scholarly journals Genetic Mapping and Functional Analysis of the Tomato Bs4 Locus Governing Recognition of the Xanthomonas campestris pv. vesicatoria AvrBs4 Protein

2001 ◽  
Vol 14 (5) ◽  
pp. 629-638 ◽  
Author(s):  
Agim Ballvora ◽  
Michéle Pierre ◽  
Guido van den Ackerveken ◽  
Sebastian Schornack ◽  
Ombeline Rossier ◽  
...  
Keyword(s):  
Xanthomonas Campestris ◽  
Resistance Locus ◽  
Bacterial Spot ◽  
Dna Templates ◽  
Nuclear Localization Signals ◽  
Bulked Dna ◽  
Capsicum Spp ◽  
Bacterial Spot Disease ◽  
Bacterial Spot Resistance ◽  
Susceptible Tomato

Xanthomonas campestris pv. vesicatoria is the causal agent of bacterial spot disease on pepper (Capsicum spp.) and tomato (Lycopersicon spp.). Analysis of 17 different Lycopersicon accessions with avrBs4-expressing X. campestris pv. vesicatoria strains identified 15 resistant and two susceptible tomato genotypes. Genetic analysis revealed that AvrBs4 recognition in tomato is governed by a single locus, designated Bs4 (bacterial spot resistance locus no. 4). Amplified fragment length polymorphism and bulked DNA templates from resistant and susceptible plants were used to define a 2.6-cM interval containing the Bs4 locus. A standard tomato mapping population was employed to localize Bs4- linked markers on the short arm of chromosome 5. Investigation of X. campestris pv. vesicatoria hrp mutant strains revealed that AvrBs4 secretion and avirulence activity are hrp dependent. Agrobacterium-based delivery of the avrBs4 gene into tomato triggered a plant response that phenotypically resembled the hypersensitive response induced by avrBs4-expressing X. campestris pv. vesicatoria strains, suggesting symplastic perception of the avirulence protein. Mutations in the avrBs4 C-terminal nuclear localization signals (NLSs) showed that NLSs are dispensable for Bs4-mediated recognition. Our data suggest that tomato Bs4 and pepper Bs3 employ different recognition modes for detection of the highly homologous X. campestris pv. vesicatoria avirulence proteins AvrBs4 and AvrBs3.

Development of gene-based markers for the Bs2 bacterial spot resistance gene for marker-assisted selection in pepper (Capsicum spp.)

2011 ◽  
Vol 52 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Hai Thi Hong Truong ◽  
Ki-Taek Kim ◽  
Su Kim ◽  
Myoung-Cheol Cho ◽  
Hyun-Ran Kim ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Marker Assisted Selection ◽  
Bacterial Spot ◽  
Capsicum Spp ◽  
Gene Based Markers ◽  
Bacterial Spot Resistance

scholarly journals Comparison of Resistant Cultivars for Management of Bacterial Spot in Peppers

1999 ◽  
Vol 9 (4) ◽  
pp. 645-655
Author(s):  
Brent Rowell ◽  
R. Terry Jones ◽  
William Nesmith ◽  
John C. Snyder
Keyword(s):  
Capsicum Annuum ◽  
Xanthomonas Campestris ◽  
Bell Pepper ◽  
Bacterial Spot ◽  
Eastern Kentucky ◽  
Breeding Lines ◽  
Resistant Cultivars ◽  
Bacterial Spot Resistance ◽  
Free Environment

Bacterial spot epidemics, caused by Xanthomonas campestris pv. vesicatoria (Doidge) Dye, continue to plague bell pepper (Capsicum annuum L.) growers in a number of southern and midwestern states. A 3-year study designed to compare cultivars and breeding lines under induced bacterial spot epidemic and bacterial spot-free conditions began soon after the first release of cultivars having the Bs2 gene for resistance to races 1 to 3 of the pathogen. Bacterial spot epidemics were created by transplanting `Merlin' plants (inoculated with races 1 to 3) into plots of each test cultivar at an isolated location in eastern Kentucky. Plots of the same trial entries at a second location were kept free of bacterial spot for 2 of the 3 years of trials; however, a moderate natural epidemic occurred at this location in 1996. Bacterial spot resistance had the greatest impact on yields and returns per acre in the inoculated trials. Cultivars with only Bs1 or a combination of Bs1 and Bs3 were highly susceptible in the inoculated trials. There were statistically significant and economically important differences in resistance among cultivars and breeding lines having the Bs2 gene; some were nearly as susceptible as susceptible checks. Although many Bs2-gene cultivars showed satisfactory levels of resistance, only a few were highly resistant, horticulturally acceptable, and comparable in yields to the best susceptible hybrids in a bacterial spot-free environment.

Effect of acidic electrolyzed water on the viability of bacterial and fungal plant pathogens and on bacterial spot disease of tomato

2006 ◽  
Vol 52 (10) ◽  
pp. 915-923 ◽  
Author(s):  
P A Abbasi ◽  
G Lazarovits
Keyword(s):  
Xanthomonas Campestris ◽  
Plant Pathogens ◽  
Disease Incidence ◽  
Bacterial Spot ◽  
Tomato Seed ◽  
Electrolyzed Water ◽  
Spot Disease ◽  
Foliar Sprays ◽  
Fungal Plant Pathogens ◽  
Bacterial Spot Disease

Acidic electrolyzed water (AEW), known to have germicidal activity, was obtained after electrolysis of 0.045% aqueous solution of sodium chloride. Freshly prepared AEW (pH 2.3–2.6, oxidation–reduction potential 1007–1025 mV, and free active chlorine concentration 27–35 ppm) was tested in vitro and (or) on tomato foliage and seed surfaces for its effects on the viability of plant pathogen propagules that could be potential seed contaminants. Foliar sprays of AEW were tested against bacterial spot disease of tomato under greenhouse and field conditions. The viability of propagules of Xanthomonas campestris pv. vesicatoria (bacterial spot pathogen), Streptomyces scabies (potato scab pathogen), and Fusarium oxysporum f.sp. lycopersici (root rot pathogen) was significantly reduced 4–8 log units within 2 min of exposure to AEW. Immersion of tomato seed from infected fruit in AEW for 1 and 3 min significantly reduced the populations of X. campestris pv. vesicatoria from the surface of the seed without affecting seed germination. Foliar sprays of AEW reduced X. campestris pv. vesicatoria populations and leaf spot severity on tomato foliage in the greenhouse. In the field, multiple sprays of AEW consistently reduced bacterial spot severity on tomato foliage. Disease incidence and severity was also reduced on fruit, but only in 2003. Fruit yield was either enhanced or not affected by the AEW sprays. These results indicate a potential use of AEW as a seed surface disinfectant or contact bactericide.Key words: electrolyzed oxidizing water, seed disinfectant, foliar sprays, bacterial spot control.

scholarly journals A Monocot Plant Identified as an Alternate Host of the Causal Agent of Bacterial Spot of Tomato and Pepper

HortScience ◽  
2002 ◽  
Vol 37 (6) ◽  
pp. 969-972 ◽  
Author(s):  
Harold A.A. Gibbs
Keyword(s):  
Xanthomonas Campestris ◽  
In Planta ◽  
Bacterial Spot ◽  
Alternate Host ◽  
Spot Disease ◽  
Commelina Benghalensis ◽  
Weed Growth ◽  
Bacterial Spot Disease ◽  
Stem Extract ◽  
Physiological Reactions

Xanthomonas campestris pv. vesicatoria (Xcv) recovered from Commelina benghalensis L., caused bacterial spot disease in cultivars of pepper and tomato susceptible to the pathogen. This is the first reported case of a dicot-infecting Xc pathovar infecting a monocot plant, represented here by a member of the Family Commelinaceae. Laboratory strains of the pathogen that included 81-23, 81-23M13, 82:4, 2595, and P6AD4, known to be pathogenic to pepper and tomato, promoted bacterial spot symptoms on leaves of C. benghalensis L. Of the 63 field isolates recovered from infected C. benghalensis L., 30 gave biochemical and physiological reactions consistent with Xcv pathogens, whereas 10 of the latter promoted bacterial spot disease in the test cultivars resulting in the identification of seven pathogenic races, including P2, P5, P6, P5T1, P5T2, P6T2, and P6T3. Bacterial spot disease symptoms developed on stems only when C. benghalensis L. was spray-inoculated with strains 81-23, 81-23M13, and P6AD4. Bacterial concentration increased in planta by as much as 103 per lesion of the leaf, whereas growth of the same strains was restricted in the stem of this weed. Growth of these three strains was, however, significantly (P ≤ 0.05) lower on NYGA amended with C. benghalensis L. stem extract than on NYGA amended with leaf extract. The ability of the bacterial spot pathogen to infect the stem of C. benghalensis L. has serious implications for management of bacterial spot disease in fields populated with this weed since stems of this plant infected with the pathogen continue to grow vegetatively and disperse throughout all fields in which it is found.

scholarly journals Improved Efficacy of Newly Formulated Bacteriophages for Management of Bacterial Spot on Tomato

Plant Disease ◽  
2003 ◽  
Vol 87 (8) ◽  
pp. 949-954 ◽  
Author(s):  
B. Balogh ◽  
J. B. Jones ◽  
M. T. Momol ◽  
S. M. Olson ◽  
A. Obradovic ◽  
...  
Keyword(s):  
Xanthomonas Campestris ◽  
Residual Activity ◽  
Skim Milk ◽  
Field Trials ◽  
Plant Surface ◽  
Bacterial Spot ◽  
Corn Flour ◽  
Disease Reduction ◽  
Plant Foliage ◽  
Bacterial Spot Disease

Bacteriophages are currently used as an alternative method for controlling bacterial spot disease on tomato incited by Xanthomonas campestris pv. vesicatoria. However, the efficacy of phage is greatly reduced due to its short residual activity on plant foliage. Three formulations that significantly increased phage longevity on the plant surface were tested in field and greenhouse trials: (i) PCF, 0.5% pregelatinized corn flour (PCF) + 0.5% sucrose; (ii) Casecrete, 0.5% Casecrete NH-400 + 0.5% sucrose + 0.25% PCF; and (iii) skim milk, 0.75% powdered skim milk + 0.5% sucrose. In greenhouse experiments, the nonformulated, PCF-, Casecrete-, and skim milk-formulated phage mixtures reduced disease severity on plants compared with the control by 1, 30, 51, and 62%, respectively. In three consecutive field trials, nonformulated phage caused 15, 20, and 9% reduction in disease on treated plants compared with untreated control plants, whereas plants treated with PCF- and Casecrete-formulated phage had 27, 32, and 12% and 30, 43, and 24% disease reduction, respectively. Plants receiving copper-mancozeb treatments were included in two field trials and had a 20% decrease in disease in the first trial and a 13% increase in the second one. Skim milk-formulated phage was tested only once and caused an 18% disease reduction. PCF-formulated phage was more effective when applied in the evening than in the morning, reducing disease on plants by 27 and 13%, respectively. The Casecrete-formulated phage populations were over 1,000-fold higher than the nonformulated phage populations 36 h after phage application.

scholarly journals Automatic Detection and Severity Assessment of Pepper Bacterial Spot Disease via MultiModels Based on Convolutional Neural Networks

2020 ◽  
Vol 11 (2) ◽  
pp. 29-43
Author(s):  
Qiufeng Wu ◽  
Miaomiao Ji ◽  
Zhao Deng
Keyword(s):  
Neural Networks ◽  
Convolutional Neural Networks ◽  
Xanthomonas Campestris ◽  
Automatic Detection ◽  
Bacterial Disease ◽  
Severity Assessment ◽  
Bacterial Spot ◽  
Deep Convolutional Neural Networks ◽  
Spot Disease ◽  
Bacterial Spot Disease

Pepper bacterial spot disease caused by Xanthomonas campestris is the most common pepper bacterial disease, which ultimately reduces productivity and quality of products. This work uses deep convolutional neural networks (CNNs) to serve fine-grained pepper bacterial spot disease severity classification tasks. The pepper bacterial spot disease leaf images collected from the PlantVillage dataset are further annotated by botanists and split into healthy samples (label1), general samples (label2), and serious samples (label3). To extract more effective and discriminative features, an integrated neural network denoted as MultiModel_VGR is proposed for automatic detection and severity assessment of pepper bacterial spot disease, which is based on three powerful and popular deep learning architectures, namely VGGNet, GoogLeNet and ResNet. Compared with state-of-the-art single CNN architectures and binary-integrated MultiModels, MultiModel_VGR yields the best overall accuracy of 95.34% on the hold-out test dataset, which may have great potential in crop disease control for modern agriculture.

scholarly journals Comparison of Greenhouse Methods for Assessing Resistance to Bacterial Leaf Spot in Plum

1993 ◽  
Vol 118 (5) ◽  
pp. 667-671 ◽  
Author(s):  
B.L. Topp ◽  
W.B. Sherman ◽  
R.E. Stall ◽  
G.V. Minsavage ◽  
C.J. Wilcox
Keyword(s):  
Leaf Spot ◽  
Xanthomonas Campestris ◽  
Field Performance ◽  
Bacterial Spot ◽  
Plant Genotype ◽  
Adaxial Side ◽  
Prunus Salicina ◽  
Leaf Mesophyll ◽  
Bacterial Spot Resistance ◽  
Spearman’S Correlation

Four greenhouse leaf inoculation methods for screening Japanese plum (Prunus salicina L. and hybrids) for resistance to Xanthomonas campestris pv. pruni (Smith) Dye were compared for repeatability, ability to differentiate among plant genotype responses, and correlations with field ratings. Clonally propagated trees were inoculated artificially in a greenhouse by immersing leaves in 2.5 × 108 cfu/ml inoculum (DIP), rubbing the adaxial side of leaves with a slurry of 2.5 × 108 cfu/ml inoculum and Carborundum powder (CARB), infiltrating leaves with 5 × 105 cfu/ml inoculum using a needle-less syringe (INFS), and infiltrating with 5 × 106 cfu/ml inoculum (INF6). No greenhouse method was superior in all assessment categories. The CARB method was most repeatable (t = 0.78) but had a low Spearman's correlation (rs = 0.29), indicating that greenhouse rankings did not correspond closely with field rankings. The INF6 method was unsuitable because it did not differentiate between plant genotypes. The DIP method appeared most suitable, having moderate repeatability (t = 0.46) for four observations per leaf and moderate Spearman's correlation with field performance (rs = 0.56). The INF5 method may be appropriate for identifying bacterial spot resistance that is associated with resistance in the leaf mesophyll.

scholarly journals Bacterial Spot Resistance, Yield, and Quality of Bell and Specialty Peppers

2001 ◽  
Vol 11 (4) ◽  
pp. 648-657 ◽  
Author(s):  
Brent Rowell ◽  
R. Terry Jones ◽  
William Nesmith ◽  
April Satanek ◽  
John C. Snyder
Keyword(s):  
Capsicum Annuum ◽  
Fruit Quality ◽  
Xanthomonas Campestris ◽  
Bell Pepper ◽  
Bacterial Spot ◽  
Eastern Kentucky ◽  
Resistant Cultivars ◽  
Yield And Quality ◽  
Bacterial Spot Resistance

Bacterial spot epidemics, caused by Xanthomonas campestris pv. vesicatoria (Xcv), are still considered serious risks for commercial pepper (Capsicum annuum) growers in a number of eastern, southern and midwestern states. Newly released bell pepper cultivars with the Bs2 gene for resistance to Xcv races 1, 2, and 3 were compared in 2000 under bacterial spot-free and severe (natural) bacterial spot epidemic conditions in central and eastern Kentucky where similar trials had been conducted from 1995 to 1997. In addition to the replicated bell pepper trials, 49 hot and specialty pepper cultivars were grown for observation in single plots at the same two locations. As in previous trials, there were economically important differences in resistance and marketable yields among bell pepper cultivars having the Bs2 gene; some resistant cultivars were as susceptible as susceptible checks. Others were highly resistant in spite of the presence of Xcv races 3 and 6 in the eastern Kentucky trial. Only a few were highly resistant with excellent fruit quality. With a few notable exceptions, most of the hot and specialty cultivars were very susceptible to bacterial spot. Two of the three new jalapeño cultivars carrying Bs2 were highly resistant to bacterial spot and high yielding under severe epidemic conditions.

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