Life Sciences Commons^™

Novel Application Of Phastsystem Polyacrylamide Gel Electrophoresis Using Restriction Fragment Length Polymorphism ± Internal Transcribed Spacer Patterns Of Individuals For Molecular Identification Of Entomopathogenic Nematodes, Horolma Pamjav, Dimitra Triga, Zsuzsanna Buzµs, Tibor Vellai, Attila Lucskai, Byron Adams, Alexander P. Reid, Ann Burnell, Christine Griffin, Itamar Glazer, Michael G. Klein, Andras Fodor

Department of Plant Pathology: Faculty Publications

A relatively rapid and economic way of identifying and assigning nematodes to taxons, which had already been determined either by comparative sequence analysis of nuclear rDNA internal transcribed spacer (ITS) region or by other methods of molecular or conventional taxonomy, is provided. Molecular identification of entomopathogenic nematodes (EPN) can be upgraded by basing it on PhastSystem polyacrylamide gel electrophoresis (PAGE) analysis of restriction fragment length polymorphism (RFLP) patterns of polymerase chain reaction (PCR)-amplified DNA derived from single nematodes of Steinernema or Heterorhabditis spp. Although analysis from single worms has previously been made on agarose gel, the resolution on PhastSystem PAGE …

Genetic Variation In Geographical Populations Of Western And Mexican Corn Rootworm, A. L. Szalanski, R. L. Roehrdanz, D. B. Taylor, L. Chandler

Department of Plant Pathology: Faculty Publications

Genetic variation in the nuclear rDNA ITS1 region of western corn rootworm, Diabrotica virgifera virgifera (WCR), and Mexican corn rootworm, D. v. zeae (MCR) was studied. Two sites were detected which differentiated WCR and MCR in the 642-base sequence. Polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) analysis of the first internal transcribed spacer region (ITS1) sequence revealed no variation within or among the twelve WCR and two MCR populations. PCR-RFLP of 75% of the mitochondrial DNA genome detected one significant polymorphic site out of the approximately 190 restriction sizes observed in WCR. The polymorphism did not differentiate geographical populations of …

Proceedings Of The 26th Annual Meeting, Southern Soybean Disease Workers (March 20-22, 1999, Robinson, Mississippi), Stephen R. Koenning, John Russin, Peggy S. King

Southern Soybean Disease Workers: Conference Proceedings

Contents

Soybean Disease Loss Estimates for the Southern United States during 1998. Phillip W Pratt

Treasurer report. Peggy S King

Contributed paper session

Resistance Ratings for 288 soybean Cultivars to the Reniform Nematode, Rotylenchulus reniformis. RT Robbins, L Rakes, and L Jackson

Evaluation of Azoxystrobin on Two Foliar Soybean Diseases in Arkansas. CM Coker

Early Soybean Production System in Missouri: Progress and Potential. JA Wrather, and DA Sleper

A New Phomopsis Disease of Soybeans in Mississippi. GL Sciumbato and BL Keeling

Reaction of Soybean Genotypes to Sudden Death Syndrome. JH Klein, ME Schmidt, RE Whelan, JS Russin, RJ Suttner, …

Crop Updates 1999 - Oilseeds, Paul Carmody, Rick Madin, David Bowran, Martin Barbetti, Ravjit Khangura, Graham Walton, Phil Parker, Francoise Berlandier, Linnet Cartwright, Ping Si, Nick Galwey, David Turner, Wayne Pluske, Roger Jones, Brenda Coutts, Bill Bowden, Isabel Arevalo-Vigne, Jeff Russell, Syed H. Zaheer, Andrew Simon, Art Diggle, Dave Eksteen, Arjen Ryder, Bill Crabtree, Serena Wyatt, Jim Baily

Crop Updates

This article contains eighteen papers

1. INTRODUCTION, Paul Carmody, Agriculture Western Australia

PLENARY SESSION

1. Transgenic canola in Western Australia: Outlook and challenges, Phil Salisbury, University of Melbourne

2. Farming system issues for herbicide tolerant canola, Rick Madin, Rick Madin and Associates, David Bowran, Agriculture Western Australia

3. Beating blackleg in 1999, Martin Barbetti, Ravjit Khangura, Paul Carmody, Graham Walton, Agriculture Western Australia

4. The Mustard Industry in Australia – Opportunities for a new oilseed, Phil Parker, NSW Agriculture

5. Management of blackleg with fungicides, Ravjit Khangura and Martin Barbetti, Agriculture Western Australia

6. Effect of aphid feeding …

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Crop Updates 1999 - Lupins, Greg Shea, Geoff Thomas, Mark Sweetingham, Bill O'Neill, Wallace Cowling, Bevan Buirchell, Hua'an Yang, David Luckett, Allan Brown, John Hamblin, Joanne E. Barton, Kedar Adhikari, Nick Galwey, Miles Dracup, Bob French, Debbie Thackray, Roger Jones, Brenda Coutts, Narelle Reeve, Y. Cheng, R. A.C. Jones, Francoise Berlandier, Linnet Cartwright, James Fisher, Art Diggle, Bill Bowden, Chris Gazey, Luigi Morsechi, Terry Piper, Peter Newman, Dave Nicholsen, Mohammad Amjad, Glen Riethmuller, Ron Javis, Paul Blackwell, C. L. White

Crop Updates

This article contains twenty three papers

1998 LUPIN HIGHLIGHTS

LUPIN ANTHRACNOSE

1. Anthracnose overview, Greg Shea, Geoff Thomas and Mark Sweetingham, Agriculture Western Australia

2. Anthracnose – Critical seed infection levels for resistant and susceptible varieties, Geoff Thomas, Mark Sweetingham, Bill O'Neill and Greg Shea, Agriculture

Western Australia

3. Fungicide seed treatment for anthracnose and brown spot control in lupin, G. Thomas and M. Sweetingham, Agriculture Western Australia

LUPIN BREEDING AND AGRONOMY

4. Anthracnose resistance in lupins – an innovative Australian research effort 1996-1998, Wallace Cowling1'2, Bevan Buirchell_1,2 Mark Sweetinqham_1,2, Hua'an Yang₂, …

Crop Updates 1999 - Cereals, Len W. Broadbridge, Doug Abrecht, D. Bakker, Greg Hamilton, Cliff Spann, Doug Rowe, Peter Fisher, Jennifer Bignell, Matthew Braimbridge, Bill Bowden, Ross Brennan, Reg Lunt, Senthold Asseng, Cherie Rowles, Simon Bedbrook, Chris Gazey, Mike Bolland, Garren Knell, Lyn Abbott, Zed Rengel, Wayne Pluske, Erin Cahill, Bill Crabtree, Matthew Evans, Tim Nielsen, Jat Bhathal, Rob Loughman, D. Rasmussen, Roger A C Jones, Sean Kelly, Ian Riley, Sharyn Tayor, Vivien Vanstone, Dominie Wright, Debbie Thackray, Simon Mckirdy, George Yan, Robin Wilson, Iain Barclay, Robin Mclean, Dean A. Diepeveen, Bill Lambe, Wal Anderson, Brenda Shackley, Mechelle Owen, Peter Burgess, Ben Curtis, Mohammed A. Hamza, Jamie Henderson, Frank Boetel, Alfredo Impiglia, Frances Hoyle, Darshan Sharma, Pierre Fievez, Blakely Paynter, Glenn Macdonald, Kevin Young, Andrew Blake, Keith Devenish, P J. Dolling, Roy Latta, Lisa-Jane Blacklow, Chris Matthews, Angelo Loi, Brad Nutt, Rochelle Mcrobb, David Webb, Andrew Mcrobb, Clinton K. Revell, James Ridsdill-Smith, Celia Pavri, David Tennant, Darryl Mclements, Ross Thompson, Mike Ewing, Tim Woodburn, Paul Yeoh, James Fisher, Art Diggle, Mark Whitten, Andrew Rate, Paul Carlile, Ed Blanchard, Bevan Buirchell, Lorraine Osborne, Tress Walmsley, Terry Piper, Cameron Weeks, Michael Dodd, Amanda Falconer, Caroline Peek, Glenn Adam, Camray Gethin, Richard Guinness, Daniel Fels, Andrew Rintoul, Mal Lamond, Roger Tapp, Craig White

Crop Updates

This article covers sixty papers

FOREWORD

ACKNOWLEDGMENTS

PLENARY PAPERS

1. Western Australia’s climate: trends and opportunities, Len W. Broadbridge, Director, Bureau of Meterorology

2. Managing seasonal variations in agriculture, Dr Doug Abrecht, Director, Dryland Research Institute, Merredin

CROP ESTABLISHMENT

3. Soil management to prevent waterlogging on duplex soils in the Great Southern, D. Bakker, Greg Hamilton, Cliff Spann and Doug Rowe, Agriculture Western Australia

4. The influence of no-till and press wheels on crop production for heavy soils, Peter Fisher, Jennifer Bignell, Matthew Braimbridge, Greg Hamilton, Agriculture

Western Australia

NUTRITION

5. Fertiliser nitrogen, applied late, needs …

Farm Operator Satisfaction With Retail Pesticide Suppliers In The Arkansas Delta, Bruce L. Dixon, Damon Mckelvey, Travis Rogers, Frank L. Farmer, Daniel M. Settlage

AAES Research Reports and Research Bulletins

Two hundred ninety farm operators in the three easternmost crop reporting districts in Arkansas responded to a mail survey in November 1996 about their preferences and satisfaction with retail pesticide suppliers.Results show most farmers are quite satisfied with their main retail pesticide supplier, although 55.5% of the farm operators used more than one retail pesticide supplier in 1996. Users of multiple suppliers were less satisfied with their suppliers than those using only one supplier. Availability of certain pesticides was the most frequently mentioned reason for using multiple suppliers. Several attributes were important in selecting the main supplier with reputation being …

Managing Lupin Anthracnose, Greg Shea, W A. Cowling, B J. Burchell, D Luckett, H Yang, Mark W. Sweetingham, Geoff J. Thomas

Journal of the Department of Agriculture, Western Australia, Series 4

Anthracnose in lupins was first reported in commercial crops in Western Australia in September 1996. By October 1996, several thousand lupin breeding lines and wild types of 11 lupin species were sown in New Zealand for resistance screening. In 1997, resistance to anthracnose was confirmed in several breeding fines and commercial cultivars of narrow-leafed lupins (I. angustifolius), landraces of albus lupins (I. albus) and wild types of several other lupin species. Important information on critical seed infection levels and fungicide seed treatment has also been determined.

Identification And Characterization Of Genes Required For Hyphal Morphogenesis In The Filamentous Fungus Aspergillus Nidulans, Steven D. Harris, Amy F. Hofmann, Hugo W. Tedford, Maurice P. Lee

Department of Plant Pathology: Faculty Publications

In the filamentous fungus Aspergillus nidulans, germination of an asexual conidiospore results in the formation of a hyphal cell. A key feature of spore germination is the switch from isotropic spore expansion to polarized apical growth. Here, temperature-sensitive mutations are used to characterize the roles of five genes (sepA, hypA, podB–podD) in the establishment and maintenance of hyphal polarity. Evidence that suggests that the hypA, podB, and sepA genes are required for multiple aspects of hyphal morphogenesis is presented. Notably, podB and sepA are needed for organization of the cytoskeleton at sites of …

Giant Viruses Infecting Algae, James L. Van Etten, Russel Meints

Department of Plant Pathology: Faculty Publications

Paramecium bursaria chlorella virus (PBCV-1) is the prototype of a family of large, icosahedral, plaque-forming, double-stranded–DNA-containing viruses that replicate in certain unicellular, eukaryotic chlorella-like green algae. DNA sequence analysis of its 330, 742-bp genome leads to the prediction that this phycodnavirus has 376 protein-encoding genes and 10 transfer RNA genes. The predicted gene products of ~40% of these genes resemble proteins of known function. The chlorella viruses have other features that distinguish them from most viruses, in addition to their large genome size. These features include the following: (a) The viruses encode multiple DNA methyltransferases and DNA site-specific endonucleases; (b) …

Colletotrichum Trifolii Mutants Disrupted In The Catalytic Subunit Of Camp-Dependent Protein Kinase Are Nonpathogenic, Zhonghui Yang, Martin B. Dickman

Department of Plant Pathology: Faculty Publications

Colletotrichum trifolii is the fungal pathogen of alfalfa that causes anthracnose disease. For successful plant infection, this fungus must undergo a series of morphological transitions following conidial attachment, including germination and subsequent differentiation, resulting in appressorium formation. Our previous studies with pharmacological effectors of signaling pathways have suggested the involvement of cyclic AMP (cAMP)-dependent protein kinase (PKA) during these processes. To more precisely evaluate the role of PKA in C. trifolii morphogenesis, the gene encoding the catalytic (C) subunit of PKA (Ct-PKAC) was isolated, sequenced, and inactivated by gene replacement. Southern blot analysis with C. trifolii genomic DNA …

Can Large Dsdna-Containing Viruses Provide Information About The Minimal Genome Size Required To Support Life?, James L. Van Etten

James Van Etten Publications

The genomes of a few viruses, such as Bacillus megaterium phage G (670 kb) and the chlorella viruses (330 to 380 kb), are larger than the predicted minimal genome size required to support life (ca. 320 kb). A comparison of the 256 proteins predicted to be required for life with the putative 376 proteins encoded by chlorella virus PBCV-1, as well as those encoded by other large viruses, indicates that viruses lack many of these “essential” genes. Consequently, it is unlikely that viruses will aid in determining the minimal number and types of genes required for life. However, viruses may …

Isolates Of Uromyces Appendiculatus With Specific Virulence To Landraces Of Phaseolus Vulgaris Of Andean Origin, Craig M. Sandlin, James R. Steadman, Carlos M. Araya, Dermot P. Coyne

Department of Plant Pathology: Faculty Publications

Five isolates of the bean rust fungus Uromyces appendiculatus were shown to be specifically virulent on bean genotypes of Andean origin. This specificity was demonstrated by the virulence of five pairs of isolates on a differential set of 30 Phaseolus vulgaris landraces. Each isolate pair was from a different country in the Americas and consisted of one Andean-specific isolate and one nonspecific isolate. Of the differential P. vulgaris landraces, 15 were of Middle American origin and 15 were of Andean origin. The Andean-specific rust isolates were highly virulent on Andean landraces but not on landraces of Middle American origin. …

Carrot Export Growth Depends On Keeping Cavity Spot Under Control, Allan Mckay, Elaine Davison

Journal of the Department of Agriculture, Western Australia, Series 4

Cavity spot is the most serious disease affecting carrot production in Ly Western Australia. With carrots now being the State's most important horticultural export, Agriculture Western Australia has undertaken extensive research to ensure the export market continues to grow.

Signaling Via Camp In Fungi: Interconnections With Mitogen-Activated Protein Kinase Pathways, James Kronstad, Adriana De Maria, Deanna Funnell, R. David Laidlaw, Nancy Lee, Mário Moniz De Sá, Marilee Ramesh

Department of Plant Pathology: Faculty Publications

The cAMP signal transduction pathway controls a wide variety of processes in fungi. For example, considerable progress has been made in describing the involvement of cAMP pathway components in the control of morphogenesis in Saccharomyces cerevisiae, Ustilago maydis, and Magnaporthe grisea. These morphological processes include the establishment of filamentous growth in S. cerevisiae and U. maydis, and the differentiation of an appressorial infection structure in M. grisea. The discovery that appressorium formation requires cAMP signaling provides an immediate connection to fungal virulence. This connection may have broader implications among fungal pathogens because recent work indicates …

The Pseudomonas Syringae Pv. Tomato Hrpw Protein Has Domains Similar To Harpins And Pectate Lyases And Can Elicit The Plant Hypersensitive Response And Bind To Pectate, Amy O. Charkowski, James R. Alfano, Gail Preston, Jing Yuan, Sheng Yang He, Alan Collmer

Center for Plant Science Innovation: Faculty Publications

The host-specific plant pathogen Pseudomonas syringae elicits the hypersensitive response (HR) in nonhost plants and secretes the HrpZ harpin in culture via the Hrp (type III) secretion system. Previous genetic evidence suggested the existence of another harpin gene in the P. syringae genome. hrpW was found in a region adjacent to the hrp cluster in P. syringae pv. tomato DC3000. hrpW encodes a 42.9-kDa protein with domains resembling harpins and pectate lyases (Pels), respectively. HrpW has key properties of harpins. It is heat stable and glycine rich, lacks cysteine, is secreted by the Hrp system, and is able to elicit …

Interactions Between The Structural Domains Of The Rna Replication Proteins Of Plant-Infecting Rna Viruses, Erin K. O'Reilly, Zhaohui Wang, Roy C. French, C. Cheng Kao

Department of Plant Pathology: Faculty Publications

Brome mosaic virus (BMV), a positive-strand RNA virus, encodes two replication proteins: the 2a protein, which contains polymerase-like sequences, and the 1a protein, with N-terminal putative capping and C-terminal helicase-like sequences. These two proteins are part of a multisubunit complex which is necessary for viral RNA replication. We have previously shown that the yeast two-hybrid assay consistently duplicated results obtained from in vivo RNA replication assays and biochemical assays of protein-protein interaction, thus permitting the identification of additional interacting domains. We now map an interaction found to take place between two 1a proteins. Using previously characterized 1a mutants, a perfect …

A Sensitive Elisa For Pythium Ultimum Using Polyclonal And Species-Specific Monoclonal Antibodies, G. Y. Yuen, J. Q. Xia, C. L. Sutula

Department of Plant Pathology: Faculty Publications

A double-antibody sandwich indirect enzyme-linked immunosorbent assay (ELISA) was developed for the detection and quantification of Pythium ultimum. A polyclonal antibody produced to cell walls of P. ultimum was used as the capture antibody, while a P. ultimum-specific monoclonal antibody (MAb E5) was used for recognition of the fungus. In the ELISA, culture extracts of 7 isolates of P. ultimum exhibited strong positive reactions, whereas none of the 37 isolates of other Pythium spp. and fungal genera had positive reactions. P. ultimum was detected by ELISA in roots of bean, cabbage, and sugar beet seedlings grown in pathogen-infested …

Mutational Analysis Of Area, A Transcriptional Activator Mediating Nitrogen Metabolite Repression In Aspergillus Nidulans And A Member Of The “Streetwise” Gata Family Of Transcription Factors, Richard A. Wilson, Herbert N. Arst Jr.

Fungal Molecular Plant-Microbe Interactions

Details a mutational analysis of AREA, a transcriptional activator mediating nitrogen metabolite repression in Aspergillus nidulans and a member of the “streetwise” GATA family of transcription factors.

A Partial Host Range Of The High Plains Virus Of Corn And Wheat, Dallas L. Seifers, Tom L. Harvey, T. J. Martin, Stanley G. Jensen

Department of Plant Pathology: Faculty Publications

Barley (Hordeum vulgare), cheat (Bromus secalinus), corn (Zea mays), oat (Avena sativa), rye (Secale cereale), and wheat (Triticum aestivum) were infected by a Kansas isolate of the High Plains virus (HPV) in greenhouse experiments, but several other grass species were not. Infection of a host was dependent upon wheat curl mite numbers. Although both green foxtail (Setaria viridis) and yellow foxtail (S. glauca) are found naturally infected by HPV, only yellow foxtail could be infected in greenhouse experiments. Field sampling (1994 to 1996) of …

Certification And The American Phytopathological Society, L. J. Stowell, J. Amador, O.W. Barnett, R. J. Cook, D. E. Mathre, A. K. Vidaver, S. A. Tolin

Department of Plant Pathology: Faculty Publications

The profession of plant pathology strives to improve the health and safety of the public through improved plant health systems. This includes the benefits afforded by well-managed urban landscapes and abundant food and fiber. However, the proud glow of the profession of plant pathology has dimmed over the past 20 years to the point that some members of the American Phytopathological Society (APS), the principal professional society of plant pathologists in the United States, are not sure what a plant pathologist should know or what a plant pathologist is responsible for (Phytopathology News 30:162). Without a unified, positive direction for …

Phylogenetic Relationships Within The Family Potyviridae: Wheat Streak Mosaic Virus And Brome Streak Mosaic Virus Are Not Members Of The Genus Rymovirus, Drake C. Stenger, Jeffrey S. Hall, Il-Ryong Choi, Roy C. French

Department of Plant Pathology: Faculty Publications

The complete nucleotide sequence of wheat streak mosaic virus (WSMV) has been determined based on complementary DNA clones derived from the 9,384-nucleotide (nt) RNA of the virus. The genome of WSMV has a 130-nt 5&#;&#;leader and 149-nt 3&#;-untranslated region and is polyadenylated at the 3&#;&#;end. WSMV RNA encodes a single polyprotein of 3,035 amino acid residues and has a deduced genome organization typical for a member of the family Potyviridae (5&#;-P1/HC-Pro/P3/6K1/CI/6K2/VPg-NIa/NIb/CP-3&#;). Because WSMV shares with ryegrass mosaic virus (RGMV) the biological property of transmission by eriophyid mites, WSMV has been assigned to the genus Rymovirus, of which RGMV is …

Expression Of Human Lactoferrin Cdna Confers Resistance To Ralstonia Solanacearum In Transgenic Tobacco Plants, Zhanyuan Zhang, Dermot P. Coyne, Anne K. Vidaver, Amitava Mitra

Department of Plant Pathology: Faculty Publications

A construct containing a human lactoferrin cDNA was used to transform tobacco (Nicotiana tabacum) using an Agrobacterium-mediated DNA-transfer system to express this human protein in transgenic plants. Transformants were analyzed by Southern, Northern, and Western blots to determine integration of the cDNA into the plant genome and lactoferrin gene expression levels. Most transgenic plants demonstrated significant delays of bacterial wilt symptoms when inoculated with the bacterial pathogen Ralstonia solanacearum. Quantification of the expressed lactoferrin protein by enzyme-linked immunosorbent assay in transgenic plants indicated a significant positive relationship between lactoferrin gene expression levels and levels of disease …

Physiologic Specialization Of Puccinia Recondita F. Sp. Tritici In Nebraska During 1995 And 1996, J. E. Watkins, S. S. Rutledge, P. Stephen Baenziger, W. Youngquist

Department of Plant Pathology: Faculty Publications

Field samples of Puccinia recondita f. sp. tritici, collected from four wheat-growing regions in Nebraska in 1995 and from three in 1996, were characterized for virulence. Twenty virulence phenotypes were identified in 1995 and 18 in 1996. Virulence phenotypes MBR-10,18 (virulent on Lr genes, 1, 3, 3ka, 10, 11, 18, and 30) and MDR-10,18 (virulent on Lr genes 1, 3, 3ka, 10, 11, 18, 24, and 30) were the most prevalent, with each phenotype comprising 21.6% of the isolates characterized in 1995. Of the 1995 isolates, 24% were virulent on 10 or more host genes. No virulence to Lr16 and …

Polymerase Chain Reaction Detection And Phylogenetic Characterization Of An Agent Associated With Yellow Vine Disease Of Cucurbits, Francisco J. Avila, Benny D. Bruton, Jacqueline Fletcher, J. L. Sherwood, Sam D. Pair, Ulrich Melcher

Department of Plant Pathology: Faculty Publications

Diagnosis of yellow vine disease (YVD) in cucurbits, an important disease in the south-central United States, relies on external symptom appearance, phloem discoloration, and the presence of bacterium-like organisms (BLOs) in phloem. Polymerase chain reaction (PCR) amplification of BLO nucleotide sequences was explored as a means to improve diagnostic techniques. PCR, using a primer pair based on sequences of the citrus-greening BLO, amplified a 0.15-kilobase (kb) fragment from the DNA of symptomatic plants, but not from that of asymptomatic plants. Its nucleotide sequence suggested that the DNA amplified was of prokaryotic origin. A primer pair, designed to amplify nonspecific prokaryotic …

Studies On The Biology Of Striga Aspera (Scrophulariaceae) In Nigeria, Emmanuel Izaka Aigbokhan

Biological Sciences Theses & Dissertations

Studies on Striga aspera are few and little information exists on its relationship with the morphologically similar and much studied S. hermonthica. Both species are sympatric in West Africa and if they hybridize, may serve as virulent gene reservoirs for each other.

The primary focus of this study was on the biology of S. aspera in Nigeria. The research focussed on its distribution, phenology, cytology, hybridization, seed dormancy, viability and germination in relation to S. hermonthica. Related studies involving the hybrids include genetic and morphological variability, pathogenicity and the simultaneous dual infection of a maize plant by both species.

In …

Managing Spring Dead Spot Of Bermudagrass, Paul C. Vincelli, David Williams

Agriculture and Natural Resources Publications

Spring dead spot is the most destructive disease of bermudagrass in Kentucky. The most serious outbreaks occur under high maintenance conditions; e.g., high nitrogen fertility, low mowing height, and frequent traffic. Moderate to severe outbreaks can occur under low-maintenance conditions as well.

High levels of resistance to spring dead spot in bermudagrass varieties have not yet been demonstrated experimentally. Limited data suggest that those varieties with best winter hardiness are somewhat less susceptible to the disease. To date, no confirmed cases of spring dead spot have been documented in “Quickstand” bermudagrass, which may indicate that this variety will suffer less …

Clubroot, Rachel Lancaster, Caroline Donald, Ian Porter

Journal of the Department of Agriculture, Western Australia, Series 4

Rachel Lancaster, Caroline Donald and Ian Palmer, outline some control measures for clubroot, one of the most serious diseases of crucifers world wide.

Lindsay M. Black, 1907 To 1997, Myron K. Brakke, D. V. R. Reddy

Department of Plant Pathology: Faculty Publications

Plant pathology and virology lost a pioneer when Lindsay MacLeod Black died on 23 December 1997. We lost a friend and mentor. Black was noted for proving conclusively that a plant virus can multiply in both leafhopper vectors and plants; characterizing unstable, leafhopper-transmitted viruses; and developing insect tissue cultures for studying plant viruses.

Signaling Via Camp In Fungi: Interconnections With Mitogen-Activated Protein Kinase Pathways, James Kronstad, Adriana De Maria, Deanna L. Funnell, R. David Laidlaw, Nancy Lee, Mário Moniz De Sá, Marilee Ramesh

Department of Plant Pathology: Faculty Publications

The cAMP signal transduction pathway controls a wide variety of processes in fungi. For example, considerable progress has been made in describing the involvement of cAMP pathway components in the control of morphogenesis in Saccharomyces cerevisiae, Ustilago maydis, and Magnaporthe grisea. These morphological processes include the establishment of filamentous growth in S. cerevisiae and U. maydis, and the differentiation of an appressorial infection structure in M. grisea. The discovery that appressorium formation requires cAMP signaling provides an immediate connection to fungal virulence. This connection may have broader implications among fungal pathogens because recent work indicates that …