scholarly journals The eggplant AG91-25 recognizes the Type III-secreted effector RipAX2 to trigger resistance to bacterial wilt (Ralstonia solanacearum species complex)

2018 ◽  
Vol 19 (11) ◽  
pp. 2459-2472 ◽  
Author(s):  
Arry Morel ◽  
Jérémy Guinard ◽  
Fabien Lonjon ◽  
Lakshmi Sujeeun ◽  
Patrick Barberis ◽  
...  
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Species Complex ◽  
Type Iii

scholarly journals Ralstonia solanacearum Requires PopS, an Ancient AvrE-Family Effector, for Virulence and To Overcome Salicylic Acid-Mediated Defenses during Tomato Pathogenesis

mBio ◽  
2013 ◽  
Vol 4 (6) ◽  
Author(s):  
Jonathan M. Jacobs ◽  
Annett Milling ◽  
Raka M. Mitra ◽  
Clifford S. Hogan ◽  
Florent Ailloud ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Species Complex ◽  
Plant Defenses ◽  
Natural Infection ◽  
Wild Type ◽  
Tomato Plants ◽  
Content Type ◽  
Type Iii

ABSTRACTDuring bacterial wilt of tomato, the plant pathogen Ralstonia solanacearum upregulates expression ofpopS, which encodes a type III-secreted effector in the AvrE family. PopS is a core effector present in all sequenced strains in theR. solanacearumspecies complex. The phylogeny ofpopSmirrors that of the species complex as a whole, suggesting that this is an ancient, vertically inherited effector needed for association with plants. ApopSmutant ofR. solanacearumUW551 had reduced virulence on agriculturally importantSolanumspp., including potato and tomato plants. However, thepopSmutant had wild-type virulence on a weed host,Solanum dulcamara, suggesting that some species can avoid the effects of PopS. ThepopSmutant was also significantly delayed in colonization of tomato stems compared to the wild type. Some AvrE-type effectors from gammaproteobacteria suppress salicylic acid (SA)-mediated plant defenses, suggesting that PopS, a betaproteobacterial ortholog, has a similar function. Indeed, thepopSmutant induced significantly higher expression of tomato SA-triggered pathogenesis-related (PR) genes than the wild type. Further, pretreatment of roots with SA exacerbated thepopSmutant virulence defect. Finally, thepopSmutant had no colonization defect on SA-deficient NahG transgenic tomato plants. Together, these results indicate that this conserved effector suppresses SA-mediated defenses in tomato roots and stems, which areR. solanacearum’s natural infection sites. Interestingly, PopS did not trigger necrosis when heterologously expressed inNicotianaleaf tissue, unlike the AvrE homolog DspEPccfrom the necrotrophPectobacterium carotovorumsubsp.carotovorum. This is consistent with the differing pathogenesis modes of necrosis-causing gammaproteobacteria and biotrophicR. solanacearum.IMPORTANCEThe type III-secreted AvrE effector family is widely distributed in high-impact plant-pathogenic bacteria and is known to suppress plant defenses for virulence. We characterized the biology of PopS, the only AvrE homolog made by the bacterial wilt pathogenRalstonia solanacearum. To our knowledge, this is the first study ofR. solanacearumeffector function in roots and stems, the natural infection sites of this pathogen. Unlike the functionally redundantR. solanacearumeffectors studied to date, PopS is required for full virulence and wild-type colonization of two natural crop hosts.R. solanacearumis a biotrophic pathogen that causes a nonnecrotic wilt. Consistent with this, PopS suppressed plant defenses but did not elicit cell death, unlike AvrE homologs from necrosis-causing plant pathogens. We propose that AvrE family effectors have functionally diverged to adapt to the necrotic or nonnecrotic lifestyle of their respective pathogens.

scholarly journals Molecular Epidemiology of Ralstonia solanacearum Species Complex Strains Causing Bacterial Wilt of Potato in Uganda

2019 ◽  
Vol 109 (11) ◽  
pp. 1922-1931 ◽  
Author(s):  
Abdulwahab Abdurahman ◽  
Monica L. Parker ◽  
Jan Kreuze ◽  
John G. Elphinstone ◽  
Paul C. Struik ◽  
...  
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Species Complex ◽  
Nationwide Survey ◽  
Potato Production ◽  
Repeat Sequence ◽  
Latently Infected ◽  
Pure Cultures ◽  
Diversity Studies ◽  
Phylotype I

Bacterial wilt (BW) caused by the Ralstonia solanacearum species complex (RSSC) is a serious threat to potato production in Uganda. However, little is known about the extent of the disease and the type of the pathogen strains involved. A nationwide survey was conducted to study BW prevalence and incidence in potato, and potato tuber and stem samples of potential alternative hosts were collected for pathogen isolation. DNA was extracted from pure cultures for genetic diversity studies. The pathogen was phylotyped by multiplex PCR; then, a subset of isolates was typed at sequevar level. Isolates of the same sequevar were then haplotyped using multilocus tandem repeat sequence typing (TRST) schemes. BW prevalence and incidence in potato farms were 81.4 and 1.7%, respectively. Three RSSC phylotypes were identified, with the majority of the strains belonging to Phylotype II (80%) followed by Phylotype I (18.5%) and III (1.5%). Phylotype I strains belonged to Sequevar 31, and Phylotype II strains belonged to Sequevar 1. Potato-associated Phylotype II Sequevar 1 strains were more diverse (27 TRST haplotypes) than nonpotato Phylotype I (5 TRST haplotypes). Mapping of TRST haplotypes revealed that three TRST haplotypes of Phylotype II Sequevar 1 strains play an important epidemiological role in BW of potato in Uganda being disseminated via latently infected seed. [Formula: see text] Copyright © 2019 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

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 Bacterial Wilt Resistance in Tomato, Pepper, and Eggplant: Genetic Resources Respond to Diverse Strains in the Ralstonia solanacearum Species Complex

2011 ◽  
Vol 101 (1) ◽  
pp. 154-165 ◽  
Author(s):  
A. Lebeau ◽  
M.-C. Daunay ◽  
A. Frary ◽  
A. Palloix ◽  
J.-F. Wang ◽  
...  
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Species Complex ◽  
Effective Control ◽  
Economic Losses ◽  
Wilt Resistance ◽  
The Core ◽  
Intermediate Phenotypes ◽  
Vascular Elements ◽  
Pathogen Strains

Bacterial wilt, caused by strains belonging to the Ralstonia solanacearum species complex, inflicts severe economic losses in many crops worldwide. Host resistance remains the most effective control strategy against this disease. However, wilt resistance is often overcome due to the considerable variation among pathogen strains. To help breeders circumvent this problem, we assembled a worldwide collection of 30 accessions of tomato, eggplant and pepper (Core-TEP), most of which are commonly used as sources of resistance to R. solanacearum or for mapping quantitative trait loci. The Core-TEP lines were challenged with a core collection of 12 pathogen strains (Core-Rs2) representing the phylogenetic diversity of R. solanacearum. We observed six interaction phenotypes, from highly susceptible to highly resistant. Intermediate phenotypes resulted from the plants' ability to tolerate latent infections (i.e., bacterial colonization of vascular elements with limited or no wilting). The Core-Rs2 strains partitioned into three pathotypes on pepper accessions, five on tomato, and six on eggplant. A “pathoprofile” concept was developed to characterize the strain clusters, which displayed six virulence patterns on the whole set of Core-TEP host accessions. Neither pathotypes nor pathoprofiles were phylotype specific. Pathoprofiles with high aggressiveness were mainly found in strains from phylotypes I, IIB, and III. One pathoprofile included a strain that overcame almost all resistance sources.

scholarly journals Evaluation of Resistance Sources of Tomato (Solanum lycopersicum L.) to Phylotype I Strains of Ralstonia solanacearum Species Complex in Benin

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1513
Author(s):  
Herbaud Zohoungbogbo ◽  
Adonis Quenum ◽  
Judith Honfoga ◽  
Jaw-Rong Chen ◽  
Enoch Achigan-Dako ◽  
...  
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Species Complex ◽  
Block Design ◽  
Agricultural System ◽  
Sources Of Resistance ◽  
Breeding Programs ◽  
Solanum Lycopersicum L ◽  
The University ◽  
Phylotype I

Finding sources of resistance to bacterial wilt (BW) caused by Ralstonia solanacearum species complex is a crucial step toward the development of improved bacterial wilt-resistant tomato varieties. Here, we evaluated new sources of bacterial wilt-tolerant/resistant tomato lines and identified associated phylotype/sequevar of R. solanacearum strains in Benin. Eighteen F5 lines and five checks were evaluated in two hotspots: the experimental site of the World Vegetable Center, Cotonou Benin, and the Laboratory of Genetics, Biotechnology and Seed Science of the University of Abomey-Calavi. Experiments were laid out in a randomized complete block design with four replicates. Data were collected on bacterial wilt incidence, horticultural and fruit traits and yield components. Across the two experiments, the F5 lines showed no wilting, while the local variety ‘Tounvi’ used as susceptible check showed 57.64% wilting. The wilting was due to BW and was associated with sequevars I-14, I-18 and I-31 of phylotype I. AVTO1803, AVTO1955-6 and H7996 were the highest yielding lines with 20.29 t·ha−1, 17.66 t·ha−1 and 17.07 t/ha, respectively. The sources of resistance to BW can be recommended to national agricultural system for dissemination or used in tomato breeding programs.

scholarly journals Low Temperature Induces Infectious Nonresuscitatable VBNC Cells in Ralstonia Pseudosolanacearum

2021 ◽  
Author(s):  
Neha Faridi ◽  
Merwyn Packia raj Samuel ◽  
Shalini Bhatt ◽  
Ankur Agrawal ◽  
Veena Pande ◽  
...  
Keyword(s):  
Low Temperature ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Species Complex ◽  
Economic Importance ◽  
Bacterial Genus ◽  
Window Period ◽  
Ralstonia Pseudosolanacearum ◽  
Uv C

Abstract Ralstonia pseudosolanacearum and other members of Ralstonia solanacearum species complex (RSSC) causes the disease bacterial wilt in many crops of economic importance. The organism is known to form Viable But Non Culturable cells (VBNC). VBNCs resuscitate invitro during the “resuscitation window” period and are infectious Previous studies have identified nonresuscitatable VBNCs in various bacterial genus including RSSC, however their infectivity was not elucidated and described. In this work, VBNCs of two Ralstonia pseudosolanacearum strains were generated by exposing the microcosms to psychrophilic stress, UV-C radiation and 70% isopropanol. Both resuscitatable and nonresuscitatable VBNCs were observed in psychrophilic and UV-C stressed microcosms. The nonresuscitatable VBNCs generated at psychrophilic temperature were found infective. Based on resuscitation properties, nonresuscitatable VBNCs can be considered as a different VBNC type from resuscitatable VBNCs.

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