scholarly journals A Non-Hypersensitive Resistance in Pepper to the Bacterial Spot Pathogen Is Associated with Two Recessive Genes

2002 ◽  
Vol 92 (3) ◽  
pp. 273-277 ◽  
Author(s):  
J. B. Jones ◽  
G. V. Minsavage ◽  
P. D. Roberts ◽  
R. R. Johnson ◽  
C. S. Kousik ◽  
...  
Keyword(s):  
Electrolyte Leakage ◽  
Visual Assessment ◽  
Field Studies ◽  
Hypersensitive Reaction ◽  
Bacterial Spot ◽  
Similar Concentration ◽  
Hypersensitive Resistance ◽  
Growth Room ◽  
Recessive Genes ◽  
Bacterial Spot Resistance

The pepper genotype, ECW-12346, was developed with bacterial spot resistance derived from Pep13, PI 271322, and ECW123 (Early Calwonder containing Bs1, Bs2, and Bs3 genes). For genetic analysis of this resistance, ECW12346, ECW123, F1, F2, and backcrosses were inoculated with a pepper race 6 (P6) strain. Two recessive genes were identified that determined resistance. The genes are designated bs5 and bs6 for the resistance derived from PI 271322 and Pep13, respectively. In greenhouse and field studies, ECW12346 was highly resistant, whereas ECW123 had significant defoliation. In growth-room studies, electrolyte leakage and population dynamics were determined. Following infiltration of both genotypes with 108 CFU/ml of a P6 strain, there was no rapid increase in electrolyte leakage within 72 h, whereas a rapid increase in electrolyte leakage occurred within 24 h when a similar concentration of a P3 strain (containing the avrBs2 gene) was infiltrated into the intercellular spaces of the leaf. When 105 CFU/ml of a P6 strain was infiltrated into leaves, complete tissue collapse was evident in ECW123 10 days later as determined by visual assessment and electrolyte leakage data, but no confluent necrosis was detected in ECW12346. Internal populations were at least two logarithmic units higher in ECW123 than in ECW12346. Therefore, ECW12346 inhibits population build-up without inducing the typical hypersensitive reaction characterized by an increase in electrolyte leakage.

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 Progress in Developing Bacterial Spot Resistance in Tomato

Agronomy ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 26 ◽  
Author(s):  
Sadikshya Sharma ◽  
Krishna Bhattarai
Keyword(s):  
Gene Pyramiding ◽  
Weather Conditions ◽  
Disease Spread ◽  
Bacterial Spot ◽  
Hypersensitive Resistance ◽  
Solanum Lycopersicum L ◽  
Industry Standard ◽  
Bacterial Spot Resistance ◽  
Wild Accessions ◽  
Multiple Strains

Bacterial spot (BS), caused by four species of Xanthomonas: X. euvesicatoria, X. vesicatoria, X. perforans and X. gardneri in tomato (Solanum lycopersicum L.) results in severe loss in yield and quality by defoliation and the appearance of lesions on fruits, respectively. The combined industry standard for BS control (foliar applications Actigard® rotated with copper plus mancozeb) does not offer sufficient protection, especially when weather conditions favor disease spread. Development of tomato cultivars with BS resistance is thus an important measure to minimize losses. Hypersensitive and non-hypersensitive resistance has been identified in different wild accessions and cultivated tomato relatives and has been transferred to cultivated tomato. However, complete resistance is yet to be obtained. With the advent of next generation sequencing and precise genome editing tools, the genetic regions that confer resistance to bacterial spot can be targeted and enriched through gene pyramiding in a new commercial cultivar which may confer higher degree of horizontal resistance to multiple strains of Xanthomonas causing bacterial spot in tomato.

Growth-room and field studies with seed tubers treated with ethylene and 1-methylcyclopropene (1-MCP) during storage

2006 ◽  
Vol 83 (2) ◽  
pp. 149-160 ◽  
Author(s):  
K. Pruski ◽  
R. K. Prange ◽  
B. J. Daniels-Lake ◽  
J. Nowak ◽  
T. Astatkie ◽  
...  
Keyword(s):  
Field Studies ◽  
Seed Tubers ◽  
Growth Room

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 Protecting vegetable cultivars in Brazil: a chili pepper case-study research

2016 ◽  
Vol 34 (2) ◽  
pp. 161-167 ◽  
Author(s):  
Samy Pimenta ◽  
Rosana Rodrigues ◽  
Cláudia P Sudré ◽  
João GT Moraes ◽  
Cíntia S Bento ◽  
...  
Keyword(s):  
Recombinant Inbred Lines ◽  
Block Design ◽  
Case Study Research ◽  
Fruit Shape ◽  
Bacterial Spot ◽  
Randomized Block Design ◽  
Dus Testing ◽  
Bacterial Spot Resistance ◽  
Test Requirements ◽  
L1 And L2

ABSTRACT: In all countries, members of the UPOV (Union Internationale pour la Protection des Obtentions Végétales), of which Brazil is a signatory, to protect a new plant variety is necessary to carry out DUS (Distinctness, Uniformity and Stability) tests. DUS testing forCapsicum spp. is based on 48 descriptors, which involve qualitative and quantitative traits, observed from germination to fruit harvest. This paper describes the performance of DUS tests on lines of chili peppers, which are candidates for protection; we discuss the main aspects related to operational difficulties, the relevance of some descriptors for the protection process and highlight the importance of protecting new plant varieties as national intellectual property. Four C. annuum var.annuum recombinant inbred lines were tested. The Capsicum Breeding Program of the Universidade Estadual do Norte Fluminense Darcy Ribeiro developed the lines, which are resistant to bacterial spot. They were tested under greenhouse conditions from June to November 2013; and from January to July 2014 in Campos dos Goytacazes, Rio de Janeiro State, Brazil. The 'Jalapeño M' commercial genotype was used as control and treatments were arranged in a randomized block design with seven plants per plot with five replications. Besides the 48 descriptors, stipulated by legislation for Capsicum DUS testing, we included a descriptor for bacterial spot resistance. The descriptors that enabled distinction varied with each line. Although being distinctive for some descriptors, L1 and L2 lines were neither homogeneous nor stable. L6 and L8 recombined lines were characterized by homogeneity and stability. Fruit shape, capsaicin presence, number of days for flowering and bacterial spot resistance were descriptors that allowed for differentiation between treatments. In conclusion, the L6 and L8 recombined lines met the DUS test requirements; therefore, they may be subjected to the protection process with the Brazilian Ministry of Agriculture, Livestock and Food Supply.

Control of Wild Oats in Oats by Barban Plus Antidote

Weed Science ◽  
1974 ◽  
Vol 22 (6) ◽  
pp. 546-548 ◽  
Author(s):  
F. Y. Chang ◽  
G. R. Stephenson ◽  
G. W. Anderson ◽  
J. D. Bandeen
Keyword(s):  
Avena Sativa ◽  
Seed Weight ◽  
Seed Treatment ◽  
Field Studies ◽  
Cereal Crops ◽  
Complete Protection ◽  
Naphthalic Anhydride ◽  
Wild Oats ◽  
Growth Room ◽  
Oat Seeds

Growth room and field studies indicated that coating the seeds of oats (Avena sativaL.) with NA (1,8-naphthalic anhydride) at rates of 0.5 to 1% by seed weight significantly reduced the phytotoxicity of barban (4-chloro-2-butynylm-chlorocarbanilate) applied to the foliage at rates up to 1.2 kg/ha. Complete protection was obtained when barban was applied at 0.4 kg/ha, the highest rate recommended for the control of wild oats (Avena fatuaL.) in cereal crops. Treatment of oat seeds with this antidote did not reduce the herbicidal effect of barban on wild oats grown in the same soil. Thus, coating oat seeds with the antidote may allow the use of barban for the selective control of wild oats in oat crops. NA seed treatment also slightly reduced oat injury from diallate [S-(2,3-dichloroallyl)diisopropylthiocarbamate] and triallate [S-(2,3,3-trichloroallyl)diisopropylthiocarbamate].

scholarly journals Factors Affecting Survival of Bacteriophage on Tomato Leaf Surfaces

2007 ◽  
Vol 73 (6) ◽  
pp. 1704-1711 ◽  
Author(s):  
F. B. Iriarte ◽  
B. Balogh ◽  
M. T. Momol ◽  
L. M. Smith ◽  
M. Wilson ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Population Decline ◽  
Skim Milk ◽  
Field Studies ◽  
Early Morning ◽  
Fluorescent Light ◽  
Slight Reduction ◽  
Light Illumination ◽  
Bacterial Spot ◽  
Early Afternoon

ABSTRACT The ability of bacteriophage to persist in the phyllosphere for extended periods is limited by many factors, including sunlight irradiation, especially in the UV zone, temperature, desiccation, and exposure to copper bactericides. The effects of these factors on persistence of phage and formulated phage (phage mixed with skim milk) were evaluated. In field studies, copper caused significant phage reduction if applied on the day of phage application but not if applied 4 or 7 days in advance. Sunlight UV was evaluated for detrimental effects on phage survival on tomato foliage in the field. Phage was applied in the early morning, midmorning, early afternoon, and late evening, while UVA plus UVB irradiation and phage populations were monitored. The intensity of UV irradiation positively correlated with phage population decline. The protective formulation reduced the UV effect. In order to demonstrate direct effects of UV, phage suspensions were exposed to UV irradiation and assayed for effectiveness against bacterial spot of tomato. UV significantly reduced phage ability to control bacterial spot. Ambient temperature had a pronounced effect on nonformulated phage but not on formulated phages. The effects of desiccation and fluorescent light illumination on phage were investigated. Desiccation caused a significant but only slight reduction in phage populations after 60 days, whereas fluorescent light eliminated phages within 2 weeks. The protective formulation eliminated the reduction caused by both of these factors. Phage persistence was dramatically affected by UV, while the other factors had less pronounced effects. Formulated phage reduced deleterious effects of the studied environmental factors.

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.

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