Life Sciences Commons^™

An Immunofluorescence Assay To Detect Urediniospores Of Phakopsora Pachyrhizi, Fulya Baysal-Gurel, Melanie L. Lewis Ivey, Anne E. Dorrance, Douglas Luster, Reid Frederick, Jill Czarnecki, Michael J. Boehm, Sally A. Miller

Department of Plant Pathology: Faculty Publications

An indirect immunofluorescence spore assay (IFSA) was developed to detect urediniospores of Phakopsora pachyrhizi, utilizing rabbit polyclonal antisera produced in response to intact nongerminated (SBR1A) or germinated (SBR2) urediniospores of P. pachyrhizi. Both antisera were specific to Phakopsora spp. and did not react with other common soybean pathogens or healthy soybean leaf tissue in enzyme-linked immunosorbent assay (ELISA). SBR1A and SBR2 bound to P. pachyrhizi and P. meibomiae urediniospores were detected with goat anti-rabbit Alexa Fluor 488-tagged antiserum using a Leica DM IRB epifluorescent microscope with an I3 blue filter (excitation 450 to 490 nm, emission 515 nm). The …

Molecular, Genetic And Biochemical Characterization Of Oleic Acid- And Glycerol-Mediated Signaling In Plant Defense, Srivathsa C. Venugopal

Theses and Dissertations--Plant Pathology

Oleic acid (18:1) is one of the important monounsaturated fatty acids, which is synthesized upon desaturation of stearic acid and this reaction is catalyzed by the SSI2 encoded stearoyl-acyl-carrier-protein-desaturase. A mutation in SSI2 leads to constitutive activation of salicylic acid (SA)-mediated defense responses. Consequently, these plants accumulate high levels of SA and show enhanced resistance to bacterial and oomycete pathogens. Replenishing 18:1 levels in ssi2 plants, via a second site mutation in GLY1 encoded glycerol-3-phosphate (G3P) dehydrogenase, suppresses all the ssi2-triggered phenotypes. Study of mechanism(s) underlying gly1-mediated suppression of ssi2 phenotypes showed that 18:1 levels are regulated via …

Virulence Diversity Of The Common Bean Rust Pathogen Within And Among Individual Bean Fields And Development Of Sampling Strategies, C. Jochua, M. I. V. Amane, J. R. Steadman, X. Xue, K. M. Eskidge

Department of Plant Pathology: Faculty Publications

There is a dearth of information on pathogen variation within an individual field. In this study, virulence diversity of Uromyces appendiculatus, cause of bean rust, within individual fields was investigated. From six bean fields in the United States, Honduras, Dominican Republic, and South Africa, 380 U. appendiculatus isolates were differentiated into 65 virulence phenotypes on bean lines containing Andean- and Middle American-derived rust resistance genes. Race variation among bean rust isolates from different geographic regions was found, and virulence phenotypes found in fields from tropical and subtropical regions were more virulent and diverse than those found in fields from …

Branching Of Fungal Hyphae: Regulation, Mechanisms And Comparison With Other Branching Systems, Steven D. Harris

Department of Plant Pathology: Faculty Publications

The ability of rapidly growing hyphae to generate new polarity axes that result in the formation of a branch represents one of the most important yet least understood aspects of fungal cell biology. Branching is central to the development of mycelial colonies and also appears to play a key role in fungal interactions with other organisms. This review presents a description of the two major patterns of hyphal branching, apical and lateral, and highlights the roles of internal and external factors in the induction of branch formation. In addition, potential mechanisms underlying branch site selection are outlined, and the possible …

First Report Of Annual Bluegrass Weevil, Listronotus Maculicollis, Damage In Ohio, John L. Koenig, David J. Shetlar, Joseph W. Rimelspach, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Annual bluegrass weevil [Listronotus maculicollis (Kirby) (1)] larvae, pupae, and adults were recovered and identified in a sample received by the C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPDC) at Ohio State University on 19 June 2007. Damage to the approaches and collars of four golf course putting greens was detected by the superintendent of Stonewater Golf Club, Highland Heights, OH (a suburb of Cleveland) during the week of 11 June 2007. The superintendent suspected damage from the larvae of the black turfgrass ataenius, Ataenius spretulus (1). Insecticide applications applied to suppress black turfgrass ataenius did not provide …

Rapid Development Of Fungicide Resistance By Sclerotinia Homoeocarpa On Turfgrass, Young-Ki Jo, Seog Won Chang, Michael J. Boehm, Geunhwa Jung

Department of Plant Pathology: Faculty Publications

Dollar spot, caused by Sclerotinia homoeocarpa, is the most prevalent and economically important turfgrass disease in North America. Increasing levels of fungicide resistance, coupled with tightening environmental scrutiny of existing fungicides, has left fewer options for managing dollar spot. More knowledge about S. homoeocarpa populations is needed to improve dollar spot management strategies, especially with respect to minimizing the development of fungicide resistance. Population diversity of S. homoeocarpa was examined using inter-simple sequence repeat markers and vegetative compatibility assays. Two subgroups were found in S. homoeocarpa field populations on both fairway and putting green turfgrass at a research field …

Inoculation Strategies To Assess Biological Interactions Between Fusarium And Alternaria Species Infecting Sorghum, Deanna L. Funnell-Harris, Jeffrey F. Pedersen

Department of Plant Pathology: Faculty Publications

New cultivars of sorghum are being developed for increased food use, as livestock feed, and for the bioenergy industry by manipulation of secondary metabolic pathways through breeding. Previous work has suggested that such modifications may have an impact on cultivar response to fungal pathogens. We investigated four inoculation strategies that may be used in studies involving pathogens of sorghum. Plants of elite sorghum genotypes ‘Wheatland’ and RTx430, commonly used in breeding programs, were inoculated with isolates of Alternaria alternata, Fusarium equiseti, Fusarium proliferatum, Fusarium solani, Fusarium thapsinum, and Fusarium verticillioides recovered from field-grown sorghum. Wound inoculation of the peduncles …

Roles Of Micrornas In Plant Abiotic Stress, Development And Viral Infection, Venugopal Mendu

University of Kentucky Doctoral Dissertations

Plant microRNAs play important roles in plant growth and development. Here we investigated the roles of miRNAs in the plant abiotic stress, development and viral infection. MicroRNA membrane array analysis using five different abiotic stress treatments resulted in the identification of 8 novel stress inducible miRNA-families. Functional studies on novel stress inducible miR168 revealed its functional relation with abiotic stress. Over expression of miR168 in Arabidopsis showed upregulation of four stress related miRNAs (miR163, miR167, miR398 and miR408). Analysis of 9 independent transgenic lines showed induction of miR398, an oxidative stress responsive miRNA with a corresponding down regulation of its …

A Dgge-Cloning Method To Characterize Arbuscular Mycorrhizal Community Structure In Soil, Zhanbei Liang, Rhae A. Drijber, Donald J. Lee, Ismail M. Dwiekat, Steven D. Harris, David A. Wedin

Department of Plant Pathology: Faculty Publications

Although arbuscular mycorrhizal fungi (AMF) are crucial for ecosystem functioning, characterizing AMF community structure in soil is challenging. In this study, nested polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) were combined with cloning of fungal 18S ribosomal gene fragments for the rapid comparison of AMF community structure in soil. Reference AMF isolates, representing four major genera of AMF, were used to develop the method. Sequential amplification of 18S rDNA fragments by nested PCR using primer pairs AM1-NS31 and Glo1-NS31GC followed by DGGE analysis yielded a high-resolution band profile. In parallel, 18S rDNA fragment clone libraries were constructed …

Comparison Of Compost Tea And Biological Fungicides For Control Of Early Blight In Organic Heirloom Tomato Production, Richard Kouyoumjian

All Theses

The efficacy of compost tea was evaluated and compared alone and in combination with two biofungicides Serenade Max and Sonata for control of early blight caused by the fungal pathogen Alternaria tomatophila on tomato Solanum lycopersicum (L), heirloom cultivar `Cherokee Purple'. Results of field experiments over two growing seasons indicated that compost tea provided a low level of protection against early blight. The results were variable; most likely due to dry conditions and the presence of bacterial wilt the first year and tomato spotted wilt virus the second year. In both 2006 and 2007 field trials compost tea was not …

Wheat Streak Mosaic Virus Lacking Helper Component-Proteinase Is Competent To Produce Disease Synergism In Double Infections With Maize Chlorotic Mottle Virus, Drake C. Stenger, Brock A. Young, Feng Qu, Thomas Jack Morris, Roy French

Department of Plant Pathology: Faculty Publications

The tritimovirus Wheat streak mosaic virus (WSMV) and the machlomovirus Maize chlorotic mottle virus (MCMV) each cause systemic chlorosis in infected maize plants. Infection of maize with both viruses produces corn lethal necrosis disease (CLND). Here, we report that complete deletion of the WSMV helper component-proteinase (HC-Pro) coding region had no effect on induction of CLND symptoms following coinoculation of maize with WSMV and MCMV. We further demonstrated that elevation of virus titers in double infections, relative to single infections, also was independent of WSMV HC-Pro. Thus, unlike potyvirus HC-Pro, WSMV HC-Pro was dispensable for disease synergism. Because disease synergism …

Heritability Of Latent Period Estimated From Wild-Type And Selected Populations Of Puccinia Triticina, Jeffery S. Lehman, Gregory Shaner

Biology and Earth Science Faculty Scholarship

Durability of partially resistant wheat cultivars to wheat leaf rust depends on the amount of genetic variation in parasitic fitness within populations of the pathogen Puccinia triticina. To assess the durability of partial resistance, selection experiments were used to explore quantitative variation in parasitic fitness of P. triticina. Fungal populations 881-WT and 882-WT were selected for shortened latent period on partially resistant cvs. CI 13277 and Sw 72469-6 for multiple generations. Fitness components were measured for wild-type and selected fungal populations. Responses to selection and selection differentials were calculated, and broad-sense, realized heritabilities for latent period were estimated for wild-type …

Genetic Diversity In Populations Of Xanthomonas Campestris Pv. Campestris In Cruciferous Weeds In Central Coastal California, A. Ignatov, A. Sechler, E. L. Schuenzel, Irina V. Agarkova, B. Oliver, A. K. Vidaver, N. W. Schaad

Department of Plant Pathology: Faculty Publications

Xanthomonas campestris pv. campestris (X. campestris) infects a large number of cruciferous plants, including weeds. California has one of the largest and most diverse populations of wild cruciferous plants in the world. Although considerable information is available on the genetic diversity of X. campestris in commercial crop plants, nothing is known about the diversity in strains infecting weeds. To assess the genetic diversity among strains of X. campestris in weeds in noncultivated and cultivated areas, strains of the pathogen were isolated from populations of cruciferous weeds growing in coastal valley crop-production sites and from remote nonproduction sites along the …

Soybean Fgam Synthase Promoters Useful In Nematode Control: U.S. Patent No. Us 7,223,901 B2, Sally Ann Mackenzie, Zarir Vaghchhipawala

Department of Plant Pathology: Faculty Publications

The subject invention relates to nematode responsive domains obtained from soybean promoters for phosphoribosylformylglycinamidine ribonucleotide (FGAM) synthase paralogs. The nematode responsive domains can be used in promoters that are linked to heterologous DNA. Such constructs can be expressed in transfected or transformed soybean and used in the control of nematode infection of soybean.

Pseudomonas Avr And Hop Proteins, Their Encoding Nucleic Acids, And Use Thereof, James R. Alfano, Alan Collmer, Samuel W. Cartinhour, David J. Schneider

Department of Plant Pathology: Faculty Publications

One aspect of the present invention relates to isolated nucleic acid molecules encoding avirulence proteins or polypeptides of Pseudomonas syringae pv. syringae DC 3000, or nucleic acid moleculues which are complementary thereto. Expression vectors, host cells, and transgenic plants which include the DNA molecules of the present invention are also disclosed. Another aspect relates to the isolated proteins or polypeptides and compositions containing the same. The various nucleic acid molecules and proteins of the present invention can be used to impart disease resistance to a plant, make a plant hypersusceptible to colonization by nonpathogenic bacteria, modify a metabolic pathway in …

Genetic Structure In Natural Populations Of Barley/Cereal Yellow Dwarf Virus Isolates From Alaska, N.L. Robertson, Roy C. French

Department of Plant Pathology: Faculty Publications

The genetic structure of natural populations of Alaskan barley yellow dwarf virus (BYDV)-PAV, BYDV-PAS, and cereal yellow dwarf virus (CYDV)- RPV from barley (Hordeum vulgare L.) and oats (Avena sativa L.) in Alaska were analyzed between 2002 and 2004. PCR products spanning the viral coat protein gene of 187 isolates were cloned and sequenced. The majority (78%) were similar to BYDV-PAS, 19% were similar to CYDV-RPV, and only about 3% resembled BYDV-PAV. The CYDVRPV isolates clustered in three groups: 44, 17, and 39% resembled RPS-like CP from Mexico, resembled RPV-like CP from New York, or formed a unique …

Functional Characterization Of The Aspergillus Fumigatus Calcineurin, Márcia Eliana Da Silva Ferreira, Thorsten Heinekamp, Albert Hartl, Axel A. Brakhage, Camile P. Semighini, Steven D. Harris, Marcela Savoldi, Paula Fagundes De Gouvêa, Maria Helena De Souza Goldman, Gustavo H. Goldman

Department of Plant Pathology: Faculty Publications

Aspergillus fumigatus is an aggressive opportunistic pathogen of humans as well as a major allergen. Environmental sensing and retrieving essential nutrients from the environment are general metabolic traits associated with the growth of this saprophytic fungus. Two important mediators of calcium signals in eukaryotic cells are the Ca²⁺-binding protein calmodulin and the Ca²⁺/calmodulin-dependent phosphatase calcineurin. Calcineurin is a heterodimer that consists of a catalytic subunit A and a Ca²⁺/calmodulin binding unit. We deleted the A. fumigatus calA gene, which encodes the calcineurin A catalytic subunit, and demonstrated that this gene is not essential in …

Loline Alkaloid Gene Clusters Of The Fungal Endophyte Neotyphodium Uncinatum, Christopher L. Schardl, Heather H. Wilkinson, Martin J. Spiering

Plant Pathology Faculty Patents

Loline alkaloids (LA), which are 1-aminopyrrolizidines with an oxygen bridge, are produced by Epichloë (anamorph=Neotyphodium) species, endophytes of grasses. LA are insecticidal, thus helping protect host plants from insect herbivory. Suppression subtractive hybridization PCR was used to isolate transcripts up-regulated during loline alkaloid production in cultures of Neotyphodium uncinatum. Subtracted cDNAs were cloned, and a λ-phage cDNA library from an LA-expressing N. uncinatum culture was screened with subtracted cDNA. In BLAST searches, several cDNAs identified had sequence similarities to aspartate kinases, and another with O-acetylhomoserine-(thiol)lyase. Differential expression of these two genes in LA-producing cultures of N. uncinatum …

A Pseudomonas Syringae Pv. Tomato Dc3000 Mutant Lacking The Type Iii Effector Hopq1-1 Is Able To Cause Disease In The Model Plant Nicotiana Benthamiana, Chia-Fong Wei, Brian H. Kvitko, Rena Shimizu, Emerson Crabill, James R. Alfano, Nai-Chun Lin, Gregory B. Martin, Hsiou-Chen Huang, Alan Collmer

Center for Plant Science Innovation: Faculty Publications

The model pathogen Pseudomonas syringae pv. tomato DC3000 causes bacterial speck in tomato and Arabidopsis, but Nicotiana benthamiana, an important model plant, is considered to be a non-host. Strain DC3000 injects approximately 28 effector proteins into plant cells via the type III secretion system (T3SS). These proteins were individually delivered into N. benthamiana leaf cells via T3SS-proficient Pseudomonas fluorescens, and eight, including HopQ1-1, showed some capacity to cause cell death in this test. Four gene clusters encoding 13 effectors were deleted from DC3000: cluster II (hopH1, hopC1), IV (hopD1, hopQ1-1, hopR1), IX (hopAA1-2, hopV1, hopAO1, hopG1), and native plasmid pDC3000A …

Crop Updates 2007 - Cereals, Rob Loughman, R. Lance, I. Barclay, G. Crosbie, S. Harasymow, W. Lambe, Chengdao Li, R. Mclean, C. Moore, K. Stefanova, A. Tarr, R. Wilson, Matu Peipi, Matt Whiting, Christine M. Zaicou-Kunesch, Shahajahan Miyan, Brenda Shackley, Len J. Wade, Lindsay W. Bell, Felicity Byrne (Nee Flugge), Mike A. Ewing, Blakely Paynter, Andrea Hills, Raj Malik, Kelly Winfield, Harmohinder Dhammu, Vince Lambert, Chris Roberts, Jeremy Lemon, Geoff J. Thomas, Ian Hartley, Andrew Taylor, Manisha Shankar, John Majewski, Vivien Vanstone, Brenda A. Coutts, Monica Kehoe, Roger Jones, Geoffrey Dwyer, Belinda Welsh, Cuiping Wang, Linda Price

Crop Updates

This session covers twenty six papers from different authors:

CEREAL BREEDING

1. Strategies for aligning producer and market imperatives in cereal breeding in Western Australia, R. Loughman, R. Lance, I. Barclay, G. Crosbie, S. Harasymow, W. Lambe, C. Li, R. McLean, C. Moore, K. Stefanova, A. Tarr and R. Wilson, Department of Agriculture and Food

2. LongReach plant breeders wheat variety trials – 2006, Matu Peipi and Matt Whiting, LongReach Plant Breeders

WHEAT AGRONOMY

3. Response of wheat varieties to sowing time in the northern agricultural region in 2006, Christine Zaicou, Department of Agriculture and Food

4. Response …

Crop Updates 2007 - Lupins, Pulses And Oilseeds, Mark Seymour, Jacinta Falconer, Ian Pritchard, Rodger Beermier, Wayne Parker, Martin Harries, Kedar Adhikari, Geoff Thomas, Peter White, Bevan Burichell, Mike Baker, Bob French, Jo Walker, Laurie Maiolo, Leigh Smith, Mark Sweetingham, Lorne Mills, Harmohinder Dhammu, Ben Tang, Qifu Ma, Zed Rengel, Bill Bowden, Ross Brennan, Reg Lunt, Tim Hilder, Tim Maling, A. Diggle, D. Thackray, R. A.C. Jones, K. H.M. Siddique, Vijay Jayasena, Leonardus Kardono, Ken Quail, Ranil Coorey, Hannah Williams, Don Elani Jayawardena, Kerry Regan, Rod Hunter, Tanveer Khan, Jenny Garlinge, Heather Clarke, W. Macleod, S. Morgan, A. Harris, Alan Meldrum, Helen Bowers, A. Bakr, Phillip Chambers, Chris Veitch, Tony Leonforte, Pam Burgess, Leanne Young, Brenda Coutts, Donna O'Keefe, Rhonda Pearce, Monica Kehoe, Terri Jasper, Tim Pope, Michael Materne, Ping Si, Mike Walsh, H. H. T. Phan, S. R. Ellwood, J. Hane, A. Williams, R. Ford, S. Thomas, R. Oliver, Katie Robinson, Mohammad Amjad, Graham Walton, Pat Fels, Andy Sutherland, Imma Farre, Michael Robertson, Senthold Asseng3, Ravjit Khangura, Moin Salam

Crop Updates

This session covers forty eight papers from different authors:

2006 REGIONAL ROUNDUP

1. South east agricultural region, Mark Seymour¹ and Jacinta Falconer², ¹Department of Agriculture and Food, ²Cooperative Bulk Handling Group

2. Central agricultural region, Ian Pritchard, Department of Agriculture and Food

3. Great Southern and Lakes region, Rodger Beermier, Department of Agriculture and Food

4. Northern agricultural region, Wayne Parker and Martin Harries, Department of Agriculture and Food

LUPINS

5. Development of anthracnose resistant and early flowering albus lupins (Lupinus albus L) in Western Australia, Kedar Adhikari and Geoff Thomas, Department of …

Crop Updates 2007 - Weeds, Alexandra Douglas, Peter Newman, Sally Peltzer, Abul Hashem, Aik Cheam, Siew Lee, Natalie Maguire, Michael Walsh, Dan Cornally, Matt Willis, Glen Riethmuller, Shahab Pathan, Michael Renton, Art Diggle, Mechelle Owen, Stephen Powles, Roberto Busi, Robert Barrett-Lennard, Andrew Storrie, David Minkey, Craig A. Ruchs, Peter Boutsalis, Catherine Borger, Nerys Wilkins, Julie Roche, Martin Harries, John Peirce, Brad Rayner, John Moore, Ray Fulwood, Chris Roberts, Paul Matson, Bob French, Laurie Maiolo, Lorne Mills, Harmohinder Dhammu, Ben Tan, Vince Lambert, Chris Roberts, Vanessa Stewart

Crop Updates

This session covers thirty two papers from different authors:

1. ACKNOWLEDGEMENTS, Alexandra Douglas CONVENOR – WEEDS DEPARTMENT OF AGRICULTURE AND FOOD

WILD RADISH MANAGEMENT

2. Decimate a wild radish seed bank in five years, Peter Newman, Sally Peltzer, Abul Hashem and Aik Cheam, Department of Agriculture and Food

3. High level of seed-set control in wild radish is achievable, Aik Cheam and Siew Lee,Department of Agriculture and Food

4. Wild radish: Best management practice, Aik Cheam and Siew Lee, Department of Agriculture and Food

5. Control of phenoxy resistant wild radish through the combined effects of wheat …

Crop Updates 2007 - Farming Systems, David Jeffries, A. Loi, B. J. Nutt, Clinton K. Revell Dr, Yvette Oliver, Michael Robertson, Bill Bowden, Kit Leake, Ashley Bonser, Ian Maling, Bindi Isbister, Garren Knell, Alison Slade, David Stephens, Michael Meuleners, David Beard, Nicolyn Short, Rob Grima, Ingrid Richardson, Ruhi Ferdowsian, Geoff Bee, David Evans, Bob Gilkes, Senthold Asseng, Jim Dixon, Felicity Byrne, Mike Ewing, Dennis Van Gool, Louise Barton, Ralf Kiese, David Gatter, Klaus Butterbach-Bahl, Renee Buck, Christoph Hinz, Daniel Murphy, Cameron Weeks, Meredith Fairbanks, John Peirce, Brad Rayner, Sandy White, Paul Damon, Qifa Ma, Zed Rengel, Ed Barrett-Lennard, Meir Altman, Tracey M. Gianatti, Lindsay Bell, Ben Webb, Caroline Peek, Paul Sanford, Paul Blackwell, Glen Riethmuller, Darshan Sharma, Mike Collins, Frank D'Emden, David Hall, G. P. Manango, D. L. Steverson, Vanessa Stewart, Julie Roche, Peter Rutherford, Imma Farre, Ian Foster, Stephen Charles, Frances Hoyle, N. Milton, M. Osman, L. K. Abbott, W. R. Cookson, S. Darmawanto, Rob Sands, David Mccarthy, Paul Carmody, J. Russell, J. Eyres, G. Fosbery, A. Roe, Phil Nichols, Andrew Bathgate, Anne Wilkins

Crop Updates

This session covers forty papers from different authors:

1. Quality Assurance and industry stewardship, David Jeffries, Better Farm IQ Manager, Cooperative Bulk Handling

2. Sothis: Trifolium dasyurum (Eastern Star clover), A. Loi, B.J. Nutt and C.K. Revell, Department of Agriculture and Food

3. Poor performing patches of the paddock – to ameliorate or live with low yield? Yvette Oliver¹, Michael Robertson¹, Bill Bowden², Kit Leake³and Ashley Bonser³, CSIRO Sustainable Ecosystems¹, Department of Food and Agriculture², Kellerberrin Farmer³

4. What evidence is there that …

Proceedings Of The 34th Annual Meeting Of The Southern Soybean Disease Workers (February 18-19, 2007, St. Louis, Missouri), Daniel H. Poston, Michael E. Schmidt, J. Allen Wrather, Jason Bond, Stephen R. Koenning

Southern Soybean Disease Workers: Conference Proceedings

Southern United States Soybean Disease Loss Estimates for 2006. SR Koenning

Stratego 250 EC, Broad Spectrum Disease Control in Soybeans. JR Bloomberg, RA Myers, and R Kraus

Asian Soybean Rust: Efficacy of Selected Fungicides and Observations on Their Use. RW Schneider, CL Clark, EP Mumma, and CG Giles

Effects of Light Intensity and Darkness Period on Infection of Soybean Rust in Controlled Conditions. J Mo, T Guo, X Li, and XB Yang

Identification of Maturity Group 3 and 4 Soybean Cultivars and Lines Resistant to Cercospora sojina by Field Screening and Molecular Markers. A Wrather, R Mian, G Shannon, J …

Association Of Ergot Alkaloids With Conidiation In Aspergillus Fumigatus, Christine M. Coyle, Shawn C. Kenaley, William R. Rittenour, Daniel G. Panaccione

Department of Plant Pathology: Faculty Publications

Ergot alkaloids are mycotoxins that affect the nervous and reproductive systems of exposed individuals through interactions with monoamine receptors. They have been studied more widely in ergot fungi and grass endophytes but also are found in Aspergillus fumigatus, an opportunistic human pathogen that reproduces and disseminates exclusively through conidia. The ergot alkaloids festuclavine and fumigaclavines A, B and C are present in or on conidia of A. fumigatus. Cultures of the fungus that are free of conidia are difficult to obtain, obscuring comparisons of conidia versus vegetative hyphae as sources of the ergot alkaloids. To create conidiation-deficient strains of A. …

Regulation Of Hyphal Morphogenesis By Cdc42 And Rac1 Homologues In Aspergillus Nidulans, Aleksandra Virag, Maurice P. Lee, Haoyu Si, Steven D. Harris

Department of Plant Pathology: Faculty Publications

The ability of filamentous fungi to form hyphae requires the establishment and maintenance of a stable polarity axis. Based on studies in yeasts and animals, the GTPases Cdc42 and Rac1 are presumed to play a central role in organizing the morphogenetic machinery to enable axis formation and stabilization. Here, we report that Cdc42 (ModA) and Rac1 (RacA) share an overlapping function required for polarity establishment in Aspergillus nidulans. Nevertheless, Cdc42 appears to have a more important role in hyphal morphogenesis in that it alone is required for the timely formation of lateral branches. In addition, we provide genetic evidence …

Response Of Soybean Cultivars To Bean Pod Mottle Virus Infection, Amy D. Ziems, Loren J. Giesler, George L. Graef, Margaret G. Redinbaugh, Jean L. Vacha, Sueann Berry, Laurence V. Madden, Anne E. Dorrance

Department of Plant Pathology: Faculty Publications

Bean pod mottle virus (BPMV) has become increasingly common in soybean throughout the north-central region of the United States. Yield loss assessments on southern soybean germplasm have reported reductions ranging from 3 to 52%. Currently, no soybean cultivars have been identified with resistance to BPMV. The objective of this study was to determine the impact of BPMV infection on soybean cultivars representing a broad range of northern soybean germplasm by comparing inoculated and noninoculated soybean plants in paired row studies. In all, 30 and 24 cultivars were evaluated in Nebraska (NE) in which soybean plants were inoculated at the V3 …

Basa Regulates Cell Wall Organization And Asexual/Sexual Sporulation Ratio In Aspergillus Nidulans, Shaojie Li, Dapeng Bao, Gary Yuen, Steven D. Harris, Ana M. Calvo

Department of Plant Pathology: Faculty Publications

Sphingolipid C4 hydroxylase catalyzes the conversion of dihydrosphingosine to phytosphingosine. In Saccharomyces cerevisiae, Sur2 is essential for sphingolipid C4 hydroxylation activity but not essential for normal growth. Here we demonstrate that the Aspergillus nidulans Sur2 homolog BasA is also required for phytosphingosine biosynthesis but is also essential for viability. We previously reported that a point missense mutation in basA resulted in aberrant cell wall thickening. Here our data suggest that accumulation of dihydrosphingosine is responsible for this phenotype. In addition, two different mutations in basA consistently accelerated the transition from asexual development to sexual development compared to the wild-type …

Free-Living Dorylaimid Nematodes From Nature Reserves In Costa Rica. The Genus Pachydorylaimus Siddiqi, 1983, A. Esquivel, P. Guerrero, R. Peña-Santiago, Thomas O. Powers

Department of Plant Pathology: Faculty Publications

A taxonomic study of three species, two known and one new, belonging to the genus Pachydorylaimus Siddiqi, 1983 from natural areas in Costa Rica is presented. Pachydorylaimus holovachovi sp. n. is described and can be distinguished by its body 0.90-1.00 mm long, lip region 14-17 μm wide, odontostyle 13-15 μm long, odontophore morphology with differentiated hyaline spindle-shaped area surrounding its junction to pharyngeal lining but lacking distinct basal flanges, total stylet length 35- 44 μm, pars refringens vaginae absent, V = 43-47, female tail straight and tapering to an acute tip (57- 78 μm, c = 12.5-15.8, c’ = 2.0-3.0), …

Structure And Function Of A Chlorella Virus Encoded Glycosyltransferase, Ying Zhang, Ye Xiang, James L. Van Etten, Michael G. Rossmann

James Van Etten Publications

Paramecium bursaria chlorella virus-1 encodes at least 5 putative glycosyltransferases that are probably involved in the synthesis of the glycan components of the viral major capsid protein. The 1.6 Å crystal structure of one of these glycosyltransferases (A64R) has a mixed α/β fold containing a central, six-stranded β-sheet flanked by α-helices. Crystal structures of A64R, complexed with UDP, CMP, or GDP, established that only UDP bound to A64R in the presence of Mn2+, consistent with its high structural similarity to glycosyltransferases which utilize UDP as the sugar carrier. The structure of the complex of A64R, UDP-glucose, and Mn2+ showed that …