Reaction of different tomato genotypes to the bacterial speck pathogen (pseudomonas syringae pv. tomato)

1986 ◽  
Vol 14 (1) ◽  
pp. 39-42 ◽  
Author(s):  
M. Pilowsky ◽  
D. Zutra
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Speck ◽  
Tomato Genotypes

scholarly journals Gene Based ­­­­Markers in Marker-Assisted Selection to Screen Tomato Genotypes Resistant to Fusarium Wilt, Late Blight, Verticillium Wilt, Leaf Mold, Bacterial Spot and Bacterial Speck

2021 ◽  
Author(s):  
Heba Mahfouze ◽  
Sherin Mahfouze
Keyword(s):  
Molecular Markers ◽  
Late Blight ◽  
Pseudomonas Syringae ◽  
Fusarium Wilt ◽  
Verticillium Wilt ◽  
Xanthomonas Campestris ◽  
Bacterial Spot ◽  
Bacterial Speck ◽  
Leaf Mold ◽  
Tomato Genotypes

Abstract The tomato crop is exposed to serious losses due to infection with several diseases and pests, which threaten tomato production in Egypt and worldwide. Therefore, selecting the tomato germplasm resistant or tolerant to a specific pathogen by molecular markers closely linked to resistance loci is a desirable goal of this study. In this work, seven co-dominant markers targeting six resistance genes (I-1, Ve, Ph3, Cf-9/Cf-4, Rx4, and Pto) for six main diseases [ fusarium wilt (Fusarium oxysporum f. sp. lycopersici), verticillium wilt (Verticillium dahliae and V. alboatrum), late blight (Phytophthora infestans), leaf mold (Cladosporium fulvum), bacterial spot (Xanthomonas campestris pv. vesicatoria) and bacterial speck (Pseudomonas syringae pv. tomato)], respectively were determined. Theses molecular markers differentiated among 19 tomato genotypes resistant (homozygote/heterozygote) and susceptible (homozygote) to the pathogens. Therefore, this study supplied us with novel tomato lines with resistance to multiple diseases, and their pyramiding inside domesticated tomato cultivars are suggested to apply in the tomato breeding programs of resistance against fungal and bacterial diseases.

scholarly journals Field Control of Bacterial Spot and Bacterial Speck of Tomato Using a Plant Activator

Plant Disease ◽  
2001 ◽  
Vol 85 (5) ◽  
pp. 481-488 ◽  
Author(s):  
F. J. Louws ◽  
M. Wilson ◽  
H. L. Campbell ◽  
D. A. Cuppels ◽  
J. B. Jones ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Systemic Acquired Resistance ◽  
Field Experiments ◽  
Production Systems ◽  
Acquired Resistance ◽  
Dry Weight ◽  
Bacterial Spot ◽  
Population Densities ◽  
Bacterial Speck ◽  
Plant Activator

Acibenzolar-S-methyl (CGA 245704 or Actigard 50WG) is a plant activator that induces systemic acquired resistance (SAR) in many different crops to a number of pathogens. Acibenzolar-S-methyl was evaluated for management of bacterial spot (Xanthomonas axonopodis pv. vesicatoria) and bacterial speck (Pseudomonas syringae pv. tomato) of tomato in 15 and 7 field experiments, respectively. Experiments were conducted over a 4-year period in Florida, Alabama, North Carolina, Ohio, and Ontario using local production systems. Applied at 35 g a.i. ha-1, acibenzolar-S-methyl reduced foliar disease severity in 14 of the 15 bacterial spot and all 7 bacterial speck experiments. Disease control was similar or superior to that obtained using a standard copper bactericide program. Acibenzolar-S-methyl also reduced bacterial fruit spot and speck incidence. Tomato yield was not affected by using the plant activator in the field when complemented with fungicides to manage foliar fungal diseases, but tomato transplant dry weight was negatively impacted. X. axonopodis pv. vesicatoria population densities on greenhouse-grown tomato transplants were reduced by acibenzolar-S-methyl treatment. Bacterial speck and spot population densities on leaves of field-grown plants were not dramatically affected. Acibenzolar-S-methyl can be integrated as a viable alternative to copper-based bactericides for field management of bacterial spot and speck, particularly where copper-resistant populations predominate.

scholarly journals Protection of Tomato Seedlings against Infection by Pseudomonas syringae pv. Tomato by Using the Plant Growth-Promoting Bacterium Azospirillum brasilense

2002 ◽  
Vol 68 (6) ◽  
pp. 2637-2643 ◽  
Author(s):  
Yoav Bashan ◽  
Luz E. de-Bashan
Keyword(s):  
Plant Growth ◽  
Pseudomonas Syringae ◽  
Azospirillum Brasilense ◽  
Dry Weight ◽  
Tomato Plants ◽  
Bacterial Speck ◽  
Plant Growth Promoting ◽  
Bacterial Speck Disease ◽  
Growth Promoting ◽  
Mist Chamber

ABSTRACT Pseudomonas syringae pv. tomato, the causal agent of bacterial speck of tomato, and the plant growth-promoting bacterium Azospirillum brasilense were inoculated onto tomato plants, either alone, as a mixed culture, or consecutively. The population dynamics in the rhizosphere and foliage, the development of bacterial speck disease, and their effects on plant growth were monitored. When inoculated onto separate plants, the A. brasilense population in the rhizosphere of tomato plants was 2 orders of magnitude greater than the population of P. syringae pv. tomato (107 versus 105 CFU/g [dry weight] of root). Under mist chamber conditions, the leaf population of P. syringae pv. tomato was 1 order of magnitude greater than that of A. brasilense (107 versus 106 CFU/g [dry weight] of leaf). Inoculation of seeds with a mixed culture of the two bacterial strains resulted in a reduction of the pathogen population in the rhizosphere, an increase in the A. brasilense population, the prevention of bacterial speck disease development, and improved plant growth. Inoculation of leaves with the mixed bacterial culture under mist conditions significantly reduced the P. syringae pv. tomato population and significantly decreased disease severity. Challenge with P. syringae pv. tomato after A. brasilense was established in the leaves further reduced both the population of P. syringae pv. tomato and disease severity and significantly enhanced plant development. Both bacteria maintained a large population in the rhizosphere for 45 days when each was inoculated separately onto tomato seeds (105 to 106 CFU/g [dry weight] of root). However, P. syringae pv. tomato did not survive in the rhizosphere in the presence of A. brasilense. Foliar inoculation of A. brasilense after P. syringae pv. tomato was established on the leaves did not alleviate bacterial speck disease, and A. brasilense did not survive well in the phyllosphere under these conditions, even in a mist chamber. Several applications of a low concentration of buffered malic acid significantly enhanced the leaf population of A. brasilense (>108 CFU/g [dry weight] of leaf), decreased the population of P. syringae pv. tomato to almost undetectable levels, almost eliminated disease development, and improved plant growth to the level of uninoculated healthy control plants. Based on our results, we propose that A. brasilense be used in prevention programs to combat the foliar bacterial speck disease caused by P. syringae pv. tomato.

Bacteriophytochromes from Pseudomonas syringae pv. tomato DC3000 modulate the early stages of plant colonization during bacterial speck disease

2020 ◽  
Vol 156 (3) ◽  
pp. 695-712 ◽  
Author(s):  
Laura Moyano ◽  
Analía Carrau ◽  
Silvana Petrocelli ◽  
Ivana Kraiselburd ◽  
Wolfgang Gärtner ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Colonization ◽  
Tomato Dc3000 ◽  
Bacterial Speck ◽  
Early Stages ◽  
Bacterial Speck Disease

Managing Bacterial Speck and Spot of Tomato with Acibenzolar-S-Methyl in Virginia

2002 ◽  
Vol 3 (1) ◽  
pp. 11 ◽  
Author(s):  
A. S. Graves ◽  
S. A. Alexander
Keyword(s):  
Pseudomonas Syringae ◽  
Systemic Acquired Resistance ◽  
Block Design ◽  
Acquired Resistance ◽  
Copper Toxicity ◽  
Bacterial Disease ◽  
Tomato Production ◽  
Bacterial Speck ◽  
Run Off ◽  
Environmentally Sensitive Areas

On the Eastern Shore of Virginia, copper compounds, which have been used for controlling bacterial disease on tomato, have been associated with pesticide run-off from commercial tomato production with copper toxicity causing losses in clam nurseries. The objective of this study was to identify and evaluate a replacement for copper that was safer for the environment and could provide effective management of bacterial diseases of tomato. Acibenzolar-S-methyl (Actigard 50 WG), a plant activator that induces systemic acquired resistance (SAR), was compared to the standard bactericide (copper hydroxide + mancozeb) for controlling Xanthomonas axonopodis pv. vesicatoria and Pseudomonas syringae pv. tomato. Plots were established in grower fields in a randomized complete block design with four replications. Acibenzolar-S-methyl, at a rate of 10.5-g a.i./ha was equal to or better than the standard copper-based bactericide for controlling bacterial speck and spot, with no adverse affect on yield. Replacing copper with acibenzolar-S-methyl would effectively eliminate the need for copper bactericides. In environmentally sensitive areas where copper toxicity can be a problem, acibenzolar-S-methyl can providean effective alternative for the management of bacterial speck and bacterial spot on tomato. Accepted for publication 26 January 2002. Published 20 February 2002.

scholarly journals Assessment of the Importance of Similarity in Carbon Source Utilization Profiles between the Biological Control Agent and the Pathogen in Biological Control of Bacterial Speck of Tomato

2002 ◽  
Vol 68 (9) ◽  
pp. 4383-4389 ◽  
Author(s):  
Pingsheng Ji ◽  
Mark Wilson
Keyword(s):  
Biological Control ◽  
Carbon Source ◽  
Disease Severity ◽  
Pseudomonas Syringae ◽  
Biological Control Agent ◽  
Carbon Sources ◽  
Control Agent ◽  
Carbon Source Utilization ◽  
Bacterial Speck

ABSTRACT Bacterial speck of tomato, caused by Pseudomonas syringae pv. tomato, was used to determine whether similarity in carbon source utilization between a preemptive biological control agent and the pathogen was significant in determining the ability of the bacterium to suppress disease. Similarity in carbon source utilization was quantified as the ratio of the number of tomato carbon sources utilized in vitro by the biological control agent to the number of tomato carbon sources utilized in vitro by the target pathogen (the niche overlap index [NOI]). Suppression of the disease was quantified as the percent reduction in disease severity compared to the pathogen-only control when nonpathogenic bacteria were applied to foliage 48 h prior to the pathogen. In the collection of 36 nonpathogenic bacterial strains, there was a significant (P < 0.01), but weak (r2 = 0.25), correlation between reduction in disease severity and similarity in carbon source utilization, suggesting that similarity in carbon source use was significant in determining ability to suppress disease. The relationship was investigated further using catabolic mutants of P. syringae strain TLP2, an effective biological control agent of speck. Catabolic mutants exhibited lower levels of similarity (NOI = 0.07 to 0.90) than did wild-type TLP2 (NOI = 0.93). With these catabolic mutants there was a significant (P < 0.01), and stronger (r2 = 0.42), correlation between reduction in disease severity and similarity in carbon source utilization. This suggests that similarity in carbon source utilization was a more important component of biological control ability for the catabolic mutants than for the nonpathogenic bacteria. Together, these studies indicate that suppression of bacterial speck of tomato was correlated with nutritional similarity between the pathogenic and nonpathogenic bacteria and suggest that preemptive utilization of carbon sources was probably involved in the biological control of the disease by both the naturally occurring nonpathogenic bacteria and the catabolic mutants.

scholarly journals The Ptr1 locus of Solanum lycopersicoides confers resistance to race 1 strains of Pseudomonas syringae pv. tomato and to Ralstonia pseudosolanacearum by recognizing the type III effectors AvrRpt2/RipBN

2019 ◽  
Author(s):  
Carolina Mazo-Molina ◽  
Samantha Mainiero ◽  
Sara R. Hind ◽  
Christine M. Kraus ◽  
Mishi Vachev ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Genetic Resistance ◽  
Site Directed Mutagenesis ◽  
Type Iii Effector ◽  
Bacterial Speck ◽  
Solanum Lycopersicoides ◽  
Type Iii ◽  
Bacterial Speck Disease ◽  
Race 1 ◽  
Ralstonia Pseudosolanacearum

AbstractRace 1 strains of Pseudomonas syringae pv. tomato, which causes bacterial speck disease of tomato, are becoming increasingly common and no simply-inherited genetic resistance to such strains is known. We discovered that a locus in Solanum lycopersicoides, termed Pseudomonas tomato race 1 (Ptr1), confers resistance to race 1 Pst strains by recognizing the type III effector AvrRpt2. In Arabidopsis, AvrRpt2 degrades the RIN4 protein thereby activating RPS2-mediated immunity. Ptr1 also recognized homologs of AvrRpt2 from diverse bacteria including one in Ralstonia pseudosolanacearum and this correlated with the ability of AvrRpt2 to degrade RIN4. Using site-directed mutagenesis of AvrRpt2 we found that Ptr1 and RPS2 recognize identical features of AvrRpt2. However, the genome sequence of S. lycopersicoides revealed no RPS2 homolog in the Ptr1 region. Ptr1 could play an important role in controlling bacterial speck disease and its future cloning may shed light on an example of convergent evolution for recognition of a widespread type III effector.

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