Analysis of Aggressiveness of Erwinia amylovora Using Disease-Dose and Time Relationships

The aggressiveness of an extensive collection of strains of Erwinia amylovora was analyzed using immature fruit and detached pear flower assays under controlled environmental conditions. The analysis was performed by means of a quantitative approach based on fitting data to mathematical models that relate infection incidence to pathogen dose and time. Probit and hyperbolic saturation models were used for disease-dose relationships and provided information on the median effective dose (ED50). Values of ED50 ranged from 103 to 106 CFU/ml (10 to 104 CFU per site of inoculation). A modified Gompertz model was used for disease-time relationships and provided information on the rate of infection incidence progression (rg) and time delayed to start of the incidence progress curve (t0). Values of rg ranged from near 0 to 1.90, and t0 varied from 1.3 to more than 10 days. The more aggressive strains showed high rg, low ED50 values, and short t0, whereas the less aggressive strains showed low rg, high ED50, and long t 0. The aggressiveness was dependent on plant material type and pear cultivars and was significantly different between strains of E. amylovora. Infectivity titration and kinetic analysis of progression of incidence of infections using the immature pear test and a standardized scale are proposed for assessment of strain aggressiveness. The implications of rg, ED50, and t0 for the epidemiology and management of fire blight are discussed, particularly the wide range of aggressiveness among strains, the degree of host specificity observed in pear isolates, the very high infective potential of this pathogen, the independent action of pathogen cells during infection, and the possible advantage of including aggressiveness parameters into fire blight risk forecasting systems.

Download Full-text

Resistance of Raspberry Cultivars to Fire Blight

HortScience ◽

10.21273/hortsci.39.6.1189 ◽

2004 ◽

Vol 39 (6) ◽

pp. 1189-1192 ◽

Cited By ~ 4

Author(s):

P.G. Braun ◽

P.D. Hildebrand ◽

A.R. Jamieson

Keyword(s):

Disease Severity ◽

Fire Blight ◽

Erwinia Amylovora ◽

Rubus Idaeus ◽

The Other ◽

Lesion Length ◽

Disease Development ◽

Red Raspberry ◽

Progress Curve ◽

Wide Range

Twenty-five cultivars of red raspberry (Rubus idaeus L.) and one purple raspberry (R. occidentalis L. × R. idaeus L.) were evaluated for their resistance to fire blight caused by Erwinia amylovora (Burr.) Winslow et al. Actively growing raspberry cane tips were wound inoculated with three isolates of the pathogen and disease development was assessed over 17 days. Three methods of evaluating resistance were used: area under the disease progress curve (AUDPC), a weighted AUDPC called the area under the disease severity curve (AUDSC), and lesion length. A wide range of resistance levels was observed, but no cultivars were symptomless. Primocane-fruiting cultivars tended to be more resistant than floricane-fruiting ones. Of the three E. amylovora isolates used in this study, one was significantly more virulent than the other two, but no cultivar × isolate interaction was detected.

Download Full-text

Survival of Apple Rootstocks to Natural Infections of Fire Blight

HortTechnology ◽

10.21273/horttech.12.2.239 ◽

2002 ◽

Vol 12 (2) ◽

pp. 239-241 ◽

Cited By ~ 3

Author(s):

D.C. Ferree ◽

J.C. Schmid ◽

B.L. Bishop

Keyword(s):

Fire Blight ◽

Erwinia Amylovora ◽

Apple Rootstocks ◽

Apple Trees ◽

Wide Range ◽

Dwarfing Rootstocks

Survival of replicated rootstock plantings of apple trees (Malus ×domestica) to fire blight (Erwinia amylovora) infection shows that a wide range of rootstock susceptibility exists. Trees on `Malling 26' (M.26), `Malling 9' (M.9), and `Mark' consistently had significant losses. Of the dwarfing rootstocks widely available commercially, `Budagovsky 9' (B.9) survived well with productive trees, but was not resistant to fire blight infection. The following experimental rootstocks had good survivability with many live productive trees in one or more trials: `Poland 2' (P.2), `Vineland 1' (V.1), `Malling 27 EMLA' (M.27 EMLA), `Budagovsky 491' (B.491), `Budagovsky 409' (B.409), `Vineland 7' (V.7), `Vineland 4' (V.4), and `Oregon Rootstock 1' (OAR1).

Download Full-text

Fire Blight Susceptibility in Pyrus Germplasm from Eastern Europe

HortScience ◽

10.21273/hortsci.25.5.566 ◽

1990 ◽

Vol 25 (5) ◽

pp. 566-568 ◽

Cited By ~ 6

Author(s):

T. van der Zwet ◽

R.L. Bell

Keyword(s):

Eastern Europe ◽

Fire Blight ◽

Erwinia Amylovora ◽

Breeding Program ◽

Plant Germplasm ◽

Plant Exploration ◽

Moderately Resistant

During 1976-1980, three plant exploration trips were made throughout eastern Europe in search of native Pyrus germplasm. A total of 384 accessions (231 from Yugoslavia, 86 from Romania, 43 from Poland, and 12 each from Hungary and Czechoslovakia) were collected as budwood and propagated at the National Plant Germplasm Quarantine Center in Glenn Dale, Md. Following 8 years of exposure to the fire blight bacterium [Erwinia amylovora (Burr.) Winsl. et al.], 17.49” of the accessions remained uninfected, 11.2% rated resistant, 6.8% moderately resistant, and 64.6% blighted severely (26% to 100% of tree blighted). Some of the superior accessions have been released for use in the pear breeding program.

Download Full-text

Batch Anaerobic Co-Digestion and Biochemical Methane Potential Analysis of Goat Manure and Food Waste

Energies ◽

10.3390/en14071952 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1952

Author(s):

Ayobami Orangun ◽

Harjinder Kaur ◽

Raghava R. Kommalapati

Keyword(s):

Food Waste ◽

Gompertz Model ◽

Water Displacement ◽

Biochemical Methane Potential ◽

Greenhouse Gasses ◽

Nonlinear Regression Models ◽

The Us ◽

Methane Potential ◽

Goat Manure ◽

Modified Gompertz Model

The improper management of goat manure from concentrated goat feeding operations and food waste leads to the emission of greenhouse gasses and water pollution in the US. The wastes were collected from the International Goat Research Center and a dining facility at Prairie View A&M University. The biochemical methane potential of these two substrates in mono and co-digestion at varied proportions was determined in triplicates and processes were evaluated using two nonlinear regression models. The experiments were conducted at 36 ± 1 °C with an inoculum to substrate ratio of 2.0. The biomethane was measured by water displacement method (pH 10:30), absorbing carbon dioxide. The cumulative yields in goat manure and food waste mono-digestions were 169.7 and 206.0 mL/gVS, respectively. Among co-digestion, 60% goat manure achieved the highest biomethane yields of 380.5 mL/gVS. The biodegradabilities of 33.5 and 65.7% were observed in goat manure and food waste mono-digestions, while 97.4% were observed in the co-digestion having 60% goat manure. The modified Gompertz model is an excellent fit in simulating the anaerobic digestion of food waste and goat manure substrates. These findings provide useful insights into the co-digestion of these substrates.

Download Full-text

Isolation and efficacy of two bacterial strains antagonists of Erwinia amylovora and Pectobacterium carotovorum

Egyptian Journal of Biological Pest Control ◽

10.1186/s41938-021-00443-0 ◽

2021 ◽

Vol 31 (1) ◽

Author(s):

M’hamed BENADA ◽

Boualem BOUMAAZA ◽

Sofiane BOUDALIA ◽

Omar KHALADI

Keyword(s):

Fire Blight ◽

Erwinia Amylovora ◽

Bacterial Species ◽

Crop Protection ◽

Soft Rot ◽

Causal Agent ◽

Plant Diseases ◽

Ecological Niches ◽

Pectobacterium Carotovorum ◽

Bacterial Strains

Abstract Background The development of ecofriendly tools against plant diseases is an important issue in crop protection. Screening and selection process of bacterial strains antagonists of 2 pathogenic bacterial species that limit very important crops, Erwinia amylovora, the causal agent of the fire blight disease, and Pectobacterium carotovorum, the causal agent of bacterial potato soft rot, were reported. Bacterial colonies were isolated from different ecological niches, where both pathogens were found: rhizosphere of potato tubers and fruits and leaves of pear trees from the northwest region of Algeria. Direct and indirect confrontation tests against strains of E. amylovora and P. carotovorum were performed. Results Results showed a significant antagonistic activity against both phytopathogenic species, using direct confrontation method and supernatants of cultures (p<0.005). In vitro assays showed growth inhibitions of both phytopathogenic species. Furthermore, results revealed that the strains of S. plymuthica had a better inhibitory effect than the strains of P. fluorescens against both pathogens. In vivo results on immature pear fruits showed a significant decrease in the progression of the fire blight symptoms, with a variation in the infection index from one antagonistic strain to another between 31.3 and 50%, and slice of potato showed total inhibition of the pathogen (P. carotovorum) by the antagonistic strains of Serratia plymuthica (p<0.005). Conclusion This study highlighted that the effective bacteria did not show any infection signs towards plant tissue, and considered as a potential strategy to limit the fire blight and soft rot diseases.

Download Full-text

Optimizing anaerobic co-digestion of goat manure and cotton gin trash using biochemical methane potential (BMP) test and mathematical modeling

SN Applied Sciences ◽

10.1007/s42452-021-04706-1 ◽

2021 ◽

Vol 3 (8) ◽

Author(s):

Harjinder Kaur ◽

Raghava R. Kommalapati

Keyword(s):

Liquid Fraction ◽

Gompertz Model ◽

Biochemical Methane Potential ◽

Methane Potential ◽

Mathematical Equations ◽

Goat Manure ◽

Bmp Test ◽

Batch Bioreactors ◽

Modified Gompertz Model ◽

Cotton Gin

AbstractAnaerobic co-digestion is widely adopted to enhance process efficacy by balancing the C/N ratio of the feedstock while converting organic wastes to biomethane. Goat manure (GM) and cotton gin trash (CGT) were anaerobically co-digested in triplicate batch bioreactors. The process was optimized and evaluated utilizing mathematical equations. The liquid fraction of the digestate was analyzed for nitrate and phosphate. The co-digestions with 10 and 20% CGT having the C/N ratios of 17.7 and 19.8 yielded the highest and statistically similar 261.4 ± 4.8 and 262.6 ± 4.2 mL/gvs biomethane, respectively. The biodegradability (BD) of GM and CGT was 94.5 ± 2.7 and 37.6 ± 0.8%, respectively. The BD decreased proportionally with an increase in CGT percentage. The co-digestion having 10% CGT yielded 80–90% of biomethane in 26–39 d. The modified Gompertz model-predicted and experimental biomethane values were similar. The highest synergistic effect index of 15.6 ± 4.7% was observed in GM/CGT; 30:70 co-digestion. The concentration of nitrate and phosphate was lower in the liquid fraction of digestate than the feedstocks, indicating that these nutrients stay in the solid fraction. The results provide important insights in agro-waste management, further studies determining the effects of effluent application on plants need to be conducted.

Download Full-text

EVALUATION AND SELECTION OF FIRE BLIGHT RESISTANCE IN APPLE WITH REFERENCE TO DIFFERENTIAL VIRULENCE IN ERWINIA AMYLOVORA

Acta Horticulturae ◽

10.17660/actahortic.1987.217.45 ◽

1987 ◽

pp. 263-264 ◽

Cited By ~ 3

Author(s):

J.L. Norelli ◽

H.S. Aldwinckle ◽

R.C. Lamb ◽

S.V. Beer

Keyword(s):

Fire Blight ◽

Erwinia Amylovora ◽

Blight Resistance ◽

Selection Of

Download Full-text

Isolation and characterization of Hena1 – a novel Erwinia amylovora bacteriophage

FEMS Microbiology Letters ◽

10.1093/femsle/fnaa070 ◽

2020 ◽

Vol 367 (9) ◽

Author(s):

Natalya V Besarab ◽

Artur E Akhremchuk ◽

Maryna A Zlatohurska ◽

Liudmyla V Romaniuk ◽

Leonid N Valentovich ◽

...

Keyword(s):

Pathogenic Bacteria ◽

Fire Blight ◽

Antimicrobial Agents ◽

Erwinia Amylovora ◽

Gc Content ◽

Control Measures ◽

Effective Control ◽

Lytic Phage ◽

Trna Genes ◽

Isolation And Characterization

ABSTRACT Fire blight, caused by plant pathogenic bacterium Erwinia amylovora, is one of the most important diseases of Rosaceae plants. Due to the lack of effective control measures, fire blight infections pose a recurrent threat on agricultural production worldwide. Recently, bacterial viruses, or bacteriophages, have been proposed as environmentally friendly natural antimicrobial agents for fire blight control. Here, we isolated a novel bacteriophage Hena1 with activity against E. amylovora. Further analysis revealed that Hena1 is a narrow-host-range lytic phage belonging to Myoviridae family. Its genome consists of a linear 148,842 bp dsDNA (48.42% GC content) encoding 240 ORFs and 23 tRNA genes. Based on virion structure and genomic composition, Hena1 was classified as a new species of bacteriophage subfamily Vequintavirinae. The comprehensive analysis of Hena1 genome may provide further insights into evolution of bacteriophages infecting plant pathogenic bacteria.

Download Full-text