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 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.

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

scholarly journals Establishment of Bacterial Antagonists of Erwinia amylovora on Pear and Apple Blossoms as Influenced by Inoculum Preparation

1998 ◽  
Vol 88 (6) ◽  
pp. 506-513 ◽  
Author(s):  
V. O. Stockwell ◽  
K. B. Johnson ◽  
J. E. Loper
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Culture Media ◽  
Field Trials ◽  
Bacterial Cells ◽  
Fluorescent Microspheres ◽  
Bacterial Antagonists ◽  
Spray Inoculation ◽  
Population Sizes ◽  
Inoculum Preparation

The influence of inoculum preparation on the establishment of bacterial antagonists that suppress fire blight and Erwinia amylovora on blossoms was evaluated. Aqueous suspensions of Pseudomonas fluorescens A506, E. herbicola C9-1R, or E. amylovora 153N were prepared from cells harvested from the surface of an agar medium or from cells that were lyophilized after culture under similar conditions. Bacterial suspensions (1 × 108 CFU/ml) were sprayed on pear and apple trees at 50% bloom near midday. The incidence of recovery (proportion of blossoms containing detectable populations) and the population sizes of the bacteria on individual blossoms with detectable populations were followed over a period of several days. Fluorescent microspheres (1 μm in diameter) were added to sprays at a concentration of 1 × 107 microspheres per ml to mark blossoms that were open during application of bacteria. After dilution-plating, the stigmas and styles of each blossom were examined for the presence of microspheres with an epifluorescence microscope. In three of five trials, bacteria applied as suspensions of lyophilized cells were recovered from a greater proportion of blossoms than bacterial cells harvested directly from culture media. Every blossom harvested within 6 days after spraying had microspheres present on the surfaces of the styles and stigmas; thus, lack of establishment of detectable populations, rather than escape of blossoms from spray inoculation, accounted for the differences in proportion of blossoms colonized by the different preparations of bacteria. The use of lyophilized cells in field trials decreased variability in the establishment of bacteria on blossoms.

scholarly journals HIPM Is a Susceptibility Gene of Malus spp.: Reduced Expression Reduces Susceptibility to Erwinia amylovora

2019 ◽  
Vol 32 (2) ◽  
pp. 167-175 ◽  
Author(s):  
Manuela Campa ◽  
Stefano Piazza ◽  
Laura Righetti ◽  
Chang-Sik Oh ◽  
Lorenza Conterno ◽  
...  
Keyword(s):  
Crop Production ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Susceptibility Gene ◽  
Bimolecular Fluorescence Complementation ◽  
Interacting Protein ◽  
Blight Disease ◽  
Oxygen Evolving ◽  
Transgenic Apple

Fire blight, a devastating disease caused by the bacterium Erwinia amylovora, is a major threat to apple crop production. To improve our understanding of the fire blight disease and to identify potential strategies to control the pathogen, we studied the apple protein HIPM (for HrpN-interacting protein from Malus spp.), which has previously been identified as interacting with the E. amylovora effector protein HrpN. Transgenic apple plants were generated with reduced HIPM expression, using an RNA interference construct, and were subsequently analyzed for susceptibility to E. amylovora infection. Lines exhibiting a greater than 50% silencing of HIPM expression showed a significant decrease in susceptibility to E. amylovora infection. Indeed, a correlation between HIPM expression and E. amylovora infection was identified, demonstrating the crucial role of HIPM during fire blight disease progression. Furthermore, an apple oxygen-evolving enhancer-like protein (MdOEE) was identified via a yeast two-hybrid screen to interact with HIPM. This result was confirmed with bimolecular fluorescence complementation assays and leads to new hypotheses concerning the response mechanism of the plant to E. amylovora as well as the mechanism of infection of the bacterium. These results suggest that MdOEE and, particularly, HIPM are promising targets for further investigations toward the genetic improvement of apple.

scholarly journals Nectar- and stigma-specific expression of a chitinase could partially protect against fire blight in certain apples

2019 ◽  
Author(s):  
Anita Kurilla ◽  
Timea Toth ◽  
Laszlo Dorgai ◽  
Zsuzsanna Darula ◽  
Tamas Lakatos ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Specific Expression ◽  
Physiological Concentration ◽  
Apple Cultivars ◽  
Nectar Protein ◽  
Blight Disease ◽  
Stigma Exudate

AbstractTo attract pollinators many angiosperms secrete stigma exudate and nectar in their flowers. As these nutritious fluids are ideal infection points for pathogens, both secretions contain various antimicrobial compounds. Erwinia amylovora, the causing bacterium of the devastating fire blight apple disease, is the model pathogen that multiplies in flower secretions and infects through the nectaries. Although Erwinia resistant apples are not available, certain cultivars are tolerant. It was reported that in stigma infection assay, the ‘Freedom’ cultivar was Erwinia tolerant while the ‘Jonagold’ was susceptible. We hypothesized that differences in the nectar protein compositions lead to different susceptibility. Indeed we found that an acidic chitinase III protein (Machi3-1) selectively accumulates in the nectar and stigma of the ‘Freedom’ cultivar. We demonstrate that MYB binding site containing repeats of the ‘Freedom’ Machi3-1 promoter are responsible for the strong nectar- and stigma-specific expression. As we found that in vitro the Machi3-1 protein impairs growth and biofilm formation of Erwinia at physiological concentration, we propose that the Machi3-1 contribute to the tolerance by inhibiting Erwinia multiplication in the stigma exudate and in the nectar. We show that the Machi3-1 allele was introgressed from Malus floribunda 821 into different apple cultivars including the ‘Freedom’.HighlightCertain apple cultivars accumulate to high levels in their nectar and stigma an acidic chitinase III protein that can protect against pathogens including fire blight disease causing Erwinia amylovora

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