David J Norman

David J Norman
University of Florida | UF · College of Agricultural and Life Sciences

PhD

About

111
Publications
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Publications

Publications (111)
Article
Brown rot of potatoes caused by Ralstonia solanacearum is common in developing countries. Historically, brown rot losses in the United States have been restricted to southern states. This trend will most likely change with new Ralstonia introductions and temperature variability. A cold tolerant Ralstonia strain was used in this study to compare res...
Article
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Ralstonia solanacearum is the causal agent of bacterial wilt in numerous species of plants. Here, we report the whole-genome sequence of three phylogenetically diverse R. solanacearum strains, P816, P822, and P824, reported for the first time as causal agents of an emerging blueberry disease in Florida.
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Background Most current methods for constructing guide RNAs (gRNA) for the CRISPR/Cas9 genome editing system, depend on traditional cloning using specific type IIS restriction enzymes and DNA ligation. These methods consist of multiple steps of cloning, and are time consuming, resource intensive and not flexible. These issues are particularly exace...
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Biological control is an eco-friendly strategy for mitigating and controlling plant diseases with negligible effects on human health and environment. Biocontrol agents are mostly isolated from field crops, and microbiomes associated with wild native plants is underexplored. The main objective of this study was to characterize the bacterial isolates...
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Strains of the Ralstonia solanacearum species complex in the phylotype IIB group are capable of causing Bacterial Wilt disease in potato and tomato at temperatures lower than 24°C. The capability of these strains to survive and to incite infection at temperatures colder than their normally tropical boundaries represents a threat to United States ag...
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A strain of Ralstonia solanacearum was associated with wilting and blight of flowering ornamentals grown from cuttings that originated in Guatemala. This isolate, UW757, could wilt geranium, Osteospermum spp., and mandevilla, but was more aggressively virulent on tomato. Although it rarely caused symptoms, after inoculation UW757 colonized the stem...
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Bacterial biological control agents (BCA) are largely used as live products to control plant pathogens. However, due to variable environmental and ecological factors, live BCA usually fail to produce desirable results against foliar pathogens. In this study, we investigated the potential of cell-free culture filtrates of 12 different bacterial BCA...
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This report investigates population structure and genetic variability of Phytophthora spp. isolated from botanically diverse plants in Florida. Internal transcribed spacer-based molecular phylogenetic analyses indicate that Phytophthora isolates recovered from ornamental plants in Florida represent a genetically diverse population and that a majori...
Chapter
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Plant growth-promoting rhizobacteria (PGPRs) release soluble and volatile compounds, which are implicated in antibiosis, cell signalling, induction of resistance and tolerance in plants against biotic and abiotic stresses. Due to public concerns about the potential environmental hazards of chemical use in agriculture, exploration of PGPRs for alter...
Article
Xanthomonas axonopodis pv. poinsettiicola is traditionally identified as the primary causal agent of bacterial leaf spot on poinsettia (family Euphorbiaceae). Sixty-seven strains of xanthomonads isolated from lesions associated with several species within the family Euphorbiaceae were collected over a 64-year period. The pathogenicity of these stra...
Article
Application of nanoparticles for controlling plant pathogens is a rapidly emerging area in plant disease management, and nanoparticles synthesis methods that are economical and eco-friendly are extensively investigated. In this project, we investigated the potential of silver nanoparticles (AgNPs) synthesized with aqueous extract of Artemisia absin...
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Ralstonia solanacearum is the causal agent of bacterial wilt of solanaceous plants. In the USA the disease is of economic importance in potato, tomato and tobacco crops. Strains of the Race 3 Biovar 2 (R3B2) can infect tomato and potato at low temperatures and are not established in North America, thus posing a threat to its agriculture. In previou...
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Ralstonia solanacearum, the causal agent of bacterial wilt, is a genetically diverse bacterial plant pathogen present in tropical and subtropical regions of the world that infects more than 200 plant species, including economically important solanaceous crops. Most strains of R. solanacearum are only pathogenic at temperatures between 25 to 30[degr...
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Ralstonia solanacearum is the causal agent of bacterial wilt, one of the most destructive bacterial plant diseases. We present the whole-genome sequence of the strain P673 (phylotype IIB, sequevar 4). This strain is capable of producing disease in tomato plants at low temperatures. P673 has 311 unique genes.
Article
Full-text available
Ralstonia solanacearum is the causal agent of bacterial wilt, one of the most destructive bacterial plant diseases. We present the whole-genome sequence of the strain P673 (phylotype IIB, sequevar 4). This strain is capable of producing disease in tomato plants at low temperatures. P673 has 311 unique genes.
Article
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A bacterial spot of rose (Rosa spp.) caused by a xanthomonad was observed in Florida and Texas. Ten representative strains collected from the two states between 2004 and 2010 were used to determine the taxonomic position of this rose pathogen. Fatty acid methyl ester analysis was performed and a nearly 2-kb 16S-23S rRNA intergenic spacer along with...
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The genus Duranta is in the Verbenaceae family and contains a number of cultivated shrubs and small trees and is native to Mexico, Florida in the USA and parts of South America. Duranta erecta (common names: Golden dewdrop, Gold mound, Pigeon berry and Skyflower) is used extensively in southern states of the US as ornamental shrub and has replaced...
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A comprehensive analysis of 175 Xanthomonas axonopodis pv. dieffenbachiae strains isolated from ten Araceae hosts was done to identify pathogen variation. The strains were subjected to repetitive extragenic palindromic sequence polymerase chain reaction (Rep-PCR) and four major phylogenetic clusters were generated. A subset of forty strains isolate...
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This is the first comprehensive study of a collection of Ralstonia solanacearum strains from the southeastern United States to be characterized based on biovar, pathogenicity, hypersensitive reaction on tobacco, and phylogenetic analyses of the egl sequence. Rigorous phylogenetic analysis of the commonly used egl gene produced robust phylogenies th...
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AdditionAl index words. cut foliage, fern anthracnose, leatherleaf fern Fern anthracnose, Colletotrichum acutatum, is a highly contagious disease in commercial ferneries causing the immature fronds of leatherleaf fern to become unmarketable for floral use. This research identifies sources that could disseminate primary inoculum, examines pathways o...
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A novel hypersensitive resistance (HR) in Capsicum baccatum var. pendulum against the bacterial spot of pepper pathogen, Xanthomonas gardneri, was introgressed into C. annuum cv. Early Calwonder (ECW) to create the near-isogenic line designated as ECW-70R. A corresponding avirulence gene avrBs7, in X. gardneri elicited a strong HR in ECW-70R. A hom...
Article
R. solanacearum strain UW551, classified as R3B2 can infect tomato and potato plants at low temperatures. R3B2 are not known to be established in the US, however, in our study we identified several R3B2 entering North America in geranium plants. We selected several strains frequently entering the United States and some considered endemic to study t...
Article
Xanthomonas strains causing bacterial spot on tomato have been classified into four different species. We have sequenced type strains belonging to B, C and D groups and compared the draft genomes against a previously sequenced X. euvesicatoria (Xcv85-10) strain and other available genomes of xanthomonads. We are analyzing pathogenicity clusters inc...
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Endospore forming bacteria were collected from root samples of 35 genera of bedding plants growing in established commercial landscape beds in Central Florida. One hundred twenty-nine bacterial strains associated with 14 species were identified using fatty acid analysis (Microbial Identification System, MIDI). All strains were evaluated for in vitr...
Article
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Ralstonia solanacearum causes bacterial wilt on a wide range of plant hosts. Most strains of R. solanacearum are nonpathogenic below 20°C; however, Race 3 Biovar 2 (R3B2) strains are classified as quarantine pathogens because of their ability to infect crops, cause disease, and survive in temperate climates. We have identified race 1 biovar 1 Phylo...
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Additional index words. bactericide, Euphorbia pulcherrima, Pelargonium Abstract. This study is the first report of using titanium dioxide (TiO 2) to control Xanthomonas bacterial blight on geranium and leaf spot on poinsettia. Potted zonal geranium 'Patriot Bright Violet' and poinsettia 'Snowcap' were grown in a greenhouse and treated with a folia...
Data
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Figure S2: 1a) Phylogenetic tree based on MUMi indices; 1b) Distance matrix based on MUMi indices. MUMi program was used to calculate pairwise distances between draft genomes and reference Xanthomonas genomes.
Data
Figure S4: AvrBs2-based HR assay confirms translocation of novel effectors. Hypersensitive response reaction indicating presence of translocation signal was recorded 24 hrs after inoculation on pepper cv. ECW20R with candidate effectors xopZ2 (a), avrBs1 (b), xopG (d), xopAM (e), xopAO (f) conjugated in race 6 strain along with control race 6 stra...
Data
Table S5: Evidence of the horizontal gene transfer using Alien_hunter analysis.
Data
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Table S7: Domain architecture and distribution of proteins with HD-GYP, GGDEF and/or EAL domains encoded by genomes of different Xanthomonas strains.
Data
Table S10: Genes unique to Xg. Genes of special interest are highlighted in red and yellow.
Data
Table S1: General features of the sequencing data and of the de novo assemblies of draft genomes of Xv, Xp and Xg using individual sequencing methods.
Data
Table S9: Genes common to all pepper pathogens but absent from Xp.
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Table S3: Whole genome comparisons using MUMmer dnadiff program. % coverage of the aligned contigs and % identities of the respective contigs against reference genomes has been shown for each draft genome.
Data
Table S6: Genes/contigs representing T6SS in draft genomes as compared to Xcv.
Data
Table S8: Genes unique to Xp, grouped in clusters.
Article
Full-text available
Bacterial spot of tomato and pepper is caused by four Xanthomonas species and is a major plant disease in warm humid climates. The four species are distinct from each other based on physiological and molecular characteristics. The genome sequence of strain 85-10, a member of one of the species, Xanthomonas euvesicatoria (Xcv) has been previously re...
Article
This study is the first report of using titanium dioxide (TiO2) to control Xanthomonas bacterial blight on geranium and leaf spot on poinsettia. Potted zonal geranium 'Patriot Bright Violet' and poinsettia 'Snowcap' were grown in a greenhouse and treated with a foliar spray of TiO2 at 25 and 75 mM, respectively, twice. Titanium-treated and control...
Chapter
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Introduction Production Conditions and Environments Foliage Plant Propagation Foliage Plant Production Postproduction The Future Literature Cited
Data
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Figure S7: topology of clade in Fig. 3 with bootstrap values.
Data
Figure S1: whole chromosome alignments of XauB and XauC scaffolds against XAC.
Data
Table S6: names, organisms, locus tags, and accession numbers for the nucleotide sequences used to build the pth gene phylogeny ( Fig. 3 ).
Data
Table S2: genes shared by XAC, XauB, and XauC but that are not found in other fully sequenced Xanthomonas and Xylella genomes.
Data
Figure S4: gene diagrams showing the contents of all 25 XAC-specific regions.
Article
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Citrus canker is a disease that has severe economic impact on the citrus industry worldwide. There are three types of canker, called A, B, and C. The three types have different phenotypes and affect different citrus species. The causative agent for type A is Xanthomonas citri subsp. citri, whose genome sequence was made available in 2002. Xanthomon...
Article
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Ralstonia solanacearum was isolated from diseased pothos (Epipremnum aureum) cuttings imported to Florida from Costa Pica. Epipremnum aureum has not previously been described as a host of R. solanacearum. Bacterial isolates were identified by standard bacteriological tests, FAME analysis (MIDI (R)), metabolic profile (Biolog (R)), and by PCP using...
Article
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Each year, large volumes of ornamental and food plant propagative stock are imported into the North America; occasionally, Ralstonia solanacearum is found systemically infecting this plant material. In this study, 107 new R. solanacearum strains were collected over a 10-year period from imported propagative stock and compared with 32 previously cha...
Article
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Sixty-one cultivars of geraniums, including zonal, regal, ivy, and scented, were tested for susceptibility to three strains of Ralstonia solanacearum: a race 1, biovar 1 (R1B1) strain P597 isolated from tomato in Florida, a R1B1 strain P673 obtained from pothos originated from Costa Rica, and a race 3, biovar 2 (R3B2) strain UW551 isolated from ger...
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ABSTRACT In order to confirm and refine the current classification scheme of Xanthomonas translucens and to identify novel strains from ornamental asparagus, a collection of field and reference strains was analyzed. Rep-polymerase chain reaction (PCR) genomic fingerprint profiles were generated from 33 isolates pathogenic to asparagus as well as 61...
Article
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Species and cultivars of Dieffenbachia Schott. (Araceae Juss.) have been important ornamental foliage plants for many decades. Their attractive foliar variegation, adaptability to interior environments, and ease of production are major reasons for their importance as ornamental foliage plants. Approximately 20 cultivars are commercially produced in...
Article
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Various bactericides were screened for efficacy in protecting geranium plants (Pelargonium hortorum) from Ralstonia solanacearum infection. Many of these bactericides were found to slow the disease progress; however, they were not able to protect the plants from infection and subsequent death. Potassium salts of phosphorous acid were found to be ef...
Article
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An 8x draft genome was obtained and annotated for Ralstonia solanacearum race 3 biovar 2 (R3B2) strain UW551, a United States Department of Agriculture Select Agent isolated from geranium. The draft UW551 genome consisted of 80,169 reads resulting in 582 contigs containing 5,925,491 base pairs, with an average 64.5% GC content. Annotation revealed...