Brion Duffy

• PhD
• Head of Department at ZHAW Zurich University of Applied Sciences

Kampala, the capital city of Uganda, is rapidly expanding without adequate wastewater treatment facilities to accommodate the current estimated population of 1.68 million people. Hence, freshwater bodies and natural ecosystems around the city are heavily polluted with organic and inorganic contaminants. Yet, there is a paucity of data on pathogenic...

The genus Pantoea contains a broad range of plant-associated bacteria, including some economically important plant pathogens as well as some beneficial members effective as biological control agents of plant pathogens. The most well-characterized representatives of biological control agents from this genus generally produce one or more antimicrobia...

Investigation of the evolutionary relationships between related bacterial species and genera with a variety of lifestyles have gained popularity in recent years. For analysing the evolution of specific traits, however, a robust phylogeny is essential. In this study we examined the evolutionary relationships among the closely related genera Erwinia,...

Mobile genetic elements among the twenty-nine compared Pnan and Pnst strains. The number of plasmids, phages, ICEs, IS elements and transposases are tabulated and their contribution to the total genomic DNA (%) and total proteins (%) encoded on the genome are described.

Digital DNA-DNA hybridization (dDDH) values and Average Nucleotide Identity (ANI) values between the twenty-nine compared Pnan1, Pnan2 and Pnst strains. ANI values are in the top half, while dDDH values are in the bottom half of the table. Values from 70 to 100% are colored in a sliding scale from light gray to black.

Pantoea ananatis is ubiquitously found in the environment and causes disease on a wide range of plant hosts. By contrast, its sister species, Pantoea stewartii subsp. stewartii is the host-specific causative agent of the devastating maize disease Stewart’s wilt. This pathogen has a restricted lifecycle, overwintering in an insect vector before bein...

Background: Type VI secretion systems (T6SS) are widespread among Gram-negative bacteria and have a potential role as essential virulence factors or to maintain symbiotic interactions. Three T6SS gene clusters were identified in the genome of E. amylovora CFBP 1430, of which T6SS-1 and T6SS-3 represent complete T6SS machineries, while T6SS-2 is re...

Background Viruses belonging to the Flaviviridae and Bunyaviridae families show considerable genetic diversity. However, this diversity is not necessarily taken into account when developing diagnostic assays, which are often based on the pairwise alignment of a limited number of sequences. Our objective was to develop and evaluate a bioinformatics...

Accession numbers. (XLSX)

Sequenced amplicons. (FASTA)

Erwinia amylovora is the causative agent of fire blight, a devastating plant disease affecting members of the Rosaceae. Alternatives to antibiotics for control of fire blight symptoms and outbreaks are highly desirable, due to increasing drug resistance and tight regulatory restrictions. Moreover, the available diagnostic methods either lack sensit...

The common assumption in potato virus epidemiology is that all daughter tubers produced by plants coming from infected mother tubers (secondary infection) will become infected via systemic translocation of the virus during growth. We hypothesize that depending on the prevalent environmental conditions, only a portion of the daughter tubers of a pla...

Molecular diagnostics of plant pathogens are crucial to prevent disease spread and to enhance food quality and security. A comparative genomics approach using genomes of different Xanthomonas species and pathovars was applied to identify highly specific targets in the genome of Xanthomonas fragariae, the causal agent of angular leaf spot of strawbe...

The aim of this study was to develop a rapid, sensitive and reliable field-based assay for detection of the quarantine pathogen Pseudomonas syringae pv. actinidiae (Psa), the causal agent of the most destructive and economically important bacterial disease of kiwifruit. A comparative genomic approach was used on the publicly available Psa genomic d...

Bacteria of the genus Pseudomonas occupy diverse environments. The Pseudomonas fluorescens group is particularly well-known for its plant-beneficial properties including pathogen suppression. Recent observations that some strains of this group also cause lethal infections in insect larvae, however, point to a more versatile ecology of these bacteri...

The molecular basis of resistance and susceptibility of host plants to fire blight, a major disease threat to pome fruit production globally, is largely unknown. RNA-sequencing data from challenged and mock-inoculated flowers were analyzed to assess the susceptible response of apple to the fire blight pathogen Erwinia amylovora. In presence of the...

A survey to obtain potential antagonists of pome fruit tree diseases yielded two yellow epiphytic bacterial isolates morphologically similar to Pantoea agglomerans, but showing no biocontrol activity. Whole-Cell MALDI-TOF mass spectrometry and analysis of 16S rRNA and gyrB gene sequences suggested the possibility of a new species with a phylogeneti...

V International Symposium on Tomato Diseases: Perspectives and Future Directions in Tomato Protection; 2016/06/13-16, Malaga, SPAIN

We report here the draft genome sequence of the biocontrol strain Pantoea agglomerans P10c, composed of a draft chromosome and two plasmids: the 559-kb large Pantoea plasmid 1 (pPag3) and a 182-kb plasmid (pPag1). A genomic island containing pantocin A biosynthesis genes was identified.

Bacteriophages have regained much attention as biocontrol agents against bacterial pathogens. However, with respect to stability, phages are biomolecules and are therefore sensitive to a number of environmental influences. UV-irradiation can readily inactivate phage infectivity, which impedes their potential application in the plant phyllosphere. T...

We sequenced the complete genome of the isolate Pseudomonas sp. CCOS 191. This strain is able to dissolve phosphate minerals and form cyanide. The genome sequence is used to establish the phylogenetic relationship of this species. FOOTNOTES Address correspondence to Theo H. M. Smits, theo.smits{at}zhaw.ch. ↵* Present address: Chantal Koechli, Depar...

Pantoea ananatis is a highly versatile enterobacterium isolated from diverse environmental sources. The ecological diversity of this species may be attributed, in part, to the acquisition of mobile genetic elements. One such element is an Integrative and Conjugative Element (ICE). By means of in silico analyses the ICE elements belonging to a novel...

Operational capacity of real-time PCR and loop-mediated isothermal amplification (LAMP) diagnostic assays for detection of Xanthomonas arboricola pv. pruni were established in a ring-test involving four laboratories. Symptomatic and healthy almond leaf samples with two methods of sample preparation were analyzed. Kappa coefficient, sensitivity, spe...

Recent genome analysis of Erwinia amylovora, the causal agent of fire blight disease on Rosaceae, has shown that the chromosome is highly conserved among strains and that plasmids are the principal source of genomic diversity. A new circular plasmid, pEA68, was found in E. amylovora strain 692 (LMG 28361), isolated in Poland from Sorbus (mountain a...

Isolates of Erwinia amylovora from Mexico were collected and tested for their resistance to antibiotics used in orchards. Isolates with resistance to streptomycin were found, but no resistance to the commonly used antibiotics tetracycline and gentamicin was detected. The genomes of three isolates were sequenced and compared to reference genomes. Th...

Certain strains of Pantoea are used as biocontrol agents for the suppression of plant diseases. However, their commercial registration is hampered in some countries because of biosafety concerns. This study compares clinical and plant-beneficial strains of P. agglomerans and related species using a phenotypic analysis approach in which plant-benefi...

Pantoea ananatis is an emerging phytopathogen that infects a broad spectrum of plant hosts. Here, we present the genomes of two South African isolates, P. ananatis PA4, which causes center rot of onion, and BD442, isolated from brown stalk rot of maize.

The Federal Office for Agriculture (FOAG) authorized the use of streptomycin to fight fire blight under controlled conditions in 2008 with the provison that the development of antibiotic resistance in the treated plots is monitored. Agroscope in Wädenswil thus performed the first study to quantitatively analyze the influence of streptomycin use in...

Pectinolytic bacteria were recently isolated from diseased potato plants exhibiting blackleg and slow wilt symptoms found in a number of European countries and Israel. These Gram-negative, motile, rods were identified as belonging to the genus Dickeya, previously the Pectobacterium chrysanthemi complex (Erwinia chrysanthemi), on the basis of a posi...

Certain strains of Pantoea are used as biocontrol agents for the suppression of plant diseases. However, their commercial registration is hampered in some countries because of biosafety concerns. This study compares clinical and plant-beneficial strains of P. agglomerans and related species using a phenotypic analysis approach in which plant-benefi...

We report draft genome sequences of three Mexican Erwinia amylovora strains. A novel plasmid, pEA78, was identified. Comparative genomics revealed an rpsL chromosomal mutation conferring high-level streptomycin resistance in two strains. In the effector gene avrRpt2, a single nucleotide polymorphism was detected that overcomes fire blight disease r...

Pectinolytic bacteria have been recently isolated from diseased potato plants exhibiting blackleg and slow wilt symptoms found in a number of European countries and Israel. These Gram-reaction-negative, motile, rods were identified as belonging to the genus Dickeya, previously the Pectobacterium chrysanthemi complex (Erwinia chrysanthemi, on the ba...

We report draft genome sequences of three Mexican Erwinia amylovora strains. A novel plasmid, pEA78, was identified. Comparative genomics revealed an rpsL chromosomal mutation conferring high-level streptomycin resistance in two strains. In the effector gene avrRpt2, a single nucleotide polymorphism was detected that overcomes fire blight disease r...

Sprouted seeds represent a great risk for infection by human enteric pathogens because of favourable growth conditions for pathogens during their germination. The aim of this study was to identify mechanisms of interactions of Salmonella enterica subsp. enterica Weltevreden with alfalfa sprouts. RNA-seq analysis of S. Weltevreden grown with sprouts...

Table S1. Genes higher transcribed in M9-glucose medium in comparison to sprouts determined by RNA-seq analysis.

Streptomycin is used as a first-line defense, and tetracycline as a second-line defense, in the fight against fire blight disease in apple and pear orchards. We have performed the first study to quantitatively analyze the influence of streptomycin use in agriculture on the abundance of streptomycin and tetracycline resistance genes in apple orchard...

Erwinia amylovora causes a major disease of pome fruit trees worldwide, and is regulated as a quarantine organism in many countries. While some diversity of isolates has been observed, molecular epidemiology of this bacterium is hindered by a lack of simple molecular typing techniques with sufficiently high resolution. We report a molecular typing...

Compost water extracts (compost teas) are gaining popularity among organic growers, largely because of their disease suppressive activity when applied to foliage or soil. Production methods often include addition of supplemental constituents, particularly molasses, to stimulate plant-beneficial microbial populations. We have found that molasses ame...

The depolymerase enzyme (DpoL1) encoded by the T7-like phage L1 efficiently degrades amylovoran, an important virulence factor and major component of the extracellular polysaccharide (EPS) of its host, the plant pathogen Erwinia amylovora. Mass spectrometry analysis of hydrolysed EPS revealed that DpoL1 cleaves the galactose-containing backbone of...

Understanding the soil bacterial resistome is essential to understanding the evolution and development of antibiotic resistance, and its spread between species and biomes. We have identified and characterized multi-drug resistance (MDR) mechanisms in the culturable soil antibiotic resistome and linked the resistance profiles to bacterial species. W...

Understanding the soil bacterial resistome is essential to understanding the evolution and development of antibiotic resistance, and its spread between species and biomes. We have identified and characterized multi-drug resistance (MDR) mechanisms in the culturable soil antibiotic resistome and linked the resistance profiles to bacterial species. W...

The tetracycline antibiotic resistance profiles of the soil bacteria separated according to soil sample. (TIF)

The colistin antibiotic resistance profiles of the soil bacteria separated according to soil sample. (TIF)

The numbers of antibiotics each soil bacterial community is resistant to as a percentage of the total bacterial popoulation within the given soil. (TIF)

The aminoglycosides antibiotic resistance profiles of the soil bacteria separated according to soil sample. (TIF)

The antibiotic resistance profiles segregated according to soil for all antibiotics. The antibiotics are color coded according to class. (TIF)

The quinolone antibiotic resistance profiles of the soil bacteria separated according to soil sample. (TIF)

The objective of this study was to develop a rapid, sensitive detection assay for the quarantine pathogen Xanthomonas arboricola pv. pruni, causal agent of stone fruit bacterial spot, an economically important disease of Prunus spp. Unique targets were identified from X. arboricola pv. pruni genomes using a comparative genomics pipeline of other Xa...

The F1 population “Harostar” × “Rouge de Mauves” was used to perform a quantitative trait loci (QTL) mapping for tree architecture traits (i.e., tree diameter, total branch number, tree shape); time to initial reproductive bud break; and fruit quality traits (i.e., ground color, fruit form, soluble solid content) using data collected from 2010 to 2...

Xanthomonas arboricola pv. pruni causes bacterial spot of stone fruit resulting in severe yield losses in apricot production systems. Present on all continents, the pathogen is regulated in Europe as a quarantine organism. Host resistance is an important component of integrated pest management; however, little work has been done describing resistan...

Antibiotic resistance concerns have been compounded by a report that soil bacteria can catabolise antibiotics, i.e. break down and use them as a sole carbon source. To date this has not been verified or reproduced, therefore in this study soil bacteria were screened to verify and reproduce this hypothesis. Survival in high concentrations of antibio...

The plant pathogen Erwinia amylovora can be divided into two host-specific groupings; strains infecting a broad range of hosts within the Rosaceae subfamily Spiraeoideae (e.g., Malus, Pyrus, Crataegus, Sorbus) and strains infecting Rubus (raspberries and blackberries). Comparative genomic analysis of 12 strains representing distinct populations (e....

Variable regions of interest in the pan-genome of E. amylovora. When two lines are present for a pan-genome locus, two different genomic islands are present. (PDF)

Comparison of the T6SS-1 loci from different strains of E. amylovora. CDS encoding conserved core T6SS proteins are shaded in green (located in regions I and III), CDS encoding T6SS effector proteins Hcp and VrgG are colored red (located in regions II and IV, the hcp and vgrG islands), non-core CDS that are conserved among all strains are dark grey...

Comparison of plasmid pEA30 of CFBP 2585 (Ea495) to the RA3 plasmid of Aeromonas hydrophila. The RA3 plasmid is the archetype of the IncU plasmids which are a distinct group of mobile elements with highly conserved backbones and variable antibiotic resistance gene cassettes. Conservation between pEA30 and RA3 (represented by the grey shaded lines)...

Analysis of the nonribosomal peptide and polyketide biosynthesis gene cluster found only in the Rubus-infecting strains of E. amylovora (remnants of which are identified in CRISPR region 1 in the Spiraeoideae-infecting strains) using the software AntiSmash. Using sequence from E. amylovora strain ATCC BAA-2158, five CDS were predicted to be part of...

Comparison of the T6SS-3 loci from different strains of E. amylovora. CDS encoding conserved core T6SS proteins are shaded in green (primarily conserved core regions I, III and V but there is also a core protein in region IV of CFBP 1430 and ATCC BAA-2158), CDS encoding T6SS effector proteins Hcp and VrgG are colored red (located in conserved core...

Statistics for the draft assemblies of nine E. amylovora strains sequenced in this study. (PDF)

Polyphasic analysis exposed important heterogeneity between bacterial strains catalogued as Xanthomonas arboricola pv. fragariae (Xaf) from different culture collections. Two draft whole-genome sequences revealed pathogenicity related genes of the type-three secretion system in strain LMG 19146, whereas none were found in the Xaf pathotype strain L...

Xanthomonas arboricola pv. pruni is a quarantine bacterial pathogen that threatens peach production by causing necrotic spots on leaves and fruits, thus with the potential of severely reducing yields. The current understanding of the host plant defense responses to the pathogen is very limited. Using whole transcriptome sequencing, differential gen...

Complete list of differentially expressed peach genes at 12 h post inoculation with X. arboricola pv. pruni. (XLSX)

Number of genes expressed at different sampling depths. Genes with FPKM values obtained by Cufflinks v.2.0.1 higher than zero were considered as expressed. Max is the total number of reads obtained in each sample. (TIFF)

Complete list of differentially expressed peach genes at 2 h post inoculation with X. arboricola pv. pruni. (XLSX)

Complete list of peach novel transcripts that are over or under represented at 2 h post inoculation with X. arboricola pv. pruni. (XLSX)

List of differentially expressed peach genes in common at 2 h and 12 h post inoculation with X. arboricola pv. pruni. (XLSX)

List of peach novel transcripts that are over or under represented at both 2 h and 12 h post inoculation with X. arboricola pv. pruni . (XLSX)

List of putative transcripts that could correspond to the PR and ERF genes identified by Sherif and colleagues [12] [74] . (XLSX)

Complete list of peach novel transcripts that are over or under represented at 12 h post inoculation with X. arboricola pv. pruni. (XLSX)

Export Date: 29 January 2013, Source: Scopus, Article in Press

Streptomycin has been authorized for restricted use in the prevention of the fire blight disease of pome fruit orchards in the EU and Switzerland. This study addresses the important topic of the influence of the use of streptomycin in agriculture on the total bacteria community within the soil ecosystem. Soil samples were taken from soils under app...

Several molecular methods have been developed for detection of Erwinia amylovora, the causal agent of fire blight in pear and apple, but none are truly applicable for on-site use in the field. We developed a fast, reliable and field applicable detection method using a novel target on the E. amylovora chromosome that we identified by applying a comp...

The LuxS enzyme, an S-ribosyl-homocysteine lyase, catalyzes the production of the signal precursor for autoinducer-2 mediated quorum sensing (QS-2) in Vibrio. Its widespread occurrence among bacteria is often considered the evidence for a universal language for interspecies communication. Presence of the luxS gene and production of the autoinducer-...

Background Pantoea spp. are frequently isolated from a wide range of ecological niches and have various biological roles, as plant epi- or endophytes, biocontrol agents, plant-growth promoters or as pathogens of both plant and animal hosts. This suggests that members of this genus have undergone extensive genotypic diversification. One means by whi...

With 3 figures and 2 tables In a previous study, a QTL analysis was conducted on a pear F1 progeny derived from a cross ‘Passe Crassane’ (PC) × ‘Harrow Sweet’ (HS). Four genomic regions associated with fire blight resistance were identified, including two main QTL located on linkage groups (LGs), 2A and 4 of ‘Harrow Sweet’ (HS02A and HS04). In the...

Pantoea agglomerans is a cosmopolitan plant epiphytic bacterium that includes some of the most effective biological antagonists against the fire blight pathogen Erwinia amylovora, a major threat to pome fruit production worldwide. Strain E325 is commercially available as Bloomtime Biological™ in the USA and Canada. New quantitative PCR (qPCR) assay...

The enterobacterial phytopathogen Erwinia amylovora causes fire blight, an invasive disease that threatens a wide range of commercial and ornamental Rosaceae host plants. The response elicited by E. amylovora in its host during disease development is similar to the hypersensitive reaction that typically leads to resistance in an incompatible host-p...

Comparative genomic analysis revealed differences in the lipopolysaccharide (LPS) biosynthesis gene cluster between the Rubus-infecting strain ATCC BAA-2158 and the Spiraeoideae-infecting strain CFBP 1430 of Erwinia amylovora. These differences corroborate rpoB-based phylogenetic clustering of E. amylovora into four different groups and enable the...

The Hrp pathogenicity island (hrpPAI) of Erwinia amylovora not only encodes a type III secretion system (T3SS) and other genes required for pathogenesis on host plants, but also includes the so-called island transfer (IT) region, a region that originates from an integrative conjugative element (ICE). Comparative genomic analysis of the IT regions o...

Pantoea vagans C9-1 is a biocontrol strain that produces at least two antibiotics inhibiting the growth of Erwinia amylovora, the causal agent of fire blight disease of pear and apple. One antibiotic, herbicolin I, was purified from culture filtrates of P. vagans C9-1 and determined to be 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine, also...

Antibiotics are essential for control of bacterial diseases of plants, especially fire blight of pear and apple and bacterial spot of peach. Streptomycin is used in several countries; the use of oxytetracycline, oxolinic acid and gentamicin is limited to only a few countries. Springtime antibiotic sprays suppress pathogen growth on flowers and leaf...

This study examined differences in antibiotic-resistant soil bacteria and the presence and quantity of resistance genes in soils with a range of management histories. We analyzed four soils from agricultural systems that were amended with manure from animals treated with erythromycin and exposed to streptomycin and/or oxytetracycline, as well as no...

The enterobacterium Pantoea ananatis is an ecologically versatile species. It has been found in the environment, as plant epiphyte and endophyte, as an emerging phytopathogen, and as a presumptive, opportunistic human pathogen. Here, we report the complete genome sequence of P. ananatis LMG 5342, isolated from a human wound.

Walnut blight (WB) is considered as the most important biotic disease that affects walnut (Juglans regia). The causal agent, Xanthomonas arboricola pv. juglandis, causes necrosis on fruits, leaves, catkins and provokes up to 65% of fruit loss. A new disease has been observed in France since 2001. This disease is characterized by vertical cankers on...