Molecular Characterization and Taxonomic Assignment of three Phage Isolates from a Collection Infecting Pseudomonas syringae pv. actinidiae and P. syringae pv. phaseolicola from Northern Italy

Bacterial kiwifruit vine disease (Pseudomonas syringae pv. actinidiae, Psa) and halo blight of bean (P. syringae pv. phaseolicola, Pph) are routinely treated with copper, leading to environmental pollution and bacterial copper resistance. An alternative sustainable control method could be based on bacteriophages, as phage biocontrol offers high specificity and does not result in the spread of toxic residues into the environment or the food chain. In this research, specific phages suitable for phage-based biocontrol strategies effective against Psa and Pph were isolated and characterized. In total, sixteen lytic Pph phage isolates and seven lytic Psa phage isolates were isolated from soil in Piedmont and Veneto in northern Italy. Genome characterization of fifteen selected phages revealed that the isolated Pph phages were highly similar and could be considered as isolates of a novel species, whereas the isolated Psa phages grouped into four distinct clades, two of which represent putative novel species. No lysogeny-, virulence- or toxin-related genes were found in four phages, making them suitable for potential biocontrol purposes. A partial biological characterization including a host range analysis was performed on a representative subset of these isolates. This analysis was a prerequisite to assess their efficacy in greenhouse and in field trials, using different delivery strategies.

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Assessment of copper resistance in Pseudomonas syringae pv. phaseolicola, the pathogen of halo blight on snap bean

Crop Protection ◽

10.1016/j.cropro.2017.03.009 ◽

2017 ◽

Vol 98 ◽

pp. 8-15 ◽

Cited By ~ 5

Author(s):

Shouan Zhang ◽

Yuqing Fu ◽

Zelalem Mersha ◽

Ken Pernezny

Keyword(s):

Pseudomonas Syringae ◽

Copper Resistance ◽

Snap Bean ◽

Halo Blight

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Epidemiology and management of bacterial leaf spot on watermelon caused byPseudomonas syringae

Plant Disease ◽

10.1094/pdis-11-16-1628-re ◽

2017 ◽

Vol 101 (7) ◽

pp. 1222-1229 ◽

Cited By ~ 4

Author(s):

E. A. Newberry ◽

L. Ritchie ◽

B. Babu ◽

T. Sanchez ◽

K. A. Beckham ◽

...

Keyword(s):

Disease Severity ◽

Pseudomonas Syringae ◽

Leaf Spot ◽

Negative Relationship ◽

Disease Outbreaks ◽

Field Trials ◽

Multiple Regression Model ◽

Bacterial Leaf Spot ◽

Progress Curve ◽

Cool Conditions

Bacterial leaf spot of watermelon caused by Pseudomonas syringae has been an emerging disease in the southeastern United States in recent years. Disease outbreaks in Florida were widespread from 2013 to 2014 and resulted in foliar blighting at the early stages of the crop and transplant losses. We conducted a series of field trials at two locations over the course of two years to examine the chemical control options that may be effective in management of this disease, and to investigate the environmental conditions conducive for bacterial leaf spot development. Weekly applications of acibenzolar-S-methyl (ASM) foliar, ASM drip, or copper hydroxide mixed with ethylene bis-dithiocarbamate were effective in reducing the standardized area under the disease progress curve (P < 0.05). Pearson’s correlation test demonstrated a negative relationship between the average weekly temperature and disease severity (–0.77, P = 0.0002). When incorporated into a multiple regression model with the square root transformed average weekly rainfall, these two variables accounted for 71% of the variability observed in the weekly disease severity (P < 0.0001). This information should be considered when choosing the planting date for watermelon seedlings as the cool conditions often encountered early in the spring season are conducive for bacterial leaf spot development.

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Comparison of materials used for cleaning equipment in retail food premises, and of two methods for the enumeration of bacteria on cleaned equipment and work surfaces

Journal of Hygiene ◽

10.1017/s0022172400028692 ◽

1970 ◽

Vol 68 (2) ◽

pp. 221-232 ◽

Cited By ~ 24

Author(s):

R. J. Gilbert

Keyword(s):

Control Method ◽

Field Trials ◽

Surface Sampling ◽

Step Procedure ◽

Cleaning Equipment ◽

Before And After ◽

Plate Counts ◽

Self Service ◽

Materials Used ◽

Retail Food

SUMMARYThere is no official scheme for testing disinfectants and detergent/disinfectants for use in the retail food trade and few recommended procedures have been given for the cleaning of equipment with these agents. Therefore, field trials were carried out in a large self-service store. Comparisons were made of the various cleaning efficiencies, as determined by bacterial plate counts, of detergent and disinfectant solutions and machine cleaning oils applied with either clean cloths or disposable paper towels to items of equipment. The most satisfactory results were always obtained when anionic detergent (0·75 % w/v) and hypochlorite (200 p.p.m. available chlorine) solutions were applied in a ‘two-step’ procedure.Tests were made to compare the calcium alginate swab-rinse and the agar sausage (Agaroid) techniques for the enumeration of bacteria on stainless steel, plastic, formica and wooden surfaces before and after a cleaning process. Although recovery rates were always greater by the swab-rinse technique, the agar sausage technique was considered to be a useful routine control method for surface sampling.

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Characterization of a Unique Chromosomal Copper Resistance Gene Cluster from Xanthomonas campestris pv. vesicatoria

Applied and Environmental Microbiology ◽

10.1128/aem.71.12.8284-8291.2005 ◽

2005 ◽

Vol 71 (12) ◽

pp. 8284-8291 ◽

Cited By ~ 44

Author(s):

Huseyin Basim ◽

Gerald V. Minsavage ◽

Robert E. Stall ◽

Jaw-Fen Wang ◽

Savita Shanker ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Resistance Genes ◽

Xanthomonas Campestris ◽

Sinorhizobium Meliloti ◽

The United States ◽

Copper Resistance ◽

Pcr Analysis ◽

Pepper Plant ◽

Gene Encoding ◽

Copper Resistance Genes

ABSTRACT We characterized the copper resistance genes in strain XvP26 of Xanthomonas campestris pv. vesicatoria, which was originally isolated from a pepper plant in Taiwan. The copper resistance genes were localized to a 7,652-bp region which, based on pulsed-field gel electrophoresis and Southern hybridization, was determined to be located on the chromosome. These genes hybridized only weakly, as determined by Southern analysis, to other copper resistance genes in Xanthomonas and Pseudomonas strains. We identified five open reading frames (ORFs) whose products exhibited high levels of amino acid sequence identity to the products of previously reported copper genes. Mutations in ORF1, ORF3, and ORF4 removed copper resistance, whereas mutations in ORF5 resulted in an intermediate copper resistance phenotype and insertions in ORF2 had no effect on resistance conferred to a copper-sensitive recipient in transconjugant tests. Based on sequence analysis, ORF1 was determined to have high levels of identity with the CopR (66%) and PcoR (63%) genes in Pseudomonas syringae pv. tomato and Escherichia coli, respectively. ORF2 and ORF5 had high levels of identity with the PcoS gene in E. coli and the gene encoding a putative copper-containing oxidoreductase signal peptide protein in Sinorhizobium meliloti, respectively. ORF3 and ORF4 exhibited 23% identity to the gene encoding a cation efflux system membrane protein, CzcC, and 62% identity to the gene encoding a putative copper-containing oxidoreductase protein, respectively. The latter two ORFs were determined to be induced following exposure to low concentrations of copper, while addition of Co, Cd, or Zn resulted in no significant induction. PCR analysis of 51 pepper and 34 tomato copper-resistant X. campestris pv. vesicatoria strains collected from several regions in Taiwan between 1987 and 2000 and nine copper-resistant strains from the United States and South America showed that successful amplification of DNA was obtained only for strain XvP26. The organization of this set of copper resistance genes appears to be uncommon, and the set appears to occur rarely in X. campestris pv. vesicatoria.

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Chemical Composition, Production of Secondary Metabolites and Antioxidant Activity in Coffee Cultivars Susceptible and Partially Resistant to Bacterial Halo Blight

Plants ◽

10.3390/plants10091915 ◽

2021 ◽

Vol 10 (9) ◽

pp. 1915

Author(s):

Joyce Alves Goulart da Silva ◽

Mário Lúcio Vilela de Resende ◽

Ingridy Simone Ribeiro ◽

Adriene Ribeiro Lima ◽

Luiz Roberto Marques Albuquerque ◽

...

Keyword(s):

Antioxidant Activity ◽

Chemical Composition ◽

Secondary Metabolites ◽

Pseudomonas Syringae ◽

Total Phenolic ◽

Leaf Extracts ◽

Defense Strategies ◽

Halo Blight ◽

Phenolic Profiles ◽

Phenolic And Flavonoid

Coffee production is one of the main agricultural activities in Brazil, and several coffee cultivars with disease resistance have already been developed. The secondary metabolites produced by plants are closely associated with defense strategies, and the resistance of coffee cultivars to bacterial halo blight (BHB) can be related to these compounds. Therefore, this study aims to compare a partially resistant coffee cultivar (Iapar-59) and a susceptible cultivar (Mundo Novo 376/4) to BHB (Pseudomonas syringae pv. garcae) in relation to the chemical composition and antioxidant activity of the leaf extracts. In addition, this study determined the total phenolic and flavonoid contents and phenolic profiles of the Iapar-59 leaf extracts of plants inoculated with P. syringae pv. garcae. The Iapar-59 extract showed a higher content of phenolic compounds and flavonoids than the Mundo Novo 376/4 extract. Both cultivars contained gallic, chlorogenic and caffeic acids; however, the highest contents were quantified in the Iapar-59 cultivar. The leaf extracts from the Iapar-59 cultivar exhibited higher antioxidant activity. Higher concentrations of gallic, caffeic and chlorogenic acids and the presence of vanillin were detected in the extract of cultivar Iapar-59 inoculated with P. syringae pv. garcae.

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Examination of Acephate Absorption, Transport, Metabolism, and Accumulation in Maize After Root Irrigation for Spodoptera Frugiperda Control

10.21203/rs.3.rs-407085/v1 ◽

2021 ◽

Author(s):

jiyingzi Wu ◽

xianjia Li ◽

ruiquan Hou ◽

kunyu Zhao ◽

yongqin Wang ◽

...

Keyword(s):

Pest Control ◽

Spodoptera Frugiperda ◽

Control Method ◽

Control Measure ◽

Fall Armyworm ◽

Extended Period ◽

Field Trials ◽

Pesticide Use ◽

Control Efficacy ◽

Maize Plants

Abstract BACKGROUND: Since the invasion of the fall armyworm moth (Spodoptera frugiperda) in China in January 2019, damage to maize crops has gradually intensified, and chemical control has become the main control measure. This study aimed to examine methods of effective pest control while monitoring the environmental impact of pesticide use. The effectiveness of S. frugiperda pest control by foliar spraying and root irrigation of maize plants with acephate was determined, and the absorption, distribution, and dissipation of acephate and methamidophos by maize were studied.RESULTS: Field trials showed that acephate treatment at 6000 g.a.i ha-1 was the most effective for controlling S. frugiperda. Acephate and methamidophos were absorbed from the roots, transported upward, and concentrated in the leaves, particularly new leaves. The terminal residues of acephate and methamidophos in maize grains were below detectable levels at 60 days after treatment.CONCLUSIONS: The results demonstrate that acephate treatment via root irrigation can more effectively control the infestation of S. frugiperda in maize than acephate treatment via foliar spraying. The translocation and distribution of acephate and methamidophos by root irrigation were more uniform, and the holding efficiency was higher than those in foliar spraying, suggesting an extended period of control efficacy. This pest control method could be utilized to reduce pesticide residues while safely and efficiently controlling S. frugiperda infestation.

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Isolation and Characterization of the Gene Coding for the Amidinotransferase Involved in the Biosynthesis of Phaseolotoxin in Pseudomonas syringae pv. phaseolicola

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2001.14.4.545 ◽

2001 ◽

Vol 14 (4) ◽

pp. 545-554 ◽

Cited By ~ 37

Author(s):

Gustavo Hernández-Guzmán ◽

Ariel Alvarez-Morales

Keyword(s):

Aspartic Acid ◽

Pseudomonas Syringae ◽

Sequence Similarity ◽

Insertion Mutant ◽

Halo Blight ◽

Streptomyces Spp ◽

Isolation And Characterization ◽

Gene Coding ◽

Blight Disease

Pseudomonas syringae pv. phaseolicola is the causal agent of the “halo blight” disease of beans. A key component in the development of the disease is a nonhost-specific toxin, Nδ-(N'-sulphodiaminophosphinyl)-ornithyl-alanyl-homoarginine, known as phaseolotoxin. The homoarginine residue in this molecule has been suggested to be the product of Larginine:lysine amidinotransferase activity, previously detected in extracts of P. syringae pv. phaseolicola grown under conditions of phaseolotoxin production. We report the isolation and characterization of an amidinotransferase gene (amtA) from P. syringae pv. phaseolicola coding for a polypeptide of 362 residues (41.36 kDa) and showing approximately 40% sequence similarity to Larginine:inosamine-phosphate amidinotransferase from three species of Streptomyces spp. and 50.4% with an Larginine:glycine amidinotransferase from human mitochondria. The cysteine, histidine, and aspartic acid residues involved in substrate binding are conserved. Furthermore, expression of the amtA and argK genes and phaseolotoxin production occurs at 18°C but not at 28°C. An amidinotransferase insertion mutant was obtained that lost the capacity to synthesize homoarginine and phaseolotoxin. These results show that the amtA gene isolated is responsible for the amidinotransferase activity detected previously and that phaseolotoxin production depends upon the activity of this gene.

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Chemical control of bacterial canker (Pseudomonas syringae pv. syringae) of apricot and cherry in Victoria

Australian Journal of Experimental Agriculture ◽

10.1071/ea9910705 ◽

1991 ◽

Vol 31 (5) ◽

pp. 705 ◽

Cited By ~ 10

Author(s):

DLS Wimalajeewa ◽

R Cahill ◽

G Hepworth ◽

HG Schneider ◽

JW Washbourne

Keyword(s):

Pseudomonas Syringae ◽

Chemical Control ◽

Bordeaux Mixture ◽

Weather Conditions ◽

Hydrated Lime ◽

Field Trials ◽

Bacterial Canker ◽

Copper Hydroxide ◽

Low Concentrations ◽

Excellent Control

Field trials were conducted during 1982-85, to develop a comprehensive spray program for the control of bacterial canker (Pseudomonas syringae pv, syringae) of apricot and cherry. Five spray schedules were evaluated as measures to reduce disease levels. Copper hydroxide at 2.5 g/L in water was applied to apricot, and bordeaux mixture at 6 g copper sulfate + 8 g hydrated lime/L in water was applied to cherry, during autumn, winter and pre-bloom spring. The effectiveness of copper sprays in reducing epiphytic populations of the pathogen during post-bloom spring was also tested. Copper hydroxide was applied to apricot, and a foliar copper nutrient and copper hydroxide were applied to cherry at low concentrations. Most spray schedules tested significantly (P<0.05) reduced canker incidence relative to controls. Excellent control of epiphytic populations of the pathogen on apricot and cherry was achieved with copper sprays applied at post-bloom in spring. A spray schedule consisting of 2 autumn, 1 winter and 2 pre-bloom spring sprays with copper hydroxide on apricot or bordeaux mixture on cherry was successful in reducing canker (>67% reduction) and is recommended for control of the disease. Two applications of copper hydroxide at 1.0 g/L in water in post-bloom spring considerably reduced (>9 1 %) epiphytic populations (P. syringae pv. syringae) on apricot and cherry leaves. Later sprays are recommended for use in combination with the autumn-winter-spring (pre-bloom) spray schedule, especially under excessively wet and cool weather conditions in spring.

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