Global regulation of pathogenicity mechanism of Ralstonia solanacearum

Hikichi, Yasufumi; Yoshimochi, Takeshi; Tsujimoto, Shintaro; Shinohara, Rena; Nakaho, Kazuhiro; Kanda, Ayami; Kiba, Akinori; Ohnishi, Kouhei

doi:10.5511/plantbiotechnology.24.149

Cited by 40 publications

(27 citation statements)

References 38 publications

(20 reference statements)

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“…Molecular approaches using microarray technology recently showed that the environmentally induced type III secretion pathway also influences the secretion of exo-poly-a-D-galacturonosidase (PehB) by HrpG [62], and an influence of HrpB on exo-PG C (PehC) was suggested by Hikichi et al [31], indicating that both exo-PGs can be stimulated by plant tissue. Thus, contact with the plant cell wall in R. solanacearum strain GMI1000 is suggested to influence the expression of PGs.…”

Section: Discussionmentioning

confidence: 98%

Endo- and exopolygalacturonases of Ralstonia solanacearum are inhibited by polygalacturonase-inhibiting protein (PGIP) activity in tomato stem extracts

Schacht

Unger

Pich

et al. 2011

Plant Physiology and Biochemistry

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Section: Discussionmentioning

confidence: 98%

Endo- and exopolygalacturonases of Ralstonia solanacearum are inhibited by polygalacturonase-inhibiting protein (PGIP) activity in tomato stem extracts

Schacht

Unger

Pich

et al. 2011

Plant Physiology and Biochemistry

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“…In addition to extracellular polysaccharide I (Denny and Baek 1991;McGarvey et al 1999), cell wall-degrading enzymes (Gonzalez and Allen 2003;Liu et al 2005), and type III-secreted effectors (Cunnac et al 2004), flagellar-driven swimming and pilus-driven twitching motility are also necessary for virulence (Tans-Kersten et al 2001;Liu et al 2001). All of these virulence factors are controlled by a complex regulatory signal transduction pathway (Schell 2000;Hikichi et al 2007) that responds to both environmental signals and quorum sensing (Brito et al 1999). Although much is understood about these virulence factors and their regulation, less is known about how R. solanacearum effectively adheres, colonizes and spreads in the host.…”

Section: Charles K Wairuri 5 Mpmimentioning

confidence: 99%

Ralstonia solanacearum Needs Flp Pili for Virulence on Potato

Wairuri¹,

Waals²,

Schalkwyk³

et al. 2012

MPMI

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Type IV pili are virulence factors in various bacteria. Several subclasses of type IV pili have been described according to the characteristics of the structural prepilin subunit. Although type IVa pili have been implicated in the virulence of Ralstonia solanacearum, type IVb pili have not previously been described in this plant pathogen. Here, we report the characterization of two distinct tad loci in the R. solanacearum genome. The tad genes encode functions necessary for biogenesis of the Flp subfamily of type IVb pili initially described for the periodontal pathogen Aggregatibacter actinomycetemcomitans. To determine the role of the tad loci in R. solanacearum virulence, we mutated the tadA2 gene located in the megaplasmid that encodes a predicted NTPase previously reported to function as the energizer for Flp pilus biogenesis. Characterization of the tadA2 mutant revealed that it was not growth impaired in vitro or in planta, produced wild-type levels of EPS galactosamine, and exhibited swimming and twitching motility comparable to the wild-type strain. However, the tadA2 mutant was impaired in its ability to cause wilting of potato plants. This is the first report where type IVb pili in a phytopathogenic bacterium contribute significantly to plant pathogenesis.

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“…During R. solanacearum infection, the xylem of the plant becomes clogged with bacteria and bacterial debris, which reduces the plant’s ability to take up water and thus wilting ensues (Genin and Boucher 2002b). Thus, wilt disease would result from water deprivation, as well as from the biotic stress in the form of R. solanacearum infection which secretes cell wall degrading enzymes and effectors directly into the plant cell (reviewed in Hikichi et al. 2007).…”

Section: Resultsmentioning

confidence: 99%

A Eucalyptus bacterial wilt isolate from South Africa is pathogenic on Arabidopsis and manipulates host defences

et al. 2011

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Summary Ralstonia solanacearum, the causal agent of bacterial wilt, has been reported from Eucalyptus plantations in at least three countries in Africa. The lack of genomics resources in Eucalyptus species led us to develop and study a pathosystem between a previously characterized South African isolate and the model plant Arabidopsis thaliana. Ralstonia solanacearum BCCF401 isolated from a Eucalyptus grandis × Eucalyptus camaldulensis hybrid was shown to cause disease on A. thaliana ecotype Col‐5. Arabidopsis genomics tools were exploited to investigate gene expression changes during wilt disease development, and thereby develop hypotheses that can be tested in Eucalyptus once genomics resources are available. Transcriptome analysis using 5000 A. thaliana ESTs was performed and revealed 141 genes that were differentially regulated by R. solanacearum infection (at a significance threshold of p < 0.03; Bonferroni corrected). A software tool ‘Rank Correlation Comparer’ was developed to compare expression profiles with Arabidopsis Affymetrix NASCArray data. High correlations were observed between the response of Arabidopsis plants to both Eucalyptus (BCCF401) and tomato (GMI1000) isolates of R. solanacearum, as well as to Pseudomonas syringae, Botrytis cinerea and treatment with abscisic acid. Basal defence responses in Col‐5 in response to R. solanacearum were investigated by comparing the expression data following R. solanacearum infection to data after treatment with the Pathogen Associated Molecular Patterns (PAMP) flg22 and lipopolysaccharide, and the Type Three Secretion System deficient Pseudomonas syringae pv. tomato hrp− mutant. A subset of the genes which were induced by PAMPs were repressed by R. solanacearum infection, and vice versa, suggesting that these genes may be repressed or induced, respectively, by specific R. solanacearum effectors. We hypothesize that these genes represent targets of R. solanacearum effectors. The pending release of the Eucalyptus genome sequence will enable orthologues to be identified and these hypotheses to be tested in Eucalyptus trees.

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Global regulation of pathogenicity mechanism of Ralstonia solanacearum

Cited by 40 publications

References 38 publications

Endo- and exopolygalacturonases of Ralstonia solanacearum are inhibited by polygalacturonase-inhibiting protein (PGIP) activity in tomato stem extracts

Endo- and exopolygalacturonases of Ralstonia solanacearum are inhibited by polygalacturonase-inhibiting protein (PGIP) activity in tomato stem extracts

Ralstonia solanacearum Needs Flp Pili for Virulence on Potato

A Eucalyptus bacterial wilt isolate from South Africa is pathogenic on Arabidopsis and manipulates host defences

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