Pathogenomics of the<i>Ralstonia solanacearum</i>Species Complex

Genin, Stéphane; Denny, Timothy P.

doi:10.1146/annurev-phyto-081211-173000

Cited by 511 publications

(562 citation statements)

References 112 publications

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“…chitinases and bglucanases) may also account for the observed degradation of FORL hyphae in the root tissues. Another example that confirms the potential of P. oligandrum for inducing local resistance against soilborne pathogens is provided by the enhanced tomato protection against Ralstonia solanacearum, the root pathogenic bacterium responsible for lethal wilting disease in over 200 different plant species (Genin & Denny, 2012). In P. oligandrum-inoculated tomato plants, bacterial spread in the root tissues is remarkably halted by structural plant defence mechanisms (Masunaka et al, 2009).…”

Section: P Oligandrum-mediated Induced Resistancementioning

confidence: 92%

Pythium oligandrum: an example of opportunistic success

et al. 2012

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Pythium oligandrum, a non-pathogenic soil-inhabiting oomycete, colonizes the root ecosystem of many crop species. Whereas most members in the genus Pythium are plant pathogens, P. oligandrum distinguishes itself from the pathogenic species by its ability to protect plants from biotic stresses in addition to promoting plant growth. The success of P. oligandrum at controlling soilborne pathogens is partly associated with direct antagonism mediated by mycoparasitism and antimicrobial compounds. Interestingly, P. oligandrum has evolved with specific mechanisms to attack its prey even when these belong to closely related species. Of particular relevance is the question of how P. oligandrum distinguishes between self-and non-self cell wall degradation during the mycoparasitic process of pathogenic oomycete species. The ability of P. oligandrum to enter and colonize the root system before rapidly degenerating is one of the most striking features that differentiate it from all other known biocontrol fungal agents. In spite of this atypical behaviour, P. oligandrum sensitizes the plant to defend itself through the production of at least two types of microbe-associated molecular patterns, including oligandrin and cell wall protein fractions, which appear to be closely involved in the early events preceding activation of the jasmonic acid-and ethylene-dependent signalling pathways and subsequent localized and systemic induced resistance. The aim of this review is to highlight the expanding knowledge of the mechanisms by which P. oligandrum provides beneficial effects to plants and to explore the potential use of this oomycete or its metabolites as new disease management strategies.

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Section: P Oligandrum-mediated Induced Resistancementioning

confidence: 92%

Pythium oligandrum: an example of opportunistic success

et al. 2012

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“…Ralstonia solanacearum, widely distributed in tropical, subtropical, and temperate regions of the world, is a complex species with considerable diversity (Hayward 1991;Genin and Denny 2012). A large number of studies have focused on the global genetic diversity of the pathogen.…”

Section: Introductionmentioning

confidence: 99%

“…Based on the host range, R. solanacearum has been phenotypically classified into five races: Race 1 (solanaceous vegetables), Race 2 (banana), Race 3 (potato and tomato from temperate regions), Race 4 (ginger), and Race 5 (mulberry) (Buddenhagen et al 1962;Wicker et al 2007). Biovar classification has been defined by their ability to utilize disaccharides and to oxidize hexose alcohols (He et al 1983;Hayward 1964Hayward , 1991Genin and Denny 2012). Although both classification schemes have been used to describe the diversity of R. solanacearum for a long time, several disadvantages have been revealed with our increasing knowledge of pathogen diversity, such as the lack of discriminating power, additional time required, and lack of correlation with the phylogenetic origin of different strains (Siri et al 2011;Genin and Denny 2012).…”

Section: Introductionmentioning

confidence: 99%

The sequevar distribution of Ralstonia solanacearum in tobacco-growing zones of China is structured by elevation

Liu

et al. 2016

Eur J Plant Pathol

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Bacterial wilt, caused by Ralstonia solanacearum, is a devastating disease resulting in tremendous losses of economic crops such as plants in the Solanaceae. Recent studies showed that R. solanacearum is spreading from the lowlands to the highlands in China. We studied 97 Chinese R. solanacearum strains that were isolated from four tobacco-growing zones over a wide range of elevations using phylotype specific multiplex polymerase chain reaction (Pmx-PCR) and phylogenetic relationships (egl and mutS). The results showed that all isolates belonged to phylotype I, which were further clustered into eight egl-sequence type groups (egl-group, sequevar): sequevars 13, 14, 15, 17, 34, 44, 54, and 55. In addition, Sequevar 55, found from the highlands, was a new/unknown one. Southeast China (Z3) had the largest number of egl-groups, containing six sequevars. The basin of the Yangzi River (Z1) and southwestern China (Z2) contained five egl-groups. The basin of the Huai River (Z4), near the north of China, where slight bacterial wilt occurred recently, contained a single group, sequevar 15. The distribution of sequevars was associated with elevation. Sequevar 15 was over-represented in lowland elevations, while sequevar 54 and the new/unknown one were only found in areas of moderate to high elevations. This finding suggested that the phylotype I strains infecting tobacco were diverse in China and regional integrated control strategies should be considered.

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“…Also referred to as the R. solanacearum species complex because of its wide phylogenetic diversity, this bacterium can cause disease on more than 200 plant species, including many important economic crops (Genin and Denny 2012). R. solanacearum accesses the plant through the root and traverses many root layers until it reaches the xylem, where it profusely multiplies.…”

mentioning

confidence: 99%

Type III Secretion–Dependent and –Independent Phenotypes Caused by Ralstonia solanacearum in Arabidopsis Roots

Planas-Marquès

et al. 2018

MPMI

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The causal agent of bacterial wilt, Ralstonia solanacearum, is a soilborne pathogen that invades plants through their roots, traversing many tissue layers until it reaches the xylem, where it multiplies and causes plant collapse. The effects of R. solanacearum infection are devastating, and no effective approach to fight the disease is so far available. The early steps of infection, essential for colonization, as well as the early plant defense responses remain mostly unknown. Here, we have set up a simple, in vitro Arabidopsis thaliana–R. solanacearum pathosystem that has allowed us to identify three clear root phenotypes specifically associated to the early stages of infection: root-growth inhibition, root-hair formation, and root-tip cell death. Using this method, we have been able to differentiate, on Arabidopsis plants, the phenotypes caused by mutants in the key bacterial virulence regulators hrpB and hrpG, which remained indistinguishable using the classical soil-drench inoculation pathogenicity assays. In addition, we have revealed the previously unknown involvement of auxins in the root rearrangements caused by R. solanacearum infection. Our system provides an easy-to-use, high-throughput tool to study R. solanacearum aggressiveness. Furthermore, the observed phenotypes may allow the identification of bacterial virulence determinants and could even be used to screen for novel forms of early plant resistance to bacterial wilt.

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Pathogenomics of theRalstonia solanacearumSpecies Complex

Cited by 511 publications

References 112 publications

Pythium oligandrum: an example of opportunistic success

Pythium oligandrum: an example of opportunistic success

The sequevar distribution of Ralstonia solanacearum in tobacco-growing zones of China is structured by elevation

Type III Secretion–Dependent and –Independent Phenotypes Caused by Ralstonia solanacearum in Arabidopsis Roots

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