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Sample records for fire blight pseudomonas

  1. FIRE BLIGHT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire blight, caused by the bacterium Erwinia amylovora, is a destructive disease of apple, pears and woody ornamentals of the rose family. The disease is indigenous to North America and has been studied for more than one century. E. amylovora can infect blossoms, stems, immature fruits, woody branch...

  2. Antagonistic potential of Pseudomonas graminis 49M against Erwinia amylovora, the causal agent of fire blight.

    PubMed

    Mikiciński, Artur; Sobiczewski, Piotr; Puławska, Joanna; Malusa, Eligio

    2016-08-01

    In a previous study (Mikiciński et al. in Eur J Plant Pathol, doi: 10.1007/s10658-015-0837-y , 2015), we described the characterization of novel strain 49M of Pseudomonas graminis, isolated from the phyllosphere of apple trees in Poland showing a good protective activity against fire blight on different organs of host plants. We now report investigations to clarify the basis for this activity. Strain 49M was found to produce siderophores on a medium containing complex CAS-Fe(3+) and HDTMA, but was not able to produce N-acyl homoserine lactones (AHLs). Moreover, it formed a biofilm on polystyrene and polyvinyl chloride (PVC) surfaces. Strain 49M gave a positive reaction in PCR with primers complementary to gacA, the regulatory gene influencing the production of several secondary metabolites including antibiotics. The genes prnD (encoding pyrrolnitrin), pltC, pltB (pyoluteorin), phlD (2,4-diacetyl-phloroglucinol) and phzC as well as phzD (and their homologs phzF and phzA encoding phenazine), described for antagonistic fluorescent pseudomonads, however, were not detected. Research into the biotic relationship between strain 49M and Erwinia amylovora strain Ea659 on five microbiological media showed that this strain clearly inhibited the growth of the pathogen on King's B and nutrient agar with glycerol media, to a very small extent on nutrient agar with sucrose, and not at all on Luria-Bertani agar. On medium 925, strain 49M even stimulated E. amylovora growth. The addition of ferric chloride to King's B resulted in the loss of its inhibitory ability. Testing the survival of 49M in vitro showed its resistance to drought, greater than that of E. amylovora. PMID:27002332

  3. Control of fire blight by Pseudomonas fluorescens A506 and Pantoea vagans C9-1 applied as single strains and mixed inocula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The biological control agents Pseudomonas fluorescens A506 and Pantoea vagans C9-1 were evaluated individually and in combination for the suppression of fire blight of pear or apple in ten field trials inoculated with the pathogen Erwinia amylovora. The formulation of pathogen inoculum applied to b...

  4. Pseudomonas blight discovered on raspberry in Watsonville

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the winter (February) of 2013, a field of raspberries in Watsonville was discovered to be infected with Pseudomonas syringae, the causal agent of Pseudomonas blight disease. This was the first documentation of this disease on raspberry in our region. The infection of raspberry plants is manifeste...

  5. Integrated Control of Fire Blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Northwest United States, the antibiotic streptomycin provided excellent control of fire blight until resistant isolates of the pathogen arose. Oxytetracycline (Mycoshield) is now sprayed as an alternative antibiotic, but it is considerably less effective than streptomycin when the latter was...

  6. Biotechnological approaches to enhance fire blight resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire blight, caused by the bacterium Erwinia amylovora, is the most serious disease of apples, pears, and quince, most major fruit and rootstock cultivars being susceptible. Modern plant biotechnologies provide methods of enhancing the resistance to fire blight in apples and pears of existing scion...

  7. Fire Blight Resistance of Budagovsky 9 Apple Rootstock

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Erwinia amylovora the causal agent of fire blight can result in a fatal infection of the apple rootstock known as rootstock blight. Budagovsky 9 (B.9) apple rootstock is reported to be highly susceptible to rootstock blight, although multiple field trials report B.9 to be resistant to rootstock bli...

  8. Functional genomic response of apple to fire blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of this project is to use a functional genomic analysis to characterize the response of apple (Malus x domestica) to fire blight disease and in doing so, identify new opportunities for improving fire blight resistance. cDNA suppression subtractive hybridization and cDNA-AFLP analysis were ...

  9. [Erwinia amylovora--the fire blight pathogen of trees in Ukraine].

    PubMed

    Iakovleva, L M; Moroz, S N; Shcherbina, T N; Ogorodnik, L E; Gvozdiak, R I; Patyka, V F

    2014-01-01

    Niduses of fire blight of fruit and ornamental trees have been found in the Kyiv and Vinnitsa regions of Ukraine. Pathogen Erwinia amylovora was isolated between April and October. The pathogen was often accompanied by bacteria Pseudomonas syringae pv. syringae. Artificial infection with a mixture of bacteria E. amylovora and P. syringae pv. syringae accelerates and enhances the disease process in the laboratory. PMID:25199342

  10. Pseudomonas blight caused by Pseudomonas syringae on raspberry in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plantings of red raspberry (Rubus idaeus var. strigosus) exhibited symptoms of a previously undocumented disease. Lesions were observable from both adaxial and abaxial leaf surfaces. As disease progressed, lesions enlarged and coalesced, resulting in significant dark brown to black blighting of the ...

  11. Cougarblight EZ, a substantial update of the Cougarblight fire blight infection risk model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of practical, but reasonably accurate fire blight infection risk models is considered a critical factor in the management of fire blight. Cougarblight, an empirically designed fire blight infection risk assessment model, was originally developed prior to significant recent advances ...

  12. Fire blight: applied genomic insights of the pathogen and host

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The enterobacterial phytopathogen, Erwinia amylovora, causes fire blight, an invasive disease that threatens a wide range of commercial and ornamental Rosaceae host plants. The response elicited by E. amylovora in its host during disease development is similar to the hypersensitive reaction that ty...

  13. Field Susceptibility of Quince Hybrids to Fire Blight in Bulgaria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spread of fire blight in Bulgaria during the last 20 years has nearly eliminated commercial production of pear and quince. Damage has increased in both nurseries and orchards, yet susceptible cultivars continue to be planted. Quince is the host most frequently attacked by Erwinia amylovora in Bulgar...

  14. Budagovsky 9 rootstock: uncovering a novel resistance to fire blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Budagovsky 9 (B.9) apple rootstock, displayed a high level of susceptibility (similar to M.9 rootstock) to fire blight bacteria (Erwinia amylovora) when leaves of non-grafted B.9 plants were inoculated. However, when older B.9 rootstock tissue was inoculated directly with E. amylovora, rootstock tis...

  15. Transcriptional response in apple to fire blight disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire blight, caused by the bacterium Erwinia amylovora, is a destructive disease of apple, pear, and other plants in the subfamily Maloideae of the Rosaceae. The goal of this study was to use a global analysis of gene expression to characterize the temporal response of apple to infection by E. amyl...

  16. Flower biology and biologically-based integrated fire blight management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire blight infection is generally initiated in flowers, and thus, research has been directed to the biology and microbial ecology of flowers as related to this disease. In addition to investigations involving apple and pear flowers, Manchurian crab apple (Malus manchurica), closely related to appl...

  17. 'Sunrise': A new early maturing fire blight resistant pear cultivar

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'Sunrise' is a new pear (Pyrus communis L.) cultivar released by the U.S. Department of Agriculture, Agricultural Research Service. It combines a high degree of resistance to fire blight with excellent fruit quality. The sources of resistance in the pedigree are the old American cultivar, 'Seckel'...

  18. Quince (Cydonia oblonga) emerges from the ashes of fire blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The two-decade history of fire blight in Bulgaria revealed quince as one of the most frequently attacked hosts and its production on a large scale has almost been entirely eliminated. Nevertheless, this species will play an important epidemiological role as a permanent source of inoculum for other p...

  19. Integrated Control of Fire Blight with Bacterial Antagonists and Oxytetracycline

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Pacific Northwest of the United States, the antibiotic streptomycin provided excellent control of fire blight until resistant isolates of Erwinia amylovora were prevalent. Oxytetracycline (Mycoshield) is now sprayed as an alternative antibiotic. We found that the duration of inhibitory acti...

  20. Integrated Control of Fire Blight with Antagonists and Oxytetracycline

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Northwest United States, the antibiotic streptomycin provided excellent control of fire blight until resistant isolates of the pathogen arose. Oxytetracycline (Mycoshield) is now sprayed as an alternative antibiotic. We found that the durability of inhibitory activity of oxytetracycline is ...

  1. Integrated Control of Fire Blight with Antagonists and Oxytetracycline

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Pacific Northwest of the United States, the antibiotic streptomycin provided excellent control of fire blight until resistant isolates of Erwinia amylovora arose. Oxytetracycline (Mycoshield) is now sprayed as an alternative antibiotic. We found that the duration of inhibitory activity of o...

  2. Chemical and Cultural Approaches to Enhance Host Resistance to Fire Blight: Growth Regulators

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire blight caused by the bacterium Erwinia amylovora [(Burrill) Winslow et al.] is one of the most destructive diseases in apple. Infection is initiated in the spring on flowers and with a second stage in late spring and summer termed shoot blight. Vigorous succulent growth favors fire blight inf...

  3. Bacteriocin Serratine-P as a biological tool in the control of fire blight Erwinia amylovora.

    PubMed

    Schoofs, H; Vandebroek, K; Pierrard, A; Thonart, P; Lepoivre, P; Beaudry, T; Deckers, T

    2002-01-01

    Fire blight, caused by the bacterium Erwinia amylovora (Burill Winslow et al.), is the most important bacterial disease in European pear growing. It can cause a lot of damage in some countries on apple and on pear trees in orchards and also in the fruit tree nurseries. In Belgium, the disease is present since 1972. Control of fire blight in Belgian fruit orchards is made on a broad basis of measurements in and around the fruit trees. The use of an antibiotic is allowed for application only during the primary blossom period under strict controlled regulations. The use of antobiotics in agriculture is strongly discussed on the European level today and will probably disappear in the near future. Therefore, the research on fire blight control concentrates on the possibilities of biological control with antagonistic bacteria such as Pantoea agglomerans (Erwinia herbicola), Bacillus subtilis or Pseudomonas syringae strain A 506. The use of Serratine-P, a phage tail-like bacteriocin, produced by Serratia plymiticum, shows an interesting antibacterial activity against Erwinia amylovora. Its mode of action consists in the perforation of the cytoplasmic membrane of the target cell, inducing perturbations in cellular exchanges and a final lysis of the bacterial cell. In this paper some trials are discussed on the use of Serratine-P at different doses and on different infection types on pear trees. The results indicate interesting protection possibilities on blossom- and fruit infections. PMID:12701444

  4. Fire blight disease reactome: RNA-seq transcriptional profile of apple host plant defense responses to Erwinia amylovora pathogen infection.

    PubMed

    Kamber, Tim; Buchmann, Jan P; Pothier, Joël F; Smits, Theo H M; Wicker, Thomas; Duffy, Brion

    2016-01-01

    The molecular basis of resistance and susceptibility of host plants to fire blight, a major disease threat to pome fruit production globally, is largely unknown. RNA-sequencing data from challenged and mock-inoculated flowers were analyzed to assess the susceptible response of apple to the fire blight pathogen Erwinia amylovora. In presence of the pathogen 1,080 transcripts were differentially expressed at 48 h post inoculation. These included putative disease resistance, stress, pathogen related, general metabolic, and phytohormone related genes. Reads, mapped to regions on the apple genome where no genes were assigned, were used to identify potential novel genes and open reading frames. To identify transcripts specifically expressed in response to E. amylovora, RT-PCRs were conducted and compared to the expression patterns of the fire blight biocontrol agent Pantoea vagans strain C9-1, another apple pathogen Pseudomonas syringae pv. papulans, and mock inoculated apple flowers. This led to the identification of a peroxidase superfamily gene that was lower expressed in response to E. amylovora suggesting a potential role in the susceptibility response. Overall, this study provides the first transcriptional profile by RNA-seq of the host plant during fire blight disease and insights into the response of susceptible apple plants to E. amylovora. PMID:26883568

  5. Fire blight disease reactome: RNA-seq transcriptional profile of apple host plant defense responses to Erwinia amylovora pathogen infection

    PubMed Central

    Kamber, Tim; Buchmann, Jan P.; Pothier, Joël F.; Smits, Theo H. M.; Wicker, Thomas; Duffy, Brion

    2016-01-01

    The molecular basis of resistance and susceptibility of host plants to fire blight, a major disease threat to pome fruit production globally, is largely unknown. RNA-sequencing data from challenged and mock-inoculated flowers were analyzed to assess the susceptible response of apple to the fire blight pathogen Erwinia amylovora. In presence of the pathogen 1,080 transcripts were differentially expressed at 48 h post inoculation. These included putative disease resistance, stress, pathogen related, general metabolic, and phytohormone related genes. Reads, mapped to regions on the apple genome where no genes were assigned, were used to identify potential novel genes and open reading frames. To identify transcripts specifically expressed in response to E. amylovora, RT-PCRs were conducted and compared to the expression patterns of the fire blight biocontrol agent Pantoea vagans strain C9-1, another apple pathogen Pseudomonas syringae pv. papulans, and mock inoculated apple flowers. This led to the identification of a peroxidase superfamily gene that was lower expressed in response to E. amylovora suggesting a potential role in the susceptibility response. Overall, this study provides the first transcriptional profile by RNA-seq of the host plant during fire blight disease and insights into the response of susceptible apple plants to E. amylovora. PMID:26883568

  6. The fire blight pathogen Erwinia amylovora requires the rpoN gene for pathogenicity in apple.

    PubMed

    Ramos, Laura S; Lehman, Brian L; Sinn, Judith P; Pfeufer, Emily E; Halbrendt, Noemi O; McNellis, Timothy W

    2013-10-01

    RpoN is a σ(54) factor regulating essential virulence gene expression in several plant pathogenic bacteria, including Pseudomonas syringae and Pectobacterium carotovorum. In this study, we found that mutation of rpoN in the fire blight pathogen Erwinia amylovora caused a nonpathogenic phenotype. The E. amylovora rpoN Tn5 transposon mutant rpoN1250::Tn5 did not cause fire blight disease symptoms on shoots of mature apple trees. In detached immature apple fruits, the rpoN1250::Tn5 mutant failed to cause fire blight disease symptoms and grew to population levels 12 orders of magnitude lower than the wild-type. In addition, the rpoN1250::Tn5 mutant failed to elicit a hypersensitive response when infiltrated into nonhost tobacco plant leaves, and rpoN1250::Tn5 cells failed to express HrpN protein when grown in hrp (hypersensitive response and pathogenicity)-inducing liquid medium. A plasmid-borne copy of the wild-type rpoN gene complemented all the rpoN1250::Tn5 mutant phenotypes tested. The rpoN1250::Tn5 mutant was prototrophic on minimal solid and liquid media, indicating that the rpoN1250::Tn5 nonpathogenic phenotype was not caused by a defect in basic metabolism or growth. This study provides clear genetic evidence that rpoN is an essential virulence gene of E. amylovora, suggesting that rpoN has the same function in E. amylovora as in P. syringae and Pe. carotovorum. PMID:23721085

  7. Candidate fire blight resistance genes in Malus identified with the use of genomic tools and approaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of this research is to utilize current advances in Rosaceae genomics to identify DNA markers for use in marker-assisted selection of durable resistance to fire blight. Candidate fire blight resistance genes were selected and ranked based upon differential expression after inoculation with ...

  8. Using functional genomics to identify molecular markers for fire blight resistance (Erwinia amylovora) in apple (Malus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire blight, caused by Erwinia amylovora (Ea), is a destructive disease of apple (Malus), pear (Pyrus) and some woody ornamentals in the rose family (Rosaceae). The goal of this project is to use a functional genomics approach to develop tools to breed fire blight resistant apples. Six hundred fifty...

  9. Functional genomic analysis of apple (Malus) EST's associated with fire blight (Erwinia amylovora)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of this project is to use a functional genomic analysis to characterize the response of apple to fire blight disease and thereby, identify new opportunities for improving fire blight resistance. Expressed sequence tags (ESTs) are derived from the mRNA isolated from a tissue and provide a c...

  10. Rootstock-regulated gene expression patterns associated with fire blight resistance in apple

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Desirable apple varieties are clonally propagated by grafting vegetative scions onto rootstocks. Rootstocks influence many phenotypic traits of the scion, including resistance to pathogens such as Erwinia amylovora, which causes fire blight, the most serious bacterial disease of apple....

  11. Antibiosis Contributes to Biological Control of Fire Blight by Pantoea agglomerans Strain Eh252 in Orchards.

    PubMed

    Stockwell, V O; Johnson, K B; Sugar, D; Loper, J E

    2002-11-01

    ABSTRACT Fire blight, caused by Erwinia amylovora, is the most serious bacterial disease of pear and apple trees. Biological control with strains of Pantoea agglomerans (syn. Erwinia herbicola) may provide an effective disease management strategy for fire blight. Most strains of P. agglomerans evaluated for suppression of fire blight produce compounds that inhibit the growth of E. amylovora in culture. The role of these inhibitory compounds in fire blight suppression in orchard environments has not been studied. In seven field trials in Oregon, we compared the population dynamics and disease suppression with P. agglomerans Eh252, a strain that produces a single antibiotic, with its near-isogenic antibiotic-deficient derivative, strain 10:12. Water or suspensions of Eh252 or 10:12 (1 x 10(8) CFU/ml) were applied at 30 and 70% bloom to pear or apple trees. Aqueous suspensions of freeze-dried cells of E. amylovora (3 x 10(5) CFU/ml) were applied at full bloom. Additional trees were treated with streptomycin or oxytetracycline at 30 and 70% bloom and in some experiments, 1 day after application of the pathogen. Population sizes of Eh252 or 10:12 on pear blossoms were estimated by spreading dilutions of blossom washes on culture media. Average population sizes of Eh252 and 10:12 on blossoms ranged from 10(5) to 10(7) CFU, and in five of six trials, the relative area under the population curve of Eh252 was not significantly different than that of its derivative 10:12. Both Eh252 and 10:12 reduced the growth of the pathogen on blossoms compared with inoculated water-treated controls. Eh252 significantly decreased the incidence of fire blight in six of seven field trials compared with the incidence on water-treated trees, and 10:12 similarly reduced the incidence of fire blight in four of seven trials. In three of seven field trials, trees treated with Eh252 had a significantly lower incidence of fire blight compared with trees treated 3 with 10:12. Overall,3 Eh252 reduced

  12. Enhanced Biological Control of Phytophthora Blight of Pepper by Biosurfactant-Producing Pseudomonas

    PubMed Central

    Özyilmaz, Ümit; Benlioglu, Kemal

    2013-01-01

    Pseudomonas isolates from different crop plants were screened for in vitro growth inhibition of Phytophthora capsici and production of biosurfactant. Two in vivo experiments were performed to determine the efficacy of selected Pseudomonas strains against Phytophthora blight of pepper by comparing two fungicide treatments [acibenzolar-S-methyl (ASM) and ASM + mefenoxam]. Bacterial isolates were applied by soil drenching (1 × 109 cells/ml), ASM (0.1 μg a.i./ml) and ASM + mefenoxam (0.2 mg product/ml) were applied by foliar spraying, and P. capsici inoculum was incorporated into the pot soil three days after treatments. In the first experiment, four Pseudomonas strains resulted in significant reduction from 48.4 to 61.3% in Phytophthora blight severity. In the second experiment, bacterial treatments combining with olive oil (5 mL per plant) significantly enhanced biological control activity, resulting in a reduction of disease level ranging from 56.8 to 81.1%. ASM + mefenoxam was the most effective treatment while ASM alone was less effective in both bioassays. These results indicate that our Pseudomonas fluorescens strains (6L10, 6ba6 and 3ss9) that have biosurfactant-producing abilities are effective against P. capsici on pepper, and enhanced disease suppression could be achieved when they were used in combination with olive oil. PMID:25288970

  13. Enhanced biological control of phytophthora blight of pepper by biosurfactant-producing pseudomonas.

    PubMed

    Ozyilmaz, Umit; Benlioglu, Kemal

    2013-12-01

    Pseudomonas isolates from different crop plants were screened for in vitro growth inhibition of Phytophthora capsici and production of biosurfactant. Two in vivo experiments were performed to determine the efficacy of selected Pseudomonas strains against Phytophthora blight of pepper by comparing two fungicide treatments [acibenzolar-S-methyl (ASM) and ASM + mefenoxam]. Bacterial isolates were applied by soil drenching (1 × 10(9) cells/ml), ASM (0.1 μg a.i./ml) and ASM + mefenoxam (0.2 mg product/ml) were applied by foliar spraying, and P. capsici inoculum was incorporated into the pot soil three days after treatments. In the first experiment, four Pseudomonas strains resulted in significant reduction from 48.4 to 61.3% in Phytophthora blight severity. In the second experiment, bacterial treatments combining with olive oil (5 mL per plant) significantly enhanced biological control activity, resulting in a reduction of disease level ranging from 56.8 to 81.1%. ASM + mefenoxam was the most effective treatment while ASM alone was less effective in both bioassays. These results indicate that our Pseudomonas fluorescens strains (6L10, 6ba6 and 3ss9) that have biosurfactant-producing abilities are effective against P. capsici on pepper, and enhanced disease suppression could be achieved when they were used in combination with olive oil. PMID:25288970

  14. Erwinia amylovora pyrC mutant causes fire blight despite pyrimidine auxotrophy.

    PubMed

    Ramos, L S; Sinn, J P; Lehman, B L; Pfeufer, E E; Peter, K A; McNellis, T W

    2015-06-01

    Erwinia amylovora bacteria cause fire blight disease, which affects apple and pear production worldwide. The Erw. amylovora pyrC gene encodes a predicted dihydroorotase enzyme involved in pyrimidine biosynthesis. Here, we discovered that the Erw. amylovora pyrC244::Tn5 mutant was a uracil auxotroph. Unexpectedly, the Erw. amylovora pyrC244::Tn5 mutant grew as well as the wild-type in detached immature apple and pear fruits. Fire blight symptoms caused by the pyrC244::Tn5 mutant in immature apple and pear fruits were attenuated compared to those caused by the wild-type. The pyrC244::Tn5 mutant also caused severe fire blight symptoms in apple tree shoots. A plasmid-borne copy of the wild-type pyrC gene restored prototrophy and symptom induction in apple and pear fruit to the pyrC244::Tn5 mutant. These results suggest that Erw. amylovora can obtain sufficient pyrimidine from the host to support bacterial growth and fire blight disease development, although de novo pyrimidine synthesis by Erw. amylovora is required for full symptom development in fruits. Significance and impact of the study: This study provides information about the fire blight host-pathogen interaction. Although the Erwinia amylovora pyrC mutant was strictly auxotrophic for pyrimidine, it grew as well as the wild-type in immature pear and apple fruits and caused severe fire blight disease in apple trees. This suggests that Erw. amylovora can obtain sufficient pyrimidines from host tissue to support growth and fire blight disease development. This situation contrasts with findings in some human bacterial pathogens, which require de novo pyrimidine synthesis for growth in host blood, for example. PMID:25789570

  15. USING FUNCTIONAL AND APPLIED GENOMICS TO IDENTIFY GENES THAT CONFER EITHER RESISTANCE OR SUSCEPTIBILITY TO FIRE BLIGHT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire blight, caused by the bacterium Erwinia amylovora, is a destructive disease of apple, pear and other plants of the Rosaceae. The goal of this project is to use functional genomics to characterize the response of apple to fire blight disease and, thereby, identify new opportunities for improvin...

  16. Putative resistance gene markers associated with quantitative trait loci for fire blight resistance in Malus 'Robusta 5' accessions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Breeding of fire blight resistant scions and rootstocks is a goal of several international apple breeding programs, as options are limited for management of this destructive disease caused by the bacterial pathogen Erwinia amylovora. A broad, large effect QTL for fire blight resistance has been pre...

  17. Complete Genome Sequence of Pseudomonas fluorescens LBUM636, a Strain with Biocontrol Capabilities against Late Blight of Potato.

    PubMed

    Morrison, Christopher K; Novinscak, Amy; Gadkar, Vijay J; Joly, David L; Filion, Martin

    2016-01-01

    Herein provided is the full-genome sequence of Pseudomonas fluorescens LBUM636. This strain is a plant growth-promoting rhizobacterium (PGPR) which produces phenazine-1-carboxylic acid, an antibiotic involved in the biocontrol of numerous plant pathogens, including late blight of potato caused by the plant pathogen Phytophthora infestans. PMID:27231373

  18. FIRST REPORT OF BACTERIAL BLIGHT OF CAULIFLOWER (BRASSICA OLERACEA VAR. BOTRYTIS) CAUSED BY PSEUDOMONAS SYRINGAE PV. ALISALENSIS IN CALIFORNIA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel bacterial blight commercial romanesca (green) cauliflower (Brassica oleracea var. botrytis) was seen for the first time in coastal California in 2005. Koch’s postulates were completed and the etiology of the pathogen was determined. Characterization showed that pathogen was Pseudomonas syrin...

  19. Complete Genome Sequence of Pseudomonas fluorescens LBUM636, a Strain with Biocontrol Capabilities against Late Blight of Potato

    PubMed Central

    Morrison, Christopher K.; Novinscak, Amy; Gadkar, Vijay J.; Joly, David L.

    2016-01-01

    Herein provided is the full-genome sequence of Pseudomonas fluorescens LBUM636. This strain is a plant growth-promoting rhizobacterium (PGPR) which produces phenazine-1-carboxylic acid, an antibiotic involved in the biocontrol of numerous plant pathogens, including late blight of potato caused by the plant pathogen Phytophthora infestans. PMID:27231373

  20. FIRST REPORT OF BACTERIAL BLIGHT OF RUTABAGA (BRASSICA NAPUS VAR. NAPOBRASSICA) CAUSED BY PSEUDOMONAS SYRINGAE PV. ALISALENSIS IN CALIFORNIA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel bacterial blight on commercial organically grown rutabaga (Brassica napus var. napobrassica) was seen for the first time in coastal California in 2005. Koch’s postulates were completed and the etiology of the pathogen was elucidated. Characterization showed that pathogen was Pseudomonas syri...

  1. Biosynthesis of the antimetabolite 6-thioguanine in Erwinia amylovora plays a key role in fire blight pathogenesis.

    PubMed

    Coyne, Sébastien; Chizzali, Cornelia; Khalil, Mohammed N A; Litomska, Agnieszka; Richter, Klaus; Beerhues, Ludger; Hertweck, Christian

    2013-09-27

    Sulfur for fire: The molecular basis for the biosynthesis of the antimetabolite 6-thioguanine (6TG) was unveiled in Erwinia amylovora, the causative agent of fire blight. Bioinformatics, heterologous pathway reconstitution in E. coli, and mutational analyses indicate that the protein YcfA mediates guanine thionation in analogy to 2-thiouridylase. Assays in planta and in cell cultures reveal for the first time a crucial role of 6TG in fire blight pathogenesis. PMID:24038828

  2. Relative Susceptibility of Quince, Pear, and Apple Cultivars to Fire Blight Following Greenhouse Inoculation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire blight caused by Erwinia amylovora (EA) is one of the most serious diseases of plants in the family Rosaceae, and Quince (Cydonia oblonga Mill.) is considered one of the most susceptible host genera. Apple (Malus sp.) and pear (Pyrus sp.) cultivars ranging from most susceptible to most resistan...

  3. Field Evaluation of Apple Rootstocks for Orchard Performance and Fire Blight Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2002, apple rootstock trials using three scion cultivars were established at Geneva, NY to evaluate 64 apple (Malus X domestica) rootstocks for horticultural performance and fire blight resistance. Field trials compared several elite Geneva® apple rootstocks, which were bred for tolerance to fir...

  4. Fire blight incidence on Malus sieversii grown in New York and Minnesota

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Malus sieversii, a wild apple species native to Central Asia, has been recognized as the major progenitor of the domestic apple. This investigation summarizes the natural infection by Erwinia amylovora (fire blight) on 2590 M. sieversii seedlings grown as own-rooted trees. At a USDA orchard in Gen...

  5. Controlled release of Pantoea agglomerans E325 for biocontrol of fire blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microencapsulation and controlled release of Pantoea agglomerans strain E325 (E325), which is an antagonist to bacterial pathogen (Erwinia amylovora) of fire blight, a devastating disease of apple and pear, have been investigated. Uniform core-shell alginate microcapsules (AMCs), 60-300 µm in diamet...

  6. Fire Blight Incidence on Malus sieversii Grown in New York and Minnesota

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Malus sieversii (Lebed.), a wild apple species native to Central Asia, has been recognized as the major progenitor of the domestic apple. This investigation summarizes the natural infection by Erwinia amylovora (fire blight) on 2590 M. sieversii seedlings grown as own-rooted trees. At a USDA orch...

  7. Performance of US 71655-014, a fire blight resistant pear selection from the USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    US 71655-014 is a fire blight resistant pear selection developed at the USDA Appalachian Fruit Research Station in Kearneysville, West Virginia. In an earlier, un-replicated trail in Oregon, it was determined that US 71655-014 had several positive attributes including precocity, annual production, ...

  8. Using functional genomics to develop tools to breed fire blight resistant apples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire blight, caused by the bacterium Erwinia amylovora, is a destructive disease of apple (Malus), pear (Pyrus) and other plants in the rose family (Rosaceae). Suppression subtractive hybridization (SSH) using cDNA from pathogen and mock-inoculated samples, and cDNA-AFLP analysis were used to ident...

  9. Computational Identification of Candidate Genes Involved in Response to Fire Blight in Apples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire blight (Erwinia amylovora) is a destructive bacterial disease affecting plants in the Rosaceae including apple, pear, and quince. The disease is common in North America, and kills blossoms, shoots, limbs, and, sometimes, entire trees. Bioinformatics tools were used in collaboration with a NRI-f...

  10. Pantoea applied genomics to understand and improve biocontrol activity against fire blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pantoea agglomerans and P. vagans (ex. Erwinia herbicola) are common epiphytes of pome fruit flowers and three strains (E325, P10c, C9-1) have been commercially developed as effective biocontrol products for managing fire blight (Erwinia amylovora). Antibiotics as a standard, reliable chemical optio...

  11. Performance of US 71655-014, a fire blight resistant pear selection from the USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    US 71655-014 is a fire blight resistant pear selection developed at the USDA-ARS, Appalachian Fruit Research Station in Kearneysville, West Virginia. In an earlier, unreplicated trial in Oregon, it was determined that US 71655-014 had several positive attributes including precocity, annual producti...

  12. A new attractive, precocious, productive, fire blight resistant pear selection. What more could you ask for?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    US 71655-014 is a fire blight resistant pear scion selection developed by the USDA, Agricultural Research Service. Preliminary trials indicated several positive attributes including precocity, high annual production, attractive fruit, long storage life, and good consumer acceptance. In 2005, a rep...

  13. DIFFERENTIAL SUSCEPTIBILITY TO FIRE BLIGHT IN COMMERCIAL AND EXPERIMENTAL APPLE ROOTSTOCK CULTIVARS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Geneva rootstock breeding program has developed several new rootstocks that exhibit disease resistance to Erwinia amylovora. Utilization of disease resistant apple rootstocks increases the survivability of young trees infected by fire blight. The goal of this experiment was to further investigat...

  14. Medfly Ceratitis capitata as Potential Vector for Fire Blight Pathogen Erwinia amylovora: Survival and Transmission

    PubMed Central

    Ordax, Mónica; Piquer-Salcedo, Jaime E.; Santander, Ricardo D.; Sabater-Muñoz, Beatriz; Biosca, Elena G.; López, María M.; Marco-Noales, Ester

    2015-01-01

    Monitoring the ability of bacterial plant pathogens to survive in insects is required for elucidating unknown aspects of their epidemiology and for designing appropriate control strategies. Erwinia amylovora is a plant pathogenic bacterium that causes fire blight, a devastating disease in apple and pear commercial orchards. Studies on fire blight spread by insects have mainly focused on pollinating agents, such as honeybees. However, the Mediterranean fruit fly (medfly) Ceratitis capitata (Diptera: Tephritidae), one of the most damaging fruit pests worldwide, is also common in pome fruit orchards. The main objective of the study was to investigate whether E. amylovora can survive and be transmitted by the medfly. Our experimental results show: i) E. amylovora can survive for at least 8 days inside the digestive tract of the medfly and until 28 days on its external surface, and ii) medflies are able to transmit the bacteria from inoculated apples to both detached shoots and pear plants, being the pathogen recovered from lesions in both cases. This is the first report on E. amylovora internalization and survival in/on C. capitata, as well as the experimental transmission of the fire blight pathogen by this insect. Our results suggest that medfly can act as a potential vector for E. amylovora, and expand our knowledge on the possible role of these and other insects in its life cycle. PMID:25978369

  15. Medfly Ceratitis capitata as Potential Vector for Fire Blight Pathogen Erwinia amylovora: Survival and Transmission.

    PubMed

    Ordax, Mónica; Piquer-Salcedo, Jaime E; Santander, Ricardo D; Sabater-Muñoz, Beatriz; Biosca, Elena G; López, María M; Marco-Noales, Ester

    2015-01-01

    Monitoring the ability of bacterial plant pathogens to survive in insects is required for elucidating unknown aspects of their epidemiology and for designing appropriate control strategies. Erwinia amylovora is a plant pathogenic bacterium that causes fire blight, a devastating disease in apple and pear commercial orchards. Studies on fire blight spread by insects have mainly focused on pollinating agents, such as honeybees. However, the Mediterranean fruit fly (medfly) Ceratitis capitata (Diptera: Tephritidae), one of the most damaging fruit pests worldwide, is also common in pome fruit orchards. The main objective of the study was to investigate whether E. amylovora can survive and be transmitted by the medfly. Our experimental results show: i) E. amylovora can survive for at least 8 days inside the digestive tract of the medfly and until 28 days on its external surface, and ii) medflies are able to transmit the bacteria from inoculated apples to both detached shoots and pear plants, being the pathogen recovered from lesions in both cases. This is the first report on E. amylovora internalization and survival in/on C. capitata, as well as the experimental transmission of the fire blight pathogen by this insect. Our results suggest that medfly can act as a potential vector for E. amylovora, and expand our knowledge on the possible role of these and other insects in its life cycle. PMID:25978369

  16. Identification of gene-specific markers for resistance to Erwinia amylovora (fire blight) in Malus (apple) by a functional genomics approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire blight, caused by Erwinia amylovora (Ea), is a destructive disease of apple (Malus), pear (Pyrus) and other plants in the rose family (Rosaceae). 650 expressed sequence tags (ESTs) associated with fire blight were identified from Ea-challenged apple leaf tissue by suppression subtractive hybrid...

  17. Cropload management and appropriate harvest timing improves final fruit size and fruit quality of US 71655-014, a new fire blight resistant European pear selection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    US71655-014 (‘Gem’) is a fire blight resistant pear selection developed at the USDA Appalachian Fruit Research Station. Despite possessing several positive attributes (precocity, high annual production, attractive fruit appearance, fire blight resistance good storability and consumer acceptance), ‘...

  18. Development of the First Cisgenic Apple with Increased Resistance to Fire Blight.

    PubMed

    Kost, Thomas D; Gessler, Cesare; Jänsch, Melanie; Flachowsky, Henryk; Patocchi, Andrea; Broggini, Giovanni A L

    2015-01-01

    The generation and selection of novel fire blight resistant apple genotypes would greatly improve the management of this devastating disease, caused by Erwinia amylovora. Such resistant genotypes are currently developed by conventional breeding, but novel breeding technologies including cisgenesis could be an alternative approach. A cisgenic apple line C44.4.146 was regenerated using the cisgene FB_MR5 from wild apple Malus ×robusta 5 (Mr5), and the previously established method involving A. tumefaciens-mediated transformation of the fire blight susceptible cultivar 'Gala Galaxy' using the binary vector p9-Dao-FLPi. The line C44.4.146 was shown to carry only the cisgene FB_MR5, controlled by its native regulatory sequences and no transgenes were detected by PCR or Southern blot following heat induced recombinase-mediated elimination of the selectable markers. Although this line contains up to 452 bp of vector sequences, it still matches the original definition of cisgenesis. A single insertion of T-DNA into the genome of 'Gala Galaxy' in chromosome 16 was identified. Transcription of FB_MR5 in line C44.4.146 was similar to the transcription in classically bred descendants of Mr5. Three independent shoot inoculation experiments with a Mr5 avirulent strain of Erwinia amylovora were performed using scissors or syringe. Significantly lower disease symptoms were detected on shoots of the cisgenic line compared to those of untransformed 'Gala Galaxy'. Despite the fact that the pathogen can overcome this resistance by a single nucleotide mutation, this is, to our knowledge, the first prototype of a cisgenic apple with increased resistance to fire blight. PMID:26624292

  19. Development of the First Cisgenic Apple with Increased Resistance to Fire Blight

    PubMed Central

    Kost, Thomas D.; Gessler, Cesare; Jänsch, Melanie; Flachowsky, Henryk; Patocchi, Andrea; Broggini, Giovanni A. L.

    2015-01-01

    The generation and selection of novel fire blight resistant apple genotypes would greatly improve the management of this devastating disease, caused by Erwinia amylovora. Such resistant genotypes are currently developed by conventional breeding, but novel breeding technologies including cisgenesis could be an alternative approach. A cisgenic apple line C44.4.146 was regenerated using the cisgene FB_MR5 from wild apple Malus ×robusta 5 (Mr5), and the previously established method involving A. tumefaciens-mediated transformation of the fire blight susceptible cultivar ‘Gala Galaxy’ using the binary vector p9-Dao-FLPi. The line C44.4.146 was shown to carry only the cisgene FB_MR5, controlled by its native regulatory sequences and no transgenes were detected by PCR or Southern blot following heat induced recombinase-mediated elimination of the selectable markers. Although this line contains up to 452 bp of vector sequences, it still matches the original definition of cisgenesis. A single insertion of T-DNA into the genome of 'Gala Galaxy' in chromosome 16 was identified. Transcription of FB_MR5 in line C44.4.146 was similar to the transcription in classically bred descendants of Mr5. Three independent shoot inoculation experiments with a Mr5 avirulent strain of Erwinia amylovora were performed using scissors or syringe. Significantly lower disease symptoms were detected on shoots of the cisgenic line compared to those of untransformed 'Gala Galaxy'. Despite the fact that the pathogen can overcome this resistance by a single nucleotide mutation, this is, to our knowledge, the first prototype of a cisgenic apple with increased resistance to fire blight. PMID:26624292

  20. Biological Control of Pseudomonas syringae pv. syringae, the Causal Agent of Basal Kernel Blight of Barley, by Antagonistic Pantoea agglomerans.

    PubMed

    Braun-Kiewnick, A; Jacobsen, B J; Sands, D C

    2000-04-01

    ABSTRACT Strains of Pantoea agglomerans (synanamorph Erwinia herbicola) suppressed the development of basal kernel blight of barley, caused by Pseudomonas syringae pv. syringae, when applied to heads prior to the Pseudomonas syringae pv. syringae infection window at the soft dough stage of kernel development. Field experiments in 1994 and 1995 revealed 45 to 74% kernel blight disease reduction, whereas glasshouse studies resulted in 50 to 100% disease control depending on the isolate used and barley cultivar screened. The efficacy of biocontrol strains was affected by time and rate of application. Percentage of kernels infected decreased significantly when P. agglomerans was applied before pathogen inoculation, but not when coinoculated. A single P. agglomerans application 3 days prior to the pathogen inoculation was sufficient to provide control since populations of about 10(7) CFU per kernel were established consistently, while Pseudomonas syringae pv. syringae populations dropped 100-fold to 2.0 x 10(4) CFU per kernel. An application to the flag leaf at EC 49 (before heading) also reduced kernel infection percentages significantly. Basal blight decreased with increasing concentrations (10(3) to 10(7) CFU/ml) of P. agglomerans, with 10(7) CFU/ml providing the best control. For long-term preservation and marketability, the survival of bacterial antagonists in several wettable powder formulations was tested. Over all formulations tested, the survival declined between 10- to >100-fold over a period of 1.5 years (r = -0.7; P = 0.000). Although not significant, storage of most formulations at 4 degrees C was better for viability (90 to 93% survival) than was storage at 22 degrees C (73 to 79%). However, long-term preservation had no adverse effect on biocontrol efficacy. PMID:18944586

  1. Preliminary results on the ability of pentatomidae to transfer fire blight Erwinia amylovora under controlled conditions.

    PubMed

    Peusens, G; Schoofs, H; Deckers, T; Belien, T

    2013-01-01

    With their piercing-sucking mouthparts stink bugs (Heteroptera: Pentatomidae), a major pest in especially organic orchards, create wounds in fruit of pear trees. As Erwinia amylovora (Burrill, Winslow et al.), a wide spread bacterial disease affecting many rosaceous plants including pome fruit trees and hawthorn, enters through openings in flowers, leaves, shoots and fruit, feeding punctures caused by these bugs might be inoculated with Erwinia bacteria. In order to investigate the ability of the bugs Pentotoma rufipes L. and Polomena prasina L. to transmit fire blight, insects were caught in an organically managed orchard without fire blight, brought into contact with artificially inoculated immature pear fruit/slices and transferred to healthy, mechanically wounded pear fruit/slices. After an incubation period potential transmission of bacteria was examined by evaluation of symptom expression (necrosis, ooze production). To assess the presence of bacteria on the exoskeleton of the tested bugs, all bugs were forced to walk on a semiselective nutrient agar medium. In another experiment the viability of Ea on the exoskeleton was tested -after previous contact with ooze- through washing and plating of the wash water. All experiments were conducted under optimal climatological conditions and according to quarantine standards. Results demonstrated the ability of stink bugs to transfer E. amylovora to fruit and the viability of bacteria on stink bugs externally - both under lab conditions. PMID:25145257

  2. [Polyvalence of bacteriophages isolated from fruit trees, affected by bacterial fire blight].

    PubMed

    Tovkach, F I; Moroz, S N; Korol', N A; Faĭdiuk, Iu V; Kushkina, A I

    2013-01-01

    Phage populations appearing as a result of a pathogenic process caused by Erwinia amylovora have been discovered and described. They accompany bacterial fire blight development in the process of quince, pear and apple trees vegetation in Zakarpattya region of Ukraine. Phage isolates of the affected pear and quince include polyvalent virulent phages able to develop on bacterial strains associated with plants--E. amylovora. E. "horticola" and Pantoea agglomerans. E. amylovora isolated from the plant tissues affected by the fire blight and detected at the same time as phages proved to be resistant to the viral infection. It is hard to explain now this characteristic however it was noticed that resistance to phages can change drastically in case of dissociation, lysogenization and mutagenesis of erwinia in laboratory conditions. Phage population study shows that they are heterogeneous and can obviously include not only polyvalent but also specific viruses. Further studies of biology and molecular genetics of pure lines of isolated phages will help to get closer to understanding the place and role of bacteriophages in the complicated network of relations between bacterial pathogens and plants. PMID:23720968

  3. Survival of Pantoea agglomerans E325 as fire blight biocontrol agent when osmoadapted in high-saline medium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pantoea agglomerans strain E325 is available commercially as the active ingredient in a freeze-dried product (Bloomtime FDTM) of Northwest Agricultural Products (NAP) for biological control of fire blight. Osmoadaptation, which involves the combination of Pantoea agglomerans strain E325 is available...

  4. TRANSGENIC EXPRESSION OF THE ERWINIA AMYLOVORA (FIRE BLIGHT) EFFECTOR PROTEIN EOP1 SUPRESSES HOST BASAL DEFENSE MECHANISMS IN MALUS (APPLE)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Erwinia amylovora (Ea) is the causative agent of fire blight, a devastating disease of apple and pear. Like many other plant and animal bacterial pathogens Ea utilizes a type three secretion system (TTSS) to deliver effector proteins into plant host cells. Once inside the host cell, effector protei...

  5. Maryblyt v. 7.1 for Windows: An Improved Fire Blight Forecasting Program for Apples and Pears

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article describes updates found in Version 7.1 of the fire blight prediction model Maryblyt, originally developed by Paul Steiner and Gary Lightner. In addition, a brief history of the development of the Maryblyt model is given. The article ends with examples comparing the performance of Versio...

  6. AN UPDATED PEST RISK ASSESSMENT FOR SPREAD OF ERWINIA AMYLOVORA AND FIRE BLIGHT VIA COMMERCIAL APPLE FRUIT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The phytosanitary risk associated with the movement of export-quality apple fruit to countries where fire blight does not occur is reassessed based upon additional data available since 1998 and clarification or correction of previously misinterpreted data present in the literature. The low epiphyti...

  7. EFFECT OF APOGEE DOSE LEVEL ON FIRE BLIGHT SHOOT INFECTION IN YOUNG 'GALA' AND 'YORK' APPLE TREES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research was to determine if the use of a reduced Apogee dose on young trees could provide significant fire blight protection without sacrificing tree growth. Three-yr-old 'Gala' and 'York' trees were either not treated, treated with a full rate of Apogee (an application of 250...

  8. Potential of osmoadaptation for improving Pantoea agglomerans E325 as biocontrol agent for fire blight of apple and pear

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pantoea agglomerans biocontrol strain E325 is the active ingredient in a commercial product for fire blight, a destructive disease of apple and pear initiated by Erwinia amylovora in flowers. Osmoadaptation, involving the combination of saline osmotic stress and osmolyte amendment to growth media, w...

  9. Rapid transcriptional response of apple to fire blight disease revealed by cDNA suppression subtractive hybridization analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fire blight, caused by the bacterium Erwinia amylovora (Ea), is a destructive disease of many tree and shrub species of the Rosaceae. Suppression subtractive cDNA hybridization (SSH) was used to identify genes that are differentially up- and down- regulated in apple (Malus X domestica) in response ...

  10. Differential expression of biphenyl synthase gene family members in fire-blight-infected apple 'Holsteiner Cox'.

    PubMed

    Chizzali, Cornelia; Gaid, Mariam M; Belkheir, Asma K; Hänsch, Robert; Richter, Klaus; Flachowsky, Henryk; Peil, Andreas; Hanke, Magda-Viola; Liu, Benye; Beerhues, Ludger

    2012-02-01

    Fire blight, caused by the bacterium Erwinia amylovora, is a devastating disease of apple (Malus × domestica). The phytoalexins of apple are biphenyls and dibenzofurans, whose carbon skeleton is formed by biphenyl synthase (BIS), a type III polyketide synthase. In the recently published genome sequence of apple 'Golden Delicious', nine BIS genes and four BIS gene fragments were detected. The nine genes fall into four subfamilies, referred to as MdBIS1 to MdBIS4. In a phylogenetic tree, the BIS amino acid sequences from apple and Sorbus aucuparia formed an individual cluster within the clade of the functionally diverse type III polyketide synthases. cDNAs encoding MdBIS1 to MdBIS4 were cloned from fire-blight-infected shoots of apple 'Holsteiner Cox,' heterologously expressed in Escherichia coli, and functionally analyzed. Benzoyl-coenzyme A and salicoyl-coenzyme A were the preferred starter substrates. In response to inoculation with E. amylovora, the BIS3 gene was expressed in stems of cv Holsteiner Cox, with highest transcript levels in the transition zone between necrotic and healthy tissues. The transition zone was the accumulation site of biphenyl and dibenzofuran phytoalexins. Leaves contained transcripts for BIS2 but failed to form immunodetectable amounts of BIS protein. In cell cultures of apple 'Cox Orange,' expression of the BIS1 to BIS3 genes was observed after the addition of an autoclaved E. amylovora suspension. Using immunofluorescence localization under a confocal laser-scanning microscope, the BIS3 protein in the transition zone of stems was detected in the parenchyma of the bark. Dot-shaped immunofluorescence was confined to the junctions between neighboring cortical parenchyma cells. PMID:22158676

  11. Fire Blight Control: The Struggle Goes On. A Comparison of Different Fire Blight Control Methods in Switzerland with Respect to Biosafety, Efficacy and Durability.

    PubMed

    Gusberti, Michele; Klemm, Urs; Meier, Matthias S; Maurhofer, Monika; Hunger-Glaser, Isabel

    2015-09-01

    Fire blight (FB), caused by Erwinia amylovora, is one of the most important pome fruit pathogens worldwide. To control this devastating disease, various chemical and biological treatments are commonly applied in Switzerland, but they fail to keep the infection at an acceptable level in years of heavy disease pressure. The Swiss authorities therefore currently allow the controlled use of the antibiotic streptomycin against FB in years that are predicted to have heavy infection periods, but only one treatment per season is permitted. Another strategy for controlling Erwinia is to breed resistant/tolerant apple cultivars. One way of accelerating the breeding process is to obtain resistant cultivars by inserting one or several major resistance genes, using genetic engineering. To date, no study summarizing the impact of different FB control measures on the environment and on human health has been performed. This study consequently aims to compare different disease-control measures (biological control, chemical control, control by antibiotics and by resistant/tolerant apple cultivars obtained through conventional or molecular breeding) applied against E. amylovora, considering different protection goals (protection of human health, environment, agricultural diversity and economic interest), with special emphasis on biosafety aspects. Information on each FB control measure in relation to the specified protection goal was assessed by literature searches and by interviews with experts. Based on our results it can be concluded that the FB control measures currently applied in Switzerland are safe for consumers, workers and the environment. However, there are several gaps in our knowledge of the human health and environmental impacts analyzed: data are missing (1) on long term studies on the efficacy of most of the analyzed FB control measures; (2) on the safety of operators handling streptomycin; (3) on residue analyses of Equisetum plant extract, the copper and aluminum

  12. Fire Blight Control: The Struggle Goes On. A Comparison of Different Fire Blight Control Methods in Switzerland with Respect to Biosafety, Efficacy and Durability

    PubMed Central

    Gusberti, Michele; Klemm, Urs; Meier, Matthias S.; Maurhofer, Monika; Hunger-Glaser, Isabel

    2015-01-01

    Fire blight (FB), caused by Erwinia amylovora, is one of the most important pome fruit pathogens worldwide. To control this devastating disease, various chemical and biological treatments are commonly applied in Switzerland, but they fail to keep the infection at an acceptable level in years of heavy disease pressure. The Swiss authorities therefore currently allow the controlled use of the antibiotic streptomycin against FB in years that are predicted to have heavy infection periods, but only one treatment per season is permitted. Another strategy for controlling Erwinia is to breed resistant/tolerant apple cultivars. One way of accelerating the breeding process is to obtain resistant cultivars by inserting one or several major resistance genes, using genetic engineering. To date, no study summarizing the impact of different FB control measures on the environment and on human health has been performed. This study consequently aims to compare different disease-control measures (biological control, chemical control, control by antibiotics and by resistant/tolerant apple cultivars obtained through conventional or molecular breeding) applied against E. amylovora, considering different protection goals (protection of human health, environment, agricultural diversity and economic interest), with special emphasis on biosafety aspects. Information on each FB control measure in relation to the specified protection goal was assessed by literature searches and by interviews with experts. Based on our results it can be concluded that the FB control measures currently applied in Switzerland are safe for consumers, workers and the environment. However, there are several gaps in our knowledge of the human health and environmental impacts analyzed: data are missing (1) on long term studies on the efficacy of most of the analyzed FB control measures; (2) on the safety of operators handling streptomycin; (3) on residue analyses of Equisetum plant extract, the copper and aluminum

  13. Potent and specific bactericidal effect of juglone (5-hydroxy-1,4-naphthoquinone) on the fire blight pathogen Erwinia amylovora.

    PubMed

    Fischer, Thilo Christopher; Gosch, Christian; Mirbeth, Beate; Gselmann, Markus; Thallmair, Veronika; Stich, Karl

    2012-12-12

    A screening of plant quinones for inhibiting effects on the bacterial fire blight pathogen Erwinia amylovora was performed. The most active compound, juglone from walnuts, has a potent and specific bactericidal effect on E. amylovora and minimal inhibitory concentrations of only 2.5-10 μM, with stronger effects at lower, but still physiological, pH values. In vitro tests with juglone and inoculated flowers of apple (Malus domestica) showed an efficacy of 67% in preventing infection. In two years of field tests juglone had variable degrees of efficacy ranging from 40 to 82%, seemingly due to environmental conditions. A phytotoxic reaction to juglone, which is known for its allelopathic effect on plants, was restricted to browning of petals; later fruit russeting was not observed. Juglone is a promising candidate for the development of a new environmentally friendly plant protectant to replace the antibiotic streptomycin currently used in fire blight control. PMID:23163769

  14. Control of plant defense mechanisms and fire blight pathogenesis through the regulation of 6-thioguanine biosynthesis in Erwinia amylovora.

    PubMed

    Coyne, Sébastien; Litomska, Agnieszka; Chizzali, Cornelia; Khalil, Mohammed N A; Richter, Klaus; Beerhues, Ludger; Hertweck, Christian

    2014-02-10

    Fire blight is a devastating disease of Rosaceae plants, such as apple and pear trees. It is characterized by necrosis of plant tissue, caused by the phytopathogenic bacterium Erwinia amylovora. The plant pathogen produces the well-known antimetabolite 6-thioguanine (6TG), which plays a key role in fire blight pathogenesis. Here we report that YcfR, a member of the LTTR family, is a major regulator of 6TG biosynthesis in E. amylovora. Inactivation of the regulator gene (ycfR) led to dramatically decreased 6TG production. Infection assays with apple plants (Malus domestica cultivar Holsteiner Cox) and cell cultures of Sorbus aucuparia (mountain ash, rowan) revealed abortive fire blight pathogenesis and reduced plant response (biphenyl and dibenzofuran phytoalexin production). In the presence of the ΔycfR mutant, apple trees were capable of activating the abscission machinery to remove infected tissue. In addition to unveiling the regulation of 6TG biosynthesis in a major plant pathogen, we demonstrate for the first time that this antimetabolite plays a pivotal role in dysregulating the plant response to infection. PMID:24449489

  15. Using Pseudomonas spp. for Integrated Biological Control.

    PubMed

    Stockwell, Virginia O; Stack, James P

    2007-02-01

    ABSTRACT Pseudomonas spp. have been studied for decades as model organisms for biological control of plant disease. Currently, there are three commercial formulations of pseudomonads registered with the U.S. Environmental Protection Agency for plant disease suppression, Bio-Save 10 LP, Bio-Save 11 LP, and BlightBan A506. Bio-Save 10 LP and Bio-Save 11 LP, products of Jet Harvest Solutions, Longwood, FL, contain Pseudomonas syringae strains ESC-10 and ESC-11, respectively. These products are applied in packinghouses to prevent postharvest fungal diseases during storage of citrus, pome, stone fruits, and potatoes. BlightBan A506, produced by NuFarm Americas, Burr Ridge, IL, contains P. fluorescens strain A506. BlightBan A506 is applied primarily to pear and apple trees during bloom to suppress the bacterial disease fire blight. Combining BlightBan A506 with the antibiotic streptomycin improves control of fire blight, even in areas with streptomycin-resistant populations of the pathogen. BlightBan A506 also may reduce fruit russet and mild frost injury. These biocontrol products consisting of Pseudomonas spp. provide moderate to excellent efficacy against multiple production constraints, are relatively easy to apply, and they can be integrated with conventional products for disease control. These characteristics will contribute to the adoption of these products by growers and packinghouses. PMID:18944382

  16. Characterization of Novel Bacteriophages for Biocontrol of Bacterial Blight in Leek Caused by Pseudomonas syringae pv. porri.

    PubMed

    Rombouts, Sofie; Volckaert, Anneleen; Venneman, Sofie; Declercq, Bart; Vandenheuvel, Dieter; Allonsius, Camille N; Van Malderghem, Cinzia; Jang, Ho B; Briers, Yves; Noben, Jean P; Klumpp, Jochen; Van Vaerenbergh, Johan; Maes, Martine; Lavigne, Rob

    2016-01-01

    Pseudomonas syringae pv. porri, the causative agent of bacterial blight in leek (Allium porrum), is increasingly frequent causing problems in leek cultivation. Because of the current lack of control measures, novel bacteriophages were isolated to control this pathogen using phage therapy. Five novel phages were isolated from infected fields in Flanders (vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, vB_PsyM_KIL4, and vB_PsyM_KIL5), and were complemented with one selected host range mutant phage (vB_PsyM_KIL3b). Genome analysis of the phages revealed genome sizes between 90 and 94 kb and an average GC-content of 44.8%. Phylogenomic networking classified them into a novel clade, named the "KIL-like viruses," related to the Felixounalikevirus genus, together with phage phiPsa374 from P. syringae pv. actinidiae. In vitro characterization demonstrated the stability and lytic potential of these phages. Host range analysis confirmed heterogeneity within P. syringae pv. porri, leading to the development of a phage cocktail with a range that covers the entire set of 41 strains tested. Specific bio-assays demonstrated the in planta efficacy of phages vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, and vB_PsyM_KIL3b. In addition, two parallel field trial experiments on three locations using a phage cocktail of the six phages showed variable results. In one trial, symptom development was attenuated. These data suggest some potential for phage therapy in controlling bacterial blight of leek, pending optimization of formulation and application methods. PMID:27014204

  17. Characterization of Novel Bacteriophages for Biocontrol of Bacterial Blight in Leek Caused by Pseudomonas syringae pv. porri

    PubMed Central

    Rombouts, Sofie; Volckaert, Anneleen; Venneman, Sofie; Declercq, Bart; Vandenheuvel, Dieter; Allonsius, Camille N.; Van Malderghem, Cinzia; Jang, Ho B.; Briers, Yves; Noben, Jean P.; Klumpp, Jochen; Van Vaerenbergh, Johan; Maes, Martine; Lavigne, Rob

    2016-01-01

    Pseudomonas syringae pv. porri, the causative agent of bacterial blight in leek (Allium porrum), is increasingly frequent causing problems in leek cultivation. Because of the current lack of control measures, novel bacteriophages were isolated to control this pathogen using phage therapy. Five novel phages were isolated from infected fields in Flanders (vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, vB_PsyM_KIL4, and vB_PsyM_KIL5), and were complemented with one selected host range mutant phage (vB_PsyM_KIL3b). Genome analysis of the phages revealed genome sizes between 90 and 94 kb and an average GC-content of 44.8%. Phylogenomic networking classified them into a novel clade, named the “KIL-like viruses,” related to the Felixounalikevirus genus, together with phage phiPsa374 from P. syringae pv. actinidiae. In vitro characterization demonstrated the stability and lytic potential of these phages. Host range analysis confirmed heterogeneity within P. syringae pv. porri, leading to the development of a phage cocktail with a range that covers the entire set of 41 strains tested. Specific bio-assays demonstrated the in planta efficacy of phages vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, and vB_PsyM_KIL3b. In addition, two parallel field trial experiments on three locations using a phage cocktail of the six phages showed variable results. In one trial, symptom development was attenuated. These data suggest some potential for phage therapy in controlling bacterial blight of leek, pending optimization of formulation and application methods. PMID:27014204

  18. Controlled release of Pantoea agglomerans E325 for biocontrol of fire blight disease of apple.

    PubMed

    Kim, In-Yong; Pusey, Paul Lawrence; Zhao, Youfu; Korban, Schuyler S; Choi, Hyungsoo; Kim, Kyekyoon Kevin

    2012-07-10

    Microencapsulation and controlled release of the biocontrol agent Pantoea agglomerans strain E325 (E325), an antagonist to the bacterial plant pathogen Erwinia amylovora that causes fire blight, a devastating disease of apple and pear, have been investigated. Uniform core-shell alginate microcapsules (AMCs), 60-300 μm in diameter, were fabricated to encapsulate E325 within the core, along with nutrients, to preserve viability and promote proliferation. Controlled release of E325 was achieved by separately adjusting alginate concentrations in the shell and core solutions, and by modifying the AMC size. Viability of E325 was monitored via fluorescent staining, revealing either lack of or minimal stress during or after encapsulation. Proliferation of E325 within AMCs, followed by their subsequent release, and colonization activities within confines of apple flowers were studied under different encapsulation conditions using rfp-labeled E325 to obtain highly promising results. This study provided a 'proof of concept' of the successful use of a microencapsulated biocontrol agent, E325, against E. amylovora, and could serve as a model for further studies on the development of effective plant disease management strategies. PMID:22516094

  19. Control of fire blight (Erwinia amylovora) on apple trees with trunk-injected plant resistance inducers and antibiotics and assessment of induction of pathogenesis-related protein genes.

    PubMed

    Aćimović, Srđan G; Zeng, Quan; McGhee, Gayle C; Sundin, George W; Wise, John C

    2015-01-01

    Management of fire blight is complicated by limitations on use of antibiotics in agriculture, antibiotic resistance development, and limited efficacy of alternative control agents. Even though successful in control, preventive antibiotic sprays also affect non-target bacteria, aiding the selection for resistance which could ultimately be transferred to the pathogen Erwinia amylovora. Trunk injection is a target-precise pesticide delivery method that utilizes tree xylem to distribute injected compounds. Trunk injection could decrease antibiotic usage in the open environment and increase the effectiveness of compounds in fire blight control. In field experiments, after 1-2 apple tree injections of either streptomycin, potassium phosphites (PH), or acibenzolar-S-methyl (ASM), significant reduction of blossom and shoot blight symptoms was observed compared to water injected control trees. Overall disease suppression with streptomycin was lower than typically observed following spray applications to flowers. Trunk injection of oxytetracycline resulted in excellent control of shoot blight severity, suggesting that injection is a superior delivery method for this antibiotic. Injection of both ASM and PH resulted in the significant induction of PR-1, PR-2, and PR-8 protein genes in apple leaves indicating induction of systemic acquired resistance (SAR) under field conditions. The time separating SAR induction and fire blight symptom suppression indicated that various defensive compounds within the SAR response were synthesized and accumulated in the canopy. ASM and PH suppressed fire blight even after cessation of induced gene expression. With the development of injectable formulations and optimization of doses and injection schedules, the injection of protective compounds could serve as an effective option for fire blight control. PMID:25717330

  20. Control of fire blight (Erwinia amylovora) on apple trees with trunk-injected plant resistance inducers and antibiotics and assessment of induction of pathogenesis-related protein genes

    PubMed Central

    Aćimović, Srđan G.; Zeng, Quan; McGhee, Gayle C.; Sundin, George W.; Wise, John C.

    2015-01-01

    Management of fire blight is complicated by limitations on use of antibiotics in agriculture, antibiotic resistance development, and limited efficacy of alternative control agents. Even though successful in control, preventive antibiotic sprays also affect non-target bacteria, aiding the selection for resistance which could ultimately be transferred to the pathogen Erwinia amylovora. Trunk injection is a target-precise pesticide delivery method that utilizes tree xylem to distribute injected compounds. Trunk injection could decrease antibiotic usage in the open environment and increase the effectiveness of compounds in fire blight control. In field experiments, after 1–2 apple tree injections of either streptomycin, potassium phosphites (PH), or acibenzolar-S-methyl (ASM), significant reduction of blossom and shoot blight symptoms was observed compared to water injected control trees. Overall disease suppression with streptomycin was lower than typically observed following spray applications to flowers. Trunk injection of oxytetracycline resulted in excellent control of shoot blight severity, suggesting that injection is a superior delivery method for this antibiotic. Injection of both ASM and PH resulted in the significant induction of PR-1, PR-2, and PR-8 protein genes in apple leaves indicating induction of systemic acquired resistance (SAR) under field conditions. The time separating SAR induction and fire blight symptom suppression indicated that various defensive compounds within the SAR response were synthesized and accumulated in the canopy. ASM and PH suppressed fire blight even after cessation of induced gene expression. With the development of injectable formulations and optimization of doses and injection schedules, the injection of protective compounds could serve as an effective option for fire blight control. PMID:25717330

  1. First report of bacterial blight of crucifers caused by Pseudomonas cannabina pv. alisalensis in Australia.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas cannabina pv. alisalensis is a severe pathogen of crucifers across the U.S. Strains isolated from diseased white mustard (Brassica hirta), Brassica nigra (black mustard) and rape (Brassica napus var. napus) in Australia were reported to be similar to a pathogen recently transferred to P....

  2. Management of Bacterial Blight of Lilac Caused by Pseudomonas syringae by Growing Plants under Plastic Shelters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas syringae pv. syringae causes some of the most economically-important bacterial diseases affecting woody perennials grown by the nursery industry in the Pacific Northwest of the United States. In this study, we evaluated a cultural control practice, placement of plants in plastic shelter...

  3. Identification of genetic loci associated with fire blight resistance in Malus through combined use of QTL and association mapping.

    PubMed

    Khan, M Awais; Zhao, Youfu Frank; Korban, Schuyler S

    2013-07-01

    Fire blight, incited by the enterobacterium Erwinia amylovora, is a destructive disease of Rosaceae, particularly of apples and pears. There are reports on the molecular mechanisms underlying E. amylovora pathogenesis and how the host activates its resistance mechanism. The host's resistance mechanism is quantitatively controlled, although some major genes might also be involved. Thus far, quantitative trait loci (QTL) mapping and differential expression studies have been used to elucidate those genes and/or genomic regions underlying quantitative resistance present in the apple genome. In this study, an effort is undertaken to dissect the genetic basis of fire blight resistance in apple using both QTL and genome-wide association mapping. On the basis of an F1 pedigree of 'Coop 16' × 'Coop 17' and a genome-wide association study (GWAS) mapping population of Malus accessions (species, old and new cultivars and selections), new QTLs and associations have been identified. A total of three QTLs for resistance to fire blight, with above 95% significant logarithm of odds threshold value of 2.5, have been identified on linkage groups (LGs) 02, 06, and 15 of the apple genome with phenotypic variation explained values of 14.7, 20.1 and 17.4, respectively. Although elevated P-values with signals for marker-trait associations are observed for some LGs, these are not found to be significant. However, a total of 34 significant associations, with P-values ≥0.02, have been detected including 8 for lesion length at 7 days following inoculation (PL1), 14 for lesion length at 14 days following inoculation (PL2), and 12 for shoot length. PMID:23627651

  4. pA506: A conjugative plasmid of the plant epiphyte Pseudomonas fluorescens A506

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas fluorescens A506 is an plant-epiphytic bacterium that is used commercially in the United States for the biological control of fire blight disease of pear and apple. Here, we demonstrate that A506 has a 57 kB conjugative plasmid that can transfer to other strains of Pseudomonas spp. and ...

  5. Expression of Biphenyl Synthase Genes and Formation of Phytoalexin Compounds in Three Fire Blight-Infected Pyrus communis Cultivars.

    PubMed

    Chizzali, Cornelia; Swiddan, Asya K; Abdelaziz, Sahar; Gaid, Mariam; Richter, Klaus; Fischer, Thilo C; Liu, Benye; Beerhues, Ludger

    2016-01-01

    Pear (Pyrus communis) is an economically important fruit crop. Drops in yield and even losses of whole plantations are caused by diseases, most importantly fire blight which is triggered by the bacterial pathogen Erwinia amylovora. In response to the infection, biphenyls and dibenzofurans are formed as phytoalexins, biosynthesis of which is initiated by biphenyl synthase (BIS). Two PcBIS transcripts were cloned from fire blight-infected leaves and the encoded enzymes were characterized regarding substrate specificities and kinetic parameters. Expression of PcBIS1 and PcBIS2 was studied in three pear cultivars after inoculation with E. amylovora. Both PcBIS1 and PcBIS2 were expressed in 'Harrow Sweet', while only PcBIS2 transcripts were detected in 'Alexander Lucas' and 'Conference'. Expression of the PcBIS genes was observed in both leaves and the transition zone of the stem; however, biphenyls and dibenzofurans were only detected in stems. The maximum phytoalexin level (~110 μg/g dry weight) was observed in the transition zone of 'Harrow Sweet', whereas the concentrations were ten times lower in 'Conference' and not even detectable in 'Alexander Lucas'. In 'Harrow Sweet', the accumulation of the maximum phytoalexin level correlated with the halt of migration of the transition zone, whereby the residual part of the shoot survived. In contrast, the transition zones of 'Alexander Lucas' and 'Conference' advanced down to the rootstock, resulting in necrosis of the entire shoots. PMID:27410389

  6. First report of bacterial leaf blight on mustard greens (Brassica juncea) caused by pseudomonas cannabina pv. alisalensis in Mississippi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2010, a brassica leafy greens grower in Sunflower County, Mississippi, observed scattered outbreaks of a leaf blight disease on mustard greens (Brassica juncea) in a 180-hectare field. A severe outbreak of leaf blight occurred on mustard greens and turnip greens (Brassica rapa) in the same field...

  7. Expression of Biphenyl Synthase Genes and Formation of Phytoalexin Compounds in Three Fire Blight-Infected Pyrus communis Cultivars

    PubMed Central

    Chizzali, Cornelia; Swiddan, Asya K.; Abdelaziz, Sahar; Gaid, Mariam; Richter, Klaus; Fischer, Thilo C.; Liu, Benye; Beerhues, Ludger

    2016-01-01

    Pear (Pyrus communis) is an economically important fruit crop. Drops in yield and even losses of whole plantations are caused by diseases, most importantly fire blight which is triggered by the bacterial pathogen Erwinia amylovora. In response to the infection, biphenyls and dibenzofurans are formed as phytoalexins, biosynthesis of which is initiated by biphenyl synthase (BIS). Two PcBIS transcripts were cloned from fire blight-infected leaves and the encoded enzymes were characterized regarding substrate specificities and kinetic parameters. Expression of PcBIS1 and PcBIS2 was studied in three pear cultivars after inoculation with E. amylovora. Both PcBIS1 and PcBIS2 were expressed in ‘Harrow Sweet’, while only PcBIS2 transcripts were detected in ‘Alexander Lucas’ and ‘Conference’. Expression of the PcBIS genes was observed in both leaves and the transition zone of the stem; however, biphenyls and dibenzofurans were only detected in stems. The maximum phytoalexin level (~110 μg/g dry weight) was observed in the transition zone of ‘Harrow Sweet’, whereas the concentrations were ten times lower in ‘Conference’ and not even detectable in ‘Alexander Lucas’. In ‘Harrow Sweet’, the accumulation of the maximum phytoalexin level correlated with the halt of migration of the transition zone, whereby the residual part of the shoot survived. In contrast, the transition zones of ‘Alexander Lucas’ and ‘Conference’ advanced down to the rootstock, resulting in necrosis of the entire shoots. PMID:27410389

  8. [Electron microscopy and restriction analysis of bacteriophages isolated from quince and pear with symptoms of fire blight].

    PubMed

    Tovkach, F I; Faĭdiuk, Iu V; Korol', N A; Kushkina, A I; Moroz, S N; Muchnik, F V

    2013-01-01

    Phage populations of isolates from quince and pear affected with fire blight disease were studied using electron microscopy, restriction analysis and both agarose gel electrophoresis of particles and host range scoping method. The isolate from quince (pMA1) comprises at least three phage populations and two phage variants that can be detected on different bacterial indicators. After titration of this isolate on Erwinia amylovora the bacteriophage KEY of B1 morphotype with the genome size of 82.4 kb was identified. The isolate pMA1 also includes a unique phage population 4*, which can be identified on the test bacteria Pantoea agglomerans (Pag) g150. Two analogous populations being also present in the isolate pMA1 that appeared to be close phage variants with almost identical Hpal-restriction patterns can be identified using Pag g157 and 9/7-1. The situation is similar in the case of phage isolates from pear, pMG. Three phage populations identified in it using three different indicators represent the same phage of C1 morphotype (TT10-27) with a genome size of 71.4 kb. At least two other phage populations were also detected in the same isolate using P. agglomerans 9/7-2 as an indicator. A model system allowing the most efficient analysis of the isolates for the presence of different phage populations and phage variants in plants infected by fire blight disease has been developed. It provides for using three indicator enterobacterial species closely associated with the plants: E. amylovora, Erwinia "horticola" and Pagglomerans and ignoring of the phage cloning procedure. PMID:24479316

  9. FIRST REPORT OF BLOSSOM BLIGHT OF STRAWBERRY (FRAGARIA X ANANASSA DUCH.) CAUSED BY PSEUDOMONAS MARGINALIS IN CALIFORNIA.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel blossom blight was detected in commercial plantings of the strawberry (Fragaria x ananassa Duch.) in 2003 in central coastal California. Koch’s postulates were completed and etiology of the pathogen was determined. Physiological and molecular characterization showed that the pathogen was rel...

  10. First report of bacterial blight of cabbage (Brassica oleracea var. capitata L.) caused by Pseudomonas cannabina pv. alisalensis in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel bacterial leaf blight was seen in field grown cabbage (Brassica oleracea var. capitata L.) in Monterey County, California in 2006. Koch’s postulates were completed and etiology of the pathogen was determined. Physiological and molecular characterization showed that the pathogen was Pseudomon...

  11. First Report of Bacterial Leaf Blight on Broccoli and Cabbage Caused by Pseudomonas syringae pv. alisalensis in South Carolina

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In May 2009, leaf spot and leaf blight symptoms were observed on broccoli (B. oleracea var. italica) and cabbage (Brassica oleracea var. capitata) on several farms in Lexington County, the major brassica-growing region of South Carolina. Affected areas ranged from scattered disease foci within fiel...

  12. Molecular analyses of Erwinia amylovora strains isolated in Russia, Poland, Slovenia and Austria describing further spread of fire blight in Europe.

    PubMed

    Jock, Susanne; Wensing, Annette; Pulawska, Joanna; Drenova, Nataliya; Dreo, Tanja; Geider, Klaus

    2013-08-25

    Fire blight, a bacteriosis of apple and pear, was assayed with molecular tools to associate its origin in Russia, Slovenia and south-eastern Austria with neighboring countries. The identification of all investigated strains was confirmed by MALDI-TOF mass spectroscopy except one. Independent isolation was verified by the level of amylovoran synthesis and by the number of short sequence DNA repeats in plasmid pEA29. DNA of gently lysed E. amylovora strains from Russia, Slovenia, Austria, Hungary, Italy, Spain, Croatia, Poland, Central Europe and Iran was treated with restriction enzymes XbaI and SpeI to create typical banding patterns for PFGE analysis. The pattern Pt2 indicated that most Russian E. amylovora strains were related to strains from Turkey and Iran. Strains from Slovenia exhibited patterns Pt3 and Pt2, both present in the neighboring countries. Strains were also probed for the recently described plasmid pEI70 detected in Pt1 strains from Poland and in Pt3 strains from other countries. The distribution of pattern Pt3 suggests distribution of fire blight from Belgium and the Netherlands to Central Spain and Northern Italy and then north to Carinthia. The PFGE patterns indicate that trade of plants may have introduced fire blight into southern parts of Europe proceeded by sequential spread. PMID:23570971

  13. Mechanistically compatible mixtures of bacterial antagonists improve biological control of fire blight of pear

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mixtures of biological control agents can be superior to individual agents in suppressing plant disease, providing enhanced efficacy and reliability from field to field relative to single biocontrol strains. Nonetheless, the efficacy of combinations of Pseudomonas fluorescens A506, a commercial bio...

  14. Erwinia amylovora Novel Plasmid pEI70: Complete Sequence, Biogeography, and Role in Aggressiveness in the Fire Blight Phytopathogen

    PubMed Central

    Llop, Pablo; Cabrefiga, Jordi; Smits, Theo H. M.; Dreo, Tanja; Barbé, Silvia; Pulawska, Joanna; Bultreys, Alain; Blom, Jochen; Duffy, Brion; Montesinos, Emilio; López, María M.

    2011-01-01

    Comparative genomics of several strains of Erwinia amylovora, a plant pathogenic bacterium causal agent of fire blight disease, revealed that its diversity is primarily attributable to the flexible genome comprised of plasmids. We recently identified and sequenced in full a novel 65.8 kb plasmid, called pEI70. Annotation revealed a lack of known virulence-related genes, but found evidence for a unique integrative conjugative element related to that of other plant and human pathogens. Comparative analyses using BLASTN showed that pEI70 is almost entirely included in plasmid pEB102 from E. billingiae, an epiphytic Erwinia of pome fruits, with sequence identities superior to 98%. A duplex PCR assay was developed to survey the prevalence of plasmid pEI70 and also that of pEA29, which had previously been described in several E. amylovora strains. Plasmid pEI70 was found widely dispersed across Europe with frequencies of 5–92%, but it was absent in E. amylovora analyzed populations from outside of Europe. Restriction analysis and hybridization demonstrated that this plasmid was identical in at least 13 strains. Curing E. amylovora strains of pEI70 reduced their aggressiveness on pear, and introducing pEI70 into low-aggressiveness strains lacking this plasmid increased symptoms development in this host. Discovery of this novel plasmid offers new insights into the biogeography, evolution and virulence determinants in E. amylovora. PMID:22174857

  15. Molecular and physiological properties of bacteriophages from North America and Germany affecting the fire blight pathogen Erwinia amylovora.

    PubMed

    Müller, Ina; Lurz, Rudi; Kube, Michael; Quedenau, Claudia; Jelkmann, Wilhelm; Geider, Klaus

    2011-11-01

    For possible control of fire blight affecting apple and pear trees, we characterized Erwinia amylovora phages from North America and Germany. The genome size determined by electron microscopy (EM) was confirmed by sequence data and major coat proteins were identified from gel bands by mass spectroscopy. By their morphology from EM data, φEa1h and φEa100 were assigned to the Podoviridae and φEa104 and φEa116 to the Myoviridae. Host ranges were essentially confined to E. amylovora, strains of the species Erwinia pyrifoliae, E. billingiae and even Pantoea stewartii were partially sensitive. The phages φEa1h and φEa100 were dependent on the amylovoran capsule of E. amylovora, φEa104 and φEa116 were not. The Myoviridae efficiently lysed their hosts and protected apple flowers significantly better than the Podoviridae against E. amylovora and should be preferred in biocontrol experiments. We have also isolated and partially characterized E. amylovora phages from apple orchards in Germany. They belong to the Podoviridae or Myoviridae with a host range similar to the phages isolated in North America. In EM measurements, the genome sizes of the Podoviridae were smaller than the genomes of the Myoviridae from North America and from Germany, which differed from each other in corresponding nucleotide sequences. PMID:21791029

  16. Pathogenicity and infection strategies of the fire blight pathogen Erwinia amylovora in Rosaceae: state of the art.

    PubMed

    Vrancken, K; Holtappels, M; Schoofs, H; Deckers, T; Valcke, R

    2013-05-01

    Plants are host to a large amount of pathogenic bacteria. Fire blight, caused by the bacterium Erwinia amylovora, is an important disease in Rosaceae. Pathogenicity of E. amylovora is greatly influenced by the production of exopolysaccharides, such as amylovoran, and the use of the type III secretion system, which enables bacteria to penetrate host tissue and cause disease. When infection takes place, plants have to rely on the ability of each cell to recognize the pathogen and the signals emanating from the infection site in order to generate several defence mechanisms. These mechanisms consist of physical barriers and the production of antimicrobial components, both in a preformed and an inducible manner. Inducible defence responses are activated upon the recognition of elicitor molecules by plant cell receptors, either derived from invading micro-organisms or from pathogen-induced degradation of plant tissue. This recognition event triggers a signal transduction cascade, leading to a range of defence responses [reactive oxygen species (ROS), plant hormones, secondary metabolites, …] and redeployment of cellular energy in a fast, efficient and multiresponsive manner, which prevents further pathogen ingress. This review highlights the research that has been performed during recent years regarding this specific plant-pathogen interaction between Erwinia amylovora and Rosaceae, with a special emphasis on the pathogenicity and the infection strategy of E. amylovora and the possible defence mechanisms of the plant against this disease. PMID:23493063

  17. Recovery of Bacillus and Pseudomonas spp. from the 'fired plots' under shifting cultivation in northeast India.

    PubMed

    Pandey, Anita; Chaudhry, Shivaji; Sharma, Avinash; Choudhary, Vipin Singh; Malviya, Mukesh Kumar; Chamoli, Swati; Rinu, K; Trivedi, Pankaj; Palni, Lok Man S

    2011-01-01

    Soil samples, collected after the fire operations at agricultural sites under shifting cultivation in northeast India, were subjected to physico-chemical and microbial analysis. The fire affected various physico-chemical properties of the soil. Significant differences in pH and electrical conductivity were recorded in soil of fired and fallow plots. Significantly higher amounts of total organic carbon and nitrogen were estimated in fallow plots as compared to the fired. Difference in total phosphates was not significant. The fire operations resulted in stimulation of microbial communities. The bacteria were the most affected group followed by actinomycetes and fungi, respectively. The bacterial and actinomycetes counts were significantly higher in fired plots as compared to the fallow plots. The representative bacterial species recovered from the 'fired plots' belonged to the genus Bacillus and Pseudomonas. 16S rRNA analysis revealed their maximum similarity with B. clausii, B. licheniformis, B. megaterium, B. subtilis, B. thuringiensis, P. aeruginosa and P. stutzeri. Most of these species were found to be positive for phosphate solubilization and antagonism in plate based assays. In view of the importance of Bacillus and Pseudomonas species in plant growth promotion and biocontrol, recovery of these species after fire operations is indicative of the microbiological merit of shifting cultivation. PMID:20625733

  18. Identification of QTLs for resistance to fire blight (Erwinia amylovora) in Malus sieversii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Malus sieversii (Ms) is the progenitor of the domestic apple. Ms PI613981 is elite scion material collected at a xerophytic site in Kazakhstan from a tree free of disease and insect damage. The F1 family GMAL4593 (‘Royal Gala’ X PI631981) is segregating for resistance to both apple scab and fire bl...

  19. THE NATURE OF RESISTANCE OF THE 'B.9' APPLE ROOTSTOCK TO FIRE BLIGHT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rising production costs, associated with replacement of high-density plantings, along with lack of efficient control, especially where streptomycin resistant Erwinia amylovora strains have developed, make the identification of resistant apple rootstocks a high priority in the battle to control fire ...

  20. Genetic characterization of the HrpL regulon of the fire blight pathogen Erwinia amylovora reveals novel virulence factors.

    PubMed

    McNally, R Ryan; Toth, Ian K; Cock, Peter J A; Pritchard, Leighton; Hedley, Pete E; Morris, Jenny A; Zhao, Youfu; Sundin, George W

    2012-02-01

    The bacterial pathogen Erwinia amylovora is the causal agent of fire blight, an economically significant disease of apple and pear. Disease initiation by E. amylovora requires the translocation of effector proteins into host cells via the hypersensitive response and pathogenicity (hrp) type III secretion system (T3SS). The alternative sigma factor HrpL positively regulates the transcription of structural and translocated components of the T3SS via hrp promoter elements. To characterize genome-wide HrpL-dependent gene expression in E. amylovora Ea1189, wild-type and Ea1189ΔhrpL strains were cultured in hrp-inducing minimal medium, and total RNA was compared using a custom microarray designed to represent the annotated genes of E. amylovora ATCC 49946. The results revealed 24 genes differentially regulated in Ea1189ΔhrpL relative to Ea1189 with fold-change expression ratios greater than 1.5; of these, 19 genes exhibited decreased transcript abundance and five genes showed increased transcript abundance relative to Ea1189. To expand our understanding of the HrpL regulon and to elucidate direct versus indirect HrpL-mediated effects on gene expression, the genome of E. amylovora ATCC 49946 was examined in silico using a hidden Markov model assembled from known Erwinia spp. hrp promoters. This technique identified 15 putative type III novel hrp promoters, seven of which were validated with quantitative polymerase chain reaction based on expression analyses. It was found that HrpL-regulated genes encode all known components of the hrp T3SS, as well as five putative type III effectors. Eight genes displayed apparent indirect HrpL regulation, suggesting that the HrpL regulon is connected to downstream signalling networks. The construction of deletion mutants of three novel HrpL-regulated genes resulted in the identification of additional virulence factors as well as mutants displaying abnormal motility and biofilm phenotypes. PMID:21831138

  1. Autoinducer-2 of the fire blight pathogen Erwinia amylovora and other plant-associated bacteria.

    PubMed

    Mohammadi, Mojtaba; Geider, Klaus

    2007-01-01

    Autoinducers are important for cellular communication of bacteria. The luxS gene has a central role in the synthesis of autoinducer-2 (AI-2). The gene was identified in a shotgun library of Erwinia amylovora and primers designed for PCR amplification from bacterial DNA. Supernatants of several Erwinia amylovora strains were assayed for AI-2 activity with a Vibrio harveyi mutant and were positive. Many other plant-associated bacteria also showed AI-2 activity such as Erwinia pyrifoliae and Erwinia tasmaniensis. The luxS genes of several bacteria were cloned, sequenced, and complemented Escherichia coli strain DH5alpha and a Salmonella typhimurium mutant, both defective in luxS, for synthesis of AI-2. Assays to detect AI-2 activity in culture supernatants of several Pseudomonas syringae pathovars failed, which may indicate the absence of AI-2 or synthesis of another type. Several reporter strains did not detect synthesis of an acyl homoserine lactone (AHL, AI-1) by Erwinia amylovora, but confirmed AHL-synthesis for Erwinia carotovora ssp. atroseptica and Pantoea stewartii. PMID:17092294

  2. First report of the crucifer pathogen Pseudomonas cannabina pv. alisalensis causing bacterial blight on radish (Raphanus sativus) in Germany

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas cannabina pv. alisalensis is a severe pathogen of crucifers across the U.S. We compared a strain isolated from diseased radish (Raphanus sativus) in Germany to pathotypes and additional strains of P. cannabina pv. alisalensis and P. syringae pv. maculicola. We demonstrated that the patho...

  3. The genome of the Erwinia amylovora phage PhiEaH1 reveals greater diversity and broadens the applicability of phages for the treatment of fire blight.

    PubMed

    Meczker, Katalin; Dömötör, Dóra; Vass, János; Rákhely, Gábor; Schneider, György; Kovács, Tamás

    2014-01-01

    The enterobacterium Erwinia amylovora is the causal agent of fire blight. This study presents the analysis of the complete genome of phage PhiEaH1, isolated from the soil surrounding an E. amylovora-infected apple tree in Hungary. Its genome is 218 kb in size, containing 244 ORFs. PhiEaH1 is the second E. amylovora infecting phage from the Siphoviridae family whose complete genome sequence was determined. Beside PhiEaH2, PhiEaH1 is the other active component of Erwiphage, the first bacteriophage-based pesticide on the market against E. amylovora. Comparative genome analysis in this study has revealed that PhiEaH1 not only differs from the 10 formerly sequenced E. amylovora bacteriophages belonging to other phage families, but also from PhiEaH2. Sequencing of more Siphoviridae phage genomes might reveal further diversity, providing opportunities for the development of even more effective biological control agents, phage cocktails against Erwinia fire blight disease of commercial fruit crops. PMID:24551880

  4. Following spread of fire blight in Western, Central and Southern Europe by molecular differentiation of Erwinia amylovora strains with PFGE analysis.

    PubMed

    Jock, Susanne; Donat, Victoria; López, Maria M; Bazzi, Carlo; Geider, Klaus

    2002-02-01

    Fire blight has been detected recently in several areas of northern Spain and north-eastern Italy. To follow spread of the disease within Europe, more than 120 Erwinia amylovora strains isolated from 1957-1900 in England, France, Germany, The Netherlands, Belgium, Poland, Italy and Spain were assayed using pulsed-field gel electrophoresis (PFGE) analysis of genomic DNA after XbaI digestion. Pattern types Pt1 and Pt4 were found for strains from England. Pt1 was also found in central Europe and eastern France, Pt4 in western France. Pt2 appeared first in Egypt, from where strains with this pattern disseminated northwards as far as into the Balkans. Pt3 was typical for northern France and Belgium. Strains from Spain displayed the pattern types Pt3 and Pt4. In Italy, Pt2 was found in the south-eastern areas, Pt3 in the north-eastern areas, and Pt1 was found very recently in orchards adjacent to the Austrian border, together with Pt3. Despite barely controlled trade with fire blight host plants and associated plant products within Europe, the PFGE patterns of the E. amylovora isolates were ordered indicating sequential spread. On the other hand, the appearance of Pt3 in northern Italy and central Spain can be explained by the import of contaminated plants by nurseries. PMID:11972620

  5. Engineering fire blight resistance into the apple cultivar 'Gala' using the FB_MR5 CC-NBS-LRR resistance gene of Malus × robusta 5.

    PubMed

    Broggini, Giovanni A L; Wöhner, Thomas; Fahrentrapp, Johannes; Kost, Thomas D; Flachowsky, Henryk; Peil, Andreas; Hanke, Maria-Viola; Richter, Klaus; Patocchi, Andrea; Gessler, Cesare

    2014-08-01

    The fire blight susceptible apple cultivar Malus × domestica Borkh. cv. 'Gala' was transformed with the candidate fire blight resistance gene FB_MR5 originating from the crab apple accession Malus × robusta 5 (Mr5). A total of five different transgenic lines were obtained. All transgenic lines were shown to be stably transformed and originate from different transgenic events. The transgenic lines express the FB_MR5 either driven by the constitutive CaMV 35S promoter and the ocs terminator or by its native promoter and terminator sequences. Phenotyping experiments were performed with Mr5-virulent and Mr5-avirulent strains of Erwinia amylovora, the causal agent of fire blight. Significantly less disease symptoms were detected on transgenic lines after inoculation with two different Mr5-avirulent E. amylovora strains, while significantly more shoot necrosis was observed after inoculation with the Mr5-virulent mutant strain ZYRKD3_1. The results of these experiments demonstrated the ability of a single gene isolated from the native gene pool of apple to protect a susceptible cultivar from fire blight. Furthermore, this gene is confirmed to be the resistance determinant of Mr5 as the transformed lines undergo the same gene-for-gene interaction in the host-pathogen relationship Mr5-E. amylovora. PMID:24618178

  6. Development of PCR and TaqMan PCR Assays to Detect Pseudomonas coronafaciens, a Causal Agent of Halo Blight of Oats

    PubMed Central

    An, Ji-Hye; Noh, Young-Hee; Kim, Yong-Eon; Lee, Hyok-In; Cha, Jae-Soon

    2015-01-01

    Pseudomonas coronafaciens causes halo blight on oats and is a plant quarantine bacterium in many countries, including the Republic of Korea. Using of the certificated seed is important for control of the disease. Since effective detection method of P. coronafaciens is not available yet, PCR and TaqMan PCR assays for specific detection of P. coronafaciens were developed in this study. PCR primers were designed from the draft genome sequence of P. coronafaciens LMG 5060 which was obtained by the next-generation sequencing in this study. The PCR primer set Pc-12-F/Pc-12-R specifically amplified 498 bp from the 13 strains of P. coronafaciens isolated in the seven different countries (Canada, Japan, United Kingdom, Zimbabwe, Kenya, Germany, and New Zealand) and the nested primer set Pc-12-ne-F/Pc-12-ne-R specifically amplified 298 bp from those strains. The target-size PCR product was not amplified from the non-target bacteria with the PCR and nested primer sets. TaqMan PCR with Pc-12-ne-F/Pc-12-ne-R and a TaqMan probe, Pc-taqman, which were designed inside of the nested PCR amplicon, generated Ct values which in a dose-dependent manner to the amount of the target DNA and the Ct values of all the P. coronafaciens strains were above the threshold Ct value for positive detection. The TaqMan PCR generated positive Ct values from the seed extracts of the artificially inoculated oat seeds above 10 cfu/ml inoculation level. PCR and TaqMan PCR assays developed in this study will be useful tools to detect and identify the plant quarantine pathogen, P. coronafaciens. PMID:25774107

  7. Same ammo, different weapons: enzymatic extracts from two apple genotypes with contrasted susceptibilities to fire blight (Erwinia amylovora) differentially convert phloridzin and phloretin in vitro.

    PubMed

    Gaucher, Matthieu; Dugé de Bernonville, Thomas; Guyot, Sylvain; Dat, James F; Brisset, Marie-Noëlle

    2013-11-01

    The necrogenic bacterium Erwinia amylovora responsible for the fire blight disease causes cell death in apple tissues to enrich intercellular spaces with nutrients. Apple leaves contain large amounts of dihydrochalcones (DHCs), including phloridzin and its aglycone phloretin. Previous work showed an important decrease in the constitutive DHCs stock in infected leaves, probably caused by transformation reactions during the infection process. At least two flavonoid transformation pathways have been described so far: deglucosylation and oxidation. The aim of the present study was to determine whether DHCs are differentially converted in two apple genotypes displaying contrasted susceptibilities to the disease. Different analyses were performed: i) enzymatic activity assays in infected leaves, ii) identification/quantification of end-products obtained after in vitro enzymatic reactions with DHCs, iii) evaluation of the bactericidal activity of end-products. The results of the enzymatic assays showed that deglucosylation was dominant over oxidation in the susceptible genotype MM106 while the opposite was observed in the resistant genotype Evereste. These data were confirmed by LC-UV/Vis-MS analysis of in vitro reaction mixtures, especially because higher levels of o-quinoid oxidation products of phloretin were measured by using the enzymatic extracts of Evereste infected leaves. Their presence correlated well with a strong bactericidal activity of the reaction mixtures. Thus, our results suggest that a differential transformation of DHCs occur in apple genotypes with a potential involvement in the establishment of the susceptibility or the resistance to fire blight, through the release of glucose or of highly bactericidal compounds respectively. PMID:23561298

  8. Differential Expression of Biphenyl Synthase Gene Family Members in Fire-Blight-Infected Apple ‘Holsteiner Cox’ 1[W][OA

    PubMed Central

    Chizzali, Cornelia; Gaid, Mariam M.; Belkheir, Asma K.; Hänsch, Robert; Richter, Klaus; Flachowsky, Henryk; Peil, Andreas; Hanke, Magda-Viola; Liu, Benye; Beerhues, Ludger

    2012-01-01

    Fire blight, caused by the bacterium Erwinia amylovora, is a devastating disease of apple (Malus × domestica). The phytoalexins of apple are biphenyls and dibenzofurans, whose carbon skeleton is formed by biphenyl synthase (BIS), a type III polyketide synthase. In the recently published genome sequence of apple ‘Golden Delicious’, nine BIS genes and four BIS gene fragments were detected. The nine genes fall into four subfamilies, referred to as MdBIS1 to MdBIS4. In a phylogenetic tree, the BIS amino acid sequences from apple and Sorbus aucuparia formed an individual cluster within the clade of the functionally diverse type III polyketide synthases. cDNAs encoding MdBIS1 to MdBIS4 were cloned from fire-blight-infected shoots of apple ‘Holsteiner Cox,’ heterologously expressed in Escherichia coli, and functionally analyzed. Benzoyl-coenzyme A and salicoyl-coenzyme A were the preferred starter substrates. In response to inoculation with E. amylovora, the BIS3 gene was expressed in stems of cv Holsteiner Cox, with highest transcript levels in the transition zone between necrotic and healthy tissues. The transition zone was the accumulation site of biphenyl and dibenzofuran phytoalexins. Leaves contained transcripts for BIS2 but failed to form immunodetectable amounts of BIS protein. In cell cultures of apple ‘Cox Orange,’ expression of the BIS1 to BIS3 genes was observed after the addition of an autoclaved E. amylovora suspension. Using immunofluorescence localization under a confocal laser-scanning microscope, the BIS3 protein in the transition zone of stems was detected in the parenchyma of the bark. Dot-shaped immunofluorescence was confined to the junctions between neighboring cortical parenchyma cells. PMID:22158676

  9. First report of bacterial blight of crucifers caused by Pseudomonas cannabina pv. alisalensis in Minnesota on arugula (Eruca vesicaria subsp. sativa)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2011, bacterial blight of arugula (Eruca vesicaria subsp. sativa; cv. Roquette) was observed in organically grown plants under overhead irrigation near Delano, MN. Approximately 80 to 100% of each planting was affected. Blue-green fluorescent pseudomonads were isolated consistently on King’s Medi...

  10. Alternaria blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternaria blight of chickpea is caused by the fungal pathogen Alternaria alternata. The pathogen has wide host range, and affects all above ground parts of the plant. The disease occurs sporadically and occasionally could be economically important and causes significant damage. The pathogen can ...

  11. The outer membrane protein TolC is required for phytoalexin resistance and virulence of the fire blight pathogen Erwinia amylovora

    PubMed Central

    Al‐Karablieh, Nehaya; Weingart, Helge; Ullrich, Matthias S.

    2009-01-01

    Summary Erwinia amylovora causes fire blight on several plant species such as apple and pear, which produce diverse phytoalexins as defence mechanisms. An evolutionary successful pathogen thus must develop resistance mechanisms towards these toxic compounds. The E. amylovora outer membrane protein, TolC, might mediate phytoalexin resistance through its interaction with the multidrug efflux pump, AcrAB. To prove this, a tolC mutant and an acrB/tolC double mutant were constructed. The minimal inhibitory concentrations of diverse antimicrobials and phytoalexins were determined for these mutants and compared with that of a previously generated acrB mutant. The tolC and arcB/tolC mutants were considerably more susceptible than the wild type but showed similar levels as the acrB mutant. The results clearly indicated that neither TolC nor AcrAB significantly interacted with other transport systems during the efflux of the tested toxic compounds. Survival and virulence assays on inoculated apple plants showed that pathogenicity and the ability of E. amylovora to colonize plant tissue were equally impaired by mutations of tolC and acrB/tolC. Our results allowed the conclusion that TolC plays an important role as a virulence and fitness factor of E. amylovora by mediating resistance towards phytoalexins through its exclusive interaction with AcrAB. PMID:21255278

  12. Erwinia amylovora loop-mediated isothermal amplification (LAMP) assay for rapid pathogen detection and on-site diagnosis of fire blight.

    PubMed

    Bühlmann, Andreas; Pothier, Joël F; Rezzonico, Fabio; Smits, Theo H M; Andreou, Michael; Boonham, Neil; Duffy, Brion; Frey, Jürg E

    2013-03-01

    Several molecular methods have been developed for the detection of Erwinia amylovora, the causal agent of fire blight in pear and apple, but none are truly applicable for on-site use in the field. We developed a fast, reliable and field applicable detection method using a novel target on the E. amylovora chromosome that we identified by applying a comparative genomic pipeline. The target coding sequences (CDSs) are both uniquely specific for and all-inclusive of E. amylovora genotypes. This avoids potential false negatives that can occur with most commonly used methods based on amplification of plasmid gene targets, which can vary among strains. Loop-mediated isothermal AMPlification (LAMP) with OptiGene Genie II chemistry and instrumentation proved to be an exceptionally rapid (under 15 min) and robust method for detecting E. amylovora in orchards, as well as simple to use in the plant diagnostic laboratory. Comparative validation results using plant samples from inoculated greenhouse trials and from natural field infections (of regional and temporal diverse origin) showed that our LAMP had an equivalent or greater performance regarding sensitivity, specificity, speed and simplicity than real-time PCR (TaqMan), other LAMP assays, immunoassays and plating, demonstrating its utility for routine testing. PMID:23275135

  13. Formation of biphenyl and dibenzofuran phytoalexins in the transition zones of fire blight-infected stems of Malus domestica cv. 'Holsteiner Cox' and Pyrus communis cv. 'Conference'.

    PubMed

    Chizzali, Cornelia; Khalil, Mohammed N A; Beuerle, Till; Schuehly, Wolfgang; Richter, Klaus; Flachowsky, Henryk; Peil, Andreas; Hanke, Magda-Viola; Liu, Benye; Beerhues, Ludger

    2012-05-01

    In the rosaceous subtribe Pyrinae (formerly subfamily Maloideae), pathogen attack leads to formation of biphenyls and dibenzofurans. Accumulation of these phytoalexins was studied in greenhouse-grown grafted shoots of Malus domestica cv. 'Holsteiner Cox' and Pyrus communis cv. 'Conference' after inoculation with the fire blight bacterium, Erwinia amylovora. No phytoalexins were found in leaves. However, both classes of defence compounds were detected in the transition zone of stems. The flanking stem segments above and below this zone, which were necrotic and healthy, respectively, were devoid of detectable phytoalexins. The transition zone of apple stems contained the biphenyls 3-hydroxy-5-methoxyaucuparin, aucuparin, noraucuparin and 2'-hydroxyaucuparin and the dibenzofurans eriobofuran and noreriobofuran. In pear, aucuparin, 2'-hydroxyaucuparin, noreriobofuran and in addition 3,4,5-trimethoxybiphenyl were detected. The total phytoalexin content in the transition zone of pear was 25 times lower than that in apple. Leaves and stems of mock-inoculated apple and pear shoots lacked phytoalexins. A number of biphenyls and dibenzofurans were tested for their in vitro antibacterial activity against some Erwinia amylovora strains. The most efficient compound was 3,5-dihydroxybiphenyl (MIC=115 μg/ml), the immediate product of biphenyl synthase which initiates phytoalexin biosynthesis. PMID:22377689

  14. Exploring new roles for the rpoS gene in the survival and virulence of the fire blight pathogen Erwinia amylovora.

    PubMed

    Santander, Ricardo D; Monte-Serrano, Mercedes; Rodríguez-Herva, José J; López-Solanilla, Emilia; Rodríguez-Palenzuela, Pablo; Biosca, Elena G

    2014-12-01

    Erwinia amylovora causes fire blight in economically important plants of the family Rosaceae. This bacterial pathogen spends part of its life cycle coping with starvation and other fluctuating environmental conditions. In many Gram-negative bacteria, starvation and other stress responses are regulated by the sigma factor RpoS. We obtained an E. amylovora rpoS mutant to explore the role of this gene in starvation responses and its potential implication in other processes not yet studied in this pathogen. Results showed that E. amylovora needs rpoS to develop normal starvation survival and viable but nonculturable (VBNC) responses. Furthermore, this gene contributed to stationary phase cross-protection against oxidative, osmotic, and acid stresses and was essential for cross-protection against heat shock, but nonessential against acid shock. RpoS also mediated regulation of motility, exopolysaccharide synthesis, and virulence in immature loquats, but not in pear plantlets, and contributed to E. amylovora survival in nonhost tissues during incompatible interactions. Our results reveal some unique roles for the rpoS gene in E. amylovora and provide new knowledge on the regulation of different processes related to its ecology, including survival in different environments and virulence in immature fruits. PMID:25331301

  15. Discovery of plant phenolic compounds that act as type III secretion system inhibitors or inducers of the fire blight pathogen, Erwinia amylovora.

    PubMed

    Khokhani, Devanshi; Zhang, Chengfang; Li, Yan; Wang, Qi; Zeng, Quan; Yamazaki, Akihiro; Hutchins, William; Zhou, Shan-Shan; Chen, Xin; Yang, Ching-Hong

    2013-09-01

    Erwinia amylovora causes a devastating disease called fire blight in rosaceous plants. The type III secretion system (T3SS) is one of the important virulence factors utilized by E. amylovora in order to successfully infect its hosts. By using a green fluorescent protein (GFP) reporter construct combined with a high-throughput flow cytometry assay, a library of phenolic compounds and their derivatives was studied for their ability to alter the expression of the T3SS. Based on the effectiveness of the compounds on the expression of the T3SS pilus, the T3SS inhibitors 4-methoxy-cinnamic acid (TMCA) and benzoic acid (BA) and one T3SS inducer, trans-2-(4-hydroxyphenyl)-ethenylsulfonate (EHPES), were chosen for further study. Both the T3SS inhibitors (TMCA and BA) and the T3SS inducer (EHPES) were found to alter the expression of T3SS through the HrpS-HrpL pathway. Additionally, TMCA altered T3SS expression through the rsmBEa-RsmAEa system. Finally, we found that TMCA and BA weakened the hypersensitive response (HR) in tobacco by suppressing the T3SS of E. amylovora. In our study, we identified phenolic compounds that specifically targeted the T3SS. The T3SS inhibitor may offer an alternative approach to antimicrobial therapy by targeting virulence factors of bacterial pathogens. PMID:23770912

  16. A Statistical Comparison of the Blossom Blight Forecasts of MARYBLYT and Cougarblight with Receiver Operating Characteristic Curve Analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Blossom blight forecasting is an important aspect of fire blight, caused by Erwinia amylovora, management for both apple and pear. A comparison of the forecast accuracy of two common fire blight forecasters, MARYBLYT and Cougarblight, was performed with receiver operating characteristic (ROC) curve ...

  17. Conventional and Real-Time PCRs for Detection of Erwinia piriflorinigrans Allow Its Distinction from the Fire Blight Pathogen, Erwinia amylovora

    PubMed Central

    Barbé, Silvia; Bertolini, Edson; Roselló, Montserrat; Llop, Pablo

    2014-01-01

    Erwinia piriflorinigrans is a new pathogenic species of the bacterial genus Erwinia that has been described recently in Spain. Accurate detection and identification of E. piriflorinigrans are challenging because its symptoms on pear blossoms are similar to those caused by Erwinia amylovora, the causal agent of fire blight. Moreover, these two species share phenotypic and molecular characteristics. Two specific and sensitive conventional and real-time PCR protocols were developed to identify and detect E. piriflorinigrans and to differentiate it from E. amylovora and other species of this genus. These protocols were based on sequences from plasmid pEPIR37, which is present in all strains of E. piriflorinigrans analyzed. After the stability of the plasmid was demonstrated, the specificities of the protocols were confirmed by the amplification of all E. piriflorinigrans strains tested, whereas 304 closely related pathogenic and nonpathogenic Erwinia strains and microbiota from pear trees were not amplified. In sensitivity assays, 103 cells/ml extract were detected in spiked plant material by conventional or real-time PCR, and 102 cells/ml were detected in DNA extracted from spiked plant material by real-time PCR. The protocols developed here succeeded in detecting E. piriflorinigrans in 102 out of 564 symptomatic and asymptomatic naturally infected pear samples (flowers, cortex stem tissue, leaves, shoots, and fruitlets), in necrotic Pyracantha sp. blossoms, and in necrotic pear and apple tissues infected with both E. amylovora and E. piriflorinigrans. Therefore, these new tools can be used in epidemiological studies that will enhance our understanding of the life cycle of E. piriflorinigrans in different hosts and plant tissues and its interaction with E. amylovora. PMID:24509928

  18. AraC/XylS family stress response regulators Rob, SoxS, PliA, and OpiA in the fire blight pathogen Erwinia amylovora.

    PubMed

    Pletzer, Daniel; Schweizer, Gabriel; Weingart, Helge

    2014-09-01

    Transcriptional regulators of the AraC/XylS family have been associated with multidrug resistance, organic solvent tolerance, oxidative stress, and virulence in clinically relevant enterobacteria. In the present study, we identified four homologous AraC/XylS regulators, Rob, SoxS, PliA, and OpiA, from the fire blight pathogen Erwinia amylovora Ea1189. Previous studies have shown that the regulators MarA, Rob, and SoxS from Escherichia coli mediate multiple-antibiotic resistance, primarily by upregulating the AcrAB-TolC efflux system. However, none of the four AraC/XylS regulators from E. amylovora was able to induce a multidrug resistance phenotype in the plant pathogen. Overexpression of rob led to a 2-fold increased expression of the acrA gene. However, the rob-overexpressing strain showed increased resistance to only a limited number of antibiotics. Furthermore, Rob was able to induce tolerance to organic solvents in E. amylovora by mechanisms other than efflux. We demonstrated that SoxS from E. amylovora is involved in superoxide resistance. A soxS-deficient mutant of Ea1189 was not able to grow on agar plates supplemented with the superoxide-generating agent paraquat. Furthermore, expression of soxS was induced by redox cycling agents. We identified two novel members of the AraC/XylS family in E. amylovora. PliA was highly upregulated during the early infection phase in apple rootstock and immature pear fruits. Multiple compounds were able to induce the expression of pliA, including apple leaf extracts, phenolic compounds, redox cycling agents, heavy metals, and decanoate. OpiA was shown to play a role in the regulation of osmotic and alkaline pH stress responses. PMID:24936054

  19. Conventional and real-time PCRs for detection of Erwinia piriflorinigrans allow its distinction from the fire blight pathogen, Erwinia amylovora.

    PubMed

    Barbé, Silvia; Bertolini, Edson; Roselló, Montserrat; Llop, Pablo; López, María M

    2014-04-01

    Erwinia piriflorinigrans is a new pathogenic species of the bacterial genus Erwinia that has been described recently in Spain. Accurate detection and identification of E. piriflorinigrans are challenging because its symptoms on pear blossoms are similar to those caused by Erwinia amylovora, the causal agent of fire blight. Moreover, these two species share phenotypic and molecular characteristics. Two specific and sensitive conventional and real-time PCR protocols were developed to identify and detect E. piriflorinigrans and to differentiate it from E. amylovora and other species of this genus. These protocols were based on sequences from plasmid pEPIR37, which is present in all strains of E. piriflorinigrans analyzed. After the stability of the plasmid was demonstrated, the specificities of the protocols were confirmed by the amplification of all E. piriflorinigrans strains tested, whereas 304 closely related pathogenic and nonpathogenic Erwinia strains and microbiota from pear trees were not amplified. In sensitivity assays, 10(3) cells/ml extract were detected in spiked plant material by conventional or real-time PCR, and 10(2) cells/ml were detected in DNA extracted from spiked plant material by real-time PCR. The protocols developed here succeeded in detecting E. piriflorinigrans in 102 out of 564 symptomatic and asymptomatic naturally infected pear samples (flowers, cortex stem tissue, leaves, shoots, and fruitlets), in necrotic Pyracantha sp. blossoms, and in necrotic pear and apple tissues infected with both E. amylovora and E. piriflorinigrans. Therefore, these new tools can be used in epidemiological studies that will enhance our understanding of the life cycle of E. piriflorinigrans in different hosts and plant tissues and its interaction with E. amylovora. PMID:24509928

  20. Characterization of AcrD, a Resistance-Nodulation-Cell Division-type multidrug efflux pump from the fire blight pathogen Erwinia amylovora

    PubMed Central

    2014-01-01

    Background Multidrug efflux pumps are membrane translocases that have the ability to extrude a variety of structurally unrelated compounds from the cell. AcrD, a resistance-nodulation-cell division (RND) transporter, was shown to be involved in efflux of highly hydrophilic aminoglycosides and a limited number of amphiphilic compounds in E. coli. Here, a homologue of AcrD in the plant pathogen and causal agent of fire blight disease Erwinia amylovora was identified. Results The substrate specificity of AcrD was studied by overexpression of the corresponding gene from a high-copy plasmid in E. amylovora Ea1189-3, which is hypersensitive to many drugs due to a deficiency of the major multidrug pump AcrB. AcrD mediated resistance to several amphiphilic compounds including clotrimazole and luteolin, two compounds hitherto not described as substrates of AcrD in enterobacteria. However, AcrD was not able to expel aminoglycosides. An acrD mutant exhibited full virulence on apple rootstock and immature pear fruits. RT-PCR analysis revealed an induction of acrD expression in infected apple tissue but not on pear fruits. Moreover, a direct binding of BaeR, the response regulator of the two-component regulatory system BaeSR, to the acrD promoter was observed as has already been shown in other enterobacteria. Conclusions AcrD from E. amylovora is involved in resistance to a limited number of amphiphilic compounds, but in contrast to AcrD of E. coli, it is not involved in resistance to aminoglycosides. The expression of acrD was up-regulated by addition of the substrates deoxycholate, naringenin, tetracycline and zinc. AcrD appears to be regulated by the BaeSR two-component system, an envelope stress signal transduction pathway. PMID:24443882

  1. Corn blight watch experiment

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The corn blight problem is briefly described how the experiment was organized and conducted, the effect of the blight on the 1971 crop, and some conclusions that may be drawn as a result of the experiment. The information is based on preliminary reports of the Corn Blight Watch Steering Committee and incorporates much illustrative material conceived at Purdue University.

  2. A statistical comparison of the reliability of the blossom blight forecasts of MARYBLYT and cougarblight with receiver operating characteristic (ROC) curve analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Blossom blight forecasting is an important aspect of fire blight, caused by Erwinia amylovora, management for both apple and pear. A comparison of the forecast accuracy of two common fire blight forecasters, MARYBLYT and Cougarblight, was performed with receiver operating characteristic (ROC) curve...

  3. Suppression of bacterial blight on mustard greens with host plant resistance and Acibenzolar-S-Methyl

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial blight, caused by Pseudomonas cannabina pv. alisalensis, attacks the leaves of most brassica vegetables, including mustard greens (Brassica juncea). ‘Carolina Broadleaf,’ a new mustard cultivar, is resistant to bacterial blight. Acibenzolar-S-methyl (trade name Actigard) has been used to m...

  4. Early changes in apoplast composition associated with defence and disease in interactions between Phaseolus vulgaris and the halo blight pathogen Pseudomonas syringae Pv. phaseolicola.

    PubMed

    O'Leary, Brendan M; Neale, Helen C; Geilfus, Christoph-Martin; Jackson, Robert W; Arnold, Dawn L; Preston, Gail M

    2016-10-01

    The apoplast is the arena in which endophytic pathogens such as Pseudomonas syringae grow and interact with plant cells. Using metabolomic and ion analysis techniques, this study shows how the composition of Phaseolus vulgaris leaf apoplastic fluid changes during the first six hours of compatible and incompatible interactions with two strains of P. syringae pv. phaseolicola (Pph) that differ in the presence of the genomic island PPHGI-1. Leaf inoculation with the avirulent island-carrying strain Pph 1302A elicited effector-triggered immunity (ETI) and resulted in specific changes in apoplast composition, including increases in conductivity, pH, citrate, γ-aminobutyrate (GABA) and K(+) , that are linked to the onset of plant defence responses. Other apoplastic changes, including increases in Ca(2+) , Fe(2/3+) Mg(2+) , sucrose, β-cyanoalanine and several amino acids, occurred to a relatively similar extent in interactions with both Pph 1302A and the virulent, island-less strain Pph RJ3. Metabolic footprinting experiments established that Pph preferentially metabolizes malate, glucose and glutamate, but excludes certain other abundant apoplastic metabolites, including citrate and GABA, until preferred metabolites are depleted. These results demonstrate that Pph is well-adapted to the leaf apoplast metabolic environment and that loss of PPHGI-1 enables Pph to avoid changes in apoplast composition linked to plant defences. PMID:27239727

  5. Nontoxigenic Strains of Pseudomonas syringae pv. phaseolicola Are a Main Cause of Halo Blight of Beans in Spain and Escape Current Detection Methods.

    PubMed

    Rico, Arantza; López, Ruth; Asensio, Carmen; Aizpún, M Teresa; Asensio-S-Manzanera, M Carmen; Murillo, Jesús

    2003-12-01

    ABSTRACT From a collection of 152 pseudomonads isolated from diseased beans in Spain, 138 (91%) of the strains were identified as Pseudomonas syringae pv. phaseolicola and the rest as P. syringae pv. syringae. The P. syringae pv. phaseolicola strains produced typical water-soaked lesions on bean pods, although 95 of them did not produce phaseolotoxin in vitro. Ninety-four of these isolates did not produce the expected 0.5-kb product after polymerase chain reaction (PCR) amplification using primers specific for open reading frame (ORF) 6 of the phaseolotoxin (tox) gene cluster and did not contain DNA homologous to ORF 6 in Southern hybridization experiments. To our knowledge, this is the first report of the widespread occurrence in the field of strains of P. syringae pv. phaseolicola lacking the tox cluster, which contrasts sharply with the general belief that Tox(+) isolates are the only ones with epidemiological importance. Additionally, the tox(-) isolates were not specifically detected by a commercial polyclonal antisera in an enzyme-linked immunosorbent assay. Accordingly, it is possible that the certification of seed lots as free of the pathogen cannot be reliably done in Spain, or in any other country where tox(-) strains might occur frequently, using current PCR or serological protocols. The amplification of three avirulence genes by PCR allowed us to make predictions of the P. syringae pv. phaseolicola race structure, as confirmed by plant assays. Six races (races 1, 2, 5, 6, 7, and 9) were identified, with race 7 being the most prevalent (46.1%) followed by races 6 (21.3%) and 1 (9.0%). All the tox(-) isolates contained gene avrPphF, typical of races 1, 5, 7, and 9. PMID:18943619

  6. Citrus blight research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With HLB now occurring throughout Florida citrus groves, citrus blight has been getting less attention even though the problem still exists. In fact, the combination of HLB and citrus blight has compounded the problem that the citrus industry is facing with decreased yields, small fruit size and tre...

  7. Rhizoctonia web blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia web blight, caused by several Rhizoctonia spp., is an important disease of evergreen azaleas and other ornamental plants in nurseries. The primary pathogens causing web blight are binucleate Rhizoctonia anastomosis groups (AG) (= Ceratobasidium D.P. Rogers, teleomorph). In southern AL an...

  8. The algT gene of Pseudomonas syringae pv. glycinea and new insights into the transcriptional organization of the algT-muc gene cluster.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The phytopathogenic bacterium Pseudomonas syringae pv. glycinea infects soybean plants and causes bacterial blight. In addition to P. syringae, the human pathogen Pseudomonas aeruginosa and the soil bacterium Azotobacter vinelandii produce the exopolysaccharide alginate, copolymer of D-mannuronic a...

  9. Botryosphaeria Stem Blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stem blight, commonly referred to as dieback, is a destructive disease of highbush and rabbiteye blueberry primarily in the southeastern United States extending north into New Jersey. Losses are most severe in young fields where plants often become infected and die in the first two years. In older...

  10. Ascochyta blight of chickpeas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chickpea is becoming increasingly important as a rotational crop in cereal production systems. Ascochyta blight is the most devastating disease of chickpea and must be appropriately managed to minimize its damage to crops and increase chickpea yield. The disease is caused by the fungus Ascochyta r...

  11. Disease Alert: Stemphylium Blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lentil leaves showing symptoms of Stemphylium blight were collected from a lentil field northeast of Garfield (near Idaho border) on July 8, 2013, and incubation of the diseased leaves showed typical spores of the pathogen Stemphylium botryosum or other Stemphylium sp. The field was planted with ‘Mo...

  12. Ascochyta blight of chickpea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ascochyta blight of chickpea is caused by the necrotrophic pathogen Ascochyta rabiei. The disease is a serious yield constraint of chickpea worldwide. The pathogen causes necrotic lesions on leaves, stems, flowers, pod and seeds under cool and humid conditions. The pathogen survives in crop debri...

  13. Southern Sclerotium blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotium rolfsii attacks a wide range of plants throughout the world. It is most severe in tropical and subtropical areas. Southern Sclerotium blight is of major concern in the eastern, southeastern, and southwestern United States and in Mexico. Although severe losses are reported annually in pe...

  14. Fires

    MedlinePlus

    Whether a fire happens in your home or in the wild, it can be very dangerous. Fire spreads quickly. There is no time to gather ... a phone call. In just two minutes, a fire can become life-threatening. In five minutes, a ...

  15. Characterization and regulation of the Resistance-Nodulation-Cell Division-type multidrug efflux pumps MdtABC and MdtUVW from the fire blight pathogen Erwinia amylovora

    PubMed Central

    2014-01-01

    Background The Gram-negative bacterium Erwinia amylovora is the causal agent of the devastating disease fire blight in rosaceous plants such as apple, pear, quince, raspberry, and cotoneaster. In order to survive and multiply in a host, microbes must be able to circumvent the toxic effects of antimicrobial plant compounds, such as flavonoids and tannins. E. amylovora uses multidrug efflux transporters that recognize and actively export toxic compounds out of the cells. Here, two heterotrimeric resistance-nodulation-cell division (RND)-type multidrug efflux pumps, MdtABC and MdtUVW, from E. amylovora were identified. These RND systems are unusual in that they contain two different RND proteins forming a functional pump. Results To find the substrate specificities of the two efflux systems, we overexpressed the transporters in a hypersensitive mutant lacking the major RND pump AcrB. Both transporters mediated resistance to several flavonoids, fusidic acid and novobiocin. Additionally, MdtABC mediated resistance towards josamycin, bile salts and silver nitrate, and MdtUVW towards clotrimazole. The ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock was reduced. Quantitative RT-PCR analyses revealed that the expression of the transporter genes was induced during infection of apple rootstock. The polyphenolic plant compound tannin, as well as the heavy metal salt tungstate was found to induce the expression of mdtABC. Finally, the expression of the mdtABC genes was shown to be regulated by BaeR, the response regulator of the two-component system BaeSR, a cell envelope stress response system that controls the adaptive responses to changes in the environment. Conclusions The expression of MdtABC and MdtUVW is induced during growth of E. amylovora in planta. We identified the plant polyphenol tannin as inducer of mdtABC expression. The reduced ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock suggests that the

  16. Chickpea Ascochyta blight and insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early symptoms of Acochyta blight and insect damages were detected in the Paliuse region.This article informs chickpea scientists and growers about current disease and insect pest problems in the Palouse region. Ascochyta blight appeared in many chickpea fields and was severe in some fields. Insec...

  17. The Pseudomonas aeruginosa antimetabolite L-2-amino-4-methoxy-trans-3-butenoic acid inhibits growth of Erwinia amylovora and acts as a seed germination-arrest factor.

    PubMed

    Lee, Xiaoyun; Azevedo, Mark D; Armstrong, Donald J; Banowetz, Gary M; Reimmann, Cornelia

    2013-02-01

    The Pseudomonas aeruginosa antimetabolite L-2-amino-4-methoxy-trans-3-butenoic acid (AMB) shares biological activities with 4-formylaminooxyvinylglycine, a related molecule produced by Pseudomonas fluorescens WH6. We found that culture filtrates of a P. aeruginosa strain overproducing AMB weakly interfered with seed germination of the grassy weed Poa annua and strongly inhibited growth of Erwinia amylovora, the causal agent of the devastating orchard crop disease known as fire blight. AMB was active against a 4-formylaminooxyvinylglycine-resistant isolate of E. amylovora, suggesting that the molecular targets of the two oxyvinylglycines in Erwinia do not, or not entirely, overlap. The AMB biosynthesis and transport genes were shown to be organized in two separate transcriptional units, ambA and ambBCDE, which were successfully expressed from IPTG-inducible tac promoters in the heterologous host P. fluorescens CHA0. Engineered AMB production enabled this model biocontrol strain to become inhibitory against E. amylovora and to weakly interfere with the germination of several graminaceous seeds. We conclude that AMB production requires no additional genes besides ambABCDE and we speculate that their expression in marketed fire blight biocontrol strains could potentially contribute to disease control. PMID:23757135

  18. Biological control of chestnut blight.

    PubMed

    Anagnostakis, S L

    1982-01-29

    After 77 years of being attacked by the chestnut blight fungus, American chestnut trees continue to sprout from gradually declining root systems. The blight fungus in Italy is now associated with virus-like agents that limit its pathogenicity, and attempts have been made to introduce these controlling agents into the blight fungus in the United States. If a way can be found to help the spread here of strains of the fungus with controlling agents, it may be possible to save the American chestnut trees in our eastern forests. PMID:17771259

  19. Late blight – Is resistance futile?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article will provide an overview of late blight resistance research that has been done within the USDA/ARS and the University of Wisconsin-Madison. The article is meant to be an informative look at the history of late blight resistance and the ability of the late blight pathogen to overcome res...

  20. Tagging and mapping Pse-1 gene for resistance to halo blight in common bean differential cultivar UI-3

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Halo blight [caused by Pseudomonas syringae pv. phaseolicola (Psp)] is a serious seed-borne bacterial disease of common bean (Phaseolus vulgaris L.). A few R genes and QTL provide control to one or more races of the pathogen. To better understand monogenic resistance and improve breeding efficienc...

  1. Rhizoctonia web blight on azalea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Currently, fungicides are the only useful control for azalea web blight, but fungicides do not eliminate the pathogen. We have discovered that Rhizoctonia colonizes the entire azalea plant 12 months of the year in the Gulf Coast climate. This results in healthy appearing stems collected for propagat...

  2. Late blight and early blight resistance from Solanum hougasii introgressed into Solanum tuberosum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Late blight, caused by Phytophthora infestans, and early blight, incited by Alternaria solani,are the two most widely occurring foliar diseases of potato in the U.S. Resistance to both diseases is necessary if growers are to reduce fungicide applications. Field resistance to late blight has previous...

  3. The 1971 corn blight watch experiment

    NASA Technical Reports Server (NTRS)

    Clifton, J. W.

    1972-01-01

    The successful fulfillment of the objectives for the 1971 corn blight watch experiment is reported. The objectives were: (1) detect the development and spread of corn blight during the growing season across the Corn Belt; (2) assess different levels of infection in the Corn Belt; (3) amplify data acquired by ground observations to better appraise current blight status and the probable impact on crop production; and (4) estimate through extrapolation the applicability of these techniques to similar situations occurring in the future.

  4. pA506, a conjugative plasmid of the plant epiphyte Pseudomonas fluorescens A506.

    PubMed

    Stockwell, Virginia O; Davis, Edward W; Carey, Alyssa; Shaffer, Brenda T; Mavrodi, Dmitri V; Hassan, Karl A; Hockett, Kevin; Thomashow, Linda S; Paulsen, Ian T; Loper, Joyce E

    2013-09-01

    Conjugative plasmids are known to facilitate the acquisition and dispersal of genes contributing to the fitness of Pseudomonas spp. Here, we report the characterization of pA506, the 57-kb conjugative plasmid of Pseudomonas fluorescens A506, a plant epiphyte used in the United States for the biological control of fire blight disease of pear and apple. Twenty-nine of the 67 open reading frames (ORFs) of pA506 have putative functions in conjugation, including a type IV secretion system related to that of MOBP6 family plasmids and a gene cluster for type IV pili. We demonstrate that pA506 is self-transmissible via conjugation between A506 and strains of Pseudomonas spp. or the Enterobacteriaceae. The origin of vegetative replication (oriV) of pA506 is typical of those in pPT23A family plasmids, which are present in many pathovars of Pseudomonas syringae, but pA506 lacks repA, a defining locus for pPT23A plasmids, and has a novel partitioning region. We selected a plasmid-cured derivative of A506 and compared it to the wild type to identify plasmid-encoded phenotypes. pA506 conferred UV resistance, presumably due to the plasmid-borne rulAB genes, but did not influence epiphytic fitness of A506 on pear or apple blossoms in the field. pA506 does not appear to confer resistance to antibiotics or other toxic elements. Based on the conjugative nature of pA506 and the large number of its genes that are shared with plasmids from diverse groups of environmental bacteria, the plasmid is likely to serve as a vehicle for genetic exchange between A506 and its coinhabitants on plant surfaces. PMID:23811504

  5. The corn blight problem: 1970 and 1971

    NASA Technical Reports Server (NTRS)

    Bauer, M. E.

    1972-01-01

    Southern corn leaf blight is caused by the fungus, Helminthosporium maydis. Race T of H maydis adapted itself to the Texas male sterile cytoplasm corn. The problems caused by this variety of the blight in 1970 and 1971 are discussed, as well as the symptoms and development of the disease.

  6. HISTOLOGY AND PHYSIOLOGY OF FUSARIUM HEAD BLIGHT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium head blight re-emerged as a devastating disease of wheat and barley in the 1990s in the midwestern U.S. Research efforts to control the disease have been hampered by limited knowledge of how the fungal head blight pathogens infect and damage head tissue and what natural defenses the plant h...

  7. Schematic Models for Potato Tuber Blight Infection Based on Foliar Blight Severity, Cultivar Resistance, Soil and Atmospheric Variables

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potato tuber blight caused by Phytophthora infestans accounts for significant losses in storage tubers. Despite research on infection and management of tuber blight, there is limited published data on models predicting tuber blight infection or development. We modeled the dynamics of tuber blight in...

  8. Development of an engineered bioluminescent reporter phage for detection of bacterial blight of crucifers.

    PubMed

    Schofield, David A; Bull, Carolee T; Rubio, Isael; Wechter, W Patrick; Westwater, Caroline; Molineux, Ian J

    2012-05-01

    Bacterial blight, caused by the phytopathogen Pseudomonas cannabina pv. alisalensis, is an emerging disease afflicting important members of the Brassicaceae family. The disease is often misdiagnosed as pepper spot, a much less severe disease caused by the related pathogen Pseudomonas syringae pv. maculicola. We have developed a phage-based diagnostic that can both identify and detect the causative agent of bacterial blight and differentiate the two pathogens. A recombinant "light"-tagged reporter phage was generated by integrating bacterial luxAB genes encoding luciferase into the genome of P. cannabina pv. alisalensis phage PBSPCA1. The PBSPCA1::luxAB reporter phage is viable and stable and retains properties similar to those of the wild-type phage. PBSPCA1::luxAB rapidly and sensitively detects P. cannabina pv. alisalensis by conferring a bioluminescent signal response to cultured cells. Detection is dependent on cell viability. Other bacterial pathogens of Brassica species such as P. syringae pv. maculicola, Pseudomonas marginalis, Pectobacterium carotovorum, Xanthomonas campestris pv. campestris, and X. campestris pv. raphani either do not produce a response or produce significantly attenuated signals with the reporter phage. Importantly, the reporter phage detects P. cannabina pv. alisalensis on diseased plant specimens, indicating its potential for disease diagnosis. PMID:22427491

  9. Development of an Engineered Bioluminescent Reporter Phage for Detection of Bacterial Blight of Crucifers

    PubMed Central

    Bull, Carolee T.; Rubio, Isael; Wechter, W. Patrick; Westwater, Caroline; Molineux, Ian J.

    2012-01-01

    Bacterial blight, caused by the phytopathogen Pseudomonas cannabina pv. alisalensis, is an emerging disease afflicting important members of the Brassicaceae family. The disease is often misdiagnosed as pepper spot, a much less severe disease caused by the related pathogen Pseudomonas syringae pv. maculicola. We have developed a phage-based diagnostic that can both identify and detect the causative agent of bacterial blight and differentiate the two pathogens. A recombinant “light”-tagged reporter phage was generated by integrating bacterial luxAB genes encoding luciferase into the genome of P. cannabina pv. alisalensis phage PBSPCA1. The PBSPCA1::luxAB reporter phage is viable and stable and retains properties similar to those of the wild-type phage. PBSPCA1::luxAB rapidly and sensitively detects P. cannabina pv. alisalensis by conferring a bioluminescent signal response to cultured cells. Detection is dependent on cell viability. Other bacterial pathogens of Brassica species such as P. syringae pv. maculicola, Pseudomonas marginalis, Pectobacterium carotovorum, Xanthomonas campestris pv. campestris, and X. campestris pv. raphani either do not produce a response or produce significantly attenuated signals with the reporter phage. Importantly, the reporter phage detects P. cannabina pv. alisalensis on diseased plant specimens, indicating its potential for disease diagnosis. PMID:22427491

  10. Irrigation water is an unlikely source of inoculum of Pseudomonas cannabina pv. alisalensis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas cannabina pv. alisalensis causes severe bacterial blight on crucifers across the United States. These experiments examined the potential of irrigation water as a source of inoculum for P. cannabina pv. alisalensis. Water samples were collected from multiple irrigation reservoirs and spri...

  11. Improved High-Quality Draft Genome Sequence of Pseudomonas fluorescens KENGFT3.

    PubMed

    Town, Jennifer; Cui, Nina; Audy, Patrice; Boyetchko, Sue; Dumonceaux, Tim J

    2016-01-01

    Pseudomonas sp. strain KENGFT3 inhibits the growth of Phytophthora infestans and is a potentially useful biopesticide for plant diseases, including potato late blight. We sequenced the 6.2-Mbp genome of this strain and assembled it into a single scaffold with 9 contigs. KENGFT3 is related to previously sequenced strains of P. fluorescens. PMID:27231365

  12. Improved High-Quality Draft Genome Sequence of Pseudomonas fluorescens KENGFT3

    PubMed Central

    Town, Jennifer; Cui, Nina; Audy, Patrice; Boyetchko, Sue

    2016-01-01

    Pseudomonas sp. strain KENGFT3 inhibits the growth of Phytophthora infestans and is a potentially useful biopesticide for plant diseases, including potato late blight. We sequenced the 6.2-Mbp genome of this strain and assembled it into a single scaffold with 9 contigs. KENGFT3 is related to previously sequenced strains of P. fluorescens. PMID:27231365

  13. Disease Alert: Chickpea Ascochyta blight has shown up early

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The manuscript describes the early appearance of Ascochyta blight in north Idaho, provides pictorial guide for identification of the disease, discusses the disease cycle, and advises chickpea growers options in managing Ascochyta blight....

  14. Validation of a tuber blight (Phytophthora infestans) prediction model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potato tuber blight caused by Phytophthora infestans accounts for significant losses in storage. There is limited published quantitative data on predicting tuber blight. We validated a tuber blight prediction model developed in New York with cultivars Allegany, NY 101, and Katahdin using independent...

  15. Results of the 1971 Corn Blight Watch experiment

    NASA Technical Reports Server (NTRS)

    Macdonald, R. B.; Allen, R. D.; Bauer, M. E.; Clifton, J. W.; Frickson, J. D.; Landgrebe, D. A.

    1972-01-01

    Advanced remote sensing techniques are used to: (1)Detect development and spread of corn leaf blight during the growing season; (2) assess the extent and severity of blight infection; (3) assess the impact of blight on corn production; and (4) estimate the applicability of these techniques to similar situations occurring in the future.

  16. Visual Blight in America, Resource Paper No. 23.

    ERIC Educational Resources Information Center

    Lewis, Peirce F.; And Others

    Five articles comprise this resource paper that considers "visual blight" in the United States and the role that geographers can play in preserving the physical environment. The first article contends that visual blight is a proper subject for debate for geographers. The second article interprets causes and effects of visual blight and suggests…

  17. A functional gene cluster for toxoflavin biosynthesis in the genome of the soil bacterium Pseudomonas protegens Pf-5

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Toxoflavin is a broad-spectrum toxin best known for its role in virulence of Burkholderia glumae, which causes panicle blight of rice. A gene cluster containing homologs of toxoflavin biosynthesis genes (toxA-E) of B. glumae is present in the genome of Pseudomonas protegens Pf-5, a biological contr...

  18. Research on Rhizoctonia Web Blight on Azalea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoctonia web blight is a reoccurring problem in compact varieties of container-grown azalea (Rhododendron sp.) in the Gulf Coast States. During the summers of 2002 and 2003, disease severity was measured weekly in the inoculated center plant of plots consisting of 49 ‘Gumpo’ azalea plants. Plant ...

  19. The early days of late blight

    PubMed Central

    2013-01-01

    Large-scale DNA sequencing of samples of foliage collected in the 19th century from plants infected with late blight has shown that the potato famines of the 1840s were triggered by a single clonal lineage of Phytophthora infestans, called HERB-1, which persisted for at least 50 years. PMID:23795302

  20. Developing Fusarium head blight resistant wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium head blight, caused by Fusarium graminearum, is a major disease problem in wheat and barley around the world. During infection, F. graminearum produces trichothecene mycotoxins that act as virulence factors and cause a reduction in grain quality. Therefore, developing approaches to detoxi...

  1. SHEATH BLIGHT RESISTANCE IN SOUTHERN RICE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight is a serious fungal disease problem in southern US rice production, making it necessary for rice farmers to diligently use fungicides for its control. There are no long grain rice varieties adapted to commercial production in the southern US that have adequate resistance to sheath bli...

  2. Biocontrol of Phytophthora Blight and Anthracnose in Pepper by Sequentially Selected Antagonistic Rhizobacteria against Phytophthora capsici

    PubMed Central

    Sang, Mee Kyung; Shrestha, Anupama; Kim, Du-Yeon; Park, Kyungseok; Pak, Chun Ho; Kim, Ki Deok

    2013-01-01

    We previously developed a sequential screening procedure to select antagonistic bacterial strains against Phytophthora capsici in pepper plants. In this study, we used a modified screening procedure to select effective biocontrol strains against P. capsici; we evaluated the effect of selected strains on Phytophthora blight and anthracnose occurrence and fruit yield in pepper plants under field and plastic house conditions from 2007 to 2009. We selected four potential biocontrol strains (Pseudomonas otitidis YJR27, P. putida YJR92, Tsukamurella tyrosinosolvens YJR102, and Novosphingobium capsulatum YJR107) among 239 bacterial strains. In the 3-year field tests, all the selected strains significantly (P < 0.05) reduced Phytophthora blight without influencing rhizosphere microbial populations; they showed similar or better levels of disease suppressions than in metalaxyl treatment in the 2007 and 2009 tests, but not in the 2008 test. In the 2-year plastic house tests, all the selected strains significantly (P < 0.05) reduced anthracnose incidence in at least one of the test years, but their biocontrol activities were variable. In addition, strains YJR27, YJR92, and YJR102, in certain harvests, increased pepper fruit numbers in field tests and red fruit weights in plastic house tests. Taken together, these results indicate that the screening procedure is rapid and reliable for the selection of potential biocontrol strains against P. capsici in pepper plants. In addition, these selected strains exhibited biocontrol activities against anthracnose, and some of the strains showed plant growth-promotion activities on pepper fruit. PMID:25288942

  3. Polysaccharide benefits dry storage survival of the biocontrol agent Pseudomonas fluorescens S11:P:12 effective against several maladies of stored potatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas fluorescens S11:P:12 (NRRL B-21133) is a biological control agent able to suppress several storage maladies of potatoes including sprouting, Fusarium dry rot incited by Gibberella pulicaris, pink rot incited by Phytophthora erythroseptica, and late blight incited by Phytophthora infestan...

  4. Bioinformatics-enabled identification of the HrpL regulon and type III secretion system effector proteins of Pseudomonas syringae pv. phaseolicola 1448A

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability of Pseudomonas syringae pv. phaseolicola to cause halo blight of bean is dependent on its ability to translocate effector proteins into host cells via the Hrp type III secretion system (T3SS). To identity genes encoding type III effectors and other potential virulence factors that are r...

  5. Fungicide timing rules to prevent azalea web blight damage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article provides directions for timing fungicide applications to control Rhizoctonia web blight. Research has shown that many azalea cultivars are infested with the web blight pathogen (binucleate Rhizoctonia). The fungus lives 12 months of the year on azaleas, yet does not harm the plant most ...

  6. Timing of fungicide sprays to prevent azalea web blight symptoms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several fungicides will control web blight, but guidelines about when to spray have not been clearly understood. Previous research has shown that a maximum daily temperatures greater than 95°F and minimum daily temperatures less than 68°F slow web blight development, but weather conditions are not s...

  7. Fungicide timing rules to prevent azalea web blight damage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article provides directions for timing fungicide applications to control Rhizoctonia web blight. Research has shown that many azalea cultivars are infested with the web blight pathogen (binucleate Rhizoctonia). The fungus lives 12 months of the year on azaleas, yet does not harm the plant most...

  8. Examination of Early Blight Resistance Derived From S. Raphanifolium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early blight of potato (Solanum tuberosum L.), caused by Alternaria solani is a major cause of economic losses in many potato growing regions. Growers and breeders are interested in the development of potato cultivars with resistance to early blight as a means to decrease usage of fungicide applica...

  9. Timing of fungicide sprays to prevent azalea web blight symptoms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Azalea web blight is an annual problem on evergreen azalea cultivars grown in containerized nursery production in the southern and eastern United States. Fungicides are the only approach currently used to control Rhizoctonia web blight; however, control is poor in some years because the specifics of...

  10. INCORPORATING FOREIGN SHEATH BLIGHT RESISTANCE GENES INTO US RICE GEMPLASM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight disease, caused by the Rhizoctonia solani fungus, has been the most economically significant rice disease throughout Texas, Louisiana, and Arkansas since the early 1970s. While diseases such as blast and straighthead can also devastate yield, sheath blight disease occurs more consiste...

  11. Detection of early blight and late blight diseases on tomato leaves using hyperspectral imaging.

    PubMed

    Xie, Chuanqi; Shao, Yongni; Li, Xiaoli; He, Yong

    2015-01-01

    This study investigated the potential of using hyperspectral imaging for detecting different diseases on tomato leaves. One hundred and twenty healthy, one hundred and twenty early blight and seventy late blight diseased leaves were selected to obtain hyperspectral images covering spectral wavelengths from 380 to 1023 nm. An extreme learning machine (ELM) classifier model was established based on full wavelengths. Successive projections algorithm (SPA) was used to identify the most important wavelengths. Based on the five selected wavelengths (442, 508, 573, 696 and 715 nm), an ELM model was re-established. Then, eight texture features (mean, variance, homogeneity, contrast, dissimilarity, entropy, second moment and correlation) based on gray level co-occurrence matrix (GLCM) at the five effective wavelengths were extracted to establish detection models. Among the models which were established based on spectral information, all performed excellently with the overall classification accuracy ranging from 97.1% to 100% in testing sets. Among the eight texture features, dissimilarity, second moment and entropy carried most of the effective information with the classification accuracy of 71.8%, 70.9% and 69.9% in the ELM models. The results demonstrated that hyperspectral imaging has the potential as a non-invasive method to identify early blight and late blight diseases on tomato leaves. PMID:26572857

  12. Detection of early blight and late blight diseases on tomato leaves using hyperspectral imaging

    PubMed Central

    Xie, Chuanqi; Shao, Yongni; Li, Xiaoli; He, Yong

    2015-01-01

    This study investigated the potential of using hyperspectral imaging for detecting different diseases on tomato leaves. One hundred and twenty healthy, one hundred and twenty early blight and seventy late blight diseased leaves were selected to obtain hyperspectral images covering spectral wavelengths from 380 to 1023 nm. An extreme learning machine (ELM) classifier model was established based on full wavelengths. Successive projections algorithm (SPA) was used to identify the most important wavelengths. Based on the five selected wavelengths (442, 508, 573, 696 and 715 nm), an ELM model was re-established. Then, eight texture features (mean, variance, homogeneity, contrast, dissimilarity, entropy, second moment and correlation) based on gray level co-occurrence matrix (GLCM) at the five effective wavelengths were extracted to establish detection models. Among the models which were established based on spectral information, all performed excellently with the overall classification accuracy ranging from 97.1% to 100% in testing sets. Among the eight texture features, dissimilarity, second moment and entropy carried most of the effective information with the classification accuracy of 71.8%, 70.9% and 69.9% in the ELM models. The results demonstrated that hyperspectral imaging has the potential as a non-invasive method to identify early blight and late blight diseases on tomato leaves. PMID:26572857

  13. Enhancing Potato System Sustainability: Microclimate, Early Blight and Late Blight Potential

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop and soil management may modify canopy and below ground microclimate; however, their effects on potential development and control of early and late blight are not well documented. Crop management systems (Status Quo (SQ), Soil Conserving (SC), Soil Improving (SI), Disease Suppressive (DS), and ...

  14. Enhancing Potato System Sustainability: Microclimate, Early Blight and Late Blight Potential

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop and soil management may modify canopy and below ground microclimate; however, their effects on potential development and control of early and late blight are not well documented. Crop management systems (Status Quo (SQ), Soil Conserving (SC), Soil Improving (SI), Disease Suppressive (DS), and c...

  15. Effects of Mulch and Potato Hilling on Development of Foliar Blight (Phytophthora infestans) and Control of Tuber Blight Infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foliar and tuber blight caused by Phytophthora infestans accounts for significant losses in potatoes in field and storage, however; limited research has documented the effect of cultural practices on late blight control. Field experiments were conducted for two years on Howard gravely loam soil in N...

  16. Pseudomonas 2007 Meeting Review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas is an important genus of bacteria. Pseudomonas aeruginosa is the third most common nosocomial pathogen in our society, associated with chronic and eventually fatal lung disease in cystic fibrosis patients, while Pseudomonas syringae species are prominent plant pathogens. The fluorescen...

  17. Three potato clones incorporating combined resistances to early blight from S. palustre and late blight from S. bulbocastanum into a S. tuberosum background

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three individuals from a segregating population derived from a cross between +297 and K41 are being released as germplasm with resistance to both early blight, caused by Alternaria solani, and late blight, caused by Phytophthora infestans. The source of resistance to early blight from +297 is the wi...

  18. SCREENING OF TRANSGENIC ANTHURIUMS FOR BACTERIAL BLIGHT AND NEMATODE RESISTANCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anthuriums exhibit limited resistance to bacterial blight caused by Xanthomonas axonopodis pv. dieffenbachiae and to the nematodes Radopholus simile and Meloidogyne javanica. Agrobacterium tumefaciens transformation of embryogenic calli with strains LBA4404, EHA105, and AGLO resulted in transgenic p...

  19. Plant Growth Promotion and Suppression of Bacterial Leaf Blight in Rice by Inoculated Bacteria

    PubMed Central

    Zaka, Abha; Imran, Asma; Zahid, Muhammad Awais; Yousaf, Sumaira; Rasul, Ghulam; Arif, Muhammad; Mirza, Muhammad Sajjad

    2016-01-01

    The present study was conducted to evaluate the potential of rice rhizosphere associated antagonistic bacteria for growth promotion and disease suppression of bacterial leaf blight (BLB). A total of 811 rhizospheric bacteria were isolated and screened against 3 prevalent strains of BLB pathogen Xanthomonas oryzae pv. oryzae (Xoo) of which five antagonistic bacteria, i.e., Pseudomonas spp. E227, E233, Rh323, Serratia sp. Rh269 and Bacillus sp. Rh219 showed antagonistic potential (zone of inhibition 1–19 mm). Production of siderophores was found to be the common biocontrol determinant and all the strains solubilized inorganic phosphate (82–116 μg mL-1) and produced indole acetic acid (0.48–1.85 mg L-1) in vitro. All antagonistic bacteria were non-pathogenic to rice, and their co-inoculation significantly improved plant health in terms of reduced diseased leaf area (80%), improved shoot length (31%), root length (41%) and plant dry weight (60%) as compared to infected control plants. Furthermore, under pathogen pressure, bacterial inoculation resulted in increased activity of defense related enzymes including phenylalanine ammonia-lyase and polyphenol oxidase, along with 86% increase in peroxidase and 53% increase in catalase enzyme activities in plants inoculated with Pseudomonas sp. Rh323 as well as co-inoculated plants. Bacterial strains showed good colonization potential in the rice rhizosphere up to 21 days after seed inoculation. Application of bacterial consortia in the field resulted in an increase of 31% in grain yield and 10% in straw yield over non-inoculated plots. Although, yield increase was statistically non-significant but was accomplished with overall saving of 20% chemical fertilizers. The study showed that Pseudomonas sp. Rh323 can be used to develop dual-purpose inoculum which can serve not only to suppress BLB but also to promote plant growth in rice. PMID:27532545

  20. Plant Growth Promotion and Suppression of Bacterial Leaf Blight in Rice by Inoculated Bacteria.

    PubMed

    Yasmin, Sumera; Zaka, Abha; Imran, Asma; Zahid, Muhammad Awais; Yousaf, Sumaira; Rasul, Ghulam; Arif, Muhammad; Mirza, Muhammad Sajjad

    2016-01-01

    The present study was conducted to evaluate the potential of rice rhizosphere associated antagonistic bacteria for growth promotion and disease suppression of bacterial leaf blight (BLB). A total of 811 rhizospheric bacteria were isolated and screened against 3 prevalent strains of BLB pathogen Xanthomonas oryzae pv. oryzae (Xoo) of which five antagonistic bacteria, i.e., Pseudomonas spp. E227, E233, Rh323, Serratia sp. Rh269 and Bacillus sp. Rh219 showed antagonistic potential (zone of inhibition 1-19 mm). Production of siderophores was found to be the common biocontrol determinant and all the strains solubilized inorganic phosphate (82-116 μg mL-1) and produced indole acetic acid (0.48-1.85 mg L-1) in vitro. All antagonistic bacteria were non-pathogenic to rice, and their co-inoculation significantly improved plant health in terms of reduced diseased leaf area (80%), improved shoot length (31%), root length (41%) and plant dry weight (60%) as compared to infected control plants. Furthermore, under pathogen pressure, bacterial inoculation resulted in increased activity of defense related enzymes including phenylalanine ammonia-lyase and polyphenol oxidase, along with 86% increase in peroxidase and 53% increase in catalase enzyme activities in plants inoculated with Pseudomonas sp. Rh323 as well as co-inoculated plants. Bacterial strains showed good colonization potential in the rice rhizosphere up to 21 days after seed inoculation. Application of bacterial consortia in the field resulted in an increase of 31% in grain yield and 10% in straw yield over non-inoculated plots. Although, yield increase was statistically non-significant but was accomplished with overall saving of 20% chemical fertilizers. The study showed that Pseudomonas sp. Rh323 can be used to develop dual-purpose inoculum which can serve not only to suppress BLB but also to promote plant growth in rice. PMID:27532545

  1. The American Chestnut Blight: An Agent of Biological and Cultural Catastrophe.

    ERIC Educational Resources Information Center

    Lunsford, Eddie

    1999-01-01

    Reviews the history and habits of the fungus commonly referred to as the "chestnut blight." Considers the impact of the blight and efforts to control it, offers personal and cultural reflections on the blight, and gives tips for incorporating the information into cross-disciplinary lessons. Contains 17 references. (WRM)

  2. Ascochyta blight of chickpea: production of phytotoxins and disease management.

    PubMed

    Shahid, Ahmad Ali; Husnain, Tayyab; Riazuddin, Sheikh

    2008-01-01

    Ascochyta blight caused by Ascochyta rabiei (Pass.) Lab., is the most devastating disease of chickpea and can occur anywhere the crop is grown. Several epidemics of blight causing complete yield losses have been reported. Despite extensive pathological and molecular studies, the nature and extent of pathogenic variability in A. rabiei have not been clearly established. Several isolates of A. rabiei were grown in liquid culture medium which secreted phytotoxic compounds of solanapyrone A, B, C and cytochalasin D. The same fungal metabolites were also recovered from extract of naturally blight stricken chickpea plants. Toxicity of purified solanapyrones as determined by cell bioassay was in the order of solanapyrone A>solanapyrone B>solanapyrone C. However, the specificity of all three compounds was dependent on the genetic identity of the chickpea cultivars. Seed treatment and foliar application of fungicides are commonly recommended for disease management, but further information on biology and survival of A. rabiei is needed to devise more effective management strategies. A short description of chickpea blight, geographical distribution, disease cycle, symptoms, losses, production of phytotoxins and disease management practices for the control of Ascochyta blight will be discussed in this review article. PMID:18616995

  3. Development of Tuber Blight (Phytophthora infestans) on Potato Cultivars Based on In-Vitro Assays and Field Evaluations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tuber blight may result from infection of wounded or unwounded potato tubers, exposed to sporangia from foliar blight, soil, or blighted tubers. However, there is limited data on the prediction of tuber blight in field or storage environments based on in-vitro assays. To assess this relationship, po...

  4. Niclosamide inhibits leaf blight caused by Xanthomonas oryzae in rice.

    PubMed

    Kim, Sung-Il; Song, Jong Tae; Jeong, Jin-Yong; Seo, Hak Soo

    2016-01-01

    Rice leaf blight, which is caused by the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo), results in huge losses in grain yield. Here, we show that Xoo-induced rice leaf blight is effectively controlled by niclosamide, an oral antihelminthic drug and molluscicide, which also functions as an anti-tumor agent. Niclosamide directly inhibited the growth of the three Xoo strains PXO99, 10208 and K3a. Niclosamide moved long distances from the site of local application to distant rice tissues. Niclosamide also increased the levels of salicylate and induced the expression of defense-related genes such as OsPR1 and OsWRKY45, which suppressed Xoo-induced leaf wilting. Niclosamide had no detrimental effects on vegetative/reproductive growth and yield. These combined results indicate that niclosamide can be used to block bacterial leaf blight in rice with no negative side effects. PMID:26879887

  5. Niclosamide inhibits leaf blight caused by Xanthomonas oryzae in rice

    PubMed Central

    Kim, Sung-Il; Song, Jong Tae; Jeong, Jin-Yong; Seo, Hak Soo

    2016-01-01

    Rice leaf blight, which is caused by the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo), results in huge losses in grain yield. Here, we show that Xoo-induced rice leaf blight is effectively controlled by niclosamide, an oral antihelminthic drug and molluscicide, which also functions as an anti-tumor agent. Niclosamide directly inhibited the growth of the three Xoo strains PXO99, 10208 and K3a. Niclosamide moved long distances from the site of local application to distant rice tissues. Niclosamide also increased the levels of salicylate and induced the expression of defense-related genes such as OsPR1 and OsWRKY45, which suppressed Xoo-induced leaf wilting. Niclosamide had no detrimental effects on vegetative/reproductive growth and yield. These combined results indicate that niclosamide can be used to block bacterial leaf blight in rice with no negative side effects. PMID:26879887

  6. Pseudomonas kuykendallii sp. nov.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This is a submission to the list of microorganisms with standing in nomenclature maintained by the International Journal of Systematic and Evolutionary Microbiology. We wish to have Pseudomonas kuykendallii sp. nov. added to the list as a valid species belonging to the genus Pseudomonas. Three str...

  7. Recombineering Pseudomonas syringae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Here we report the identification of functions that promote genomic recombination of linear DNA introduced into Pseudomonas cells by electroporation. The genes encoding these functions were identified in Pseudomonas syringae pv. syringae B728a based on similarity to the lambda Red Exo/Beta and RecE...

  8. Pseudomonas screening assay

    NASA Technical Reports Server (NTRS)

    Margalit, Ruth (Inventor)

    1993-01-01

    A method for the detection of Pseudomonas bacteria is described where an Azurin-specific antibody is employed for detecting the presence of Azurin in a test sample. The detection of the presence of Azurin in the sample is a conclusive indicator of the presence of the Pseudomonas bacteria since the Azurin protein is a specific marker for this bacterial strain.

  9. Development of late blight resistant potatoes by cisgene stacking

    PubMed Central

    2014-01-01

    Background Phytophthora infestans, causing late blight in potato, remains one of the most devastating pathogens in potato production and late blight resistance is a top priority in potato breeding. The introduction of multiple resistance (R) genes with different spectra from crossable species into potato varieties is required. Cisgenesis is a promising approach that introduces native genes from the crops own gene pool using GM technology, thereby retaining favourable characteristics of established varieties. Results We pursued a cisgenesis approach to introduce two broad spectrum potato late blight R genes, Rpi-sto1 and Rpi-vnt1.1 from the crossable species Solanum stoloniferum and Solanum venturii, respectively, into three different potato varieties. First, single R gene-containing transgenic plants were produced for all varieties to be used as references for the resistance levels and spectra to be expected in the respective genetic backgrounds. Next, a construct containing both cisgenic late blight R genes (Rpi-vnt1.1 and Rpi-sto1), but lacking the bacterial kanamycin resistance selection marker (NPTII) was transformed to the three selected potato varieties using Agrobacterium-mediated transformation. Gene transfer events were selected by PCR among regenerated shoots. Through further analyses involving morphological evaluations in the greenhouse, responsiveness to Avr genes and late blight resistance in detached leaf assays, the selection was narrowed down to eight independent events. These cisgenic events were selected because they showed broad spectrum late blight resistance due to the activity of both introduced R genes. The marker-free transformation was compared to kanamycin resistance assisted transformation in terms of T-DNA and vector backbone integration frequency. Also, differences in regeneration time and genotype dependency were evaluated. Conclusions We developed a marker-free transformation pipeline to select potato plants functionally expressing a

  10. The Anti-Phytophthora Effect of Selected Potato-Associated Pseudomonas Strains: From the Laboratory to the Field.

    PubMed

    Guyer, Anouk; De Vrieze, Mout; Bönisch, Denise; Gloor, Ramona; Musa, Tomke; Bodenhausen, Natacha; Bailly, Aurélien; Weisskopf, Laure

    2015-01-01

    Late blight, caused by the oomycete Phytophthora infestans, is the most devastating disease of potato. In organic farming, late blight is controlled by repeated applications of copper-based products, which negatively impact the environment. To find alternative solutions for late blight management, we have previously isolated a large collection of bacteria from the phyllosphere and the rhizosphere of potatoes. Here we report the antagonistic potential of these strains when co-cultivated with P. infestans as well as with other potato pathogens. We then focused on three Pseudomonas strains and compared their protective impact against late blight to that of well-known biocontrol strains in planta using a high-throughput leaf disk assay with automated picture analysis. When sprayed on the leaves of potatoes in the greenhouse, the strains were able to survive for at least 15 days. Under field conditions, populations decreased faster but all tested strains could still be retrieved after 8 days. The most active strain in vitro, P. chlororaphis R47, was also the best protectant on leaf disks from plants grown in the greenhouse experiment, but its protection potential could not be verified in the field due to unfavorable infection conditions. However, its protective effect against P. infestans in planta, its survival in the phyllosphere as well as its ability to colonize the potato rhizosphere in very high population densities, suggest a potential for field application, e.g., in the form of tuber treatment or leaf spray. PMID:26640460

  11. The Anti-Phytophthora Effect of Selected Potato-Associated Pseudomonas Strains: From the Laboratory to the Field

    PubMed Central

    Guyer, Anouk; De Vrieze, Mout; Bönisch, Denise; Gloor, Ramona; Musa, Tomke; Bodenhausen, Natacha; Bailly, Aurélien; Weisskopf, Laure

    2015-01-01

    Late blight, caused by the oomycete Phytophthora infestans, is the most devastating disease of potato. In organic farming, late blight is controlled by repeated applications of copper-based products, which negatively impact the environment. To find alternative solutions for late blight management, we have previously isolated a large collection of bacteria from the phyllosphere and the rhizosphere of potatoes. Here we report the antagonistic potential of these strains when co-cultivated with P. infestans as well as with other potato pathogens. We then focused on three Pseudomonas strains and compared their protective impact against late blight to that of well-known biocontrol strains in planta using a high-throughput leaf disk assay with automated picture analysis. When sprayed on the leaves of potatoes in the greenhouse, the strains were able to survive for at least 15 days. Under field conditions, populations decreased faster but all tested strains could still be retrieved after 8 days. The most active strain in vitro, P. chlororaphis R47, was also the best protectant on leaf disks from plants grown in the greenhouse experiment, but its protection potential could not be verified in the field due to unfavorable infection conditions. However, its protective effect against P. infestans in planta, its survival in the phyllosphere as well as its ability to colonize the potato rhizosphere in very high population densities, suggest a potential for field application, e.g., in the form of tuber treatment or leaf spray. PMID:26640460

  12. Ascochyta blight and insect pests of chickpeas in the Palouse

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This newsletter article informs chickpea growers in the Palouse region about current disease and insect pest problems. Ascochyta blight appeared in many chickpea fields and was severe in some fields. Insect pests including loopers and armyworms were rampant. Appropriate management practices for t...

  13. MICROCLIMATE AND POTENTIAL FOR LATE BLIGHT DEVELOPMENT IN IRRIGATED POTATO

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Application of irrigation water can improve potato growth and tuber yield during periods of deficit rainfall. A variety of water application techniques exists; however, little is known of their relative impacts on potato late blight potential. The effects of sprinkler, sub-surface drip, and surface ...

  14. Identification of an emergent bacterial blight of garlic in Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Outbreaks of a bacterial blight disease occurred on garlic (Allium sativum) cultivars Roxo Caxiense, Quiteria and Cacador in Southern Brazil, and threatened the main production regions of Rio Grande do Sul State. Symptoms were characterized by watersoaked reddish streaks along the leaf midrib, follo...

  15. SUSCEPTIBILITY OF SOUTHERN HIGHBUSH BLUEBERRY CULTIVARS TO STEM BLIGHT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stem blight, caused by the fungus Botryosphaeria dothidea, is a widespread and destructive disease of rabbiteye blueberries (V. ashei Reade) in the southeastern United States. Plants that become infected may die within the first two years of planting. In older plants the initial infection of a ste...

  16. Towards Managing Stemphylium Blight of Lentil in the Pacific Northwest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stemphylium blight of lentil, caused by the fungus Stemphylium botryosum, has recently emerged as a disease problem in the Pacific Northwest, particularly on the recently released lentil cultivar ‘Morena’. The first step toward managing the disease is to correctly identify early signs of the diseas...

  17. Characterization Of The RB-Mediated Late Blight Resistance Phenotype

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Late blight, caused by the oomycete pathogen Phytophthora infestans, continues to be the most devastating disease of potato. Although great efforts have been made in selection and breeding for resistance, many current potato cultivars remain susceptible. One of the reasons is that the resistance in ...

  18. Characterization of Early Blight Resistance in Interspecific Potato Hybrids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early blight, caused by the fungal pathogen Alternaria solani Sorauer, is a serious foliar disease of potato and tomato worldwide. It is characterized by severe defoliation resulting in significant losses in yield. Fungicides are the main method of control; however, they are undesirable due to their...

  19. Prospects for advanced late blight resistance breeding in potato

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potato late blight pathogen, Phytophthora infestans, is able to rapidly evolve to overcome resistance genes. The pathogen accomplishes this by secreting an arsenal of proteins, termed effectors, that function to modify host cells. Although hundreds of candidate effectors have been identified in ...

  20. Resistance to ascochyta blights of cool season food legumes.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ascochyta blight is the most important disease problem of the cool season food legumes (peas, lentils, chickpeas, and faba beans) and is found in nearly all production regions around the world. Despite of the same common disease name, the pathogen species differ for each of the crops. These disease...

  1. Genetic Characterization of Early Blight Resistance in Interspecific Potato Hybrids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early blight, caused by the fungal pathogen Alternaria solani Sorauer, is a serious foliar disease of potato and tomato worldwide. It is characterized by substantial yield loss resulting from severe defoliation, especially under hot, humid conditions. Fungicides are the main method of control, how...

  2. Fusarium seed stalk blight and rot in sugar beet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium can cause damage to seed stalks that can cause reductions or complete loss of seed production. Fusarium oxysporum has been the reported cause of seed stalk blight, which is characterized by vascular discoloration. We sampled diseased seed stalks and examined isolates for their pathogenicity...

  3. Late Blight Resistance of RB Transgenic Potato Lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Late blight of potato, caused by Phytophthora infestans, is a devastating disease effecting tuber yield and storage. Recent work has isolated a resistance gene, RB, from the wild species Solanum bulbocastanum. Field evaluations with a RB containing somatic hybrid have reported significant levels of ...

  4. MANAGEMENT OF SCLEROTINIA BLIGHT AND VERTICILLIUM WILT IN PEANUTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some of the objectives of this research are to study the biology of economically important peanut pathogens including Tomato Spotted Wilt Virus (TSWV), and to determine the role of disease resistance in managing soil-borne peanut pathogens, particularly Sclerotinia blight, Verticillium wilt, and Sou...

  5. A ROLE FOR ASCOSPORES IN WHEAT HEAD BLIGHT EPIDEMICS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Ascomycete Gibberella zeae (asexual state Fusarium graminearum) causes serious epidemics of wheat head blight worldwide and contaminates grain with trichothecene mycotoxins that are harmful to human and animal health. Anecdotal evidence dating back to the 19th century indicates that G. zeae asc...

  6. Evaluation of Commercial Watermelon Rootstocks for Tolerance to Phytophthora Blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytophthora blight and fruit rot caused by Phytophthora capsici is becoming an important and emerging disease of watermelons (Citrullus lanatus). The disease mainly occurs in low lying areas of the fields where water logged conditions may be present. In recent years, the practice of grafting seed...

  7. TAL effector-mediated susceptibility to bacterial blight of cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial blight of cotton (BBC) caused by Xanthomonas campestris pv. malvacearum (Xcm) is a destructive disease that has recently re-emerged in the U.S. Xcm injects transcription activator-like (TAL) effectors that directly induce the expression of host susceptibility (S) or resistance (R) genes. ...

  8. Biological control of post-harvest late blight of potatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction of US-8 genotypes of Phytophthora infestans has coincided with an increase in severity of potato late blight in North America. As alternatives to chemical fungicides, 18 bacterial strains patented as biological control agents (BCA) of both sprouting and Fusarium dry rot were cultivated...

  9. Transgenic resistance to Fusarium head blight in barley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium head blight (FHB) and its mycotoxin deoxynivalenol (DON) have been a major problem in the primary malting barley growing regions in North America since 1993. Resistance to FHB and DON accumulation in barley is quantitative, with no immunity available in the primary or secondary gene pools. ...

  10. Genetic variability in the pistachio late blight fungus, Alternaria alternata

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic variation in the pistachio late blight fungus, Alternaria alternata, was investigated by restriction fragment length polymorphism (RFLP) in the rDNA region. Southern hybridization of EcoRI, HindIII, and Xbal digested fungal DNA with a RNA probe derived from Alt1, an rDNA clone isolated from ...

  11. Fusarium stalk blight and rot in sugar beet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium stalk blight of sugar beet can cause reductions or complete loss of seed production. The causal agent is Fusarium oxysporum. In addition, Fusarium solani has been demonstrated to cause a rot of sugar beet seed stalk, and other species have been reported associated with sugar beet fruit, but...

  12. Indicator For Pseudomonas Bacteria

    NASA Technical Reports Server (NTRS)

    Margalit, Ruth

    1990-01-01

    Characteristic protein extracted and detected. Natural protein marker found in Pseudomonas bacteria. Azurin, protein containing copper readily extracted, purified, and used to prepare antibodies. Possible to develop simple, fast, and accurate test for marker carried out in doctor's office.

  13. 40 CFR 180.1114 - Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS; exemptions from the requirement of a tolerance... Tolerances § 180.1114 Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas...

  14. 40 CFR 180.1114 - Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS; exemptions from the requirement of a tolerance... Tolerances § 180.1114 Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas...

  15. 40 CFR 180.1114 - Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS; exemptions from the requirement of a tolerance... Tolerances § 180.1114 Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas...

  16. 40 CFR 180.1114 - Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS; exemptions from the requirement of a tolerance... Tolerances § 180.1114 Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas...

  17. 40 CFR 180.1114 - Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS; exemptions from the requirement of a tolerance... Tolerances § 180.1114 Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas...

  18. Understory Fires

    NASA Video Gallery

    The flames of understory fires in the southern Amazon reach on average only a few feet tall, but the fire type can claim anywhere from 10 to 50 percent of a burn area's trees. Credit: NASA/Doug Morton

  19. Texas Fires

    Atmospheric Science Data Center

    2014-05-15

    article title:  Wind-Whipped Fires in East Texas     View Larger Image ... western side of the storm stoked fires throughout eastern Texas, which was already suffering from the worst one-year drought on record ...

  20. Fire Detector

    NASA Technical Reports Server (NTRS)

    1978-01-01

    An early warning fire detection sensor developed for NASA's Space Shuttle Orbiter is being evaluated as a possible hazard prevention system for mining operations. The incipient Fire Detector represents an advancement over commercially available smoke detectors in that it senses and signals the presence of a fire condition before the appearance of flame and smoke, offering an extra margin of safety.

  1. Genomic Distribution and Divergence of Levansucrase-Coding Genes in Pseudomonas syringae.

    PubMed

    Srivastava, Abhishek; Al-Karablieh, Nehaya; Khandekar, Shaunak; Sharmin, Arifa; Weingart, Helge; Ullrich, Matthias S

    2012-01-01

    In the plant pathogenic bacterium, Pseudomonas syringae, the exopolysaccharide levan is synthesized by extracellular levansucrase (Lsc), which is encoded by two conserved 1,296-bp genes termed lscB and lscC in P. syringae strain PG4180. A third gene, lscA, is homologous to the 1,248-bp lsc gene of the bacterium Erwinia amylovora, causing fire blight. However, lscA is not expressed in P. syringae strain PG4180. Herein, PG4180 lscA was shown to be expressed from its native promoter in the Lsc-deficient E. amylovora mutant, Ea7/74-LS6, suggesting that lscA might be closely related to the E. amylovora lsc gene. Nucleotide sequence analysis revealed that lscB and lscC homologs in several P. syringae strains are part of a highly conserved 1.8-kb region containing the ORF, flanked by 450-452-bp and 49-51-bp up- and downstream sequences, respectively. Interestingly, the 450-452-bp upstream sequence, along with the initial 48-bp ORF sequence encoding for the N-terminal 16 amino acid residues of Lsc, were found to be highly similar to the respective sequence of a putatively prophage-borne glycosyl hydrolase-encoding gene in several P. syringae genomes. Minimal promoter regions of lscB and lscC were mapped in PG4180 by deletion analysis and were found to be located in similar positions upstream of lsc genes in three P. syringae genomes. Thus, a putative 498-500-bp promoter element was identified, which possesses the prophage-associated com gene and DNA encoding common N-terminal sequences of all 1,296-bp Lsc and two glycosyl hydrolases. Since the gene product of the non-expressed 1,248-bp lscA is lacking this conserved N-terminal region but is otherwise highly homologous to those of lscB and lscC, it was concluded that lscA might have been the ancestral lsc gene in E. amylovora and P. syringae. Our data indicated that its highly expressed paralogs in P. syringae are probably derived from subsequent recombination events initiated by insertion of the 498-500-bp promoter element

  2. Hot Tub Rash (Pseudomonas Folliculitis)

    MedlinePlus

    ... rash and rashes clinical tools newsletter | contact Share | Hot Tub Rash ( Pseudomonas Folliculitis) Information for adults A ... the skin and small pus-filled lesions. Overview Hot tub rash ( Pseudomonas folliculitis) is an infection of ...

  3. Production of a bioflocculant from Pseudomonas veronii L918 using the hydrolyzate of peanut hull and its application in the treatment of ash-flushing wastewater generated from coal fired power plant.

    PubMed

    Liu, Weijie; Hao, Yan; Jiang, Jihong; Zhu, Aihua; Zhu, Jingrong; Dong, Zhen

    2016-10-01

    In this study, bioflocculant produced by Pseudomonas veronii L918 was applied to treat ash-flushing wastewater. The strain L918 could convert the hydrolyzate of peanut hull into bioflocculant, which can effectively reduce the production cost of bioflocculant. The yield of 3.39g/L bioflocculant MBF-L918 was achieved when 300mL/L peanut hull hydrolyzate was used as carbon source. The bioflocculant MBF-L918 contains 77.14% polysaccharides and 4.84% proteins, and the molecular weight (MW) of MBF-L918 is 24.77kDa. Furthermore, MBF-L918 showed good flocculating efficiency of 92.51% to ash-flushing wastewater when 2.83mg/L MBF-L918 was added, and thus achieved the recycling of ash-flushing wastewater. This study reported for the first time that the bioflocculant was produced using peanut hull hydrolyzate and effectively applied in the treatment of coal ash-flushing wastewater. PMID:27372012

  4. Biological Control Activities of Rice-Associated Bacillus sp. Strains against Sheath Blight and Bacterial Panicle Blight of Rice.

    PubMed

    Shrestha, Bishnu K; Karki, Hari Sharan; Groth, Donald E; Jungkhun, Nootjarin; Ham, Jong Hyun

    2016-01-01

    Potential biological control agents for two major rice diseases, sheath blight and bacterial panicle blight, were isolated from rice plants in this study. Rice-associated bacteria (RABs) isolated from rice plants grown in the field were tested for their antagonistic activities against the rice pathogens, Rhizoctonia solani and Burkholderia glumae, which cause sheath blight and bacterial panicle blight, respectively. Twenty-nine RABs were initially screened based on their antagonistic activities against both R. solani and B. glumae. In follow-up retests, 26 RABs of the 29 RABs were confirmed to have antimicrobial activities, but the rest three RABs did not reproduce any observable antagonistic activity against R. solani or B. glumae. According to16S rDNA sequence identity, 12 of the 26 antagonistic RABs were closest to Bacillus amyloliquefaciens, while seven RABs were to B. methylotrophicus and B, subtilis, respectively. The 16S rDNA sequences of the three non-antagonistic RABs were closest to Lysinibacillus sphaericus (RAB1 and RAB12) and Lysinibacillus macroides (RAB5). The five selected RABs showing highest antimicrobial activities (RAB6, RAB9, RAB16, RAB17S, and RAB18) were closest to B. amyloliquefaciens in DNA sequence of 16S rDNA and gyrB, but to B. subtilis in that of recA. These RABs were observed to inhibit the sclerotial germination of R. solani on potato dextrose agar and the lesion development on detached rice leaves by artificial inoculation of R. solani. These antagonistic RABs also significantly suppressed the disease development of sheath blight and bacterial panicle blight in a field condition, suggesting that they can be potential biological control agents for these rice diseases. However, these antagonistic RABs showed diminished disease suppression activities in the repeated field trial conducted in the following year probably due to their reduced antagonistic activities to the pathogens during the long-term storage in -70C, suggesting that

  5. Biological Control Activities of Rice-Associated Bacillus sp. Strains against Sheath Blight and Bacterial Panicle Blight of Rice

    PubMed Central

    Shrestha, Bishnu K.; Karki, Hari Sharan; Groth, Donald E.; Jungkhun, Nootjarin; Ham, Jong Hyun

    2016-01-01

    Potential biological control agents for two major rice diseases, sheath blight and bacterial panicle blight, were isolated from rice plants in this study. Rice-associated bacteria (RABs) isolated from rice plants grown in the field were tested for their antagonistic activities against the rice pathogens, Rhizoctonia solani and Burkholderia glumae, which cause sheath blight and bacterial panicle blight, respectively. Twenty-nine RABs were initially screened based on their antagonistic activities against both R. solani and B. glumae. In follow-up retests, 26 RABs of the 29 RABs were confirmed to have antimicrobial activities, but the rest three RABs did not reproduce any observable antagonistic activity against R. solani or B. glumae. According to16S rDNA sequence identity, 12 of the 26 antagonistic RABs were closest to Bacillus amyloliquefaciens, while seven RABs were to B. methylotrophicus and B, subtilis, respectively. The 16S rDNA sequences of the three non-antagonistic RABs were closest to Lysinibacillus sphaericus (RAB1 and RAB12) and Lysinibacillus macroides (RAB5). The five selected RABs showing highest antimicrobial activities (RAB6, RAB9, RAB16, RAB17S, and RAB18) were closest to B. amyloliquefaciens in DNA sequence of 16S rDNA and gyrB, but to B. subtilis in that of recA. These RABs were observed to inhibit the sclerotial germination of R. solani on potato dextrose agar and the lesion development on detached rice leaves by artificial inoculation of R. solani. These antagonistic RABs also significantly suppressed the disease development of sheath blight and bacterial panicle blight in a field condition, suggesting that they can be potential biological control agents for these rice diseases. However, these antagonistic RABs showed diminished disease suppression activities in the repeated field trial conducted in the following year probably due to their reduced antagonistic activities to the pathogens during the long-term storage in -70C, suggesting that

  6. Mapping and validation of QTLs for rice sheath blight resistance.

    PubMed

    Taguchi-Shiobara, Fumio; Ozaki, Hidenobu; Sato, Hiroyuki; Maeda, Hiroaki; Kojima, Yoichiro; Ebitani, Takeshi; Yano, Masahiro

    2013-09-01

    Sheath blight, caused by Rhizoctonia solani, is one of the most serious diseases of rice. Among 33 rice accessions, mainly from National Institute of Agrobiological Sciences (NIAS) Core Collection, we found three landraces from the Himalayas-Jarjan, Nepal 555 and Nepal 8-with resistance to sheath blight in 3 years' field testing. Backcrossed inbred lines (BILs) derived from a cross between Jarjan and the leading Japanese cultivar Koshihikari were used in QTL analyses. Since later-heading lines show fewer lesions, we used only earlier-heading BILs to avoid association with heading date. We detected eight QTLs; the Jarjan allele of three of these increased resistance. Only one QTL, on chromosome 9 (between markers Nag08KK18184 and Nag08KK18871), was detected in all 3 years. Chromosome segment substitution lines (CSSLs) carrying it showed resistance in field tests. Thirty F2 lines derived from a cross between Koshihikari and one CSSL supported the QTL. PMID:24273425

  7. Polymicrobial Ventriculitis Involving Pseudomonas fulva

    PubMed Central

    Rebolledo, Paulina A.; Vu, Catphuong Cathy L.; Carlson, Renee Donahue; Kraft, Colleen S.; Anderson, Evan J.

    2014-01-01

    Infections due to Pseudomonas fulva remain a rare but emerging concern. A case of ventriculitis due to Enterobacter cloacae and Pseudomonas fulva following placement of an external ventricular drain is described. Similar to other reports, the organism was initially misidentified as Pseudomonas putida. The infection was successfully treated with levofloxacin. PMID:24648556

  8. Pseudomonas psychrotolerans sp. nov.

    PubMed

    Hauser, Elke; Kämpfer, Peter; Busse, Hans-Jürgen

    2004-09-01

    Three yellow-pigmented, Gram-negative, rod-shaped, non-spore-forming bacterial strains, C36T, C37 and C39, were isolated in the Medical Clinic for Small Animals and Ungulates at the University for Veterinary Medicine in Vienna, Austria. On the basis of 16S rRNA gene sequence similarity, strain C36T was shown to belong to the genus Pseudomonas; Pseudomonas oleovorans DSM 1045T was the nearest relative (99.5 % sequence similarity). Other Pseudomonas species shared <97 % sequence similarity with strain C36T. The presence of Q-9 as the major ubiquinone, the predominance of putrescine and spermidine in its polyamine patterns and its fatty acid profile [i.e. the predominance of C(16 : 0), summed feature 3 (C(16 : 1)omega7c and/or 2-OH C(15 : 0) iso), C(18 : 1)omega7c and the presence of 3-OH C(10 : 0), 3-OH C(12 : 0) and 2-OH C(12 : 0)] were in agreement with identification of this strain as a member of the genus Pseudomonas. Physiological and biochemical characteristics and the results of genomic fingerprinting clearly differentiated strain C36T from its phylogenetic relative P. oleovorans DSM 1045T. Results from DNA-DNA hybridization showed that strain C36T represents a species that is distinct from P. oleovorans DSM 1045T. These data demonstrate that strain C36T represents a novel species of the genus Pseudomonas, for which the name Pseudomonas psychrotolerans sp. nov. is proposed. The type strain is C36T (= LMG 21977T = DSM 15758T). Additionally, physiological, biochemical, chemotaxonomic and genomic fingerprints indicate that P. oleovorans ATCC 29347 may not be a member of the species P. oleovorans sensu stricto. PMID:15388721

  9. The 2009 late blight pandemic in eastern USA – causes and results

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The tomato late blight pandemic of 2009 made late blight into a household term in much of the Eastern United States. Many home gardeners and organic producers lost most if not all of their tomato crop, and their experiences were reported in the mainstream press. Some CSAs (Community Supported Agricu...

  10. Survival potential of Phytophthora infestans in relation to environmental factors and late blight occurrence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potato is an important crop globally and late blight (Phytophthora infestans) often results in severe crop loss. The cost for late blight control can be in excess of $210 million in the United States. We utilized a non-parametric density distribution analysis of local temperature (Temp) and relative...

  11. Breeding for resistance to early blight in potato (Solanum tuberosum L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early blight of potato (Solanum tuberosum L.), caused by Alternaria solani, is a major cause of economic losses in many potato growing regions. We have identified two early blight resistant clones EB24-24 and EB24-3, which are hybrids between the cultivated (S. tuberosum) potato clone US-W4 (2x=24) ...

  12. Late blight-resistant tuber-bearing Solanum species in field and laboratory trials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Late blight, caused by Phytophthora infestans, is the most disastrous and widespread disease of potato. One of the most effective means of controlling late blight is through the use of resistant cultivars, but newly developed resistant cultivars often lose their resistance after a few years of comm...

  13. Confirming QTLs and finding additional loci responsible for resistance to rice sheath blight disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice sheath blight disease (Rhizoctonia solani AG1-1AKühn) is one of the most destructive rice diseases worldwide. Utilization of host resistance is the most economical and environmentally sound strategy in managing sheath blight (ShB). Ten ShB-QTLs were previously mapped in a LJRIL population using...

  14. Development of early and late blight under different cropping systems and irrigation management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop and soil management may influence development and control of early and late blight; however, their effects are not well documented. From 2006-2008, we evaluated the effects of cropping system and irrigation on incidence and severity of early and late blight of potato, and on microclimatic param...

  15. Release of four new breeding lines having resistance to blast and sheath blight diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight and rice blast diseases are serious threats to rice production worldwide. High-yielding cultural management practices, such as high nitrogen application and high plant populations, encourage development of these diseases. Complete resistance to sheath blight has not been identified, al...

  16. Breeding for Early Blight Resistance in Potato Using the Wild Species Solanum Raphanifolium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early blight of potato (Solanum tuberosum L.), caused by Alternaria solani is a major cause of economic losses in many potato growing regions. Growers are interested in the development of potato cultivars with resistance to early blight as a means to decrease usage of fungicide applications. Using w...

  17. Inheritance and linkage map positions of genes conferring resistance to stemphylium blight in lentil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stemphylium blight (caused by Stemphylium botryosum Wallr.) is one of the major diseases of lentil (Lens culinaris Medik.) in South Asia and North America. The objective of the study was to identify linkage map position of the genes conferring resistance to stemphylium blight and the markers linked ...

  18. PROTEOMIC ANALYSIS OF POTATO LATE BLIGHT RESISTANCE MEDIATED BY THE RB RESISTANCE GENE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Late blight, caused by the oomycete pathogen, Phytophthora infestans, is a devastating disease of potatoes and tomatoes. A gene RB, cloned from the Mexican diploid potato species Solanum bulbocastanum, confers robust resistance to potato late blight. RB encodes a protein belonging to the CC-NBS-LRR ...

  19. IDENTIFICATION OF RB-ORTHOLOGOUS GENES FROM LATE BLIGHT RESISTANT DIPLOID POTATO

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Late blight, caused by the oomycete pathogen, Phytophthora infestans, is a devastating disease of potatoes and tomatoes. A gene RB, cloned from the Mexican diploid potato species Solanum bulbocastanum, confers broad spectrum resistance to potato late blight. To identify RB-like genes and understand ...

  20. Azalea Web Blight Control: Fungicide Timing in the Nursery and Hot Water Treatment of Stem Cuttings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Azalea web blight is an annual problem on some evergreen azalea cultivars grown in containerized nursery production in the southern and eastern United States. Multiple control strategies are being investigated to control the binucleate Rhizoctonia species that cause web blight. The disease will deve...

  1. Development and characterization of RiceCAP QTL mapping population for sheath blight resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    RiceCAP is a USDA CSREES funded project that has as one of its main objectives developing genetic markers associated with sheath blight resistance. Sheath blight, caused by Rhizoctonia solani, is an important disease of rice in the southern US. Tolerance to the disease is quantitatively inherited an...

  2. Leaf Petiole and Stem Blight Disease of Sweet Potato Caused by Alternaria Bataticola in Uganda

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternaria leaf petiole and stem blight is an important disease of sweet potato (Ipomoea batatus (L.) Lam.) in tropical and sub-tropical regions. In surveys conducted in Uganda from 2001 to 2003, disease incidence ranged from 0-49%. Symptoms of Alternaria leaf and stem blight disease consisted of sm...

  3. Greenhouse-based inoculation methods for Sclerotinia blight resistance in peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Greenhouse-based assays for screening germplasm for resistance to Sclerotinia blight in peanuts can be conducted year-round, and thus may accelerate progress in breeding for resistant plants. Several techniques for assaying Sclerotinia blight resistance in the greenhouse have been proposed including...

  4. Site-specific risk factors for ray blight in Tasmanian pyrethrum fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ray blight of pyrethrum, caused by Phoma ligulicola var. inoxydablis can cause significant reductions in crop growth and pyrethrin yield. Weather and site-specific disease risk factors for ray blight have not been identified or quantified in terms of relative risk, which has limited the efficiency ...

  5. Effect of nitrogen fertilization and fungicides on Botryosphaeria stem blight lesion development on detached blueberry stems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Botryosphaeria stem blight is a destructive disease of blueberries. Field observations indicate stem blight is more severe on vigorous plants than on slower growing plants. Two studies compared the effect of two types of fertilizers applied at four rates and nine fungicides on lesion development fo...

  6. Botryosphaeria Stem Blight on Blueberries: Effect of Vaccinium Cultivar, Botryosphaeriaceae Species and Temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Botryosphaeria stem blight is a destructive disease of blueberries grown in the southern United States. Historically stem blight has been reported to be caused by the fungus Botryosphaeria dothidea. Recently, other genera in the Botryosphaeriaceae family have been identified as causal pathogens of ...

  7. Segregation of progeny of Solanum tuberosum subsp. andigena for foliar and tuber resistance to late blight.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Breeding solely for foliar resistance to late blight without emphasis on tuber resistance has the potential to exacerbate tuber infection. Wild potato species are valuable sources of foliar and tuber blight resistance. However, most species are difficult to sexually hybridize with cultivated potat...

  8. Reaction of the core collection of peanut germplasm to Sclerotinia blight and pepper spot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2001, entries from the peanut core collection, a subset of the USDA peanut germplasm collection, were planted in non-replicated plots in a field with a history of Sclerotinia blight. Variability existed among entries for reaction to Sclerotinia blight. Of the 744 entries evaluated, 11% had no d...

  9. PGPR: A novel strategy for the control of rice sheath blight disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight caused by Rhizoctonia solani is the most important rice disease in Texas, Arkansas, Mississippi and other southern states. Due to the lack of sheath blight resistance in most commonly planted cultivars, southern rice famers apply more than 1 million pounds of fungicides annually to co...

  10. Fusarium Head Blight resistance QTL in the NC-Neuse / AGS2000 recombinant inbred population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Breeding for resistance to Fusarium Head Blight is of major importance as the disease can have serious negative impacts on wheat production in warm and humid regions of the world, including the state of North Carolina. Fusarium Head Blight can cause significant grain yield reduction, but also severe...