scholarly journals Temporal and spatial dynamics in the apple flower microbiome in the presence of the phytopathogen Erwinia amylovora

2020 ◽  
Author(s):  
Zhouqi Cui ◽  
Regan B. Huntley ◽  
Quan Zeng ◽  
Blaire Steven
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Temporal Dynamics ◽  
Spatial Dynamics ◽  
Potential Interaction ◽  
Specific Gene ◽  
Large Populations ◽  
Single Flower ◽  
Temporal And Spatial ◽  
Blight Disease

AbstractPlant microbiomes have important roles in plant health and productivity. However, despite flowers being directly linked to reproductive outcomes, little is known about the microbiomes of flowers and their potential interaction with pathogen infection. Here, we investigated the temporal dynamics and spatial traits of the apple stigma microbiome when challenged with a phytopathogen Erwinia amylovora, the causal agent of fire blight disease. We profiled the microbiome from the stigmas of a single flower, greatly increasing the resolution at which we can characterize shifts in the composition of the microbiome. Individual flowers harbored unique microbiomes at the OTU level. However, taxonomic analysis of community succession showed a population gradually dominated by bacteria within the families Enterobacteriaceae and Pseudomonadaceae. Flowers inoculated E. amylovora established large populations of the phytopathogen, with pathogen specific gene counts of >3.0 × 107 in 90% of the flowers. Yet, only 42% of inoculated flowers later developed fire blight symptoms. This reveals pathogen amount on the stigma is not sufficient to predict disease outcome. Our data demonstrate that apple flowers represent an excellent model in which to characterize how plant microbiomes establish, develop, and interact with biological processes such as disease progression in an experimentally tractable plant organ.

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 Episodic Dynamics of Tar Spot of Annual Lespedeza Within and Among Years

Plant Disease ◽  
1997 ◽  
Vol 81 (5) ◽  
pp. 535-540 ◽  
Author(s):  
J. D. Mihail ◽  
R. L. McGraw ◽  
P. E. Verslues ◽  
S. J. Taylor
Keyword(s):  
Disease Severity ◽  
Temporal Dynamics ◽  
Disease Incidence ◽  
Spatial Dynamics ◽  
Silty Clay ◽  
Disease Dynamics ◽  
Silty Clay Loam ◽  
Row Crops ◽  
Tar Spot ◽  
Temporal And Spatial

The temporal and spatial dynamics of six tar spot epidemics were examined at two sites in mid-Missouri during 1990 to 1992. The sites, 48 km apart, differed in topography (flat versus slope), soil texture (silt loam versus silty-clay loam), and cropping history (orchard versus row crops). Temporal dynamics of disease incidence differed more among years than between sites. During 1990, temporal dynamics of the two epidemics followed a classic monotonic increase, whereas disease increase was episodic for the four epidemics observed during 1991 and 1992. Disease increase was associated with shading of the plant canopy or with the presence of dodder. Disease increase was related inversely to intercepted photosynthetically active radiation. Taken together, these observations suggest that factors that increase shading in the lespedeza canopy also increase tar spot incidence. For only two of the six epidemics was there a significant relationship between disease incidence (proportion of leaflets diseased) and disease severity (proportion of leaflet area diseased), with disease severity rarely exceeding 10%. These observations suggest that relatively low tar spot incidence may result in significant leaf losses, which would reduce lespedeza hay quality and yield. Further, this study demonstrates the importance of experimental repetition in both space and time to fully appreciate the range of disease dynamics for a single pathosystem.

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 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 Translatome Profiling of Plum Pox Virus–Infected Leaves in European Plum Reveals Temporal and Spatial Coordination of Defense Responses in Phloem Tissues

2020 ◽  
Vol 33 (1) ◽  
pp. 66-77 ◽  
Author(s):  
Tamara D. Collum ◽  
Andrew L. Stone ◽  
Diana J. Sherman ◽  
Elizabeth E. Rogers ◽  
Christopher Dardick ◽  
...  
Keyword(s):  
Virus Infection ◽  
Affinity Purification ◽  
Spatial Dynamics ◽  
Leaf Tissue ◽  
Defense Responses ◽  
Specific Gene ◽  
Plum Pox Virus ◽  
Leaf Morphogenesis ◽  
Perennial Plant ◽  
Temporal And Spatial

Plum pox virus (PPV) is the causative agent of sharka, a devastating disease of stone fruits including peaches, apricots, and plums. PPV infection levels and associated disease symptoms can vary greatly, depending upon the virus strain, host species, or cultivar as well as developmental age of the infected tissues. For example, peaches often exhibit mild symptoms in leaves and fruit while European plums typically display severe chlorotic rings. Systemic virus spread into all host tissues occurs via the phloem, a process that is poorly understood in perennial plant species that undergo a period of dormancy and must annually renew phloem tissues. Currently, little is known about how phloem tissues respond to virus infection. Here, we used translating ribosome affinity purification followed by RNA sequencing to identify phloem- and nonphloem-specific gene responses to PPV infection during leaf development in European plum (Prunus domestica L.). Results showed that, during secondary leaf morphogenesis (4- and 6-week-old leaves), the phloem had a disproportionate response to PPV infection with two- to sixfold more differentially expressed genes (DEGs) in phloem than nonphloem tissues, despite similar levels of viral transcripts. In contrast, in mature 12-week-old leaves, virus transcript levels dropped significantly in phloem tissues but not in nonphloem tissues. This drop in virus transcripts correlated with an 18-fold drop in phloem-specific DEGs. Furthermore, genes associated with defense responses including RNA silencing were spatially coordinated in response to PPV accumulation and were specifically induced in phloem tissues at 4 to 6 weeks. Combined, these findings highlight the temporal and spatial dynamics of leaf tissue responses to virus infection and reveal the importance of phloem responses within a perennial host.

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