Can the inclusion of uniconazole improve the effectiveness of acibenzolar-S-methyl in managing bacterial speck (Pseudomonas syringae pv. tomato) and bacterial spot (Xanthomonas gardneri) in tomato?

2019 ◽  
Vol 155 (3) ◽  
pp. 927-942
Author(s):  
Cheryl L. Trueman ◽  
Steven A. Loewen ◽  
Paul H. Goodwin
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Spot ◽  
Bacterial Speck

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 Development and Evaluation of PCR-Based Diagnostic Assays for the Bacterial Speck and Bacterial Spot Pathogens of Tomato

Plant Disease ◽  
2006 ◽  
Vol 90 (4) ◽  
pp. 451-458 ◽  
Author(s):  
Diane A. Cuppels ◽  
Frank J. Louws ◽  
Teresa Ainsworth
Keyword(s):  
Pseudomonas Syringae ◽  
Disease Diagnosis ◽  
Bacterial Spot ◽  
Pcr Assay ◽  
Diagnostic Assays ◽  
Bacterial Speck ◽  
Pcr Product ◽  
Polymerase Chain ◽  
Primer Sets ◽  
Group D

Bacterial speck and bacterial spot lesions can easily be confused with each other and with those formed by other tomato pathogens. To facilitate disease diagnosis, we developed and evaluated polymerase chain reaction (PCR)-based lesion assays using crude DNA extracts and primer sets COR1/2 (bacterial speck) and BSX1/2 (bacterial spot). All 29 pathogenic Pseudomonas syringae pv. tomato strains tested produced a 689-bp amplicon with COR1/2; 28 of the 37 geographically diverse bacterial spot-causing xanthomonad (BSX) strains that were tested generated the 579-bp BSX1/2 amplicon. The detection limit with plant samples was 30 to 50 CFU/reaction. In a 6-year study, the COR1/2 PCR assay diverged from the culture-based classical assay for only 3 of 70 bacterial speck lesion samples collected from Ontario greenhouses and tomato fields; the BSX1/2 assay was positive for 112 of the 124 confirmed bacterial spot lesions sampled. The majority (66%) of the BSX strains isolated from these lesions belonged to group D; the 12 strains that were BSX1/2-negative belonged to group C. Group D strains produced a 425-bp PCR product with crude DNA extracts but a 579-bp product with purified DNA; the former was identical to the latter except that it was missing 150 bp from the middle of the 579-bp sequence.

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 Marker-assisted Selection for Combining Resistance to Bacterial Spot and Bacterial Speck in Tomato

2005 ◽  
Vol 130 (5) ◽  
pp. 716-721 ◽  
Author(s):  
Wencai Yang ◽  
David M. Francis
Keyword(s):  
Pseudomonas Syringae ◽  
Marker Assisted Selection ◽  
Field Trials ◽  
Bacterial Spot ◽  
Breeding Lines ◽  
Repulsion Phase ◽  
Bacterial Diseases ◽  
Bacterial Speck ◽  
Worldwide Distribution ◽  
Elite Breeding Lines

The lack of resistance to bacterial diseases increases both the financial cost and environmental impact of tomato (Lycopersicon esculentum Mill.) production while reducing yield and quality. Because several bacterial diseases can be present in the same field, developing varieties with resistance to multiple diseases is a desirable goal. Bacterial spot (caused by four Xanthomonas Dowson species) and bacterial speck (caused by Pseudomonas syringae pv. tomato Young, Dye and Wilkie) are two economically important diseases of tomato with a worldwide distribution. The resistance gene Pto confers a hypersensitive response (HR) to race 0 strains of the bacterial speck pathogen. The locus Rx3 explains up to 41% of the variation for resistance to bacterial spot race T1 in field trials, and is associated with HR following infiltration. Both Pto and Rx3 are linked in repulsion phase on chromosome 5. We made a cross between two elite breeding lines, Ohio 981205 carrying Pto and Ohio 9834 carrying Rx3, to develop an F2 population and subsequent inbred generations. Marker-assisted selection (MAS) was applied to the F2 progeny and to F2:3 families in order to select for coupling-phase resistance. Thirteen homozygous progeny from 419 F2 plants and 20 homozygous families from 3716 F3 plants were obtained. Resistance was confirmed in all selected families based on HR in greenhouse screens using bacterial speck race 0 and bacterial spot race T1 isolates. Resistance to bacterial spot race T1 was confirmed in the field for 33 of the selected families. All selected families were also resistant to bacterial speck in the field. MAS was an efficient tool to select for desirable recombination events and pyramid resistance.

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.

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