Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 14 of 14
Full-Text Articles in Life Sciences
An Evolutionary Perspective Of Pierce’S Disease Of Grapevine, Citrus Variegated Chlorosis, And Mulberry Leaf Scorch Diseases, Jianchi Chen, John S. Hartung, Chung-Jan Chang, Anne K. Vidaver
An Evolutionary Perspective Of Pierce’S Disease Of Grapevine, Citrus Variegated Chlorosis, And Mulberry Leaf Scorch Diseases, Jianchi Chen, John S. Hartung, Chung-Jan Chang, Anne K. Vidaver
Department of Plant Pathology: Faculty Publications
Xylella fastidiosa causes diseases on a growing list of economically important plants. An understanding of how xylellae diseases originated and evolved is important for disease prevention and management. In this study, we evaluated the phylogenetic relationships of X. fastidiosa strains from citrus, grapevine, and mulberry through the analyses of random amplified polymorphic DNAs (RAPDs) and conserved 16S rDNA genes. RAPD analysis emphasized the vigorous genome-wide divergence of X. fastidiosa and detected three clonal groups of strains that cause Pierce’s disease (PD) of grapevine, citrus variegated chlorosis (CVC), and mulberry leaf scorch (MLS). Analysis of 16S rDNA sequences also identified the …
Isolation And Characterization Of Endophytic Colonizing Bacteria From Agronomic Crops And Prairie Plants, Denise K. Zinniel, Patricia A. Lambrecht, N. Beth Harris, Zhengyu Feng, Daniel Kuczmarski, Phyllis Higley, Carol A. Ishimaru, Alahari Arunakumari, Raul G. Barletta, Anne K. Vidaver
Isolation And Characterization Of Endophytic Colonizing Bacteria From Agronomic Crops And Prairie Plants, Denise K. Zinniel, Patricia A. Lambrecht, N. Beth Harris, Zhengyu Feng, Daniel Kuczmarski, Phyllis Higley, Carol A. Ishimaru, Alahari Arunakumari, Raul G. Barletta, Anne K. Vidaver
Department of Plant Pathology: Faculty Publications
Endophytic bacteria reside within plant hosts without causing disease symptoms. In this study, 853 endophytic strains were isolated from aerial tissues of four agronomic crop species and 27 prairie plant species. We determined several phenotypic properties and found approximately equal numbers of gram-negative and gram-positive isolates. In a greenhouse study, 28 of 86 prairie plant endophytes were found to colonize their original hosts at 42 days postinoculation at levels of 3.5 to 7.7 log10 CFU/g (fresh weight). More comprehensive colonization studies were conducted with 373 corn and sorghum endophytes. In growth room studies, none of the isolates displayed pathogenicity, …
Uses Of Antimicrobials In Plant Agriculture, Anne K. Vidaver
Uses Of Antimicrobials In Plant Agriculture, Anne K. Vidaver
Department of Plant Pathology: Faculty Publications
Bacterial diseases of plants are less prevalent than diseases caused by fungi and viruses. Antimicrobials for prophylactic treatment of bacterial diseases of plants are limited in availability, use, and efficacy, and therapeutic use is largely ineffective. Most applications are by spray treatments in orchards. Monitoring and surveillance for drug resistance are not routinely done. In the United States, data on use of antimicrobials for treatment of bacterial diseases of plants are limited to streptomycin and oxytetracycline. Resistance to streptomycin has become widespread among bacterial phytopathogens; no resistance among these bacteria has yet been reported for oxytetracycline. No human health effects …
Characterization Of The Aspergillus Nidulans 14-3-3 Homologue, Arta, Peter R. Kraus, Amy F. Hoffman, Steven D. Harris
Characterization Of The Aspergillus Nidulans 14-3-3 Homologue, Arta, Peter R. Kraus, Amy F. Hoffman, Steven D. Harris
Department of Plant Pathology: Faculty Publications
The 14-3-3 family of proteins function as small adaptors that facilitate a diverse array of cellular processes by mediating specific protein interactions. One such process is the DNA damage checkpoint, where these proteins prevent inappropriate activation of cyclin-dependent kinases. The filamentous fungus Aspergillus nidulans possesses a highly conserved 14- 3-3 homologue (artA) that may function in an analogous manner to prevent septum formation. However, instead of blocking septation, over-expression of artA causes a severe delay in the polarization of conidiospores. This observation suggests that these proteins play an important role in hyphal morphogenesis.
Phylogenetic Relationships, Strain Diversity And Biogeography Of Tritimoviruses, Frank Rabenstein, Dallas L. Seifers, Jorg Schubert, Roy C. French, Drake C. Stenger
Phylogenetic Relationships, Strain Diversity And Biogeography Of Tritimoviruses, Frank Rabenstein, Dallas L. Seifers, Jorg Schubert, Roy C. French, Drake C. Stenger
Department of Plant Pathology: Faculty Publications
North American and Eurasian isolates of Wheat streak mosaic virus (WSMV; genus Tritimovirus) and Oat necrotic mottle virus (ONMV; genus Rymovirus) were examined. Nine WSMV isolates differentially infected oat, barley, inbred maize line SDp2 and sorghum line KS56. The WSMV isolates clustered into groups based on phylogenetic analyses of the capsid protein (CP) cistron and flanking regions. WSMV isolates from the United States (US) and Turkey were closely related, suggesting recent movement between continents. Although more divergent, WSMV from Iran (WSMV-I) also shared a most recent common ancestor with the US and Turkish isolates. Another group of WSMV …
Functional Characterization And Localization Of The Aspergillus Nidulan Formin Sepa, Kathryn E. Sharpless, Steven D. Harris
Functional Characterization And Localization Of The Aspergillus Nidulan Formin Sepa, Kathryn E. Sharpless, Steven D. Harris
Department of Plant Pathology: Faculty Publications
Formins are a family of multidomain scaffold proteins involved in actin-dependent morphogenetic events. In Aspergillus nidulans, the formin SEPA participates in two actin-mediated processes, septum formation and polarized growth. In this study, we use a new null mutant to demonstrate that SEPA is required for the formation of actin rings at septation sites. In addition, we find that a functional SEPA::GFP fusion protein localizes simultaneously to septation sites and hyphal tips, and that SEPA colocalizes with actin at each site. Using live imaging, we show that SEPA localization at septation sites and hyphal tips is dynamic. Notably, at septation …
Adenylyl Cyclase Functions Downstream Of The Gα Protein Gpa1 And Controls Mating And Pathogenicity Of Cryptococcus Neoformans, J. Andrew Alspaugh, Read Pukkila-Worley, Toshiaki Harashima, Lora M. Cavallo, Deanna L. Funnell, Gary M. Cox, John R. Perfect, James W. Kronstad, Joseph Heitman
Adenylyl Cyclase Functions Downstream Of The Gα Protein Gpa1 And Controls Mating And Pathogenicity Of Cryptococcus Neoformans, J. Andrew Alspaugh, Read Pukkila-Worley, Toshiaki Harashima, Lora M. Cavallo, Deanna L. Funnell, Gary M. Cox, John R. Perfect, James W. Kronstad, Joseph Heitman
Department of Plant Pathology: Faculty Publications
The signaling molecule cyclic AMP (cAMP) is a ubiquitous second messenger that enables cells to detect and respond to extracellular signals. cAMP is generated by the enzyme adenylyl cyclase, which is activated or inhibited by the Gα subunits of heterotrimeric G proteins in response to ligand-activated G-protein-coupled receptors. Here we identified the unique gene (CAC1) encoding adenylyl cyclase in the opportunistic fungal pathogen Cryptococcus neoformans. The CAC1 gene was disrupted by transformation and homologous recombination. In stark contrast to the situation for Saccharomyces cerevisiae, in which adenylyl cyclase is essential, C. neoformans cac1 mutant strains were viable and …
Genomewide Identification Of Proteins Secreted By The Hrp Type Iii Protein Secretion System Of Pseudomonas Syringae Pv. Tomato Dc3000, Tanja Petnicki-Ocwieja, David J. Schneider, Vincent C. Tam, Scott T. Chancey, Libo Shan, Yashitola Jamir, Lisa M. Schechter, Misty Janes, C. Robin Buell, Xiaoyan Tang, Alan Collmer, James R. Alfano
Genomewide Identification Of Proteins Secreted By The Hrp Type Iii Protein Secretion System Of Pseudomonas Syringae Pv. Tomato Dc3000, Tanja Petnicki-Ocwieja, David J. Schneider, Vincent C. Tam, Scott T. Chancey, Libo Shan, Yashitola Jamir, Lisa M. Schechter, Misty Janes, C. Robin Buell, Xiaoyan Tang, Alan Collmer, James R. Alfano
Department of Plant Pathology: Faculty Publications
The ability of Pseudomonas syringae pv. tomato DC3000 to be pathogenic on plants depends on the Hrp (hypersensitive response and pathogenicity) type III protein secretion system and the effector proteins it translocates into plant cells. Through iterative application of experimental and computational techniques, the DC3000 effector inventory has been substantially enlarged. Five homologs of known avirulence (Avr) proteins and five effector candidates, encoded by genes with putative Hrp promoters and signatures of horizontal acquisition, were demonstrated to be secreted in culture and/or translocated into Arabidopsis in a Hrp-dependent manner. These 10 Hrp-dependent outer proteins (Hops) were designated HopPtoC (Avr- PpiC2 …
Isolation And Characterization Of A Virus That Infects Emiliania Huxleyi (Haptophyta), Tonje Castberg, Runar Thyrhaug, Aud Larsen, Ruth-Anne Sandaa, Mikal Heldal, James L. Van Etten, Gunnar Bratbak
Isolation And Characterization Of A Virus That Infects Emiliania Huxleyi (Haptophyta), Tonje Castberg, Runar Thyrhaug, Aud Larsen, Ruth-Anne Sandaa, Mikal Heldal, James L. Van Etten, Gunnar Bratbak
Department of Plant Pathology: Faculty Publications
The isolation and characterization of a virus (designated EhV) that infects the marine coccolithophorid Emiliania huxleyi (Lohmann) Hay & Mohler are described. Three independent clones of EhV were isolated from Norwegian coastal waters in years 1999 and 2000. EhV is a double-stranded DNA-containing virus with a genome size of ~415 kilo-base pairs. The viral particle is an icosahedron with a diameter of 160–180 nm. The virus particle contains at least nine proteins ranging from 10 to 140 kDa; the major capsid protein weighs ~54 kDa. EhV has a latent period of 12–14 h and a burst size of 400–1000 (mean, …
Greenhouse And Field Evaluation Of Biological Control Of Fusarium Head Blight On Durum Wheat, D. A. Schisler, N. I. Khan, Michael J. Boehm, P. J. Slininger
Greenhouse And Field Evaluation Of Biological Control Of Fusarium Head Blight On Durum Wheat, D. A. Schisler, N. I. Khan, Michael J. Boehm, P. J. Slininger
Department of Plant Pathology: Faculty Publications
Fusarium head blight (FHB) is a devastating disease that causes extensive yield and quality losses to wheat and barley. In durum wheat, the pathogen-produced toxin deoxynivalenol (DON) is retained in semolina at ~50%, and the causal agent of FHB, Gibberella zeae, has a strong adverse effect on pasta color. Two bacteria and two yeast strains with known efficacy against G. zeae on hexaploid wheats were produced in liquid culture and assayed on two cultivars of durum wheat in greenhouse bioassays. All antagonists reduced FHB severity on cultivar Renville, and three of the four reduced severity on cultivar Ben, with …
The P23 Protein Of Citrus Tristeza Virus Controls Asymmetrical Rna Accumulation, Satyanarayana Tatineni, Siddarame Gowda, Maria A. Ayllon, Maria R. Albiach-Marti, Shailaja Rabindran, William O. Dawson
The P23 Protein Of Citrus Tristeza Virus Controls Asymmetrical Rna Accumulation, Satyanarayana Tatineni, Siddarame Gowda, Maria A. Ayllon, Maria R. Albiach-Marti, Shailaja Rabindran, William O. Dawson
Department of Plant Pathology: Faculty Publications
Citrus tristeza virus (CTV), a member of the Closteroviridae, has a 19.3-kb positive-stranded RNA genome that is organized into 12 open reading frames (ORFs) with the 10 3' genes expressed via a nested set of nine or ten 3'-coterminal subgenomic mRNAs (sgRNAs). Relatively large amounts of negative-stranded RNAs complementary to both genomic and sgRNAs accumulate in infected cells. As is characteristic of RNA viruses, wild-type CTV produced more positive than negative strands, with the plus-to-minus ratios of genomic and sgRNAs estimated at 10 to 20:1 and 40 to 50:1, respectively. However, a mutant with all of the 3' genes …
Mapping Of The P1 Proteinase Cleavage Site In The Polyprotein Of Wheat Streak Mosaic Virus (Genus Tritimovirus), Il-Ryong Choi, Kempton M. Horken, Drake C. Stenger, Roy C. French
Mapping Of The P1 Proteinase Cleavage Site In The Polyprotein Of Wheat Streak Mosaic Virus (Genus Tritimovirus), Il-Ryong Choi, Kempton M. Horken, Drake C. Stenger, Roy C. French
Department of Plant Pathology: Faculty Publications
Monopartite members of the family Potyviridae utilize three virus-encoded proteinases to cleave the viral polyprotein into mature proteins. The amino-terminal region of the viral polyprotein is autolytically cleaved by the P1 proteinase. A domain required for P1 proteinase activity of Wheat streak mosaic virus (WSMV) was mapped using a series of templates with nested 3’-truncations or 5’-deletions to program in vitro transcription–translation reactions. The WSMV P1 proteinase cleavage site was mapped to a position downstream of amino acid residue 348 and upstream of amino acid residue 353, with the peptide bond between amino acid residues Y 352 and G 353 …
Selected Soybean Plant Introductions With Partial Resistance To Sclerotinia Sclerotiorum, D. D. Hoffman, B. W. Diers, G. L. Hartman, C. D. Nickell, R. L. Nelson, W. L. Pedersen, E. R. Cober, George L. Graef, J. R. Steadman, C. R. Grau, B. D. Nelson, L. E. Del Rio, T. Helms, T. Anderson, V. Poysa, University Of Guelph, W. C. Stienstra
Selected Soybean Plant Introductions With Partial Resistance To Sclerotinia Sclerotiorum, D. D. Hoffman, B. W. Diers, G. L. Hartman, C. D. Nickell, R. L. Nelson, W. L. Pedersen, E. R. Cober, George L. Graef, J. R. Steadman, C. R. Grau, B. D. Nelson, L. E. Del Rio, T. Helms, T. Anderson, V. Poysa, University Of Guelph, W. C. Stienstra
Department of Plant Pathology: Faculty Publications
Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a major soybean (Glycine max) disease in north-central regions of the United States and throughout the world. Current sources of resistance to Sclerotinia stem rot express partial resistance, and are limited in number within soybean germ plasm. A total of 6,520 maturity group (MG) 0 to IV plant introductions (PIs) were evaluated for Sclerotinia stem rot resistance in the United States and Canada in small plots or in the greenhouse from 1995 to 1997. Selected PIs with the most resistance were evaluated for resistance in the United States and …
Bean Pod Mottle Virus: A Threat To U.S. Soybean Production, Loren J. Giesler, Said A. Ghabrial, Thomas E. Hunt, John H. Hill
Bean Pod Mottle Virus: A Threat To U.S. Soybean Production, Loren J. Giesler, Said A. Ghabrial, Thomas E. Hunt, John H. Hill
Department of Plant Pathology: Faculty Publications
Bean pod mottle virus (BPMV) is widespread in the major soybean-growing areas in the southern and southeastern United States. A severe outbreak of BPMV in the north central and northern Great Plains states is currently causing serious concern to soybean growers and to the soybean industry in this region (30). BPMV is efficiently transmitted in nature, within and between soybean fields, by several species of leaf-feeding beetles. The deleterious effects of BPMV infection not only reduce yield but also reduce seed quality, as seeds from infected plants may be discolored. Furthermore, BPMV predisposes soybeans to Phomopsis spp. seed infection (85), …