scholarly journals Tomato Bacterial Spot Resistance Derived from PI 114490; Inheritance of Resistance to Race T2 and Relationship across Three Pathogen Races

2003 ◽  
Vol 128 (5) ◽  
pp. 698-703 ◽  
Author(s):  
J.W. Scott ◽  
D.M. Francis ◽  
S.A. Miller ◽  
G.C. Somodi ◽  
J.B. Jones
Keyword(s):  
Disease Severity ◽  
Xanthomonas Campestris ◽  
The Other ◽  
Bacterial Spot ◽  
Resistance Level ◽  
Narrow Sense Heritability ◽  
Backcross Population ◽  
Locus Model ◽  
Bacterial Spot Resistance ◽  
Inbred Backcross

Crosses were made between tomato (Lycopersicon esculentum Mill.) inbreds susceptible to races T2 and T3 of bacterial spot (Xanthomonas vesicatoria and Xanthomonas campestris pv. vesicatoria, respectively) and accession PI 114490 with resistance to races T1, T2, and T3. Resistance to race T2 was analyzed using the parents, F1, and F2 generations from one of the crosses. The F1 was intermediate between the parents for disease severity suggesting additive gene action. The segregation of F2 progeny fit a two-locus model (χ2 = 0.96, P = 0.9-0.5) where four resistance alleles are required for a high resistance level, two or three resistance alleles provide intermediate resistance, and zero or one resistance allele results in susceptibility. The narrow sense heritability of resistance to T2 strains was estimated to be 0.37 ± 0.1 based on F2 to F3 parent-offspring regression. A second cross was developed into an inbred backcross (IBC) population to facilitate multilocation replicated testing with multiple races. Segregation for T2 resistance in the inbred backcross population also suggested control was by two loci, lending support to the two-locus model hypothesized based on the F2 segregation. To determine if the same loci conferred resistance to the other races, selections for race T2 resistance were made in the F2 and F3 generations and for race T3 resistance in the F2 through F4 generations. Six T3 selections (F5), 13 T2 selections (F4's that diverged from seven F2 selections), and control lines were then evaluated for disease severity to races T1, T2, and T3 over two seasons. Linear correlations were used to estimate the efficiency of selecting for resistance to multiple races based on a disease nursery inoculated with a single race. Race T1 and race T2 disease severities were correlated (r ≥ 0.80, P< 0.001) within and between years while neither was correlated to race T3 either year. These results suggest that selecting for race T2 resistance in progeny derived from crosses to PI 114490 would be an effective strategy to obtain resistance to both race T1 and T2 in the populations tested. In contrast, selection for race T3 or T2 will be less likely to result in lines with resistance to the other race. PI 114490 had less resistance to T3 than to T2 or T1. Independent segregation of T2 and T3 resistance from the IBC population derived from PI 114490 suggests that T3 resistance is not controlled by the same genes as T2 resistance, supporting the linear correlation data.

Inheritance of Glyphosate Resistance in Hairy Fleabane (Conyza bonariensis) from California

Weed Science ◽  
2014 ◽  
Vol 62 (2) ◽  
pp. 258-266 ◽  
Author(s):  
Miki Okada ◽  
Marie Jasieniuk
Keyword(s):  
Resistance Mechanism ◽  
Glyphosate Resistance ◽  
Population Based ◽  
Single Individual ◽  
Resistance Level ◽  
Backcross Population ◽  
Resistant Parent ◽  
Susceptible Population ◽  
Locus Model ◽  
Hairy Fleabane

Inheritance of glyphosate resistance was investigated in hairy fleabane populations from California as part of providing the information needed to predict and manage resistance and to gain insight into resistance mechanism (or mechanisms) present in the populations. Three glyphosate-resistant individuals grown from seed collected from distinct sites near Fresno, CA, were crossed to individuals from the same susceptible population to create reciprocal F1populations. A single individual from each of the F1populations was used to create a backcross population with a susceptible maternal parent, and an F2population. Based on dose response analyses, reciprocal F1populations were not statistically different from each other, more similar to the resistant parent, and statistically different from the susceptible parent, consistent with nuclear control of the trait and dominance to incomplete dominance of resistance over susceptibility in all three crosses. Glyphosate resistance in two of the three crosses segregated in the backcross and the F2populations as a single-locus trait. In the remaining cross, the resistant parent had approximately half the resistance level as the other two resistant parents, and the segregation of glyphosate resistance in backcross and F2populations conformed to a two-locus model with resistance alleles acting additively and at least two copies of the allele required for expression of resistance. This two-locus model of the segregation of glyphosate resistance has not been reported previously. Variation in the pattern of inheritance and the level of resistance indicate that multiple resistance mechanisms may be present in hairy fleabane populations in California.

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.

scholarly journals Host Genotype and Hypersensitive Reaction Influence Population Levels of Xanthomonas campestris pv. vitians in Lettuce

2015 ◽  
Vol 105 (3) ◽  
pp. 316-324 ◽  
Author(s):  
Carolee T. Bull ◽  
Samantha J. Gebben ◽  
Polly H. Goldman ◽  
Mark Trent ◽  
Ryan J. Hayes
Keyword(s):  
Disease Severity ◽  
Xanthomonas Campestris ◽  
Resistance Mechanisms ◽  
Hypersensitive Reaction ◽  
The Other ◽  
Host Genotype ◽  
Resistant Cultivars ◽  
Bacterial Titer ◽  
Lettuce Breeding ◽  
Dynamics Of Population

Dynamics of population sizes of Xanthomonas campestris pv. vitians inoculated onto or into lettuce leaves were monitored on susceptible and resistant cultivars. In general, population growth was greater for susceptible (Clemente, Salinas 88, Vista Verde) than resistant (Batavia Reine des Glaces, Iceberg, Little Gem) cultivars. When spray-inoculated or infiltrated, population levels of X. campestris pv. vitians were consistently significantly lower on Little Gem than on susceptible cultivars, while differences in the other resistant cultivars were not consistently statistically significant. Populations increased at an intermediate rate on cultivars Iceberg and Batavia Reine des Glaces. There were significant positive correlations between bacterial concentration applied and disease severity for all cultivars, but bacterial titer had a significantly greater influence on disease severity in the susceptible cultivars than in Little Gem and an intermediate influence in Iceberg and Batavia Reine des Glaces. Infiltration of X. campestris pv. vitians strains into leaves of Little Gem resulted in an incompatible reaction, whereas compatible reactions were observed in all other cultivars. It appears that the differences in the relationship between population dynamics for Little Gem and the other cultivars tested were due to the hypersensitive response in cultivar Little Gem. These findings have implications for disease management and lettuce breeding because X. campestris pv. vitians interacts differently with cultivars that differ for resistance mechanisms.

scholarly journals Resistance in Lycopersicon esculentum Intraspecific Crosses to Race T1 Strains of Xanthomonas campestris pv. vesicatoria Causing Bacterial Spot of Tomato

2005 ◽  
Vol 95 (5) ◽  
pp. 519-527 ◽  
Author(s):  
Wencai Yang ◽  
Erik J. Sacks ◽  
Melanie L. Lewis Ivey ◽  
Sally A. Miller ◽  
David M. Francis
Keyword(s):  
Molecular Markers ◽  
Lycopersicon Esculentum ◽  
Phenotypic Variation ◽  
Xanthomonas Campestris ◽  
Chromosome 1 ◽  
Bacterial Spot ◽  
Chromosome 5 ◽  
Backcross Population ◽  
Bacterial Populations ◽  
Advanced Backcross

We used molecular markers to identify quantitative trait loci (QTL) that confer resistance in the field to Xanthomonas campestris pv. vesicatoria race T1, a causal agent of bacterial spot of tomato. An F2 population derived from a cross between Hawaii 7998 (H 7998) and an elite breeding line, Ohio 88119, was used for the initial identification of an association between molecular markers and resistance as measured by bacterial populations in individual plants in the greenhouse. Polymorphism in this cross between a Lycopersicon esculentum donor of resistance and an elite L. esculentum parent was limited. The targeted use of a core set of 148 polymerase chain reaction-based markers that were identified as polymorphic in L. esculentum × L. esculentum crosses resulted in the identification of 37 markers that were polymorphic for the cross of interest. Previous studies using an H 7998 × L. pennellii wide cross implicated three loci, Rx1, Rx2, and Rx3, in the hypersensitive response to T1 strains. Markers that we identified were linked to the Rx1 and Rx3 loci, but no markers were identified in the region of chromosome 1 where Rx2 is located. Single marker-trait analysis suggested that chromosome 5, near the Rx3 locus, contributed to reduced bacterial populations in lines carrying the locus from H 7998. The locus on chromosome 5 explained 25% of the phenotypic variation in bacterial populations developing in infected plants. An advanced backcross population and subsequent inbred backcross lines developed using Ohio 88119 as a recurrent parent were used to confirm QTL associations detected in the F2 population. Markers on chromosome 5 explained 41% of the phenotypic variation for resistance in replicated field trials. In contrast, the Rx1 locus on chromosome 1 did not play a role in resistance to X. campestris pv. vesicatoria race T1 strains as measured by bacterial populations in the greenhouse or symptoms in the field. A locus from H 7998 on chromosome 4 was associated with susceptibility to disease and explained 11% of the total phenotypic variation. Additional variation in resistance was explained by plant maturity (6%), with early maturing families expressing lower levels of resistance, and plant habit (6%), with indeterminate plants displaying more resistance. The markers linked to Rx3 will be useful in selection for resistance in elite × elite crosses.

scholarly journals Nutritional Similarity between Leaf-Associated Nonpathogenic Bacteria and the Pathogen Is Not Predictive of Efficacy in Biological Control of Bacterial Spot of Tomato

2003 ◽  
Vol 69 (6) ◽  
pp. 3484-3491 ◽  
Author(s):  
Alexei C. Dianese ◽  
Pingsheng Ji ◽  
Mark Wilson
Keyword(s):  
Population Size ◽  
Disease Severity ◽  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Leaf Surface ◽  
Nitrogen Sources ◽  
Niche Overlap ◽  
Bacterial Spot ◽  
Pathogen Population

ABSTRACT It has been demonstrated that for a nonpathogenic, leaf-associated bacterium, effectiveness in the control of bacterial speck of tomato is correlated with the similarity in the nutritional needs of the nonpathogenic bacterium and the pathogen Pseudomonas syringae pv. tomato. This relationship was investigated further in this study by using the pathogen Xanthomonas campestris pv. vesicatoria, the causal agent of bacterial spot of tomato, and a collection of nonpathogenic bacteria isolated from tomato foliage. The effects of inoculation of tomato plants with one of 34 nonpathogenic bacteria prior to inoculation with the pathogen X. campestris pv. vesicatoria were quantified by determining (i) the reduction in disease severity (number of lesions per square centimeter) in greenhouse assays and (ii) the reduction in leaf surface pathogen population size (log10 of the number of CFU per leaflet) in growth chamber assays. Nutritional similarity between the nonpathogenic bacteria and X. campestris pv. vesicatoria was quantified by using either niche overlap indices (NOI) or relatedness in cluster analyses based upon in vitro utilization of carbon or nitrogen sources reported to be present in tomato tissues or in Biolog GN plates. In contrast to studies with P. syringae pv. tomato, nutritional similarity between the nonpathogenic bacteria and the pathogen X. campestris pv. vesicatoria was not correlated with reductions in disease severity. Nutritional similarity was also not correlated with reductions in pathogen population size. Further, the percentage of reduction in leaf surface pathogen population size was not correlated with the percentage of reduction in disease severity, suggesting that the epiphytic population size of X. campestris pv. vesicatoria is not related to disease severity and that X. campestris pv. vesicatoria exhibits behavior in the phyllosphere prior to lesion formation that is different from that of P. syringae pv. tomato.

scholarly journals Reduction of Bacterial Spot Disease Severity on Tomato and Pepper Plants with Foliar Applications of Ammonium Lignosulfonate and Potassium Phosphate

Plant Disease ◽  
2002 ◽  
Vol 86 (11) ◽  
pp. 1232-1236 ◽  
Author(s):  
Pervaiz A. Abbasi ◽  
Nader Soltani ◽  
Diane A. Cuppels ◽  
George Lazarovits
Keyword(s):  
Disease Management ◽  
Disease Severity ◽  
Xanthomonas Campestris ◽  
Management Practices ◽  
Tomato Fruit ◽  
Potassium Phosphate ◽  
The United States ◽  
Bacterial Spot ◽  
Phytotoxic Effect ◽  
Pepper Plants

Bacterial spot is a serious and persistent disease problem of tomato and bell pepper in both the United States and Canada. Current disease management practices, based primarily on fixed copper bactericides, do not give consistent, effective protection. Foliar applications of ammonium lignosulfonate (ALS), derived from the wood pulping process, and the fertilizer potassium phosphate (KP) were tested for their ability to control this disease under both greenhouse and field conditions. Acibenzolar-S-methyl was included as a control. Greenhouse-grown tomato transplants treated with acibenzolar-S-methyl, 2 or 4% (vol/vol) ALS, 25 mM KP, or 2% ALS plus 10 mM KP and then inoculated with Xanthomonas campestris pv. vesicatoria had significantly less disease than the unprotected controls. Weekly foliar applications of acibenzolar-S-methyl, ALS, or KP significantly reduced disease severity on the foliage of inoculated field-grown tomato and pepper plants; although less disease appeared on the fruit of these plants, the effect was not always statistically significant except for the acibenzolar-S-methyl treatment. Acibenzolar-S-methyl increased the yield of marketable tomato fruit in 2 of 3 years of the study and that of pepper fruit in 1 of 2 years. There was a marked increase in the yield of marketable fruit on all ALS-treated pepper plants in 2001. None of the treatments significantly increased total tomato or pepper yield. ALS and KP had no observable phytotoxic effect on tomato or pepper foliage. Our results indicate that future integrated disease management programs for bacterial spot may be enhanced by including foliar sprays of these two products.

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.

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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