Fire Blight Of Apple Research Articles

In-Vitro Management of Erwinia amylovora caused by Fire Blight of Apple with Synthetic Chemicals

Apple (Malus pomila L) belongs to family Rosacea and it is an edible fruit; mostly utilized by different age groups. Apple trees are grown worldwide. It is considered an important fruit in the temperate region of Balochistan, Pakistan. Fire blight is caused by the pathogen Erwinia amylovora the most damaging disease of apple and other pomes orchards in the world. The aim of the present study was conducted to record the incidence of the disease and management through the use of chemicals. For this purpose, survey was conducted for disease samples from the various districts of Balochistan Viz., Quetta, Ziarat, Killa Saifullah and Kalat. Among all the districts Ziarat was found to be most severe by pathogen with 20% incidence followed by Quetta having 18.67%, Kalat14.31% and Killa Saifullah 13.44% incidence, and different chemicals, i.e. Streptomycin, Tetracycline, Gentamicin, Kasugomycin, Oxytetracycline at different doses were tested against the pathogen and all the chemicals shown great effectiveness against Erwiana amylorora In-vitro conditions. The maximum inhibition zone made by chemical streptomycin with value 15.50 and minimum value of tetracycline with 10.90.and there was no inhibition zone observed in control treatment. All the data was statistically analyzed

Emergence Characteristics of Fire Blight from 2019 to 2023 in Korea

Erwinia amylovora is a gram-negative plant pathogen that causes fire blight in apple and pear trees, resulting in significant damage worldwide. In this study, we monitored the emergence of fire blight from 2019 to 2023 to determine the emergence patterns and the factors affecting the outbreak of the disease. As a result of the 5-year survey on the emergence of fire blight, a total of 2,029 cases have emerged, mostly in apple trees of 1,378 cases (67.9%) followed by 645 cases (31.8%) in pear trees, and from quince, hawthorn, and mountain ash trees. Fire blight appeared in specific areas of Gyeonggi, Chungnam, Gangwon, and Chungbuk provinces in 2019, but spread to Andong and Yesan in 2021, Muju and Bonghwa in 2023. In 2020 and 2021, there were 744 and 618 cases of fire blight outbreaks, respectively, compared to other years (188–245 cases/year). Notably, 914 of these cases were observed in apple trees from May to July, with 667 cases reported in Chungju and Jecheon. The incidence of fire blight was positively correlated with the daily maximum temperatures and rainy days in January and February, as well as the rainy days in May and June. The average age of the diseased pear trees was 25 years, higher than the 10-year average age of the apple trees. This study provides fundamental information to understand the status and factors affecting the fire blight emergence in Korea. Prevention measures should be established through continuous analysis of the status of fire blight.

In-Vitro Management of Erwinia amylovora caused by Fire Blight of Apple with Synthetic Chemicals

In-Vitro Management of Erwinia amylovora caused by Fire Blight of Apple with Synthetic Chemicals

Control Effect against Apple Fire Blight Using Bee Vectoring Dispenser for Pollinating Bees

Control Effect against Apple Fire Blight Using Bee Vectoring Dispenser for Pollinating Bees

Persistence and evidence for accelerated biodegradation of streptomycin in agricultural soils

Some antibiotics are used for the treatment of various bacterial crop diseases, and there is a concern that this practice may represent a selection pressure that increases the reservoir of antibiotic resistance carried by bacteria in crop production systems. Since the 1950s the aminoglycoside antibiotic streptomycin has been widely used for the treatment of some bacterial crop diseases such as fire blight in apples and pears. Following application, the time that bacteria will be exposed to the antibiotic, and therefore the pressure for selection of resistance, will vary according to the environmental persistence of the antibiotic. In the present study, the dissipation of streptomycin was examined in soils supplemented with 5 mg streptomycin/kg soil and incubated for 21 days under laboratory conditions. The impact of two key rate-controlling variables, soil texture (sandy loam, loam, clay loam) and temperature (4, 20, 30 °C) on streptomycin persistence were explored. -Robust methods for streptomycin extraction and analysis by LC-MS/MS were developed. Streptomycin dissipation followed first order kinetics, with the time to dissipate 50 % of the parent compound (DT50) in soils of varying texture incubated at 20 °C ranging from about seven to 15 days. In contrast, the DT50 of streptomycin in autoclaved loam soil incubated at 20 °C was about 111 days. At 4 °C the DT50 ranged from 49 to 137 days. Under no incubation conditions were any extractable transformation products obtained. Streptomycin was dissipated significantly more rapidly in field soil that had a prior history of exposure to the antibiotic than in soil that did not. Taken together, these results indicate that streptomycin is amenable to biodegradation in agricultural soils with DT50s of several days when temperature is permissive.

Exploration of a multifunctional biocontrol agent Streptomyces sp. JCK-8055 for the management of apple fire blight.

Apple fire blight, caused by the bacterium Erwinia amylovora, is a devastating disease of apple and pear trees. Biological control methods have attracted much attention from researchers to manage plant diseases as they are eco-friendly and viable alternatives to synthetic pesticides. Herein, we isolated Streptomyces sp. JCK-8055 from the root of pepper and investigated its mechanisms of action against E. amylovora. Streptomyces sp. JCK-8055 produced aureothricin and thiolutin, which antagonistically affect E. amylovora. JCK-8055 and its two active metabolites have a broad-spectrum in vitro activity against various phytopathogenic bacteria and fungi. They also effectively suppressed tomato bacterial wilt and apple fire blight in in vivo experiments. Interestingly, JCK-8055 colonizes roots as a tomato seed coating and induces apple leaf shedding at the abscission zone, ultimately halting the growth of pathogenic bacteria. Additionally, JCK-8055 can produce the plant growth regulation hormone indole-3-acetic acid (IAA) and hydrolytic enzymes, including protease, gelatinase, and cellulase. JCK-8055 treatment also triggered the expression of salicylate (SA) and jasmonate (JA) signaling pathway marker genes, such as PR1, PR2, and PR3. Overall, our findings demonstrate that Streptomyces sp. JCK-8055 can control a wide range of plant diseases, particularly apple fire blight, through a combination of mechanisms such as antibiosis and induced resistance, highlighting its excellent potential as a biocontrol agent. KEY POINTS: • JCK-8055 produces the systemic antimicrobial metabolites, aureothricin, and thiolutin. • JCK-8055 treatment upregulates PR gene expression in apple plants against E. amylovora. • JCK-8055 controls plant diseases with antibiotics and induced resistance.

Copper-Based Compounds against Erwinia amylovora: Response Parameter Analysis and Suppression of Fire Blight in Apple

Fire blight, caused by Erwinia amylovora, is one of the major bacterial disease of apple and pear, causing enormous economic losses worldwide. Several control measures against E. amylovora have been reported till date, however, none of them have proved to be effective significantly against the pathogen. In this study, mechanisms of the copper-based control agents (CBCAs): copper oxychloride (COCHL), copper oxide (COX), copper hydroxide (CHY), copper sulfate basic (CSB), and tribasic copper sulfate (TCS) and their disease severity reduction efficacy against E. amylovora were analyzed. Bis-1,3-dibutylbarbituric acid trimethine oxonol, carboxyl fluorescein diacetate succinimidyl ester, and 5-cyano-2,3-ditolyl tetrazolium chloride staining were used to check the damage of membrane potential, cytoplasmic pHin, and respiration of CBCAs-treated E. amylovora, respectively. High disturbance in the membrane potential of E. amylovora was found under COX and COCHL treatments. Similarly, higher significant changes in the inner cytoplasmic pHin were observed under COX, COCHL, and TCS treatment. CHY and COCHL-treated E. amylovora showed a significant reduction in respiration. In vitro bioassay results revealed that CHY, CSB, and TCS at 2,000 ppm reduced the severity of fire blight both in pre- and post-treatment of CBCAs in immature apple fruits and seedlings. Overall, the most effective CBCAs against E. amylovora could be CHY at 2,000 ppm as its showed inhibition mechanisms and disease severity reduction.

Host-derived chimeric peptides clear the causative bacteria and augment host innate immunity during infection: A case study of HLB in citrus and fire blight in apple.

Bacterial diseases cause severe losses in the production and revenue of many fruit crops, including citrus and apple. Huanglongbing (HLB) in citrus and fire blight in apple are two deadly diseases without any cure. In this article, we introduce a novel therapy for HLB and fire blight by enhancing the innate immunity of the host plants. Specifically, we constructed in silico a library of chimeras containing two different host peptides with observed or predicted antibacterial activity. Subsequently, we performed bactericidal and toxicity tests in vitro to select a few non-toxic chimeras with high antibacterial activity. Finally, we conducted ex planta studies to show that not only do the chimeras clear the causative bacteria from citrus leaves with HLB and from apple leaves with fire blight but they also augment the host's innate immunity during infection. This platform technology can be extended to design host-derived chimeras against multiple pathogenic bacteria that cause diseases in plants and animals of agricultural importance and in humans.

Physicochemical Characterization and Antimicrobial Activity against Erwinia amylovora, Erwinia vitivora, and Diplodia seriata of a Light Purple Hibiscus syriacus L. Cultivar.

Phytochemicals are essential raw materials for the production of formulations that can be helpful in crop protection. In particular, Hibiscus spp., which are often used in traditional medicine, are rich in potential bioactive molecules. This study presents an analysis of the thermal, vibrational, and phytochemical characteristics of a light purple variety of Hibiscus syriacus, using thermal gravimetric and differential scanning calorimetry, Fourier-transform infrared spectroscopy, and gas chromatography-mass spectroscopy techniques. Further, with a view to its valorization, the antimicrobial activity of its extracts has been investigated in vitro against Erwinia amylovora (the phytopathogen responsible for fire blight in apples, pears, and some other members of the family Rosaceae), Erwinia vitivora (the causal agent of the “maladie d’Oléron” in grapevines), and Diplodia seriata (responsible for “Bot canker”). Higher heating values and thermal features showed similarities with kenaf biomass. The main compounds identified in the hydro-methanolic extracts were: in flowers, 1-heptacosanol, heptacosane, 1-tetracosanol, hexadecenoic acid, 9,12,15-octadecatrienoic acid, and 9,12-octadecadienoic acid; and in leaves, the coumarin derivative 4,4,6,8-tetramethyl-2-chromanone, vitamin E, phytol, and sitosterol. MIC values of 500 and 375 μg·mL−1 were obtained against E. amylovora for flower and leaf extracts, respectively, upon conjugation with chitosan oligomers (to improve solubility and bioavailability). In the case of E. vitivora, MIC values of 250 and 500 μg·mL−1, respectively, were registered. Regarding the antifungal activity, EC90 values of 975.8 and 603.5 μg·mL−1, respectively, were found. These findings suggest that H. syriacus (cv. ‘Mathilde’) may be a promising source of antimicrobials for agriculture.

Physicochemical Characterization of Crithmum maritimum L. and Daucus carota subsp. gummifer (Syme) Hook.fil. and Their Antimicrobial Activity against Apple Tree and Grapevine Phytopathogens

Crithmum maritimum and Daucus carota subsp. gummifer are two species of the Apiaceae family that share multiple characteristics: both are halophitic, live on cliffs in the same geographic habitats, and are edible. While C. maritimum is rich in essential oils and flavonoids, D. carota is rich in terpenes and a gum producer. In the work presented herein, the biomass of these two wild plants and the bioactive compounds present in their extracts have been studied by elemental and thermal analysis, infrared spectroscopy, and gas chromatography-mass spectroscopy. To explore their bioactivities, both their hydroalcoholic extracts and their major constituents (apiole in C. maritimum and geranyl acetate in D. carota), either alone or in combination with chitosan oligomers, were assayed in vitro against bacterial and fungal pathogens that affect apple trees (Malus domestica) and grapevine (Vitis vinifera). Remarkable inhibition was observed against Erwinia amylovora, the causal agent of fire blight in apple; Xylophilus ampelinus [syn. Erwinia vitivora], the causal agent of bacterial blight of grapevine; and Diplodia seriata, a virulent pathogen of grapevines that also causes canker, leaf spot and fruit rot of apple. In view of their effectiveness against these three phytopathogens, a potential application of these two medicinal plants in organic farming may be envisaged.

Use of a growth regulator (prohexadione-Ca) and summer pruning as post symptom rescue treatments following a fire blight infection during bloom

Fire blight of apples (Erwinia amylovora) can be a serious disease depending on production area and year. Bloom is the most frequent starting point for infection and the primary focus for sprays which can prevent infection, or of growth regulators such as prohexadione-Ca (ProCa) to limit spread. Because of the sporadic cases, many growers opt to forego bloom sprays when disease pressure is low. When symptoms do appear, quickly pruning out affected branches is currently the most effective control measure. Our goal was to determine if ProCa applied when symptoms appear, instead of during bloom when infection risks are predicted, could be used to limit disease spread, and if this would interact with summer symptom removal. The study was carried out in 2018 and 2019 at the IRDA orchard in Saint-Bruno-de-Montarville, Quebec. Plots inoculated during bloom were allocated to treatments in which diseased branches were either pruned during summer or only in winter, and trees sprayed with ProCa starting at bloom, when symptoms appeared, or not. Potential for disease progression was assessed by inoculating shoots and rating them for disease severity and ooze production. Significantly less wood was removed from trees pruned during the summer as opposed to winter, but total yield was reduced. ProCa had no effect on the amount of dead wood pruned, but still reduced disease severity. We found that ProCa reduced ooze on inoculated shoots and that post symptom timing was as effective as the bloom spray. Delaying sprays until symptoms appear could become an alternative strategy to reduce summer spread of fire blight.

Inhibition of Erwinia amylovora by Bacillus nakamurai.

A variety of potential inhibitors were tested for the first time for the suppression of Erwinia amylovora, the causal agent of fire blight in apples and pears. Strain variability was evident in susceptibility to inhibitors among five independently isolated virulent strains of E. amylovora. However, most strains were susceptible to culture supernatants from strains of Bacillus spp., and particularly to the recently described species B. nakamurai. Minimal inhibitory concentrations (MICs) were 5-20% (vol/vol) of culture supernatant from B. nakamurai against all five strains of E. amylovora. Although Bacillus species have been previously reported to produce lipopeptide inhibitors of E. amylovora, matrix-assisted laser desorption time of flight mass spectrometry (MALDI-TOF MS) and column chromatography indicated that the inhibitor from B. nakamurai was not a lipopeptide, but rather a novel inhibitor.

Optimization of Fermentation Conditions of Lentinula edodes (Berk.) Pegler (Shiitake Mushroom) Mycelia as a Potential Biopesticide

The shiitake mushroom [Lentinula edodes (Berk.) Pegler], is a new source of biopesticide against bacterial spot of tomato having similar efficacy as that of traditional antibiotics in vitro. The culture-filtrates of fifteen commercially available L. edodes strains were screened for antibacterial activity against Erwinia amylovora (Ea) and Xanthomonas campestris pv. vesicatoria (Xcv), based on fermentation time and carbon source for minimum oxalic acid production. Two different carbon sources, glucose and sucrose for fifteen and 30 days were used for fermentation. The detection and quantification of oxalic acid in culture filtrates were performed by using HPLC. Most of the L. edodes strains inhibited the growth of Ea (13 out of 15) and Xcv (14 out of 15) with similar efficacy as that of the control treatment of 100 µg mL–1 streptomycin sulfate. Two of the L. edodes strains, ATCC 38164 and ATCC 28760 released the least amount of oxalic acid in both carbon sources, but did not differ from each other significantly. The concentration of oxalic acid in glucose medium was generally lower than that in sucrose medium, while strains ATCC 20635 and ATCC 38167 released the highest and similar concentrations in both carbon sources. This study provides preliminary evidence that L. edodes strains may be potential alternatives to streptomycin and copper compounds as a source of metabolites against bacterial spot of tomato and fire blight of apple [Malus × domestica (Borkh.)] and merits further investigation.

Toward a Weather-Based Forecasting System for Fire Blight and Downy Mildew

The aim of this research is to present a weather-based forecasting system for apple fire blight (Erwinia amylovora) and downy mildew of grapevine (Plasmopara viticola) under Serbian agroecological conditions and test its efficacy. The weather-based forecasting system contains Numerical Weather Prediction (NWP) model outputs and a disease occurrence model. The weather forecast used is a product of the high-resolution forecast (HRES) atmospheric model by the European Centre for Medium-Range Weather Forecasts (ECMWF). For disease modelling, we selected a biometeorological system for messages on the occurrence of diseases in fruits and vines (BAHUS) because it contains both diseases with well-known and tested algorithms. Several comparisons were made: (1) forecasted variables for the fifth day are compared against measurements from the agrometeorological network at seven locations for three months (March, April, and May) in the period 2012–2018 to determine forecast efficacy; (2) BAHUS runs driven with observed and forecast meteorology were compared to test the impact of forecasted meteorological data; and (3) BAHUS runs were compared with field disease observations to estimate system efficacy in plant disease forecasts. The BAHUS runs with forecasted and observed meteorology were in good agreement. The results obtained encourage further development, with the goal of fully utilizing this weather-based forecasting system.

Development of an Improved Loop-Mediated Isothermal Amplification Assay for On-Site Diagnosis of Fire Blight in Apple and Pear.

Fast and accurate diagnosis is needed to eradicate and manage economically important and invasive diseases like fire blight. Loop-mediated isothermal amplification (LAMP) is known as the best on-site diagnostic, because it is fast, highly specific to a target, and less sensitive to inhibitors in samples. In this study, LAMP assay that gives more consistent results for on-site diagnosis of fire blight than the previous developed LAMP assays was developed. Primers for new LAMP assay (named as DS-LAMP) were designed from a histidine-tRNA ligase gene (EAMY_RS32025) of E. amylovora CFBP1430 genome. The DS-LAMP amplified DNA (positive detection) only from genomic DNA of E. amylovora strains, not from either E. pyrifoliae (causing black shoot blight) or from Pseudomonas syringae pv. syringae (causing shoot blight on apple trees). The detection limit of DS-LAMP was 10 cells per LAMP reaction, equivalent to 104 cells per ml of the sample extract. DS-LAMP successfully diagnosed the pathogens on four fire-blight infected apple and pear orchards. In addition, it could distinguish black shoot blight from fire blight. The Bühlmann-LAMP, developed previously for on-site diagnosis of fire blight, did not give consistent results for specificity to E. amylovora and on-site diagnosis; it gave positive reactions to three strains of E. pyrifoliae and two strains of P. syringae pv. syringae. It also, gave positive reactions to some healthy sample extracts. DS-LAMP, developed in this study, would give more accurate on-site diagnosis of fire blight, especially in the Republic of Korea, where fire blight and black shoot blight coexist.

Fire Blight of Apple, Caused by Erwinia amylovora, a New Disease in Korea

Fire Blight of Apple, Caused by <i>Erwinia amylovora</i>, a New Disease in Korea

English

The bacterial antagonist Pantoea agglomerans P10c was evaluated for efficacy to control fire blight in Morocco. It was evaluated in the laboratory on detached blossoms (pre and post-inoculation of pathogen) and under field for its ability to suppress growth of Erwinia amylovora on blossoms of pear trees (Pyrus communis); and for its aptitude to establish on and to colonize the blossoms of apple tree (Malus domestica) under field conditions. Results revealed that the installation of P. agglomerans P10c strain on detached blossom before the inoculation with the E. amylovora (preventive treatment) allows an efficient control of the disease (96%), with an incidence that never exceed the level 2.5%. but for curative treatment the incidence increased to 40% and the efficiency was only about 32%. Under field, P. agglomerans P10c applied a twice (10 and 60% bloom time) at 108 CFU/ml reduced significantly the incidence of fire blight by 64.7 to 76.9%. The experiment of the establishment and the survivability of P. agglomerans P10c in the stigma showed a positive evolution which increased from 4.5×104 to 7.6×105 CFU/flower. Results from this work illustrate that this antagonistic strain is able to control efficiently fire blight in apple and pear trees under the conditions of the arias of Meknes. Keys words: Erwinia amylovora, Pantoea agglomerans P10c, antagonist, blossom, preventive treatment, apple tree, pear tree, Meknes.

Effectiveness of a Peptide-rich Fraction from &lt;i&gt;Xenorhabdus budapestensis&lt;/i&gt; Culture against Fire Blight Disease on Apple Blossoms

Erwinia amylovora is one of the most frequently occurred plant pathogenic bacterium. It causes necrosis and blight symptoms on host plantsand it lead to considerable yield losses throughout the world on apple trees. There is no effective chemical treatment is currently available against fire blight. The purpose of the present study was to search a new, alternative control method. The evaluation of the plant protection potential of an enriched fraction of Xenorhabdus budapestensis cell-free conditioned media was investigated. Purified samples were tested in vitro and in plantaagainst the phytopathogenic bacterium. A reproducible method for isolation of a peptide-rich fraction from Xenorhabdus cell-free conditionedmedia was established. The process resulted in 400 mg of dry sample prepared from three litres of Xenorhabdus cell culture. Significant correlation was found between the concentration of the purified preparation and the induced inactivation zones against Erwinia amylovora Ea1 in agardiffusion test method. The minimum inhibitory concentration and minimum bactericidal concentration of the purified fraction against Ea1strain were 8 ;g/mL and 16 ;g/mL, respectively. In planta experiments were tested on an apple cultivar (‘Watson Jonathan’) susceptible to fireblight. The effective range of concentration was 62-200 μg/mL, while treatment with 300 μg/mL and larger amounts caused necrotic symptomson the petals of flowers. Current study pointed to the effectiveness of the compounds produced by X. budapestensis against fire blight. Thedevelopment of a commercially applicable formulation of these compounds would allow growers to effectively control fire blight in apple and pearorchards.

Effectiveness of a Peptide-rich Fraction from &lt;i&gt;Xenorhabdus budapestensis&lt;/i&gt; Culture against Fire Blight Disease on Apple Blossoms

Erwinia amylovora is one of the most frequently occurred plant pathogenic bacterium. It causes necrosis and blight symptoms on host plantsand it lead to considerable yield losses throughout the world on apple trees. There is no effective chemical treatment is currently available against fire blight. The purpose of the present study was to search a new, alternative control method. The evaluation of the plant protection potential of an enriched fraction of Xenorhabdus budapestensis cell-free conditioned media was investigated. Purified samples were tested in vitro and in plantaagainst the phytopathogenic bacterium. A reproducible method for isolation of a peptide-rich fraction from Xenorhabdus cell-free conditionedmedia was established. The process resulted in 400 mg of dry sample prepared from three litres of Xenorhabdus cell culture. Significant correlation was found between the concentration of the purified preparation and the induced inactivation zones against Erwinia amylovora Ea1 in agardiffusion test method. The minimum inhibitory concentration and minimum bactericidal concentration of the purified fraction against Ea1strain were 8 ;g/mL and 16 ;g/mL, respectively. In planta experiments were tested on an apple cultivar (‘Watson Jonathan’) susceptible to fireblight. The effective range of concentration was 62-200 μg/mL, while treatment with 300 μg/mL and larger amounts caused necrotic symptomson the petals of flowers. Current study pointed to the effectiveness of the compounds produced by X. budapestensis against fire blight. Thedevelopment of a commercially applicable formulation of these compounds would allow growers to effectively control fire blight in apple and pearorchards.

Mutation of the Erwinia amylovora argD gene causes arginine auxotrophy, nonpathogenicity in apples, and reduced virulence in pears.

Fire blight is caused by Erwinia amylovora and is the most destructive bacterial disease of apples and pears worldwide. In this study, we found that E. amylovora argD(1000)::Tn5, an argD Tn5 transposon mutant that has the Tn5 transposon inserted after nucleotide 999 in the argD gene-coding region, was an arginine auxotroph that did not cause fire blight in apple and had reduced virulence in immature pear fruits. The E. amylovora argD gene encodes a predicted N-acetylornithine aminotransferase enzyme, which is involved in the production of the amino acid arginine. A plasmid-borne copy of the wild-type argD gene complemented both the nonpathogenic and the arginine auxotrophic phenotypes of the argD(1000)::Tn5 mutant. However, even when mixed with virulent E. amylovora cells and inoculated onto immature apple fruit, the argD(1000)::Tn5 mutant still failed to grow, while the virulent strain grew and caused disease. Furthermore, the pCR2.1-argD complementation plasmid was stably maintained in the argD(1000)::Tn5 mutant growing in host tissues without any antibiotic selection. Therefore, the pCR2.1-argD complementation plasmid could be useful for the expression of genes, markers, and reporters in E. amylovora growing in planta, without concern about losing the plasmid over time. The ArgD protein cannot be considered an E. amylovora virulence factor because the argD(1000)::Tn5 mutant was auxotrophic and had a primary metabolism defect. Nevertheless, these results are informative about the parasitic nature of the fire blight disease interaction, since they indicate that E. amylovora cannot obtain sufficient arginine from apple and pear fruit tissues or from apple vegetative tissues, either at the beginning of the infection process or after the infection has progressed to an advanced state.