scholarly journals Super-Multiple Deletion Analysis of Type III Effectors in Ralstonia solanacearum OE1-1 for Full Virulence Toward Host Plants

2020 ◽  
Vol 11 ◽  
Author(s):  
Ni Lei ◽  
Li Chen ◽  
Akinori Kiba ◽  
Yasufumi Hikichi ◽  
Yong Zhang ◽  
...  
Keyword(s):  
Ralstonia Solanacearum ◽  
Host Plants ◽  
Deletion Analysis ◽  
Type Iii Effectors ◽  
Type Iii

scholarly journals Ralstonia solanacearum requires F-box-like domain-containing type III effectors to promote disease on several host plants

2006 ◽  
Vol 103 (39) ◽  
pp. 14620-14625 ◽  
Author(s):  
A. Angot ◽  
N. Peeters ◽  
E. Lechner ◽  
F. Vailleau ◽  
C. Baud ◽  
...  
Keyword(s):  
Ralstonia Solanacearum ◽  
Host Plants ◽  
Type Iii Effectors ◽  
Type Iii

scholarly journals Towards the Identification of Type III Effectors Associated with Ralstonia solanacearum Virulence on Tomato and Eggplant

2015 ◽  
Vol 105 (12) ◽  
pp. 1529-1544 ◽  
Author(s):  
Flora Pensec ◽  
Aurore Lebeau ◽  
M. C. Daunay ◽  
Frédéric Chiroleu ◽  
Alice Guidot ◽  
...  
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Evolutionary Dynamics ◽  
Allelic Diversity ◽  
Chain Reaction ◽  
Field Collection ◽  
Type Iii Effectors ◽  
Type Iii ◽  
Dna Microarray Data ◽  
Polymerase Chain

For the development of pathogen-informed breeding strategies, identifying the microbial genes involved in interactions with the plant is a critical step. To identify type III effector (T3E) repertoires associated with virulence of the bacterial wilt pathogen Ralstonia solanacearum on Solanaceous crops, we used an original association genetics approach combining DNA microarray data and pathogenicity data on resistant eggplant, pepper, and tomato accessions. From this first screen, 25 T3Es were further full-length polymerase chain reaction-amplified within a 35-strain field collection, to assess their distribution and allelic diversity. Six T3E repertoire groups were identified, within which 11 representative strains were chosen to challenge the bacterial wilt-resistant eggplants ‘Dingras multiple Purple’ and ‘AG91-25’, and tomato Hawaii7996. The virulence or avirulence phenotypes could not be explained by specific T3E repertoires, but rather by individual T3E genes. We identified seven highly avirulence-associated genes, among which ripP2, primarily referenced as conferring avirulence to Arabidopsis thaliana. Interestingly, no T3E was associated with avirulence to both eggplants. Highly virulence-associated genes were also identified: ripA5_2, ripU, and ripV2. This study should be regarded as a first step toward investigating both avirulence and virulence function of the highlighted genes, but also their evolutionary dynamics in natural R. solanacearum populations.

scholarly journals The awr Gene Family Encodes a Novel Class of Ralstonia solanacearum Type III Effectors Displaying Virulence and Avirulence Activities

2012 ◽  
Vol 25 (7) ◽  
pp. 941-953 ◽  
Author(s):  
Montserrat Solé ◽  
Crina Popa ◽  
Oriane Mith ◽  
Kee Hoon Sohn ◽  
Jonathan D. G. Jones ◽  
...  
Keyword(s):  
Gene Family ◽  
Pseudomonas Syringae ◽  
Ralstonia Solanacearum ◽  
Tomato Dc3000 ◽  
Type Iii Effectors ◽  
Type Iii ◽  
New Gene ◽  
Transient Overexpression ◽  
Effector Recognition

We present here the characterization of a new gene family, awr, found in all sequenced Ralstonia solanacearum strains and in other bacterial pathogens. We demonstrate that the five paralogues in strain GMI1000 encode type III-secreted effectors and that deletion of all awr genes severely impairs its capacity to multiply in natural host plants. Complementation studies show that the AWR (alanine-tryptophan-arginine tryad) effectors display some functional redundancy, although AWR2 is the major contributor to virulence. In contrast, the strain devoid of all awr genes (Δawr1-5) exhibits enhanced pathogenicity on Arabidopsis plants. A gain-of-function approach expressing AWR in Pseudomonas syringae pv. tomato DC3000 proves that this is likely due to effector recognition, because AWR5 and AWR4 restrict growth of this bacterium in Arabidopsis. Transient overexpression of AWR in nonhost tobacco species caused macroscopic cell death to varying extents, which, in the case of AWR5, shows characteristics of a typical hypersensitive response. Our work demonstrates that AWR, which show no similarity to any protein with known function, can specify either virulence or avirulence in the interaction of R. solanacearum with its plant hosts.

Isolation of Ralstonia solanacearum hrpB constitutive mutants and secretion analysis of hrpB-regulated gene products that share homology with known type III effectors and enzymes

Microbiology ◽  
2005 ◽  
Vol 151 (9) ◽  
pp. 2873-2884 ◽  
Author(s):  
Naoyuki Tamura ◽  
Yukio Murata ◽  
Takafumi Mukaihara
Keyword(s):  
Pseudomonas Syringae ◽  
Ralstonia Solanacearum ◽  
Type Iii Secretion ◽  
Effector Proteins ◽  
Gene Products ◽  
Nudix Hydrolase ◽  
Type Iii Effectors ◽  
Type Iii ◽  
Extracellular Secretion ◽  
Culture Supernatants

The Hrp type III secretion system (TTSS) is essential for the pathogenicity of the Gram-negative plant pathogen Ralstonia solanacearum. To examine the secretion of type III effector proteins via the Hrp TTSS, a screen was done of mutants constitutively expressing the hrpB gene, which encodes an AraC-type transcriptional activator for the hrp regulon. A mutant was isolated that in an hrp-inducing medium expresses several hrpB-regulated genes 4·9–83-fold higher than the wild-type. R. solanacearum Hrp-secreted outer proteins PopA and PopC were secreted at high levels into the culture supernatants of the hrpB constitutive (hrpB c) mutant. Using hrpB c mutants, the extracellular secretion of several hrpB-regulated (hpx) gene products that share homology with known type III effectors and enzymes was examined. Hpx23, Hpx24 and Hpx25, which are similar in sequence to Pseudomonas syringae pv. tomato effector proteins HopPtoA1, HolPtoR and HopPtoD1, are also secreted via the Hrp TTSS in R. solanacearum. The secretion of two hpx gene products that share homology with known enzymes, glyoxalase I (Hpx19) and Nudix hydrolase (Hpx26), was also examined. Hpx19 is accumulated inside the cell, but interestingly, Hpx26 is secreted outside the cell as an Hrp-secreted outer protein, suggesting that Hpx19 functions intracellularly but Hpx26 is a novel effector protein of R. solanacearum.

scholarly journals HpaB-Dependent Secretion of Type III Effectors in the Plant Pathogens Ralstonia solanacearum and Xanthomonas campestris pv. vesicatoria

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Fabien Lonjon ◽  
David Lohou ◽  
Anne-Claire Cazalé ◽  
Daniela Büttner ◽  
Barbara Gomes Ribeiro ◽  
...  
Keyword(s):  
Ralstonia Solanacearum ◽  
Xanthomonas Campestris ◽  
Plant Pathogens ◽  
Type Iii Effectors ◽  
Type Iii

scholarly journals A Competitive Index Assay Identifies Several Ralstonia solanacearum Type III Effector Mutant Strains with Reduced Fitness in Host Plants

2010 ◽  
Vol 23 (9) ◽  
pp. 1197-1205 ◽  
Author(s):  
Alberto P. Macho ◽  
Alice Guidot ◽  
Patrick Barberis ◽  
Carmen R. Beuzón ◽  
Stéphane Genin
Keyword(s):  
Ralstonia Solanacearum ◽  
Host Plants ◽  
Optimal Growth ◽  
Large Set ◽  
Susceptible Host ◽  
Plant Leaf ◽  
Type Iii ◽  
Wide Range ◽  
Leaf Tissues ◽  
Bacterial Fitness

Ralstonia solanacearum, the causal agent of bacterial wilt, is a soil bacterium which can naturally infect a wide range of host plants through the root system. Pathogenicity relies on a type III secretion system which delivers a large set of approximately 75 type III effectors (T3E) into plant cells. On several plants, pathogenicity assays based on quantification of wilting symptoms failed to detect a significant contribution of R. solanacearum T3E in this process, thus revealing the collective effect of T3E in pathogenesis. We developed a mixed infection-based method with R. solanacearum to monitor bacterial fitness in plant leaf tissues as a virulence assay. This accurate and sensitive assay provides evidence that growth defects can be detected for T3E mutants: we identified 12 genes contributing to bacterial fitness in eggplant leaves and 3 of them were also implicated in bacterial fitness on two other hosts, tomato and bean. Contribution to fitness of several T3E appears to be host specific, and we show that some known avirulence determinants such as popP2 or avrA do provide competitive advantages on some susceptible host plants. In addition, this assay revealed that the efe gene, which directs the production of ethylene by bacteria in plant tissues, and hdfB, involved in the biosynthesis of the secondary metabolite 3-hydroxy-oxindole, are also required for optimal growth in plant leaf tissues.

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