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Department of Plant Pathology: Faculty Publications

Articles 331 - 360 of 409

Full-Text Articles in Other Plant Sciences

Expression Analysis Of Rice Defense-Related Genes In Turfgrass In Response To Magnaporthe Grisea, Young-Ki Jo, Guo-Liang Wang, Michael J. Boehm Jan 2007

Expression Analysis Of Rice Defense-Related Genes In Turfgrass In Response To Magnaporthe Grisea, Young-Ki Jo, Guo-Liang Wang, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Magnaporthe grisea (anamorph = Pyricularia grisea) causes blast on rice (Oryza sativa) and gray leaf spot on turfgrass. Gray leaf spot is a serious disease on St. Augustinegrass (Stenotaphrum secundatum), perennial ryegrass (Lolium perenne), and tall fescue (Festuca arundinacea). Virulence assays performed in this study revealed that M. grisea collected from rice could also cause disease on St. Augustinegrass and tall fescue. One rice isolate, Che86061, caused similar disease reactions on susceptible cultivars of rice and St. Augustinegrass and an incompatible interaction on resistant cultivars of both species. To explore whether …

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Whole-Genome Expression Profiling Defines The Hrpl Regulon Of Pseudomonas Syringae Pv. Tomato Dc3000, Allows De Novo Reconstruction Of The Hrp Cis Element, And Identifies Novel Coregulated Genes, Adriana O. Ferreira, Christopher R. Myers, Jeffrey S. Gordon, Gregory B. Martin, Monica Vencato, Alan Collmer, Misty D. Wehling, James R. Alfano, Gabriel Moreno-Hagelsieb, Warren F. Lamboy, Geneviene Declerck, David J. Schneider, Samuel W. Cartinhour Nov 2006

Whole-Genome Expression Profiling Defines The Hrpl Regulon Of Pseudomonas Syringae Pv. Tomato Dc3000, Allows De Novo Reconstruction Of The Hrp Cis Element, And Identifies Novel Coregulated Genes, Adriana O. Ferreira, Christopher R. Myers, Jeffrey S. Gordon, Gregory B. Martin, Monica Vencato, Alan Collmer, Misty D. Wehling, James R. Alfano, Gabriel Moreno-Hagelsieb, Warren F. Lamboy, Geneviene Declerck, David J. Schneider, Samuel W. Cartinhour

Department of Plant Pathology: Faculty Publications

Pseudomonas syringae pv. tomato DC3000 is a model pathogen of tomato and Arabidopsis that uses a hypersensitive response and pathogenicity (Hrp) type III secretion system (T3SS) to deliver virulence effector proteins into host cells. Expression of the Hrp system and many effector genes is activated by the HrpL alternative sigma factor. Here, an open reading frame-specific whole-genome microarray was constructed for DC3000 and used to comprehensively identify genes that are differentially expressed in wild-type and ΔhrpL strains. Among the genes whose differential regulation was statistically significant, 119 were upregulated and 76 were downregulated in the wild-type compared with the ΔhrpL …

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Microbial Content Of Abattoir Wastewater And Its Contaminated Soil In Lagos, Nigeria, A. O. Adesemoye, B. O. Opere, S. C. O. Makinde Oct 2006

Microbial Content Of Abattoir Wastewater And Its Contaminated Soil In Lagos, Nigeria, A. O. Adesemoye, B. O. Opere, S. C. O. Makinde

Department of Plant Pathology: Faculty Publications

Microbial content of wastewater in two abattoirs and the impact on microbial population of receiving soil was studied in Agege and Ojo Local Government Areas in Lagos State, Nigeria. Wastewater samples were collected from each of the abattoirs over three months period and examined for microbial content. Soil samples contaminated with the wastewaters were also collected and analyzed for microbial content as compared to soil without wastewater contamination in the neighborhood (control). Some physico-chemical parameters of the samples such as total dissolved solid, chemical oxygen demand, etc., were examined. The wastewater samples from both abattoirs were highly contaminated; Agege abattoir …

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Inducible Yeast System For Viral Rna Recombination Reveals Requirement For An Rna Replication Signal On Both Parental Rnas, Hernan Garcia-Ruiz, Paul Ahlquist Sep 2006

Inducible Yeast System For Viral Rna Recombination Reveals Requirement For An Rna Replication Signal On Both Parental Rnas, Hernan Garcia-Ruiz, Paul Ahlquist

Department of Plant Pathology: Faculty Publications

To facilitate RNA recombination studies, we tested whether Saccharomyces cerevisiae, which supports brome mosaic virus (BMV) replication, also supports BMV RNA recombination. Yeast strains expressing BMV RNA replication proteins 1a and 2apol were engineered to transiently coexpress two independently inducible, overlapping, nonreplicating derivatives of BMV genomic RNA3. B33' lacked the coat protein gene and negative-strand RNA promoter. B35' lacked the positive-strand RNA promoter and had the coat gene replaced by the selectable URA3 gene. After 12 to 72 h of induction, B33' and B35' transcription was repressed and Ura+ yeast cells were selected. All Ura+ cells …

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Bacillus Species Nrrl B-30212 For Reducing Fusarium Head Blight In Cereals, David A. Schisler, Naseem L. Khan, Michael J. Boehm Feb 2006

Bacillus Species Nrrl B-30212 For Reducing Fusarium Head Blight In Cereals, David A. Schisler, Naseem L. Khan, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Four yeasts (NRRL Y-30213, NRRL Y-30214, NRRL Y-30215, and NRRL Y-30216) and 1 bacterium (NRRL B-30212) have been identified as being superior antagonists capable of suppressing Fusarium head blight (head scab) in cereals, particularly in wheat and barley. Fusarium head blight is primarily caused by the fungus Gibberella zeae (anamorph=Fusarium graminearum).

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Carbon-To-Nitrogen Ratio And Carbon Loading Of Production Media Influence Freeze-Drying Survival And Biocontrol Efficacy Of Cryptococcus Nodaensis Oh 182.9, Shouan Zhang, David A. Schisler, Michael J. Boehm, Patricia J. Slininger Jan 2006

Carbon-To-Nitrogen Ratio And Carbon Loading Of Production Media Influence Freeze-Drying Survival And Biocontrol Efficacy Of Cryptococcus Nodaensis Oh 182.9, Shouan Zhang, David A. Schisler, Michael J. Boehm, Patricia J. Slininger

Department of Plant Pathology: Faculty Publications

Fusarium head blight (FHB), caused by Gibberella zeae, is a devastating disease of wheat worldwide. Cryptococcus nodaensis OH 182.9 is an effective biocontrol agent for this disease. Development of a dried product of OH 182.9 would have potential advantages of ease of handling, favorable economics, and acceptance by end users. Isolate OH 182.9 was grown for 48 and 72 h in semi-defined complete liquid (SDCL) medium with carbon-to-nitrogen (C/N) ratios of 6.5:1, 9:1, 11:1, 15:1, and 30:1, and in SDCL C/N 30:1 media with varied carbon loadings of 7, 14, 21, and 28 g/liter. Total biomass production and cell …

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First Report Of Sudden Death Syndrome Of Soybean Caused By Fusarium Solani F. Sp. Glycines In Nebraska, A. D. Ziems, L. J. Giesler, G. Y. Yuen Jan 2006

First Report Of Sudden Death Syndrome Of Soybean Caused By Fusarium Solani F. Sp. Glycines In Nebraska, A. D. Ziems, L. J. Giesler, G. Y. Yuen

Department of Plant Pathology: Faculty Publications

During August of 2004, soybean (Glycine max (L.) Merr.) plants exhibiting symptoms typical of sudden death syndrome (SDS) caused by Fusarium solani (Mart.) Sacc. f. sp. glycines (= Fusarium virguliforme Akoi, O'Donnell, Homma, & Lattanzi) (1) were observed in Nemaha and Pierce counties in eastern Nebraska. Leaf symptoms ranged from small chlorotic spots to prominent interveinal necrosis on plants at R5-R6 growth stages. Taproots of symptomatic plants were plated on potato dextrose agar (PDA) amended with hymexazol, ampicillin, and rifampicin (HAR). Resulting fungal isolates grew slowly and developed masses of blue macroconidia, characteristic of F. solani f. sp. glycines …

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Avenacin Production In Creeping Bentgrass (Agrostis Stolonifera) And Its Influence On The Host Range Of Gaeumannomyces Graminis, S. L. Thomas, P. Bonello, P. E. Lipps, Michael J. Boehm Jan 2006

Avenacin Production In Creeping Bentgrass (Agrostis Stolonifera) And Its Influence On The Host Range Of Gaeumannomyces Graminis, S. L. Thomas, P. Bonello, P. E. Lipps, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Avenacinase activity has been shown to be a key factor determining the host range of Gaeumannomyces graminis on oats (Avena sativa). G. graminis var. avenae produces avenacinase, which detoxifies the oat root saponin avenacin, enabling it to infect oats. G. graminis var. tritici does not produce avenacinase and is unable to infect oats. G. graminis var. avenae is also reported to incite take-all patch on creeping bentgrass (Agrostis stolonifera). It is unknown whether creeping bentgrass produces avenacin and if the avenacin-avenacinase interaction influences G. graminis pathogenicity on creeping bentgrass. The root extracts of six creeping bentgrass …

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Fungicide Sensitivity Of Sclerotinia Homoeocarpa From Golf Courses In Ohio, Young-Ki Jo, Amy L. Niver, Joseph W. Rimelspach, Michael J. Boehm Jan 2006

Fungicide Sensitivity Of Sclerotinia Homoeocarpa From Golf Courses In Ohio, Young-Ki Jo, Amy L. Niver, Joseph W. Rimelspach, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Managing dollar spot, the most common and chronic disease on intensively cultivated turfgrass, relies on the judicious use of fungicides. The heavy use of fungicides has led to the development of isolates of Sclerotinia homoeocarpa insensitive to several classes of fungicides, including benzimidazoles, demethylation-inhibitors, and dicarboximides. In vitro fungicide sensitivity assays using single discriminatory concentrations of thiophanate-methyl, propiconazole, and iprodione were developed in this study for evaluating field efficacy of these fungicides and the prevalence of fungicide insensitivity within S. homoeocarpa isolated from golf courses throughout Ohio. Discriminatory concentrations for these fungicides were determined to be: thiophanate-methyl = 1,000 μg …

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First Report Of Leaf Spot Of Smooth Bromegrass Caused By Pithomyces Chartarum In Nebraska, C. Eken, C. C. Jochum, G. Y. Yuen Jan 2006

First Report Of Leaf Spot Of Smooth Bromegrass Caused By Pithomyces Chartarum In Nebraska, C. Eken, C. C. Jochum, G. Y. Yuen

Department of Plant Pathology: Faculty Publications

Smooth bromegrass (Bromus inermis Leyss.) is the most common perennial grass species cultivated for forage in North America. During late fall of 2004, smooth bromegrass plants in Lincoln, NE were observed to have brown lesions on leaf midveins that were several centimeters long. Symptomatic leaves were surface disinfested for 1 min in 2% NaOCl and incubated at 25°C on potato dextrose agar (PDA) and water agar. The fungus, Pithomyces chartarum (Berk. & Curt) Ellis, was isolated consistently and identified on the basis of morphological characteristics (1). Colonies were effused and black on PDA. Conidiophores measured 3.5 to 8 …

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Bioinformatics-Enabled Identification Of The Hrpl Regulon And Type Iii Secretion System Effector Proteins Of Pseudomonas Syringae Pv. Phaseolicola 1448a, Monica Vencato, Fang Tian, James R. Alfano, C. Robin Buell, Samuel Cartinhour, Genevieve A. Declerck, David S. Guttman, John Stavrinides, Vinita Joardar, Magdalen Lindeberg, Philip A. Bronstein, John W. Mansfield, Christopher R. Myers, Alan Collmer, David J. Schneider Jan 2006

Bioinformatics-Enabled Identification Of The Hrpl Regulon And Type Iii Secretion System Effector Proteins Of Pseudomonas Syringae Pv. Phaseolicola 1448a, Monica Vencato, Fang Tian, James R. Alfano, C. Robin Buell, Samuel Cartinhour, Genevieve A. Declerck, David S. Guttman, John Stavrinides, Vinita Joardar, Magdalen Lindeberg, Philip A. Bronstein, John W. Mansfield, Christopher R. Myers, Alan Collmer, David J. Schneider

Department of Plant Pathology: Faculty Publications

The ability of Pseudomonas syringae pv. phaseolicola to cause halo blight of bean is dependent on its ability to translocate effector proteins into host cells via the hypersensitive response and pathogenicity (Hrp) type III secretion system (T3SS). To identify genes encoding type III effectors and other potential virulence factors that are regulated by the HrpL alternative sigma factor, we used a hidden Markov model, weight matrix model, and type III targeting-associated patterns to search the genome of P. syringae pv. phaseolicola 1448A, which recently was sequenced to completion. We identified 44 high-probability putative Hrp promoters upstream of genes encoding the …

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Regulation Of Hyphal Morphogenesis And The Dna Damage Response By The Aspergillus Nidulans Atm Homolog Atma, Iran Malavazi, Camile P. Semighini, Marcia Regina Von Zeska Kress, Steven D. Harris, Gustavo H. Goldman Jan 2006

Regulation Of Hyphal Morphogenesis And The Dna Damage Response By The Aspergillus Nidulans Atm Homolog Atma, Iran Malavazi, Camile P. Semighini, Marcia Regina Von Zeska Kress, Steven D. Harris, Gustavo H. Goldman

Department of Plant Pathology: Faculty Publications

Ataxia telangiectasia (A-T) is an inherited disorder characterized by progressive loss of motor function and susceptibility to cancer. The most prominent clinical feature observed in A-T patients is the degeneration of Purkinje motor neurons. Numerous studies have emphasized the role of the affected gene product, ATM, in the regulation of the DNA damage response. However, in Purkinje cells, the bulk of ATM localizes to the cytoplasm and may play a role in vesicle trafficking. The nature of this function, and its involvement in the pathology underlying A-T, remain unknown. Here we characterize the homolog of ATM (AtmA) in the filamentous …

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First Report Of Crown And Stem Rot Of Orchid (Orchis Palustris) Caused By Sclerotinia Minor, C. Eken, S. Ercişli, A. Eşitken, E. Demirci, G. Y. Yuen Aug 2005

First Report Of Crown And Stem Rot Of Orchid (Orchis Palustris) Caused By Sclerotinia Minor, C. Eken, S. Ercişli, A. Eşitken, E. Demirci, G. Y. Yuen

Department of Plant Pathology: Faculty Publications

Orchis palustris Jacq. is a wild orchid native to wetlands in eastern Anatolia. During June of 2003, near Erzurum, Turkey, a decline of this orchid was observed in several meadows that had been irrigated for forage production. Stems were chlorotic, wilted, and collapsed. There was a soft, watery rot at the crowns and lower stems. White mycelium and black sclerotia formed on necrotic stem and crown tissues. The fungus was isolated from sclerotia on potato dextrose agar (PDA) and identified as Sclerotinia minor Jagger on the basis of small sclerotia (0.5 to 2.5 mm long) scattered throughout the colonies (2). …

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Mutagenesis Of Β-1,3-Glucanase Genes In Lysobacter Enzymogenes Strain C3 Results In Reduced Biological Control Activity Toward Bipolaris Leaf Spot Of Tall Fescue And Pythium Damping-Off Of Sugar Beet, Jeffrey D. Palumbo, Gary Y. Yuen, C. Christine Jochum, Kristin Tatum, Donald Y. Kobayashi Jun 2005

Mutagenesis Of Β-1,3-Glucanase Genes In Lysobacter Enzymogenes Strain C3 Results In Reduced Biological Control Activity Toward Bipolaris Leaf Spot Of Tall Fescue And Pythium Damping-Off Of Sugar Beet, Jeffrey D. Palumbo, Gary Y. Yuen, C. Christine Jochum, Kristin Tatum, Donald Y. Kobayashi

Department of Plant Pathology: Faculty Publications

Lysobacter enzymogenes produces extracellular lytic enzymes capable of degrading the cell walls of fungi and oomycetes. Many of these enzymes, including β-1,3-glucanases, are thought to contribute to the biological control activity expressed by several strains of the species. L. enzymogenes strain C3 produces multiple extracellular β-1,3-glucanases encoded by the gluA, gluB, and gluC genes. Analysis of the genes indicates they are homologous to previously characterized genes in the related strain N4-7, each sharing >95% amino acid sequence identity to their respective counterparts. The gluA and gluC gene products encode enzymes belonging to family 16 glycosyl …

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Proposed Guidelines For A Unified Nomenclature And Phylogenetic Analysis Of Type Iii Hop Effector Proteins In The Plant Pathogen Pseudomonas Syringae, Magdalen Lindeberg, John Stavrinides, Jeffrey H. Chang, James R. Alfano, Alan Collmer, Jeffrey L. Dangl, Jean T. Greenberg, John W. Mansfield, David S. Guttman Apr 2005

Proposed Guidelines For A Unified Nomenclature And Phylogenetic Analysis Of Type Iii Hop Effector Proteins In The Plant Pathogen Pseudomonas Syringae, Magdalen Lindeberg, John Stavrinides, Jeffrey H. Chang, James R. Alfano, Alan Collmer, Jeffrey L. Dangl, Jean T. Greenberg, John W. Mansfield, David S. Guttman

Department of Plant Pathology: Faculty Publications

Pathovars of Pseudomonas syringae interact with their plant hosts via the action of Hrp outer protein (Hop) effector proteins, injected into plant cells by the type III secretion system (TTSS). Recent availability of complete genome sequences for a number of P. syringae pathovars has led to a significant increase in the rate of effector discovery. However, lack of a systematic nomenclature has resulted in multiple names being assigned to the same Hop, unrelated Hops designated by the same alphabetic character, and failure of name choices to reflect consistent standards of experimental confirmation or phylogenetic relatedness. Therefore, specific experimental and bioinformatic …

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Mutual Interference Between Genomic Rna Replication And Subgenomic Mrna Transcription In Brome Mosaic Virus, Valery Z. Grdzelishvili, Hernan Garcia-Ruiz, Tokiko Watanabe, Paul Ahlquist Feb 2005

Mutual Interference Between Genomic Rna Replication And Subgenomic Mrna Transcription In Brome Mosaic Virus, Valery Z. Grdzelishvili, Hernan Garcia-Ruiz, Tokiko Watanabe, Paul Ahlquist

Department of Plant Pathology: Faculty Publications

Replication by many positive-strand RNA viruses includes genomic RNA amplification and subgenomic mRNA (sgRNA) transcription. For brome mosaic virus (BMV), both processes occur in virus-induced, membrane- associated compartments, require BMV replication factors 1a and 2a, and use negative-strand RNA3 as a template for genomic RNA3 and sgRNA syntheses. To begin elucidating their relations, we examined the interaction of RNA3 replication and sgRNA transcription in Saccharomyces cerevisiae expressing 1a and 2a, which support the full RNA3 replication cycle. Blocking sgRNA transcription stimulated RNA3 replication by up to 350%, implying that sgRNA transcription inhibits RNA3 replication. Such inhibition was independent of the …

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The Glycosphingolipid Globotriaosylceramide In The Metastatic Transformation Of Colon Cancer, Olga Kovbasnjuk, Rakhilya Mourtazina, Boris Baibakov, Thomas Wang, Christian Elowsky, Michael A. Choti, Anne Kane, Mark Donowitz Jan 2005

The Glycosphingolipid Globotriaosylceramide In The Metastatic Transformation Of Colon Cancer, Olga Kovbasnjuk, Rakhilya Mourtazina, Boris Baibakov, Thomas Wang, Christian Elowsky, Michael A. Choti, Anne Kane, Mark Donowitz

Department of Plant Pathology: Faculty Publications

The most devastating aspect of cancer is the emergence of metastases. Thus, identification of potentially metastatic cells among a tumor cell population and the underlying molecular changes that switch cells to a metastatic state are among the most important issues in cancer biology. Here we show that, although normal human colonic epithelial cells lack the glycosphingolipid globotriaosylceramide (Gb3), this molecule is highly expressed in metastatic colon cancer. In addition, a subpopulation of cells that are greatly enriched in Gb3 and have an invasive phenotype was identified in human colon cancer cell lines. In epithelial cells in culture, …

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Morphogenesis In Germinating Fusarium Graminearum Macroconidia, Steven D. Harris Jan 2005

Morphogenesis In Germinating Fusarium Graminearum Macroconidia, Steven D. Harris

Department of Plant Pathology: Faculty Publications

Fusarium graminearum (teleomorph Gibberella zeae) is a significant pathogen of wheat and corn. F. graminearum forms multicellular macroconidia that play an important role in dissemination of the disease. The spatial pattern of morphogenesis in germinating macroconidia is described. Germ tubes preferentially emerge from the apical cells in a bipolar pattern that appears to be common to filamentous fungi. Chitin deposition occurs at two locations: the spore apices and cortical regions of macroconidial cells that subsequently produce a germ tube. The spatial pattern of morphogenesis requires the presence of functional microtubules, which may be responsible for the transport of key …

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Chlorella Virus Marburg Topoisomerase Ii: High Dna Cleavage Activity As A Characteristic Of Chlorella Virus Type Ii Enzymes, Jennifer S. Dickey, Tae-Jin Choi, James L. Van Etten, Neil Osheroff Jan 2005

Chlorella Virus Marburg Topoisomerase Ii: High Dna Cleavage Activity As A Characteristic Of Chlorella Virus Type Ii Enzymes, Jennifer S. Dickey, Tae-Jin Choi, James L. Van Etten, Neil Osheroff

Department of Plant Pathology: Faculty Publications

Although the formation of a covalent enzyme-cleaved DNA complex is a prerequisite for the essential functions of topoisomerase II, this reaction intermediate has the potential to destabilize the genome. Consequently, all known eukaryotic type II enzymes maintain this complex at a low steady-state level. Recently, however, a novel topoisomerase II was discovered in Paramecium bursaria chlorella virus-1 (PBCV-1) that has an exceptionally high DNA cleavage activity [Fortune et al. (2001) J. Biol. Chem. 276, 24401-24408]. If robust DNA cleavage is critical to the physiological functions of chlorella virus topoisomerase II, then this remarkable characteristic should be …

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Promoters From Chlorella Virus Genes Providing For Expression Of Genes In Prokaryotic And Eukaryotic Hosts, Amitava Mitra, James L. Van Etten Jun 2004

Promoters From Chlorella Virus Genes Providing For Expression Of Genes In Prokaryotic And Eukaryotic Hosts, Amitava Mitra, James L. Van Etten

Department of Plant Pathology: Faculty Publications

The invention is directed to novel promoters or mutants thereof from Chlorella virus DNA methyltansferase genes. A Chlorella Virus gene promoter is operably linked to a first and/or Second DNA sequence encoding a gene that is different from the Chlorella virus to form an expression cassette. An expression cassette can be introduced into prokaryotic and/or eukaryotic cells and can provide for a high level of expression of the gene encoded by the first and/or Second DNA sequence. The invention also provides a method for Screening other Chlorella virus genes for promoters that can function to express a heterologous gene in …

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Closterovirus Bipolar Virion: Evidence For Initiation Of Assembly By Minor Coat Protein And Its Restriction To The Genomic Rna 5' Region, Satyanarayana Tatineni, Siddarame Gowda, Maria A. Ayllon, William O. Dawson Jan 2004

Closterovirus Bipolar Virion: Evidence For Initiation Of Assembly By Minor Coat Protein And Its Restriction To The Genomic Rna 5' Region, Satyanarayana Tatineni, Siddarame Gowda, Maria A. Ayllon, William O. Dawson

Department of Plant Pathology: Faculty Publications

The long flexuous virions of the Closteroviridae have a unique bipolar architecture incorporating two coat proteins, with most of the helical nucleocapsid encapsidated by the major coat protein (CP) and a small portion of one end encapsidated by the minor coat protein (CPm). It is not known whether CPm encapsidates the genomic RNA and, if so, which end and what effects transition between the two coat proteins. Two other virus-encoded proteins, an HSP70 homolog (HSP70h) and an = 61-kDa protein, are required to augment virion assembly. In this work, we examine the in vivo encapsidation of Citrus tristeza virus by …

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Molecular Differentiation Of Two Sibling Species Of The Black Fly Simulium Vittatum (Diptera: Simuliidae) Based On Random Amplified Polymorphic Dna, G. A. Duncan, P. H. Adler, K. P. Pruess, Thomas O. Powers Jan 2004

Molecular Differentiation Of Two Sibling Species Of The Black Fly Simulium Vittatum (Diptera: Simuliidae) Based On Random Amplified Polymorphic Dna, G. A. Duncan, P. H. Adler, K. P. Pruess, Thomas O. Powers

Department of Plant Pathology: Faculty Publications

Larvae of the black fly morphospecies Simulium vittatum from Colorado, Montana, Nebraska, and New Hampshire were cytologically identified as either the IS-7 or the IIIL-1 cytospecies. DNA was PCR amplified from cytotyped larvae using eight 10-mer primers, labeled with 33P, and run on polyacrylamide gels. The entire data set of 96 amplicons produced incomplete separation of the two cytospecies when subjected to neighbor-joining and maximum parsimony analyses. However, when analyzed within geographical regions, separate species status was supported. Boot- strap support for distinctness of the two cytospecies was best in Colorado where they were collected in true sympatry. The …

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The Hopptof Locus Of Pseudomonas Syringae Pv. Tomato Dc3000 Encodes A Type Iii Chaperone And A Cognate Effector, Libo Shan, Hye-Sook Oh, Jianfu Chen, Ming Guo, Jianmin Zhou, James R. Alfano, Alan Collmer, Xu Jia, Xiaoyan Tang Jan 2004

The Hopptof Locus Of Pseudomonas Syringae Pv. Tomato Dc3000 Encodes A Type Iii Chaperone And A Cognate Effector, Libo Shan, Hye-Sook Oh, Jianfu Chen, Ming Guo, Jianmin Zhou, James R. Alfano, Alan Collmer, Xu Jia, Xiaoyan Tang

Department of Plant Pathology: Faculty Publications

Type III secretion systems are highly conserved among gram-negative plant and animal pathogenic bacteria. Through the type III secretion system, bacteria inject a number of virulence proteins into the host cells. Analysis of the whole genome sequence of Pseudomonas syringae pv. tomato DC3000 strain identified a locus, named HopPtoF, that is homologous to the avirulence gene locus avrPphF in P. syringae pv. phaseolicola. The HopPtoF locus harbors two genes, ShcFPto and HopFPto, that are preceded by a single hrp box promoter. We present evidence here to show that ShcFPto and HopFPto encode a type …

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Effects Of Choline, Betaine, And Wheat Floral Extracts On Growth Of Fusarium Graminearum, Jessica S. Engle, Patrick E. Lipps, Terry L. Graham, Michael J. Boehm Jan 2004

Effects Of Choline, Betaine, And Wheat Floral Extracts On Growth Of Fusarium Graminearum, Jessica S. Engle, Patrick E. Lipps, Terry L. Graham, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Fusarium head blight has been more severe when infection occurs during anthesis, indicating that floral organs may be important infection courts. Choline acetate and glycinebetaine have been extracted from wheat and reported to be growth stimulants of Fusarium graminearum. They are hypothesized to enhance infection and tissue colonization. Growth of F. graminearum was examined on media amended with extracts from floral parts of nine wheat genotypes with various Fusarium head blight resistance levels. Results indicated no significant effect of anther, palea, or lemma extracts on radial growth when compared with unamended controls. Effects on spore germination and hyphal growth …

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Nematode Molecular Diagnostics: From Bands To Barcodes, Tom Powers Jan 2004

Nematode Molecular Diagnostics: From Bands To Barcodes, Tom Powers

Department of Plant Pathology: Faculty Publications

Nematodes are considered among the most difficult animals to identify. DNA-based diagnostic methods have already gained acceptance in applications ranging from quarantine determinations to assessments of biodiversity. Researchers are currently in an information-gathering mode, with intensive efforts applied to accumulating nucleotide sequence of 18S and 28S ribosomal genes, internally transcribed spacer regions, and mitochondrial genes. Important linkages with collateral data such as digitized images, video clips and specimen voucher web pages are being established on GenBank and NemATOL, the nematode-specific Tree of Life database. The growing DNA taxonomy of nematodes has lead to their use in testing specific short sequences …

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Type Iii Secretion System Effector Proteins: Double Agents In Bacterial Disease And Plant Defense, James R. Alfano, Alan Collmer Jan 2004

Type Iii Secretion System Effector Proteins: Double Agents In Bacterial Disease And Plant Defense, James R. Alfano, Alan Collmer

Department of Plant Pathology: Faculty Publications

Many phytopathogenic bacteria inject virulence effector proteins into plant cells via a Hrp type III secretion system (TTSS). Without the TTSS, these pathogens cannot defeat basal defenses, grow in plants, produce disease lesions in hosts, or elicit the hypersensitive response (HR) in nonhosts. Pathogen genome projects employing bioinformatic methods to identify TTSS Hrp regulon promoters and TTSS pathway targeting signals suggest that phytopathogenic Pseudomonas, Xanthomonas, and Ralstonia spp. harbor large arsenals of effectors. The Hrp TTSS employs cus- tomized cytoplasmic chaperones, conserved export components in the bacterial en- velope (also used by the TTSS of animal pathogens), and …

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Gaca, The Response Regulator Of A Two-Component System, Acts As A Master Regulator In Pseudomonas Syringae Pv. Tomato Dc3000 By Controlling Regulatory Rna, Transcriptional Activators, And Alternate Sigma Factors, Asita Chatterjee, Yaya Cui, Hailian Yang, Alan Collmer, James R. Alfano, Arun K. Chatterjee Nov 2003

Gaca, The Response Regulator Of A Two-Component System, Acts As A Master Regulator In Pseudomonas Syringae Pv. Tomato Dc3000 By Controlling Regulatory Rna, Transcriptional Activators, And Alternate Sigma Factors, Asita Chatterjee, Yaya Cui, Hailian Yang, Alan Collmer, James R. Alfano, Arun K. Chatterjee

Department of Plant Pathology: Faculty Publications

Concerted investigations of factors affecting host-pathogen interactions are now possible with the model plant Arabidopsis thaliana and its model pathogen Pseudomonas syringae pv. tomato DC3000, as their whole genome sequences have become available. As a prelude to analysis of the regulatory genes and their targets, we have focused on GacA, the response regulator of a two-component system. The DC3000 gene was cloned by testing for the reversal of phenotypes of an Erwinia GacA– mutant. A GacA– mutant of DC3000 constructed by marker exchange produces much-reduced levels of transcripts of three alternate sigma factors: HrpL, required for the production of effector …

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Effects Of Modification Of The Transcription Initiation Site Context On Citrus Tristeza Virus Subgenomic Rna Synthesis, Maria A. Ayllon, Siddarame Gowda, Satyanarayana Tatineni, Alexander V. Karasev, Scott Adkins, Munir Mawassi, Jose Guerri, Pedro Moreno, William O. Dawson Sep 2003

Effects Of Modification Of The Transcription Initiation Site Context On Citrus Tristeza Virus Subgenomic Rna Synthesis, Maria A. Ayllon, Siddarame Gowda, Satyanarayana Tatineni, Alexander V. Karasev, Scott Adkins, Munir Mawassi, Jose Guerri, Pedro Moreno, William O. Dawson

Department of Plant Pathology: Faculty Publications

Citrus tristeza virus (CTV), a member of the Closteroviridae, has a positive-sense RNA genome of about 20 kb organized into 12 open reading frames (ORFs). The last 10 ORFs are expressed through 3'-coterminal subgenomic RNAs (sgRNAs) regulated in both amounts and timing. Additionally, relatively large amounts of complementary sgRNAs are produced. We have been unable to determine whether these sgRNAs are produced by internal promotion from the full-length template minus strand or by transcription from the minus-stranded sgRNAs. Understanding the regulation of 10 sgRNAs is a conceptual challenge. In analyzing commonalities of a replicase complex in producing so many …

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Induced Resistance As A Mechanism Of Biological Control By Lysobacter Enzymogenes Strain C3, Ozlem Kilic-Ekici, Gary Y. Yuen Apr 2003

Induced Resistance As A Mechanism Of Biological Control By Lysobacter Enzymogenes Strain C3, Ozlem Kilic-Ekici, Gary Y. Yuen

Department of Plant Pathology: Faculty Publications

Induced resistance was found to be a mechanism for biological control of leaf spot, caused by Bipolaris sorokiniana, in tall fescue (Festuca arundinacea) using the bacterium Lysobacter enzymogenes strain C3. Resistance elicited by C3 suppressed germination of B. sorokiniana conidia on the phylloplane in addition to reducing the severity of leaf spot. The pathogen-inhibitory effect could be separated from antibiosis by using heat-inactivated cells of C3 that retained no antifungal activity. Application of live or heat-killed cells to tall fescue leaves resulted only in localized resistance confined to the treated leaf, whereas treatment of roots resulted in …

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Fungal Biology And Agriculture: Revisiting The Field, O. Yarden, D. J. Ebbole, S. Freeman, R. J. Rodriguez, M. B. Dickman Jan 2003

Fungal Biology And Agriculture: Revisiting The Field, O. Yarden, D. J. Ebbole, S. Freeman, R. J. Rodriguez, M. B. Dickman

Department of Plant Pathology: Faculty Publications

Plant pathology has made significant progress over the years, a process that involved overcoming a variety of conceptual and technological hurdles. Descriptive mycology and the advent of chemical plant-disease management have been followed by biochemical and physiological studies of fungi and their hosts. The later establishment of biochemical genetics along with the introduction of DNA-mediated transformation have set the stage for dissection of gene function and advances in our understanding of fungal cell biology and plant–fungus interactions. Currently, with the advent of high-throughput technologies, we have the capacity to acquire vast data sets that have direct relevance to the numerous …

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