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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 …}

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), …

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 400–1,000 (mean, …

Characterization Of Wound-Inducible Genes Encoding Enzymes For Terpenoid Biosynthesis In Medicago Truncatula, Mandy M. Cox

Inquiry: The University of Arkansas Undergraduate Research Journal

In addition to having numerous applications as food flavorings and pharmaceuticals, terpenoids are an important class of defensive compounds that can accumulate in plants after pathogen infection or injury by insects. Sequences of DNA encoding putative terpene synthases and an oxidosqualene synthase, isolated from insect-damaged Medicago truncatula leaves, were selected from an expressed sequence tag (EST) database. The eDNA clones were used as radiolabeled probes to analyze gene expression in leaves treated with factors known to trigger a defense response in plants. Transcript levels for all of the genes examined increased in response to artificial wounding, insect herbivory, and methyl …

Endophyte Ergot Alkaloid Synthetic Compounds, Compounds Which Encode Therefor And Related Methods, Christopher L. Schardl, Jinhung Wang

Plant Pathology Faculty Patents

The present invention provides, inter alia, dmaW nucleic acid sequences and the proteins for which they encode. Also provided are methods for the utilization of knockout mutants of the sequences which are useful for engineering ergot alkaloid-deficient fungal symbionts (endophytes) of plants. Other methods and materials related to these sequences are also provided.

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 …

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 …

Expression Patterns Of Novel Wound-Inducible Plant Genes In Medicago Truncatula, Mandy M. Cox, Kenneth L. Korth

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Terpenoids are an important class of defensive compounds that can accumulate in plants after pathogen infection or injury by chewing insects. Clones encoding putative terpene synthases and an oxidosqualene synthase, isolated from insect-damaged Medicagotruncatula leaves, were selected from an expressed sequence tag (EST) database. The cDNA clones were used as radiolabeled probes to analyze gene expression in leaves treated by known factors that can trigger a defense response in plants. Transcript levels for all of the genes examined increased in response to artificial wounding, insect herbivory, and methyl jasmonate (meJA) treatments, whereas salicylic acid (SA) and glucose oxidase (GOX) had …

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 …

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 …

The Short Term Effects Of A Fire Fighting Foam And Fire Retardant On Selected Flora From Australia's Southwest, Andrew B. Kennedy

Theses : Honours

Chemical fire suppressants arc used extensively throughout Australia's Southwest to contain and suppress wildfires. Despite several studies being conducted into their effects on terrestrial vegetation in North America and Eastern Australia, where a variety of significant effects were found, no such investigation has been carried out in Australia's Southwest. This study examined the short-term effects of a fire fighting foam and fire retardant on selected flora from Australia's Southwest. Various concentrations of fire fighting foam and fire retardant were applied to seeds and seedlings of several native species. Native species were chosen for their high abundance and widespread distribution throughout …

The Ns5a Protein Of Bovine Viral Diarrhoea Virus Interacts With The Α Subunit Of Translation Elongation Factor-1, Craig M. Johnson, Daniel R. Perez, Roy C. French, William C. Merrick, Ruben O. Donis

Department of Plant Pathology: Faculty Publications

A cellular protein that interacts with the NS5A polypeptide of bovine viral diarrhoea virus (BVDV) was identified in a yeast two-hybrid screen. The NS5A interactor was identified as the a subunit of bovine translation elongation factor 1A (eEF1A). Cell-free binding studies were performed with chimeric NS5A fused to glutathione S-transferase (GST–NS5A) expressed in bacteria. GST–NS5A bound specifically to both in vitro-translated and mammalian cell-expressed eEF1A. Moreover, purified eEF1A bound specifically to GST–NS5A attached to a solid phase. Conservation of this interaction was then analysed using a set of NS5A proteins derived from divergent BVDV strains encompassing known biotypes and genotypes. …

Structure And Temporal Dynamics Of Populations Within Wheat Streak Mosaic Virus Isolates, Jeffrey S. Hall, Roy C. French, Thomas Jack Morris, Drake C. Stenger

Department of Plant Pathology: Faculty Publications

Variation within the Type and Sidney 81 strains of wheat streak mosaic virus was assessed by single-strand conformation polymorphism (SSCP) analysis and confirmed by nucleotide sequencing. Limiting-dilution subisolates (LDSIs) of each strain were evaluated for polymorphism in the P1, P3, NIa, and CP cistrons. Different SSCP patterns among LDSIs of a strain were associated with single-nucleotide substitutions. Sidney 81 LDSI-S10 was used as founding inoculum to establish three lineages each in wheat, corn, and barley. The P1, HC-Pro, P3, CI, NIa, NIb, and CP cistrons of LDSI-S10 and each lineage at passages 1, 3, 6, and 9 were evaluated for …

Avian And Mammalian Use Of Three Small Urban Wetlands Invaded By A Pest Species, Reed Canarygrass (Phalaris Arundinacea L.), Laurie Dizney

Dissertations and Theses

Small urban wetlands are being destroyed and degraded at an alarming rate. One result of degradation is invasion by pest species, such as reed canarygrass (Phalaris arundinacea L. ). Reed canarygrass forms virtual monocultures in a wide range of wetland types. Wetlands normally have high plant species richness and abundance, which is widely believed to lead to faunal diversity. The purpose of the present study was to determine to what extent birds and mammals use a wetland dominated by reed canarygrass. The research was conducted at Tualatin Hills Nature Park in Beaverton, Washington County, Oregon. I examined three sites …

First Report Of Columbia Root Knot Nematode (Meloidogyne Chitwoodi) In Potato In Texas, A. L. Szalanski, P. G. Mullin, T. S. Harris, T. O. Powers

Department of Plant Pathology: Faculty Publications

Columbia root-knot nematode, Meloidogyne chitwoodi Golden et al. (1) was identified from potatoes, Solanum tuberosum L., collected from Dallam County, Texas in October 2000. Seed potatoes are the most likely source for this introduction. This nematode is currently found infecting potatoes grown in California, Colorado, Idaho, New Mexico, Nevada, Oregon, Utah, and Washington. Some countries prohibit import of both seed and table stock potatoes originating in states known to harbor M. chitwoodi. Lesions on the potatoes had discrete brown coloration with white central spots in the outer 1 cm of the tuber flesh. Female nematode densities averaged 3 per square …

Contributions Of Genetic Drift And Negative Selection On The Evolution Of Three Strains Of Wheat Streak Mosaic Tritimovirus, I.-R. Choi, J.S. Hall, M. Henry, Lingyu Zhang, G. L. Hein, Roy C. French, D.C. Stenger

Department of Plant Pathology: Faculty Publications

Genome sequences of three Wheat streak mosaic virus (WSMV) strains were compared. The Type and Sidney 81 strains of WSMV from the American Great Plains were closely related, with sequence identities of 97.6% (nucleotide) and 98.7% (amino acid). In contrast, the El Batán 3 strain from central Mexico was divergent, and shared only 79.2–79.3% (nucleotide) and 90.3–90.5% (amino acid) sequence identity with Type and Sidney 81. All threeWSMVstrains were serologically related, however the El Batán 3 capsid protein (CP) had 15 fewer amino acid residues. Phylogenetic analysis of the CP cistron indicated that Type, Sidney 81, and nine other American …

Crop Updates 2001 - Lupins, Mark Sweetingham, Beven J. Buirchell, Bob French, Laurie Wahlsten, Janet Wtoth, Kirsty Bayliss, Wallace Cowling, R. F. Brennan, Miles Dracup, Nick Galwey, Bob Thomsom, Moin Salam, Art Diggle, Geoff Thomas, Bill O'Neill, Debbie Thackray, Kevin Walden, M. Shankar, Dominie Wright, Nichole Burges, Hu'aan Yang, Ming Pei You, David Bowran, Abul Hashem, Nerys Wilkins, Aik Cheam, Terry Piper, Paul Blackwell, Miles Obst, Andrew Sandison, Cameron Weeks, Erin Hasson, Luigi Moreschi, Brett Glencross, Jon Clements, Miles Dracup, Ramon Hall, Stuart Johnson, Madeleine Ball, Sofia Sipsas, David Petterson

Crop Updates

This session covers twenty six papers from different authors:

INTRODUCTION,

1. Introduction, Dr Mark Sweetingham LUPIN RESEARCH AND INDUSTRY DEVELOPMENT, Agriculture Western Australia

VARIETIES

2. Lupin variety performance: Are you making the most of it? Bevan J. Buirchell, Agriculture Western Australia

3. Adaption of restricted-branching lupins in Western Australia, Bob French and Laurie Wahlsten, Agriculture Western Australia

4. Isolated microspore culture of lupin for production of doubled haploids, Dr Janet Wroth, Dr Kirsty Bayliss and A/Prof. Wallace Cowling, Plant Sciences, Faculty of Agriculture, The University of Western Australia

NUTRITION

5. Banding manganese fertiliser below the seed increases seed …

Crop Updates 2001 - Weeds, Vanessa Stewart, David Bowran, Alexandra Wallace, Bill Roy, Peter Newman, Cameron Weeks, Tony Blake, Dave Nicholson, Clinton Revell, Candy Hudson, Abul Hashem, Nerys Wilkins, Terry Piper, Aik Cheam, Amanda Ellery, Ross Chapman, Sally Peltzert, Robert Barrett-Lennard, Marta Monjardino, David Pannell, Stephen Powles, Rick Llewellyn, Paul Blackwell, Maurice Black, Miles Obst, Mike Collins, Julie Roche, Harmohinder S. Dhammu, Siew Lee, Mario D'Antuono, Ian Rose, Diana Fedorenko, Clayton Butterly, Stuart Mcalpine, Keith Devenish, John Moore, Paul Matson, Shannon Barraclough, Lionel Martin, Mike Clarke, Jonas Hodgson, Lawrence Price, Craig Brown, Gordon Cumming, Bill Crabtree, Jenny Hawkes, Roger Jones

Crop Updates

This session covers forty six papers from different authors:

1. INTRODUCTION, Vanessa Stewart, Agriculture Western Australia

PLENARY

2. Wild radish – the implications for our rotations, David Bowran, Centre for Cropping Systems

INTEGRATED WEED MANAGEMENT

IWM system studies/demonstration sites

3. Integrated weed management: Cadoux, Alexandra Wallace, Agriculture Western Australia

4. A system approach to managing resistant ryegrass, Bill Roy, Agricultural Consulting and Research Services Pty Ltd, York

5. Long term herbicide resistance demonstration, Peter Newman, Agriculture Western Australia, Cameron Weeks, Tony Blake and Dave Nicholson

6. Integrated weed management: Katanning, Alexandra Wallace, Agriculture Western Australia

7. Integrated …

Virulence Of Puccinia Triticina On Wheat In Nebraska During 1997 And 1998, J. E. Watkins, J. Schimelfenig, P. Stephen Baenziger, Kent M. Eskridge

Department of Plant Pathology: Faculty Publications

Urediniospore isolates of Puccinia triticina were obtained from wheat leaf collections made in three wheat-growing regions in Nebraska in 1997 and in four regions in 1998. Using 16 Thatcher lines that are near-isogenic for leaf rust resistance, 17 virulence phenotypes were found among 121 single uredinial isolates in 1997, and 42 virulence phenotypes were found among 178 isolates in 1998. The most prevalent phenotype in 1997 was MDRR (virulent on Lr1, 3, 3ka, 10, 11, 18, 23, 24, and 30). In 1998, virulence phenotypes MDRR and MDRM (virulent on Lr1, 3, 3ka, 10, 11, 23, 24, and 30 …

Use Of Flow Cytometry, Fluorescence Microscopy, And Pcr-Based Techniques To Assess Intraspecific And Interspecific Matings Of Armillaria Species, Mee-Sook Kim, Ned B. Klopfenstein, Geral I. Mcdonald, Kathiravetpillai Arumuganathan, Anne K. Vidaver

Department of Plant Pathology: Faculty Publications

For assessments of intraspecific mating using flow cytometry and fluorescence microscopy, two compatible basidiospore-derived isolates were selected from each of four parental basidiomata of North American Biological Species (NABS) X. The nuclear status in NABS X varied with basidiospore-derived isolates. Nuclei within basidiospore-derived isolates existed as haploids, diploids (doubled haploids), or a mixture of haploids and diploids (doubled haploids). Depending on the nuclear status of the basidiospore-derived lines of NABS X, intraspecifically mated cultures can exist as diploids or tetraploids, and possibly triploids or aneuploids under in vitro conditions. Based on previous in vitro mating studies, seven basidiospore isolates were …

Abrogation Of Disease Development In Plants Expressing Animal Antiapoptotic Genes, M. B. Dickman, Y. K. Park, T. Oltersdorf, W. Li, T. Clemente, Roy C. French

Department of Plant Pathology: Faculty Publications

An emerging topic in plant biology is whether plants display analogous elements of mammalian programmed cell death during development and defense against pathogen attack. In many plant– pathogen interactions, plant cell death occurs in both susceptible and resistant host responses. For example, specific recognition responses in plants trigger formation of the hypersensitive response and activation of host defense mechanisms, resulting in restriction of pathogen growth and disease development. Several studies indicate that cell death during hypersensitive response involves activation of a plant-encoded pathway for cell death. Many susceptible interactions also result in host cell death, although it is not clear …

Three Distinct Mechanisms Facilitate Genetic Isolation Of Sympatric Wheat Streak Mosaic Virus Lineages, Jeffrey Hall, Roy C. French, Gary L. Hein, Thomas Jack Morris, Drake Stenger

Department of Plant Pathology: Faculty Publications

Cross-protection and vector transmission bottlenecks have been proposed as mechanisms facilitating genetic isolation of sympatric viral lineages. Molecular markers were used to monitor establishment and resolution of mixed infections with genetically defined strains of wheat streak mosaic virus (WSMV). Two closely related WSMV strains from the U.S. (Type and Sidney 81) exhibited reciprocal cross-protection in wheat, confirming this classic phenomenon as a mechanism of genetic isolation. In contrast, cross-protection between either U.S. strain and the divergent El Batan 3 strain from Mexico was unilateral, erratic, and only partially effective. Distribution of WSMV strains within individual leaves of plants supporting a …

Chitinases From The Plant Disease Biocontrol Agent, Stenotrophomonas Maltophilia C3, Z. Zhang, Gary Yuen, Gautam Sarath, A. R. Penheiter

Department of Plant Pathology: Faculty Publications

Stenotrophomonas maltophilia strain C3, a biocontrol agent of Bipolaris sorokiniana in turfgrass, produced chitinases in broth media containing chitin. Chitinases were partially purified from culture fluid by ammonium sulfate precipitation and chitin affinity chromatography. The chromatography fraction with the highest specific chitinase activity was inhibitory to conidial germination and germ-tube elongation of B. sorokiniana, but it was less inhibitory than the protein fraction or the raw culture filtrate. The fraction exhibited strong exochitinase and weak endochitinase activity. Optimum temperature and pH for chitinase activity were 45 to 50°C and 4.5 to 5.0, respectively. Chitinase activity was inhibited by Hg …

Identification Of Seed Gall Nematodes Of Agronomic And Regulatory Concern With Pcr-Rflp Of Its1, Thomas O. Powers, Allen L. Szalanski, P. G. Mullin, T. S. Harris, T. Bertozzi, J. A. Griesbach

Department of Plant Pathology: Faculty Publications

A molecular analysis of eight described species of seed gall nematode, along with six undescribed isolates from different hosts, has revealed a strong association between nucleotide sequence polymorphism and host status. Each anguinid nematode associated with a unique host produced a unique PCR-RFLP pattern for the ITS1 region. Anguina species that had been synonymized in the past, Anguina agrostis, A. funesta, and A. wevelli (Afrina wevelli), were readily discriminated. Two undescribed species from northern New South Wales and southeastern South Australia, reported to be vectors of Rathyaibacter toxicus in the disease called ‘‘floodplain staggers,’’ were differentiated …

Bacillus Species For Reducing Fusarium Head Blight In Cereals, David A. Schisler, Naseem I. Khan, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Microbial antagonists that will suppress Fusarium head blight (head scab) in cereals, particularly in wheat and barley have been identified. Two superior antagonists include NRRL B-30210 and NRRL B-30211.

Selection And Evaluation Of Microorganisms For Biocontrol Of Fusarium Head Blight Of Wheat Incited By Gibberella Zeae, N. I. Khan, D. A. Schisler, Michael J. Boehm, P. J. Slininger, R. J. Bothast

Department of Plant Pathology: Faculty Publications

Gibberella zeae incites Fusarium head blight (FHB), a devastating disease that causes extensive yield and quality losses to wheat and barley. Of over 700 microbial strains obtained from wheat anthers, 54 were able to utilize tartaric acid as a carbon source when the compound was supplied as choline bitartrate in liquid culture. Four tartaric acid–utilizing and three nonutilizing strains reduced FHB in initial tests and were selected for further assays. Antagonists were effective against three different isolates of G. zeae when single wheat florets were inoculated with pathogen and antagonist inoculum. All seven antagonists increased 100-kernel weight when applied simultaneously …

Characterization Of A PorosTm-Fumonisin B1 Affinity Column For Isolating Ceramide Synthase From Rat Liver, S. Jernigan, W. B. Melchior Jr., G. R. Jenkins, K. L. Rowland, D. W. Roberts, P. C. Howard, H. Tolleson

Journal of the Arkansas Academy of Science

Fumonisin B1 is a mycotoxin produced by fungi of the genus Fusarium, common pathogens of corn and other grain plants. Toxic effects associated with fumonisin B1 include equine leukoencephalomacia, porcine pulmonary edema, rat renal carcinoma, and murine hepatocellular carcinoma. Increased risk for esophageal cancer in humans has been epidemiologically associated with consumption of corn contaminated with Fusarium, suggesting that fumonisin B1 may be involved. The biological effects of fumonisin B1 exposure result primarily from disruption of de novo sphingolipid biosynthesis via inhibition of ceramide synthase. Exposure of animals or cultured cells to fumonisin B1 results in the characteristic accumulation of …

Fungal Symbiosis From Mutualism To Parasitism: Who Controls The Outcome, Host Or Invader?, Regina S. Redman, David Dunigan, Rusty J. Rodriguez

Department of Plant Pathology: Faculty Publications

• Plant symbiotic fungi are generally thought to express a single lifestyle that might increase (mutualism), decrease (parasitism), or have no influence (commensalism) on host fitness. However, data are presented here demonstrating that plant pathogenic Colletotrichum species are able to asymptomatically colonize plants and express nonpathogenic lifestyles.

• Experiments were conducted in growth chambers and plant colonization was assessed by emergence of fungi from surface sterilized plant tissues. Expression of symbiotic lifestyles was assessed by monitoring the ability of fungi to confer disease resistance, drought tolerance and growth enhancement.

• Several pathogenic Colletotrichum species expressed either mutualistic or commensal lifestyles …

The Aspergillus Nidulans Snt Genes Are Required For The Regulation Of Septum Formation And Cell Cycle Checkpoints, Peter R. Kraus, Steven D. Harris

Department of Plant Pathology: Faculty Publications

In Aspergillus nidulans, germinating conidia undergo multiple rounds of nuclear division before forming a septum. Previous genetic results suggest that the ability to separate nuclear division and septum formation depends upon a threshold level of activity of the cyclin-dependent kinase NIMXcdk1. Mutations in nimX and nimT, the gene encoding the NIMXcdk1-activating phosphatase, have revealed that Tyr-15 phosphorylation is important for determining the timing of the formation of the first septum. Here, we describe a screen for suppressors of nimT23 (snt), designed to identify additional components of the pathway regulating septum formation. We show that a subset …

Age-Related Resistance In Bell Pepper To Cucumber Mosaic Virus , Hernan Garcia-Ruiz, John F. Murphy

Department of Plant Pathology: Faculty Publications

We demonstrated the occurrence of mature plant resistance in Capsicum annuum 'Early Calwonder' to Cucumber mosaic virus (CMV) under greenhouse conditions. When Early Cal wonder plants were sown at 10 day intervals and transplanted to 10-cm square pots, three distinct plant sizes were identified that were designated small, medium and large. Trials conducted during each season showed that CMV accumulated in inoculated leaves of all plants of each size category. All small plants (with the exception of the winter trial) developed a systemic infection that included accumulation of CMV in uninoculated leaves and severe systemic symptoms. Medium plants had a …