, mutation of rpfF or rpfC results in reduction of virulence (Dow et al, 2003;He & Zhang, 2008;Siciliano et al, 2006;Thowthampitak et al, 2008). In contrast, in Xylella fastidiosa, rpfF mutants are more virulent than the wildtype strain when mechanically inoculated into plants (Newman et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

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The RpfCG two-component system negatively regulates the colonization of sugar cane stalks by Xanthomonas albilineans

et al. 2013

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The genome of Xanthomonas albilineans, the causal agent of sugar cane leaf scald, carries a gene cluster encoding a predicted quorum sensing system that is highly related to the diffusible signalling factor (DSF) systems of the plant pathogens Xylella fastidiosa and Xanthomonas campestris. In these latter pathogens, a cluster of regulation of pathogenicity factors (rpf) genes encodes the DSF system and is involved in control of various cellular processes. Mutation of Xanthomonas albilineans rpfF, encoding a predicted DSF synthase, in Florida strain XaFL07-1 resulted in a small reduction of disease severity (DS). Single-knockout mutations of rpfC and rpfG (encoding a predicted DSF sensor and regulator, respectively) had no effect on DS or swimming motility of the pathogen. However, capacity of the pathogen to cause disease was slightly reduced and swimming motility was severely affected when rpfG and rpfC were both deleted. Similar results were obtained when the entire rpfGCF region was deleted. Surprisingly, when the pathogen was mutated in rpfG or rpfC (single or double mutations) it was able to colonize sugar cane spatially more efficiently than the wild-type. Mutation in rpfF alone did not affect the degree of spatial invasion. We conclude that the DSF signal contributes to symptom expression but not to invasion of sugar cane stalks by Xanthomonas albilineans strain XaFL07-1, which is mainly controlled by the RpfCG two-component system.

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Section: Quorum Sensing In Xanthomonas Albilineanssupporting

confidence: 83%

Section: Quorum Sensing In Xanthomonas Albilineansmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The RpfCG two-component system negatively regulates the colonization of sugar cane stalks by Xanthomonas albilineans

et al. 2013

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“…citri before it invades intercellular spaces (34). The monofunctional catalase KatE (40) and the rpf cell-to-cell quorum-sensing system, which is involved in exopolysaccharide, endoglucanase, and protease production (36), also contribute to the development of canker symptoms.…”

mentioning

confidence: 99%

The ColR/ColS Two-Component System Plays Multiple Roles in the Pathogenicity of the Citrus Canker Pathogen Xanthomonas citri subsp. citri

Yan

Wang

2011

J Bacteriol

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Bacterial citrus canker disease, which is caused by Xanthomonas citri subsp. citri, is one of the most devastating diseases of citrus plants. In this study, we characterized the role of the two-component regulatory system ColR/ColS in the pathogenicity of X. citri subsp. citri. colS mutants (256A10 and 421E7), colR mutants (386C6 and 417E10), and a colR colS double mutant (306DSR) all lost pathogenicity and produced no symptoms on grapefruit leaves inoculated by either pressure infiltration or the spray method. The pathogenicity defect of the colS, colR, and colR colS mutants could be complemented using the wild-type colS, colR, and colR colS genes, respectively. Mutation of colS or colR significantly reduced X. citri subsp. citri growth in planta. The ColR/ColS system also played important roles in bacterial biofilm formation in glass tubes and on leaf surfaces, lipopolysaccharide (LPS) production, catalase activity, and tolerance of environmental stress, including phenol, copper, and hydrogen peroxide. Furthermore, quantitative reverse transcription-PCR assays demonstrated that the ColR/ColS system positively regulated the expression of important virulence genes, including hrpD6, hpaF, the O-antigen LPS synthesis gene rfbC, and the catalase gene katE. Overall, our data indicate that the two-component regulatory system ColR/ColS is critical for X. citri subsp. citri virulence, growth in planta, biofilm formation, catalase activity, LPS production, and resistance to environmental stress. Xanthomonas

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“…The regulation of pathogenicity factors (rpf) genes control the synthesis of diffusible signal factor (DSF), which plays a major role in quorum sensing, thus controlling various virulence factors in X. axonopodis pv. citri (94). Three core genes, rpfF, rpfC, and rpfG, control the synthesis of the DSF molecule and signal transduction.…”

Section: T3ss Gene Clustersmentioning

confidence: 99%

Comparative Genomic Analysis of Xanthomonas axonopodis pv. citrumelo F1, Which Causes Citrus Bacterial Spot Disease, and Related Strains Provides Insights into Virulence and Host Specificit

et al. 2011

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Xanthomonas axonopodis pv. citrumelo is a citrus pathogen causing citrus bacterial spot disease that is geographically restricted within the state of Florida. Illumina, 454 sequencing, and optical mapping were used to obtain a complete genome sequence of X. axonopodis pv. citrumelo strain F1, 4.9 Mb in size. The strain lacks plasmids, in contrast to other citrus Xanthomonas pathogens. Phylogenetic analysis revealed that this pathogen is very close to the tomato bacterial spot pathogen X. campestris pv. vesicatoria 85-10, with a completely different host range. We also compared X. axonopodis pv. citrumelo to the genome of citrus canker pathogen X. axonopodis pv. citri 306. Comparative genomic analysis showed differences in several gene clusters, like those for type III effectors, the type IV secretion system, lipopolysaccharide synthesis, and others. In addition to pthA, effectors such as xopE3, xopAI, and hrpW were absent from X. axonopodis pv. citrumelo while present in X. axonopodis pv. citri. These effectors might be responsible for survival and the low virulence of this pathogen on citrus compared to that of X. axonopodis pv. citri. We also identified unique effectors in X. axonopodis pv. citrumelo that may be related to the different host range as compared to that of X. axonopodis pv. citri. X. axonopodis pv. citrumelo also lacks various genes, such as syrE1, syrE2, and RTX toxin family genes, which were present in X. axonopodis pv. citri. These may be associated with the distinct virulences of X. axonopodis pv. citrumelo and X. axonopodis pv. citri. Comparison of the complete genome sequence of X. axonopodis pv. citrumelo to those of X. axonopodis pv. citri and X. campestris pv. vesicatoria provides valuable insights into the mechanism of bacterial virulence and host specificity.Xanthomonas is an important genus of plant pathogenic bacteria (87). These Gram-negative rod-shaped pathogens belong to the class Gammaproteobacteria and can infect over 350 species of plants (12). Among the diseases on citrus, citrus bacterial canker (CBC) and citrus bacterial spot (CBS) are caused by distinct pathovars of Xanthomonas species. Citrus canker is caused by several pathogenic variants of X. axonopodis pv. citri (synonyms Xanthomonas citri, Xanthomonas campestris pv. citri, or Xanthomonas citri subsp. citri) (90, 109), whereas CBS is caused by X. axonopodis pv. citrumelo. X. axonopodis pv. citri strain 306 with a suspected origin in southeastern Asia causes Asiatic type A canker and is the most widespread and virulent form of CBC. It produces hyperplasic and hypertrophic (corky) lesions surrounded by oily or watersoaked margins and a yellow halo on leaves, stems, and fruits.In 1984, a disease similar to citrus canker was discovered in citrus nurseries in central Florida, leading to the destruction of millions of seedlings (98). This new form of citrus canker was described as the "E-strain" group, also known as nursery strain canker. Leaf spots of this strain are irregular to round, 3 to 5 mm in diameter, flat, water so...

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Analysis of the molecular basis of Xanthomonas axonopodis pv. citri pathogenesis in Citrus limon

Cited by 47 publications

References 8 publications

The RpfCG two-component system negatively regulates the colonization of sugar cane stalks by Xanthomonas albilineans

The RpfCG two-component system negatively regulates the colonization of sugar cane stalks by Xanthomonas albilineans

The ColR/ColS Two-Component System Plays Multiple Roles in the Pathogenicity of the Citrus Canker Pathogen Xanthomonas citri subsp. citri

Comparative Genomic Analysis of Xanthomonas axonopodis pv. citrumelo F1, Which Causes Citrus Bacterial Spot Disease, and Related Strains Provides Insights into Virulence and Host Specificit

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