Characteristics of Erwinia amylovora bacteriophage and its possible role in the epidemiology of fire blight

1973 ◽  
Vol 19 (7) ◽  
pp. 837-845 ◽  
Author(s):  
J. M. Erskine
Keyword(s):  
Uv Irradiation ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Resistant Mutant ◽  
Fruit Trees ◽  
Symptom Development ◽  
Phage Resistant Mutant ◽  
Pathogenicity Tests ◽  
Optimal Efficiency ◽  
Blight Disease

Bacteriophage (S1) of Erwinia amylovora, isolated from soil at the base of fire-blight-infected trees, was characterized by small, clear plaques on E. amylovora strain PR1 and hazy plaques of the same size on a closely related, yellow, saprophytic bacterium, Y, which was isolated together with PR1 from the diseased trees. Phage S1 plated with optimal efficiency at 10C on PR1 and at 28C on Y was relatively unstable to storage at temperatures typical of summer and to ultraviolet (UV) irradiation, and lysogenized Y but not PR1. Pathogenicity tests in pear slices demonstrated that symptom development was (i) delayed when mixtures of either PR1 and phage S1 or PR1 and Y were inoculated, (ii) delayed when a culture of a phage-resistant mutant of PR1 was inoculated, and (iii) prevented from appearing at all when PR1 and the lysogenic form of Y, Y (S1), were inoculated together. Strain Y was easily lysogenized and Y (S1) released phage spontaneously and after UV irradiation. It is suggested that the yellow saprophyte, which is invariably isolated from fruit trees with E. amylovora, may frequently occur in its lysogenic form in nature and serve as a reservoir of phage which may exert some influence on the occurrence and severity of fire-blight disease.

scholarly journals Causative Pathogen of Fire Blight of Fruit Trees in Georgia

2021 ◽  
Author(s):  
Nanuli Amashukeli ◽  
Dali Gaganidze ◽  
Mariam Aznarashvili ◽  
Shorena Kharadze ◽  
Neli Sturua ◽  
...  
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Fruit Trees ◽  
Visual Observation ◽  
Pcr Analysis ◽  
Causative Pathogen ◽  
Plant Samples ◽  
Immunological Test ◽  
Blight Disease

Fire blight is a devastating disease of fruit trees that first appeared in Georgia in 2016. Above 40 samples – fruit trees twigs, buds, flowers and fruitlets, suspected on the fire blight disease were collected in the Mtskheta-Mtianeti and Shida Kartli Regions, eastern Georgia in Summer of 2020. Based on visual observation and immunological test (Ea AgriStrip), 20 plant samples were selected for further study. PCR analysis was performed to detect pathogen in these samples with primers pair A: 5′-CGG TTT TTA ACG CTG GG-3′ and B: 5′-GGG CAA ATA CTC GGA TT-3 ′ and 2XPCR BIOTAG Mix using PCR BIOSYSTEMS. The pathogen Erwinia amylovora was detected in 6 samples: N10 and N11 apple samples (Ksovrisi);

scholarly journals Evaluation of Susceptibility of Different Pear Hybrid Populations to Fire Blight (Erwinia amylovora)

2011 ◽  
Vol 39 (1) ◽  
pp. 226 ◽  
Author(s):  
Yasemin EVRENOSOĞLU ◽  
Adalet MISIRLI ◽  
Hikmet SAYGILI ◽  
Emre BİLEN ◽  
Özlem BOZTEPE ◽  
...  
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Open Pollination ◽  
Resistance Level ◽  
Class A ◽  
Class B ◽  
Artificial Inoculations ◽  
Serious Disease ◽  
Blight Disease ◽  
Santa Maria

Fire blight disease caused by pathogenic bacterium Erwinia amylovora, is the serious disease of pear, and there is not a certain chemical management against this disease except antibiotic-type compounds such as streptomycin. It is very important to improve new fire blight resistant cultivars in case of integrated disease management. With this purpose, different crosses have been made between Pyrus communis varieties that have good fruit characteristics and resistant cultigens. Besides, self and open pollination treatments have been carried out in maternal plants. The disease resistance level of the hybrids obtained from these combinations was determined by artificial inoculations by Erwinia amylovora in greenhouse conditions. A total of 3284 hybrids were inoculated, and 2631 of them survived and were distributed to different susceptibility classes. 19.88% of the inoculated hybrids was killed by Erwinia amylovora. Total distribution of the hybrids to susceptibility classes was as 6.18% in class “A- slightly susceptible”, 3.11% in class “B- less susceptible”, 8.89% in class “C- mid-susceptible”, 20.28% in class “D- susceptible”, and 61.54% in class “E- very susceptible”. Majority of class “A- slightly susceptible” hybrids were obtained from ‘Magness’ x ‘Ankara’ combination. ‘Kieffer’ x ‘Santa Maria’, ‘Kieffer’ open pollination, ‘Magness’ x ‘Akça’, ‘Magness’ x ‘Kieffer’, ‘Magness’ x ‘Santa Maria’, ‘Mustafa Bey’ x ‘Moonglow’ treatments displayed good results with respect to “A- slightly susceptible” character. It is very important to evaluate these hybrid pear populations through different fruit and tree characteristics in the future.

New potential bacterial antagonists for the biocontrol of fire blight disease (Erwinia amylovora) in Morocco

2018 ◽  
Vol 117 ◽  
pp. 7-15 ◽  
Author(s):  
Smail Ait Bahadou ◽  
Abderrahmane Ouijja ◽  
Abdelkarim Karfach ◽  
Abdessalem Tahiri ◽  
Rachid Lahlali
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Bacterial Antagonists ◽  
Blight Disease

scholarly journals Blackberry and raspberry are alternative resistance sources to fire blight

2017 ◽  
Vol 97 (1) ◽  
pp. 12-16 ◽  
Author(s):  
Ozer Calis ◽  
Cetin Cekic ◽  
Serhat Kara ◽  
Demet Celik Ertekin
Keyword(s):  
Bacterial Growth ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Bacterial Pathogen ◽  
Post Inoculation ◽  
Resistance Sources ◽  
Pathogenicity Tests ◽  
Susceptibility And Resistance ◽  
Resistant Genotypes ◽  
Moderate Susceptibility

Erwinia amylovora causes fire blight mainly on pear, apple and quince trees. This bacterial pathogen also infects other Rosaceous plants, such as blackberry and raspberry. A race structure was established between an isolate of E. amylovora and berries using 40 wild blackberry and 7 wild raspberry genotypes. In pathogenicity tests, wild blackberry and raspberry genotypes had three phenotypic reactions: enhanced susceptibility, moderate susceptibility and resistance. We noted a higher bacterial growth of over 300 × 109 cfu mL-1 in plants with enhanced susceptibility, with resistant genotypes showing a bacterial growth of around 150 × 109 cfu mL-1. These results are also associated with symptoms observed at 29 days post-inoculation. This resistance is being evaluated to control fire blight.

scholarly journals CRISPR genotyping as complementary tool for epidemiological surveillance of Erwinia amylovora outbreaks

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250280
Author(s):  
Rafael J. Mendes ◽  
João Pedro Luz ◽  
Conceição Santos ◽  
Fernando Tavares
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Blot Hybridization ◽  
Fruit Trees ◽  
Epidemiological Surveillance ◽  
Economic Losses ◽  
Pome Fruit ◽  
Dot Blot ◽  
Virulence Markers ◽  
Clonal Population Structure

Fire blight is a destructive plant disease caused by Erwinia amylovora affecting pome fruit trees, and responsible for large yield declines, long phytosanitary confinements, and high economic losses. In Portugal, the first major fire blight outbreaks occurred in 2010 and 2011, and although later considered eradicated, the emergence of other outbreaks in recent years stressed the need to characterize the E. amylovora populations associated with these outbreaks. In this regard, CRISPR genotyping, assessment of three virulence markers, and semi-quantitative virulence bioassays, were carried out to determine the genotype, and assess the virulence of thirty-six E. amylovora isolates associated with outbreaks occurring between 2010 and 2017 and affecting apple and pear orchards located in the country central-west, known as the main producing region of pome fruits in Portugal. The data gathered reveal that 35 E. amylovora isolates belong to one of the widely-distributed CRISPR genotypes (5-24-38 / D-a-α) regardless the host species, year and region. Ea 680 was the single isolate revealing a new CRISPR genotype due to a novel CR2 spacer located closer to the leader sequence and therefore thought to be recently acquired. Regarding pathogenicity, although dot-blot hybridization assays showed the presence of key virulence factors, namely hrpL (T3SS), hrpN (T3E) and amsG from the amylovoran biosynthesis operon in all E. amylovora isolates studied, pathogenicity bioassays on immature pear slices allowed to distinguish four virulence levels, with most of the isolates revealing an intermediate to severe virulence phenotype. Regardless the clonal population structure of the E. amylovora associated to the outbreaks occurring in Portugal between 2010 and 2017, the different virulence phenotypes, suggests that E. amylovora may have been introduced at different instances into the country. This is the first study regarding E. amylovora in Portugal, and it discloses a novel CRISPR genotype for this bacterium.

scholarly journals Reactions of different plant organs of pear cultivars to Erwinia amylovora infection

2003 ◽  
Vol 9 (1) ◽  
Author(s):  
K. Honty ◽  
Z. Boldog ◽  
M. Göndör ◽  
J. Papp ◽  
K. Kása ◽  
...  
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Process Development ◽  
Disease Process ◽  
Research Project ◽  
Plant Organs ◽  
Blight Disease

Research project has been initiated in 1999 with the aim of evaluating the degree of susceptibility/resistance of pear cultivars grown in Hungary to fire blight disease caused by Erwinia amylovora. The recently selected promising cultivars were also examined. Inoculation experiments were conducted in controlled greenhouse conditions because of quarantine regulations in Hungary. Following the disease process, development of symptoms of plant organs (shoots, flower parts, fruits) was observed. Suspension of two E. amylovora strains (Ea 21, Ea 23) isolated from pear was used in a mixture (5x108 cells x m1-1) for the inoculation. Twenty-six pear cultivars were examined and grouped into four categories: low susceptibility, moderately susceptible, susceptible and very susceptible. Most of the cultivars were susceptible or very susceptible while some promising 'Eldorado', 'Harrow Delight' and `Hosui' showed low susceptibility.

scholarly journals Management of Erwinia amylovora by Potential Bio-Pesticides in vitro and in vivo Conditions

2020 ◽  
Vol 8 (sp1) ◽  
pp. 38-45
Author(s):  
Kubilay Kurtulus Bastas
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Shoot Length ◽  
Absolute Methanol ◽  
Diffusion Method ◽  
Thymus Vulgaris ◽  
Blight Disease ◽  
Santa Maria

Erwinia amylovora, the causative agent of fire blight disease, threatens a lot of species of the Rosaceae family. Antibiotics and copper compounds in chemical applications are most frequently are applied, but these can be phytotoxic and cause resistant strains of the pathogen. In our experiments, 20 herbal materials were tested for their antimicrobial effectiveness against the fire blight pathogen in vitro and in planta. The air-dried plants ground into fine powder and extraction was performed at room temperature by maceration with 80% (v/v) methanol/distilled water. The minimum inhibitory concentration values were determined by using disc diffusion method and streptomycin was used as control in all experiments. Antimicrobial activity was evaluated by measuring the inhibition zones in reference to the pathogen. Among the tested plants, Szygium aromaticum, Thymus vulgaris and Rhus cararia showed a good antibacterial activity and they inhibited the growth of E. amylovora with inhibition zone diameter ranging from 21 to 27 mm at 20% (w/v) in absolute methanol compared to streptomycin (31 mm) in vitro conditions. In vivo tests were performed by using highly virulent E. amylovora isolate (Eak24b, 91%) grown on TSA medium and inoculation on young shoots of 3-year-old Gala variety of apple and Santa Maria variety of pear seedlings at 107 CFU ml-1 density of the pathogen. Disease severity (%) was assessed by by proportion of blighted shoot length to the whole shoot length and also efficacy of the extracts was determined by using Abbott formula. The highest efficacy was obtained by S. aromaticum and T. vulgaris extracts of reducing shoot blight of cv. Gala and cv. Santa Maria by 67.81% - 64-12% and 51.50% - 51.04% ratios, respectively. Obtaining results showed that some medicinal and aromatic plant extracts might be used against fire blight disease as potential new generation chemicals on pome fruits within integrated and organic control programs.

scholarly journals First report of Erwina amylovora in Tuscany, Italy

2021 ◽  
Vol 60 (2) ◽  
pp. 253-257
Author(s):  
Duccio MIGLIORINI ◽  
Francesco PECORI ◽  
Aida RAIO ◽  
Nicola LUCHI ◽  
Domenico RIZZO ◽  
...  
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Chromosomal Region ◽  
Reca Gene ◽  
Plant Tissues ◽  
Molecular Assays ◽  
Pcr Assays ◽  
Blight Disease ◽  
Fruit Orchards ◽  
Symptomatic Plant

2-years-old plants of Pyrus communis showing symptoms of fire blight disease were sampled in an orchard in Tuscany (Italy) during Autumn 2020. Plants were obtained the previous spring from a commercial nursery located in a region where the disease is present since 1994. The collected material was processed in the lab in order to verify the presence of the bacterium Erwinia amylovora, the causal agent of fire blight. Pure isolates showing white mucoid colonies and levan producers on Levan medium were putatively assimilated to E. amylovora. DNA was extracted from the cultures and analysed with three molecular assays, including duplex PCR of the 29-Kb plasmid pEA29 and the ams chromosomal region, sequencing of the 16S rDNA and recA gene regions, two real-time PCR assays on symptomatic plant tissues. All tests confirmed the presence of E. amylovora. Symptomatic and surrounding plants were removed and immediately destroyed according to the regional phytosanitary protocol. This outcome poses a serious threat for fruit orchards in the area.

The Occurrence of Fire Blight Disease caused by Erwinia amylovora and its Official Management in Chungbuk Province in 2019

2021 ◽  
Vol 33 (1) ◽  
pp. 22-28
Author(s):  
Young-Uk Park ◽  
Jong-Woo Han ◽  
Chul-Ku Yoon ◽  
Seok-Ho Lee ◽  
Song Yoon ◽  
...  
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Blight Disease
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