Effect of kasugamycin, oxytetracycline, and streptomycin on in-orchard population dynamics of Erwinia amylovora on apple flower stigmas

Plant Disease ◽  
2020 ◽  
Author(s):  
Suzanne Slack ◽  
Kellie J Walters ◽  
Cory Outwater ◽  
George W. Sundin
Keyword(s):  
Population Dynamics ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Disease Incidence ◽  
Population Data ◽  
Antibiotic Activity ◽  
The Other ◽  
Control Efficacy ◽  
Weather Parameters

We assessed the effect of three antibiotics (streptomycin, oxytetracycline, and kasugamycin) on populations of the fire blight pathogen Erwinia amylovora on apple flower stigmas during three field seasons. Timing of application relative to E. amylovora presence on flower stigmas had little impact on both population dynamics and subsequent disease incidence. While E. amylovora populations on water-treated flowers increased to 106-7 cfu flower-1 after 4-5 days in each experiment, the antibiotics streptomycin and kasugamycin caused statistically-significant reductions of stigma populations by as many as 4-5 logs over a 4-5 day period in two of the three experiments. In contrast, the effect of oxytetracycline on E. amylovora populations on stigmas was more variable, with reductions in E. amylovora populations only observed in one of the three experiments. In agreement with the population data, disease incidence was significantly higher on oxytetracycline-treated flowers compared to the other antibiotic treatments in two of three years. Statistical analyses of effects of weather parameters on antibiotic activity revealed that solar radiation and temperature negatively impacted the activity of both kasugamycin and oxytetracycline. We further assessed the potential for photodegradation of formulated kasugamycin (Kasumin 2L, Arysta LifeSciences), and found that Kasumin 2L was susceptible to degradation in vitro after exposure to a 16-hr photoperiod of daily light integrals (DLIs) varying from 6 to 35 mol·m–2·d–1. We further determined that exposure to three consecutive 16-hr photoperiods of DLIs of 23 or 35 mol·m–2·d–1 reduced the available concentration of Kasumin 2L (assessed using a bioassay) from 100 g ml-1 to 10-20 g ml-1. Our results correlate the superior blossom blight control efficacy of kasugamycin and streptomycin to significant population reductions of E. amylovora on apple flower stigmas but indicate that, similar to oxytetracycline, kasugamycin is vulnerable to photodegradation which would suggest that further considerations should be made when applying this antibiotic.

In-orchard population dynamics of Erwinia amylovora on apple flower stigmas

2022 ◽  
Author(s):  
Suzanne Slack ◽  
Jeff Schachterle ◽  
Emma Sweeney ◽  
Roshni Kharadi ◽  
Jingyu Peng ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Wind Speed ◽  
Relative Humidity ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Field Studies ◽  
Post Inoculation ◽  
Time Period ◽  
Weather Parameters ◽  
Frequent Sampling

Populations of the fire blight pathogen Erwinia amylovora Ea110 on apple flower stigmas were tracked over the course of apple bloom in field studies conducted between 2016 and 2019. In 18 of 23 experiments, flower stigmas inoculated on the 1st day of opening were found to harbor large (106-107 cells / flower) populations of E. amylovora when assessed three to five days post-inoculation. However, populations inoculated on stigmas of flowers that were already open for three days did not reach 106 cells / flower, and populations inoculated on stigmas of flowers that were already open for five days never exceeded 104 cells / flower. During this study, >10-fold increases in E. amylovora stigma populations in a 24-hr time period (termed population surges) were observed on 34.8%, 20.0%, and 4.0% of possible days on 1-day, 3-day, and 5-day open flowers, respectively. Population surges occurred on days with average temperatures as high as 24.5°C and as low as 6.1°C. Experiments incorporating more frequent sampling during days and overnight revealed that many population surges occurred between 10:00 PM and 2:00 AM. A Pearson’s correlation analysis of weather parameters occurring during surge events indicated that population surges were significantly associated with situations where overnight temperatures either increased or remained constant, where wind speed decreased, and where relative humidity increased. This study refines our knowledge of E. amylovora population dynamics and further indicates that E. amylovora is able to infect flowers during exposure to colder field temperatures than previously reported.

scholarly journals Assessment of fire blight resistance in apple clonal rootstocks using molecular markers

2021 ◽  
Vol 181 (4) ◽  
pp. 185-191
Author(s):  
I. N. Shamshin ◽  
M. V. Maslova ◽  
N. V. Drenova ◽  
M. L. Dubrovsky ◽  
O. V. Parusova
Keyword(s):  
Microsatellite Marker ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Leaf Explants ◽  
The Other ◽  
Scar Markers ◽  
Apple Rootstock ◽  
Apple Rootstocks ◽  
Main Components

Background. Clonal apple rootstocks are one of the main components of intensive gardening. The degree of rootstock damage by fire blight affects the resistance of the variety–rootstock combination. The paper presents a study on marking quantitative trait loci (QTL) of resistance to fire blight Erwinia amylovora in clonal apple rootstock.Materials and methods. A collection of 20 rootstock forms was analyzed. For the study, SCAR markers GE-8019, AE10-375 and microsatellite marker CH-F7-FB1 were used.Results. Polymorphism was observed for all three markers, and their various combinations in one genotype were revealed. It was previously noted that genotypes that carry all three markers were more resistant than those that lack them. The presence of all three markers was observed only in forms 62-396 (В10), 16-1 and 2-9-102. The other genotypes did not have the GE8019 marker. The AE10-375 marker was identified in eight clonal rootstocks. Microsatellite marker CH-F7-FB1 was present in all tested rootstocks. However, polymorphism was detected there. Most genotypes had a 174 bp fragment, but a 210 bp fragment was identified in two of the 20 forms. Clonal rootstock 70-20-21 proved heterozygous for this marker. The analyzed collection also included samples that had only the microsatellite marker: G16, Malysh Budagovskogo, Paradizka Budagovskogo (B9), 54-118 (В118), 57-491, 70-20-20 (В119), 70-20-21, 71-7-22, 76-3-6, 83-1-15, 87-7-12, and 2-12-10. The study of rootstock forms on the basis of resistance to metabolites of the fire blight pathogen was carried out under laboratory conditions using the E. amylovora culture filtrate in vitro on leaf explants. Most of the studied genotypes had different combinations of markers. However, the experiments showed that forms 62-396 and 14-1 with two out of three markers (AE10-375 and CH-F7-FB1) phenotypically manifested the trait of resistance to metabolites of E. amylovora. 

scholarly journals Susceptibility of some traditional pear cultivars of Hungarian and foreign origin to the pathogenic bacterium Erwinia amylovora

2004 ◽  
Vol 10 (3) ◽  
Author(s):  
K. Honty ◽  
M. Hevesi ◽  
M. Göndör ◽  
G. Tóth M. ◽  
V. Bács-Várkuti ◽  
...  
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Control Measure ◽  
Unknown Origin ◽  
The Other ◽  
High Susceptibility ◽  
Resistant Cultivars ◽  
Susceptibility To Infection ◽  
Prospective Control ◽  
Complete Resistance

Fire blight, a disease caused by the bacterium Erwinia amylovora (Burrill) Winslow et al., has been causing serious damage in Hungarian pear plantations since 1996. A prospective control measure could be the use of resistant cultivars. For that purpose ten pear cultivars have been tested under laboratory and greenhouse conditions for resistance to Erwinia amylovora strains collected in Hungary. Six of these cultivars are Hungarian ones of unknown origin, while four are traditional old varieties. Resistant cultivars should serve as germplasm for future breeding. Inoculations were made with a mixture of different pear isolates of the bacteria collected from various growing regions of Hungary (Ea 21, 23), at a density of 5x108 cells/ml. Susceptibility/resistance has been assessed on the basis of intensity of blight symptoms observed on shoots, flower parts and fruits. Cultivars were assigned to three susceptibility groups (low, moderate and high). Complete resistance was not found among the cultivars tested. The highest level of resistance was found in cultivar 'Kieffer', while the other cultivars displayed either moderate or high susceptibility to infection.

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 Evaluation of Kasugamycin for Fire Blight Management, Effect on Nontarget Bacteria, and Assessment of Kasugamycin Resistance Potential in Erwinia amylovora

2011 ◽  
Vol 101 (2) ◽  
pp. 192-204 ◽  
Author(s):  
Gayle C. McGhee ◽  
George W. Sundin
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Management Strategies ◽  
Resistance Management ◽  
Aminoglycoside Antibiotic ◽  
Relative Fitness ◽  
Industry Standard ◽  
High Concentrations ◽  
New Compounds

The emergence and spread of streptomycin-resistant strains of Erwinia amylovora in Michigan has necessitated the evaluation of new compounds effective for fire blight control. The aminoglycoside antibiotic kasugamycin (Ks) targets the bacterial ribosome and is particularly active against E. amylovora. The efficacy of Ks formulated as Kasumin 2L for control of fire blight was evaluated in six experiments conducted over four field seasons in our experimental orchards in East Lansing, MI. Blossom blight control was statistically equivalent to the industry standard streptomycin in all experiments. E. amylovora populations remained constant on apple flower stigmas pretreated with Kasumin and were ≈100-fold lower than on stigmas treated with water. Kasumin applied to apple trees in the field also resulted in a 100-fold reduced total culturable bacterial population compared with trees treated with water. We performed a prospective analysis of the potential for kasugamycin resistance (KsR) development in E. amylovora which focused on spontaneous resistance development and acquisition of a transferrable KsR gene. In replicated lab experiments, the development of spontaneous resistance in E. amylovora to Ks at 250 or 500 ppm was not observed when cells were directly plated on medium containing high concentrations of the antibiotic. However, exposure to increasing concentrations of Ks in media (initial concentration 25 μg ml–1) resulted in the selection of Ks resistance (at 150 μg ml–1) in the E. amylovora strains Ea110, Ea273, and Ea1189. Analysis of mutants indicated that they harbored mutations in the kasugamycin target ksgA gene and that all mutants were impacted in relative fitness observable through a reduced growth rate in vitro and decreased virulence in immature pear fruit. The possible occurrence of a reservoir of KsR genes in orchard environments was also examined. Culturable gram-negative bacteria were surveyed from six experimental apple orchards that had received at least one Kasumin application. In total, 401 KsR isolates (42 different species) were recovered from apple flowers and leaves and orchard soil samples. Although we have not established the presence of a transferrable KsR gene in orchard bacteria, the frequency, number of species, and presence of KsR enterobacterial species in orchard samples suggests the possible role of nontarget bacteria in the future transfer of a KsR gene to E. amylovora. Our data confirm the importance of kasugamycin as an alternate antibiotic for fire blight management and lay the groundwork for the development and incorporation of resistance management strategies.

scholarly journals Antibiosis Activity of Pantoea agglomerans Biocontrol Strain E325 Against Erwinia amylovora on Apple Flower Stigmas

2011 ◽  
Vol 101 (10) ◽  
pp. 1234-1241 ◽  
Author(s):  
P. L. Pusey ◽  
V. O. Stockwell ◽  
C. L. Reardon ◽  
T. H. M. Smits ◽  
B. Duffy
Keyword(s):  
Parental Strain ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Pantoea Agglomerans ◽  
Relative Area ◽  
Pathogen Inhibition ◽  
Growth Chambers ◽  
Biocontrol Strain ◽  
Crab Apple

Pantoea agglomerans E325, the active ingredient in a commercial product for fire blight control, was previously shown in vitro to produce a unique alkaline- and phosphate-sensitive antibiotic specific to Erwinia amylovora. Antibiosis was evaluated as a mode of antagonism on flower stigmas using two antibiosis-deficient mutants. On King's medium B, mutants E325ad1 and E325ad2 have stable smooth-butyrous or hypermucoid colony morphologies, respectively, and the parental strain E325 exhibits phenotypic plasticity with predominantly hypermucoid colonies accompanied by slower-growing, smooth-butyrous colonies. Mutants were tested against E. amylovora on stigmas of detached flowers of crab apple (Malus mandshurica) in growth chambers and apple (Malus domestica) in the orchard. Epiphytic fitness of the antibiosis-negative mutants was similar or greater than the parental strain as determined by relative area under the population curve (RAUPC). In laboratory and orchard trials, both mutants had significantly lower inhibitory activity against the pathogen (i.e., less reduction of E. amylovora RAUPC) compared with the parental strain. E325 and the mutants caused similar decreases in pH in a broth medium, indicating that acidification, which was previously reported as a possible mechanism of pathogen inhibition on stigmas, is not directly related to antibiosis. In this study we provide the first evidence for E325 antibiosis involved in E. amylovora growth suppression on apple flower stigmas.

EFFICACY OF TRANSMISSION OF FIRE BLIGHT RESISTANCE IN PYRUS

1968 ◽  
Vol 48 (3) ◽  
pp. 231-243 ◽  
Author(s):  
R. E. C. Layne ◽  
Catherine H. Bailey ◽  
L. F. Hough
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Common Species ◽  
The Other ◽  
Breeding Value ◽  
Screening Procedure ◽  
Blight Resistance ◽  
Quantitative Inheritance ◽  
Segregation Data

An efficient, reproducible seedling-screening procedure was devised that gave almost 100% infection yet differential levels of resistance to Erwinia amylovora. Seedling segregation for resistance to fire blight was studied for 48 separate progenies with segregation data based on 7,462 seedlings. Sources of high, intermediate or low resistance derived from P. ussuriensis, P. serotina or P. communis were compared for ability to transmit resistance to their offspring. P. communis selections that were most efficient in transmitting resistance to their progeny included: Magness, Purdue 80-51, Maxine and Mich. US 437. Similarly, the most efficient sources in the P. ussuriensis group included: Purdue 77-73, NJ 484338262 and NJ 487601174; and the most efficient in the P. serotina group included: Purdue 110-9 and Kieffer. The breeding value of the most efficient P. communis sources was considered to be superior to the other two species sources in view of the larger size and higher quality of fruit associated with P. communis.Continuous distributions rather than discontinuous segregation were obtained with most progenies, regardless of species source or level of resistance. Some distributions were similar to those associated with quantitative inheritance, others were more representative of qualitative inheritance, with dominance of resistance in each case. No consistent type of segregation distribution characterized progenies having a common species source of resistance.

scholarly journals The Role of luxS in the Fire Blight Pathogen Erwinia amylovora Is Limited to Metabolism and Does Not Involve Quorum Sensing

2007 ◽  
Vol 20 (10) ◽  
pp. 1284-1297 ◽  
Author(s):  
Fabio Rezzonico ◽  
Brion Duffy
Keyword(s):  
Gene Expression ◽  
Quorum Sensing ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Mutational Analysis ◽  
Pome Fruit ◽  
Autoinducer 2 ◽  
Metabolic Genes ◽  
Metabolic Role

Erwinia amylovora is a gram-negative phytopathogen that causes fire blight of pome fruit and related members of the family Rosaceae. We sequenced the putative autoinducer-2 (AI-2) synthase gene luxS from E. amylovora. Diversity analysis indicated that this gene is extremely conserved among E. amylovora strains. Quorum sensing mediated by LuxS has been implicated in coordinated gene expression, growth, and virulence in other enterobacteria; however, our evidence suggests this is not the function in E. amylovora. Mutational analysis pointed to a role in colonization of apple blossoms, the primary infection court for fire blight, although little if any role in virulence on apple shoots and pear fruit was observed. Expression of key virulence genes hrpL and dspA/E was reduced in mutants of two E. amylovora strains. Stronger effects on gene expression were observed for metabolic genes involved in the activated methyl cycle with mutants having greater levels of expression. No quorum-sensing effect was observed in co-culture experiments with wild-type and mutant strains either in vitro or in apple blossoms. Known receptors essential for AI-2 quorum sensing, the LuxPQ sensor kinase or the Lsr ABC-transporter, are absent in E. amylovora, further suggesting a primarily metabolic role for luxS in this bacterium.

scholarly journals Apple Proteins that Interact with DspA/E, a Pathogenicity Effector of Erwinia amylovora, the Fire Blight Pathogen

2006 ◽  
Vol 19 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Xiangdong Meng ◽  
Jean M. Bonasera ◽  
Jihyun F. Kim ◽  
Riitta M. Nissinen ◽  
Steven V. Beer
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
In Silico Analysis ◽  
Physical Interaction ◽  
Susceptibility Factors ◽  
Genes Encoding ◽  
Important Host ◽  
Two Hybrid ◽  
Silico Analysis

The disease-specific (dsp) gene dspA/E of Erwinia amylovora encodes an essential pathogenicity effector of 198 kDa, which is critical to the development of the devastating plant disease fire blight. A yeast two-hybrid assay and in vitro protein pull-down assay demonstrated that DspA/E interacts physically and specifically with four similar putative leucine-rich repeat (LRR) receptor-like serine/threonine kinases (RLK) from apple, an important host of E. amylovora. The genes encoding these four DspA/E-interacting proteins of Malus ×domestica (DIPM1 to 4) are conserved in all genera of hosts of E. amylovora tested. They also are conserved in all cultivars of apple tested that range in susceptibility to fire blight from highly susceptible to highly resistant. The four DIPMs have been characterized, and they are expressed constitutively in host plants. In silico analysis indicated that the DIPMs have similar sequence structure and resemble LRR RLKs from other organisms. Evidence is presented for direct physical interaction between DspA/E and the apple proteins encoded by the four identified clones, which may act as susceptibility factors and be essential to disease development. Knowledge of DIPMs and the interaction with DspA/E thus may facilitate understanding of fire blight development and lead to new approaches to control of disease.

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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