scholarly journals Analysis of Sequenced Genomes of Xanthomonas perforans Identifies Candidate Targets for Resistance Breeding in Tomato

2016 ◽  
Vol 106 (10) ◽  
pp. 1097-1104 ◽  
Author(s):  
Sujan Timilsina ◽  
Peter Abrahamian ◽  
Neha Potnis ◽  
Gerald V. Minsavage ◽  
Frank F. White ◽  
...  
Keyword(s):  
Resistance Breeding ◽  
Effector Protein ◽  
Bacterial Disease ◽  
Bacterial Spot ◽  
Genome Sequences ◽  
Xanthomonas Perforans ◽  
Modern Agriculture ◽  
Rapid Changes ◽  
Pathogen Populations ◽  
Race 4

Bacterial disease management is a challenge for modern agriculture due to rapid changes in pathogen populations. Genome sequences for hosts and pathogens provide detailed information that facilitates effector-based breeding strategies. Tomato genotypes have gene-for-gene resistance to the bacterial spot pathogen Xanthomonas perforans. The bacterial spot populations in Florida shifted from tomato race 3 to 4, such that the corresponding tomato resistance gene no longer recognizes the effector protein AvrXv3. Genome sequencing showed variation in effector profiles among race 4 strains collected in 2006 and 2012 and compared with a race 3 strain collected in 1991. We examined variation in putative targets of resistance among Florida strains of X. perforans collected from 1991 to 2006. Consistent with race change, avrXv3 was present in race 3 strains but nonfunctional in race 4 strains due to multiple independent mutations. Effectors xopJ4 and avrBs2 were unchanged in all strains. The effector avrBsT was absent in race 3 strains collected in the 1990s but present in race 3 strains collected in 2006 and nearly all race 4 strains. These changes in effector profiles suggest that xopJ4 and avrBsT are currently the best targets for resistance breeding against bacterial spot in tomato.

scholarly journals Advanced Copper Composites Against Copper-Tolerant Xanthomonas perforans and Tomato Bacterial Spot

2018 ◽  
Vol 108 (2) ◽  
pp. 196-205 ◽  
Author(s):  
A. Strayer-Scherer ◽  
Y. Y. Liao ◽  
M. Young ◽  
L. Ritchie ◽  
G. E. Vallad ◽  
...  
Keyword(s):  
Disease Severity ◽  
Metallic Copper ◽  
Field Studies ◽  
Bacterial Disease ◽  
Bacterial Spot ◽  
Water Control ◽  
Xanthomonas Perforans ◽  
Bacterial Spot Disease ◽  
Copper Tolerant

Bacterial spot, caused by Xanthomonas spp., is a widespread and damaging bacterial disease of tomato (Solanum lycopersicum). For disease management, growers rely on copper bactericides, which are often ineffective due to the presence of copper-tolerant Xanthomonas strains. This study evaluated the antibacterial activity of the new copper composites core-shell copper (CS-Cu), multivalent copper (MV-Cu), and fixed quaternary ammonium copper (FQ-Cu) as potential alternatives to commercially available micron-sized copper bactericides for controlling copper-tolerant Xanthomonas perforans. In vitro, metallic copper from CS-Cu and FQ-Cu at 100 μg/ml killed the copper-tolerant X. perforans strain within 1 h of exposure. In contrast, none of the micron-sized copper rates (100 to 1,000 μg/ml) from Kocide 3000 significantly reduced copper-tolerant X. perforans populations after 48 h of exposure compared with the water control (P < 0.05). All copper-based treatments killed the copper-sensitive X. perforans strain within 1 h. Greenhouse studies demonstrated that all copper composites significantly reduced bacterial spot disease severity when compared with copper-mancozeb and water controls (P < 0.05). Although there was no significant impact on yield, copper composites significantly reduced disease severity when compared with water controls, using 80% less metallic copper in comparison with copper-mancozeb in field studies (P < 0.05). This study highlights the discovery that copper composites have the potential to manage copper-tolerant X. perforans and tomato bacterial spot.

scholarly journals Genomic Inference of Recombination-Mediated Evolution in Xanthomonas euvesicatoria and X. perforans

2018 ◽  
Vol 84 (13) ◽  
pp. e00136-18 ◽  
Author(s):  
Mustafa O. Jibrin ◽  
Neha Potnis ◽  
Sujan Timilsina ◽  
Gerald V. Minsavage ◽  
Gary E. Vallad ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Resistance Breeding ◽  
Secretion System ◽  
Bacterial Spot ◽  
Bacterial Populations ◽  
Content Type ◽  
Type Iii ◽  
Xanthomonas Perforans ◽  
Xanthomonas Euvesicatoria

ABSTRACT Recombination is a major driver of evolution in bacterial populations, because it can spread and combine independently evolved beneficial mutations. Recombinant lineages of bacterial pathogens of plants are typically associated with the colonization of novel hosts and the emergence of new diseases. Here we show that recombination between evolutionarily and phenotypically distinct plant-pathogenic lineages generated recombinant lineages with unique combinations of pathogenicity and virulence factors. Xanthomonas euvesicatoria and Xanthomonas perforans are two closely related lineages causing bacterial spot disease on tomato and pepper worldwide. We sequenced the genomes of atypical strains collected from tomato in Nigeria and observed recombination in the type III secretion system and effector genes, which showed alleles from both X. euvesicatoria and X. perforans. Wider horizontal gene transfer was indicated by the fact that the lipopolysaccharide cluster of one strain was most similar to that of a distantly related Xanthomonas pathogen of barley. This strain and others have experienced extensive genomewide homologous recombination, and both species exhibited dynamic open pangenomes. Variation in effector gene repertoires within and between species must be taken into consideration when one is breeding tomatoes for disease resistance. Resistance breeding strategies that target specific effectors must consider possibly dramatic variation in bacterial spot populations across global production regions, as illustrated by the recombinant strains observed here. IMPORTANCE The pathogens that cause bacterial spot of tomato and pepper are extensively studied models of plant-microbe interactions and cause problematic disease worldwide. Atypical bacterial spot strains collected from tomato in Nigeria, and other strains from Italy, India, and Florida, showed evidence of genomewide recombination that generated genetically distinct pathogenic lineages. The strains from Nigeria and Italy were found to have a mix of type III secretion system genes from X. perforans and X. euvesicatoria, as well as effectors from Xanthomonas gardneri. These genes and effectors are important in the establishment of disease, and effectors are common targets of resistance breeding. Our findings point to global diversity in the genomes of bacterial spot pathogens, which is likely to affect the host-pathogen interaction and influence management decisions.

scholarly journals Development of Bacterial Spot on Near-Isogenic Lines of Bell Pepper Carrying Gene Pyramids Composed of Defeated Major Resistance Genes

1999 ◽  
Vol 89 (11) ◽  
pp. 1066-1072 ◽  
Author(s):  
C. S. Kousik ◽  
D. F. Ritchie
Keyword(s):  
Disease Severity ◽  
Resistance Genes ◽  
Field Studies ◽  
Residual Effects ◽  
Specific Gene ◽  
Near Isogenic Lines ◽  
Bacterial Spot ◽  
Isogenic Lines ◽  
Major Resistance Genes ◽  
Race 4

Disease severity caused by races 1 through 6 of Xanthomonas campestris pv. vesicatoria on eight near-isogenic lines (isolines) of Early Calwonder (ECW) with three major resistance genes (Bs1, Bs2, and Bs3) in different combinations was evaluated in the greenhouse and field. Strains representing races 1, 3, 4, and 6 caused similar high levels of disease severity, followed by races 2 and 5 on susceptible ECW. Race 3 caused severe disease on all isolines lacking resistance gene Bs2. Race 4, which defeats Bs1 and Bs2, caused less disease on isoline ECW-12R (carries Bs1 + Bs2), than on isolines ECW, ECW-10R (carries Bs1), and ECW-20R (carries Bs2). Similar results were obtained with race 4 strains in field studies conducted during 1997 and 1998. In greenhouse studies, race 6, which defeats all three major genes, caused less disease on isoline ECW-13R (carries Bs1 + Bs3) and ECW-123R (carries Bs1 + Bs2 + Bs3) than on isolines ECW, ECW-10R, ECW-20R, and ECW-30R (carries Bs3), but not on ECW-23R (carries Bs2 + Bs3). In greenhouse studies with commercial hybrids, strains of races 4 and 6 caused less disease on Boynton Bell (carries Bs1 + Bs2) than on Camelot (carries no known resistance genes), King Arthur (carries Bs1), and X3R Camelot (carries Bs2). Race 6 caused less disease on hybrid R6015 (carries Bs1 + Bs2 + Bs3) and Sentinel (carries Bs1 + Bs3) than on Camelot. Residual effects were not as evident in field studies with race 6 strains. Defeated major resistance genes deployed in specific gene combinations (i.e., gene pyramids) were associated with less area under the disease progress curve than when genes were deployed individually in isolines of ECW or commercial hybrids. Successful management of bacterial spot of pepper is achieved incrementally by integrating multiple tactics. Although there is evidence of residual effects from defeated genes, these effects alone likely will not provide acceptable bacterial spot control in commercial production fields. However, when combined with sanitation practices and a judicious spray program, pyramids of defeated resistance genes may aid in reducing the risk of major losses due to bacterial spot.

scholarly journals First Report of Bacterial Spot of Tomato Caused by Xanthomonas perforans in Mississippi

Plant Disease ◽  
2019 ◽  
Vol 103 (1) ◽  
pp. 147-147
Author(s):  
P. Abrahamian ◽  
J. M. Klein ◽  
J. B. Jones ◽  
G. E. Vallad ◽  
R. A. Melanson
Keyword(s):  
Bacterial Spot ◽  
First Report ◽  
Xanthomonas Perforans

scholarly journals Characterization of Hypersensitive Resistance to Bacterial Spot Race T3 (Xanthomonas perforans) from Tomato Accession PI 128216

2009 ◽  
Vol 99 (9) ◽  
pp. 1037-1044 ◽  
Author(s):  
Matthew D. Robbins ◽  
Audrey Darrigues ◽  
Sung-Chur Sim ◽  
Mohammed Abu Taher Masud ◽  
David M. Francis
Keyword(s):  
Gene Dosage ◽  
Hypersensitive Reaction ◽  
Recurrent Parent ◽  
Chromosome 6 ◽  
Chromosome 11 ◽  
Bacterial Spot ◽  
Hypersensitive Resistance ◽  
Xanthomonas Perforans ◽  
Additive Gene ◽  
Candidate Loci

Bacterial spot of tomato is caused by four species of Xanthomonas. The accession PI 128216 (Solanum pimpinellifolium) displays a hypersensitive reaction (HR) to race T3 strains (predominately Xanthomonas perforans). We developed an inbred backcross (IBC) population (BC2S5, 178 families) derived from PI 128216 and OH88119 (S. lycopersicum) as the susceptible recurrent parent for simultaneous introgression and genetic analysis of the HR response. These IBC families were evaluated in the greenhouse for HR to race T3 strain Xcv761. The IBC population was genotyped with molecular markers distributed throughout the genome in order to identify candidate loci conferring resistance. We treated the IBC population as a hypothesis forming generation to guide validation in subsequent crosses. Nonparametric analysis identified an association between HR and markers clustered on chromosome 11 (P < 0.05 to 0.0001) and chromosome 6 (0.04 > P > 0.002). Further analysis of the IBC population suggested that markers on chromosome 6 and 11 failed to assort independently, a phenomenon known as gametic phase disequilibrium. Therefore, to validate marker-trait linkages, resistant IBC plants were crossed with OH88119 and BC3F2 progeny were evaluated for HR in the greenhouse. In these subsequent populations, the HR response was associated with the chromosome 11 markers (P < 0.0002) but not with the markers on chromosome 6 (P > 0.25). Independent F2 families were developed by crossing resistant IBC lines to OH8245, OH88119, and OH7530. These populations were genotyped, organized into classes based on chromosome 11 markers, and evaluated for resistance in the field. The PI 128216 locus on chromosome 11 provided resistance that was dependent on gene dosage and genetic background. These results define a single locus, Rx-4, from PI 128216, which provides resistance to bacterial spot race T3, has additive gene action, and is located on chromosome 11.

scholarly journals Transcriptome-Based Analysis of Tomato Genotypes Resistant to Bacterial Spot (Xanthomonas perforans) Race T4

2020 ◽  
Vol 21 (11) ◽  
pp. 4070
Author(s):  
Rui Shi ◽  
Dilip R. Panthee
Keyword(s):  
Biotic Stress ◽  
Breeding Line ◽  
Rna Seq ◽  
Susceptible Genotype ◽  
Bacterial Spot ◽  
Resistant Genotype ◽  
Xanthomonas Perforans ◽  
Sequence Variations ◽  
Stress Pathway ◽  
Go Terms

Bacterial spot (BS) is one of the most devastating foliar bacterial diseases of tomato and is caused by multiple species of Xanthomonas. We performed the RNA sequencing (RNA-Seq) analysis of three tomato lines with different levels of resistance to Xanthomonas perforans race T4 to study the differentially expressed genes (DEGs) and transcript-based sequence variations. Analysis between inoculated and control samples revealed that resistant genotype Solanum pimpinellifolium accession PI 270443 had more DEGs (834), followed by susceptible genotype tomato (S. lycopersicum L) breeding line NC 714 (373), and intermediate genotype tomato breeding line NC 1CELBR (154). Gene ontology (GO) terms revealed that more GO terms (51) were enriched for upregulated DEGs in the resistant genotype PI 270443, and more downregulated DEGs (67) were enriched in the susceptible genotype NC 714. DEGs in the biotic stress pathway showed more upregulated biotic stress pathway DEGs (67) for PI 270443 compared to more downregulated DEGs (125) for the susceptible NC 714 genotype. Resistant genotype PI 270443 has three upregulated DEGs for pathogenesis-related (PR) proteins, and susceptible genotype NC 714 has one downregulated R gene. Sequence variations called from RNA-Seq reads against the reference genome of susceptible Heinz 1706 showed that chr11, which has multiple reported resistance quantitative trait loci (QTLs) to BS race T4, is identical between two resistant lines, PI 270443 and NC 1CELBR, suggesting that these two lines share the same resistance QTLs on this chromosome. Several loci for PR resistance proteins with sequence variation between the resistant and susceptible tomato lines were near the known Rx4 resistance gene on chr11, and additional biotic stress associated DEGs near to the known Rx4 resistance gene were also identified from the susceptible NC 714 line.

scholarly journals Plant Extract Treatments Induce Resistance to Bacterial Spot by Tomato Plants for a Sustainable System

Horticulturae ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 36
Author(s):  
Kamal A. M. Abo-Elyousr ◽  
Najeeb M. Almasoudi ◽  
Ahmed W. M. Abdelmagid ◽  
Sergio R. Roberto ◽  
Khamis Youssef
Keyword(s):  
Antibacterial Activity ◽  
Plant Extracts ◽  
Integrated Management ◽  
Nerium Oleander ◽  
Bacterial Spot ◽  
Tomato Plants ◽  
Sustainable System ◽  
Pathogen Populations

The aim of this study is to assess the effect of extracts of Nerium oleander, Eucalyptus chamadulonsis and Citrullus colocynthis against bacterial spot disease of tomato and to investigate the induction of resistance by tomato (Solanum lycopersicum) in order to promote a sustainable management system. The antibacterial activity of aqueous and ethanol plant extracts was tested against Xanthomonas axonopodis pv. vesicatoria, isolate PHYXV3, in vitro and in vivo. The highest antibacterial activity in vitro was obtained with C. colocynthis, N. oleander and E. chamadulonsis, respectively. In vivo, ethanol extracts of N. oleander and E. chamadulonsis were more effective than aqueous extracts in reducing pathogen populations on tomato leaves. Under greenhouse conditions, application of the plant extracts at 15% (v/v) to tomato plants significantly reduced disease severity and increased the shoot weight of ‘Super Marmande’ tomato. In most cases, plant extracts significantly increased total phenol and salicylic acid content of tomato plants compared to either healthy or infected ones. In addition, C. colocynthis and E. chamadulonsis extracts significantly increased peroxidase activity while only E. chamadulonsis increased polyphenol oxidase after infection with the causal agent. The results indicated that the plant extracts showed promising antibacterial activity and could be considered an effective tool in integrated management programs for a sustainable system of tomato bacterial spot control.

scholarly journals Effectors as Tools in Disease Resistance Breeding Against Biotrophic, Hemibiotrophic, and Necrotrophic Plant Pathogens

2014 ◽  
Vol 27 (3) ◽  
pp. 196-206 ◽  
Author(s):  
Vivianne G. A. A. Vleeshouwers ◽  
Richard P. Oliver
Keyword(s):  
Fungicide Resistance ◽  
Plant Pathogens ◽  
Functional Characterization ◽  
Resistance Breeding ◽  
World Population ◽  
Breeding Programs ◽  
Genome Wide ◽  
Disease Resistance Breeding ◽  
Pathogen Populations ◽  
New Strategies

One of most important challenges in plant breeding is improving resistance to the plethora of pathogens that threaten our crops. The ever-growing world population, changing pathogen populations, and fungicide resistance issues have increased the urgency of this task. In addition to a vital inflow of novel resistance sources into breeding programs, the functional characterization and deployment of resistance also needs improvement. Therefore, plant breeders need to adopt new strategies and techniques. In modern resistance breeding, effectors are emerging as tools to accelerate and improve the identification, functional characterization, and deployment of resistance genes. Since genome-wide catalogues of effectors have become available for various pathogens, including biotrophs as well as necrotrophs, effector-assisted breeding has been shown to be successful for various crops. “Effectoromics” has contributed to classical resistance breeding as well as for genetically modified approaches. Here, we present an overview of how effector-assisted breeding and deployment is being exploited for various pathosystems.

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