Plant Pathology Commons^™

Crop Updates 2001 - Cereals, Ross Kingwell, Wal Anderson, Eddy Pol, Peter Burgess, Ashley Bacon, D. M. Bakker, G. J. Hamilton, D. Houlbrooke, C. Spann, M. A. Hamza, Paul Blackwell, M. D. A. Bolland, Maurice Black, R. F. Brennan, W. L. Crabtree, Bill Bowden, Chris Gazey, Rochelle Strahan, Bob Gilkes, Zed Rengel, Stephen Loss, Tim O'Dea, Patrick Gethin, Ryan Guthrie, Lisa Leaver, David Phelps, Darshan Sharma, Mohammad Amjad, Md Sanajahanh Miyan, James Fisher, Senthold Asseng, Bill Bowden, Michael Robertson, Glenn Macdonald, Kevin Young, Blakely Paynter, Jatinderpal Bathal, Cameron Weeks, Kithsiri Jayasena, Rob Loughman, Q. Knight, Dominie Wright, Nichole Burges, Lisa-Jane Blacklow, Rob Hulme, Rob Griffith, Jenny Hawkes, Roger Jones, Debbie Thackray, S. B. Sharma, S. Kelly, Peter Newman, Dave Nicholson, Harmohinder Dhammu, Terry Piper, Mario F. D'Antuono, Mehmet Cakir, Nick Galwey, David Poulsen, Garry Ablett, Reg Lance, Greg Platz, Joe Panozzo, Barbara Read, David Moody, Andy Barr, Peter Langridge, Tina Botwright, Tony Condon, Robin Wilson, Iain Barclay, Howard Carr, Greg Shea, Ian Foster, David Tennant

Crop Updates

This session covers forty two papers from different authors:

PLENARY

1. Planning your cropping program in season 2001, Dr Ross Kingwell, Agriculture Western Australia and University of Western Australia

WORKSHOP

2. Can we produce high yields without high inputs? Wal Anderson, Centre for Cropping Systems, Agriculture Western Australia

VARIETIES

3. Local and interstate wheat variety performance and $ return to WA growers, Eddy Pol, Peter Burgess and Ashley Bacon, Agritech Crop Research

CROP ESTABLISHMENT

4 Soil management of waterlogged soils, D.M. Bakker, G.J. Hamilton, D. Houlbrooke and C. Spann, Agriculture Western Australia

5. Effect of soil …

Crop Updates 2001 - Oilseeds, Mervyn Mcdougall, Debbie Thackray, Kevin Walden, G. Walton, Kevin Morthorne, Stephen Addenbrooke, Paul Carmody, Rafiul Alam, Glen Riethmuller, Greg Hamilton, Paul Blackwell, M. D. A. Bolland, M. J. Baker, A. J. Diggle, Chris Gazey, Imma Farre, Michael J. Robertson, Senthold Asseng, Ping Si, David Turner, David Harris, Françoise Berlandier, Christiaan Valentine, David Cook, Peter Mangano, David Cousins, Darryl Hardie, Ravjit Khangura, Martin Barbetti, Jenny Hawkes, Roger Jones, Cameron Weeks, Erin Hasson, David Eksteen, John Moore, Paul Matson, Carla Thomas, Lionel Martin

Crop Updates

ABSTRACT

This session covers twenty five papers from different authors:

FORWARD, Mervyn McDougall, CHAIRMAN, PULSES AND OILSEEDS PARTNERSHIP GROUP

PLENARY

1. Implications of the ‘green-bridge’ for viral and fungal disease carry-over between seasons, Debbie Thackray, Agriculture Western Australia and Centre for Legumes in Mediterranean Agriculture

2. Insect pest development in WA via the ‘green-bridge’, Kevin Walden, Agriculture Western Australia

VARIETIES

3. Performance of new canola varieties in AGWEST variety trials, G. Walton, Crop Improvement Institute, Agriculture Western Australia

4. New herbicide tolerant varieties in WA, Kevin Morthorpe, Stephen Addenbrooke, Pioneer Hi-Bred Australia P/L

5. IT v’s TT – …

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 …

Crop Updates 2001 - Pulses, M. Harries, W. O'Neill, R. French, N. Brandon, N. Runciman, S. White, M. Seymour, P. White, T. White, C. Veitch, J. Berger, N. C. Turner, K. H. M. Siddique, H. Clarke, G. P. Riethmuller, W. Macleod, J. Millar, T. N. Khan, R. Beermier, N. Brown, H. Dhammu, T. Piper, D. Nicholson, M. D'Antuono, K. Regan, J. Clements, C. Francis, C. Hanbury, C. White, B. Mullan, B. Hughes, R. Bowie, J. Warburton, P. Fisher, M. Braimbridge, F. Hoyle, W. Bowden, S. Lawrence, Z. Rengel, S. P. Loss, M. D. A. Bolland, R. Brennan, P. Tille, N. Schoknecht, J. Galloway, D. Wright, N. Burges, R. Jones, L. Latham, O Edwards, J. Ridsdill-Smith, M. J. De Sousa Majer, N. C. Turner, D. Hardie, P. Smith, R. Emery, E. Kostas

Crop Updates

This session covers sixty six papers from different authors:

1. Pulse Industry Highlights

2. CONTRIBUTORS

3. BACKGROUND

4. SUMMARY OF PREVIOUS RESULTS

2000 REGIONAL ROUNDUP

5. Northern agricultural Region, M. Harries, W. O’Neill, Agriculture Western Australia

6. Central Agricultural Region, R. French, Agriculture Western Australia

7. Great Southern and Lakes,N. Brandon, N. Runciman and S. White,Agriculture Western Australia

8. Esperance, M. Seymour, Agriculture Western Australia

PULSE PRODUCTION AGRONOMY AND GENETIC IMPROVEMENT

Faba bean:

9. germplasm evaluation,

10. Variety evaluation,

11. Sowing rate and time of sowing, Variation in root morphology, P. White and T. Pope, Agriculture Western …

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 …

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 …

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 …

Sequences Of Citrus Tristeza Virus Separated In Time And Space Are Essentially Identical, Maria R. Albiach-Marti, Munir Mawassi, Siddarame Gowda, Satyanarayana Tatineni, Mark E. Hilf, Savita Shanker, Ernesto C. Almira, Maria C. Vives, Carmelo Lopez, Jose Guerri, Ricardo Flores, Pedro Moreno, Steve M. Garnsey, William O. Dawson

Department of Plant Pathology: Faculty Publications

The first Citrus tristeza virus (CTV) genomes completely sequenced (19.3-kb positive-sense RNA), from four biologically distinct isolates, are unexpectedly divergent in nucleotide sequence (up to 60% divergence). Understanding of whether these large sequence differences resulted from recent evolution is important for the design of disease management strategies, particularly the use of genetically engineered mild (essentially symptomless)-strain cross protection and RNA-mediated transgenic resistance. The complete sequence of a mild isolate (T30) which has been endemic in Florida for about a century was found to be nearly identical to the genomic sequence of a mild isolate (T385) from Spain. Moreover, samples of …

Utility Of The Mitochondrial Cytochrome Oxidase Ii Gene For Resolving Relationships Among Black Flies (Diptera: Simuliidae), K. P. Pruess, B. J. Adams, T. J. Parsons, X. Zhu, Thomas O. Powers

Department of Plant Pathology: Faculty Publications

The complete mitochondrial cytochrome oxidase II gene was sequenced from 17 black flies, representing 13 putative species, and used to infer phylogenetic relationships. A midge (Paratanytarsus sp.) and three mosquitoes (Aedes aegypti, Anopheles quadrimaculatus, and Culex quinquefasciatus) were used as outgroup taxa. All outgroup taxa were highly divergent from black flies. Phylogenetic trees based on weighted parsimony (a priori and a posteriori), maximum likelihood, and neighbor-joining (log-determinant distances) differed topologically, with deeper nodes being the least well-supported. All analyses supported current classification into species groups but relationships among those groups were poorly resolved. The majority of phylogenetic …

Condition Of Green Ash, Incidence Of Ash Yellows Phytoplasmas, And Their Association In The Great Plains And Rocky Mountain Regions Of North America, J. A. Walla, W. R. Jacobi, N. A. Tisserat, M. O. Harrell, J. J. Ball, G. B. Neil, D. A. Reynard, Y. H. Guo, L. Spiegel

Department of Plant Pathology: Faculty Publications

About 50% of 1,057 green ash (Fraxinus pennsylvanica) systematically sampled in the Great Plains and Rocky Mountain regions had substantial dieback (>10% of crown branches with dieback), and the average growth ring width during the last 20 years was 2.9 mm. The overall condition of the population was rated fair. Ash yellows phytoplasmas were identified at 102 of 106 sites throughout six U.S. states (North Dakota, South Dakota, Wyoming, Nebraska, Colorado, Kansas) and three Canadian provinces (Alberta, Saskatchewan, Manitoba). These phytoplasmas had not previously been known in Alberta, Saskatchewan, Manitoba, Wyoming, Colorado, or Kansas. Incidence of phytoplasmal …

Crop Updates 2000 - Lupins, Bill O'Neill, Geoff Thomas, Mark Sweetinham, Kedar Adhikari, Nick Galwey, Miles Dracup, Bob French, Debbie Thackray, Jenny Hawkes, Roger Jones, Françoise Berlandier, Yvonne Cheng, Lisa Smith, Chris Gazey, Michael O'Connell, Peter Carlton, John R. Peirce, Brad J. Rayner, Terry Piper, Peter Newman, Cameron Weeks, Mohammad Amjad, Glen Riethmuller, Paul Blackwell, Jairo A. Palta, Neil C. Turner, Robert J. French, Tim Setter

Crop Updates

This session covers nineteen papers from different authors:

1.1999 Lupin Highlights, Bill O’Neill, LUPIN PRODUCTIVITY IMPROVEMENTS AND INDUSTRY DEVELOPMENT

LUPIN ANTHRACNOSE

2. Anthracnose – 1999/2000, Geoff Thomas and Mark Sweetingham, Agriculture Western Australia

LUPIN BREEDING AND AGRONOMY

3. The genetic control of mildly restricted branching in narrow-leafed lupin (Lupinus augustifolius L), Kedar Adhikari^1,3, Nick Galwey^1,3 and Miles Dracup^2,3 1Plant Sciences, University of Western Australia 2Agriculture Western Australia ³Cooperative Research Centre for Legumes in Mediterranean Agriculture, University of Western Australia

4. Genotype x time of sowing interaction in lupins – Mingenew, Bob French, …

Crop Updates 2000 - Pulses, Kerry Regan, Peter White, Kamdambot Siddique, W. O'Neill, J. Russell, R. J. French, N. Brandon, C. Gaskin, N. Runciman, M. Seymore, J. Berger, N. C. Turner, R. Carpenter, C. Ludwig, R. Kenny, Q. Ma, M. H. Behboudian, J. A. Palta, H. Clarke, J. Stott, J. Howieson, K. L. Regan, R. Shackles, C. Francis, N. Acikgoz, N. Atikyilmaz, R. S. Malholtra, M. Baker, J. Clements, C. Hanbury, C. White, B. P. Mullan, R. Lancaster, I. Guthridge, I. Pritchard, P. Fisher, M. Braimbridge, J. Bignell, R. Beermier, W. Bowden, M. D. A. Bolland, G. P. Riethmuller, R. F. Brennan, S. Lawrence, Zen Rengel, S. P. Loss, P. Vedeniapine, C. Kirkwood, D. Wright, L. Latham, R. Jones, M. J. De Sousa Majer, D. Hardie, Oonagh Byrne, Penny Smith, Françoise Berlandier, N. Keals, R. Emery

Crop Updates

This session covers fifty nine papers from different authors:

1.1999 PULSE INDUSTRY HIGHLIGHTS

2. CONTRIBUTORS

3. BACKGROUND

4. SUMMARY OF PREVIOUS RESULTS

5. 1999 REGIONAL ROUNDUP

6. Northern Agricultural Region^, W. O’Neill, AGWEST

7. Central Agricultural Region J. Russell and R.J. French AGWEST

8. Great Southern and Lakes N. Brandon, C. Gaskin and N. Runciman, AGWEST

9. Esperance Mallee M. Seymour, AGWEST

PULSE PRODUCTION AGRONOMY AND GENETIC IMPROVEMENT

10. Faba Bean

11. Desi chickpea Traits associated with drought resistance in chickpea, J. Berger, N.C. Turner, CLIMA and CSIRO Plant Industry, R.J. French, AGWEST, R. Carpenter, C. Ludwig and R. …

Basic Biotechnology, Jennifer Flak, Julie Albrecht

Plant and Soil Sciences eLibrary

An introduction to traditional cross-breeding and genetic engineering of plants, and to biotechnology.

Objectives - Basic Biotechnology

After completing Nutrition Basic Biotechnology, participants should be able to:

• Describe one similarity between traditional cross-breeding and genetic engineering of plants.
• Give two limitations that are encountered with traditional cross-breeding of plants.
• Explain why genetic engineering is not limited in the same way as traditional cross-breeding.
• Define biotechnology in broad terms.
• List three plant applications of biotechnology.
• List the three areas of nutritional profiles that have been improved with biotechnology.

Modules:

• Lesson home
• Objectives - Basic Biotechnology
• Historical Uses of Biotechnology
• Basic Understanding …

Phylogeny Of Calostoma, The Gelatinous-Stalked Puffball, Based On Nuclear And Mitochondrial Ribosomal Dna Sequences, Brandi D. Hughey, Gerard C. Adams, Tom D. Bruns, David S. Hibbett

Department of Plant Pathology: Faculty Publications

Nucleotide sequence of the nuclear small and large subunit and the mitochondrial small and large ribosomal genes of Calostoma were used to investigate evolutionary relationships with other Basidiomycetes. In separate analyses with each gene, Calostoma was placed within the Boletales and outside the clades containing most gilled mushrooms, puffballs, stalked puffballs, earthstars, stinkhorns, and nonboletalean Gasteromycetes. This contradicted previous taxonomic hypotheses. Calostoma was most closely related to Gyroporus, Pisolithus, and Scleroderma based on maximum parsimony and maximum likelihood analysis of the mitochondrial large ribosomal gene database, which contained several representatives of most genera of the Boletales. In three …

Soybean Cyst Nematode Reproduction In The North Central United States, J. Wang, P. A. Donald, T. L. Niblack, G. W. Bird, J. Faghihi, J. M. Ferris, C. Grau, D. J. Jardine, P. E. Lipps, A. E. Macguidwin, H. Melakeberhan, G. R. Noel, P. Pierson, P. M. Riedel, P. R. Sellers, W. C. Stienstra, T. C. Todd, G. L. Tylka, T. A. Wheeler, D. S. Wysong

Department of Plant Pathology: Faculty Publications

An experiment was conducted in Heterodera glycines–infested fields in 40 north central U.S. environments (21 sites in 1994 and 19 sites in 1995) to assess reproduction of this nematode. Two resistant and two susceptible soybean cultivars from each of the maturity groups (MG) I through IV were grown at each site in 6.1 m by 4 row plots. Soil samples were collected from each plot at planting and harvest and processed at Iowa State University to determine H. glycines initial (Pi) and final (Pf) population densities as eggs per 100 cm3 of soil. Overall, reproduction (Pf/Pi) of H. glycines …

Biological Control Of Bipolaris Sorokiniana On Tall Fescue By Stenotrophomonas Maltophilia Strain C3, Z. Zhang, G. Y. Yuen

Department of Plant Pathology: Faculty Publications

Stenotrophomonas maltophilia strain C3 was evaluated for control of leaf spot on tall fescue (Festuca arundinacea) caused by Bipolaris sorokiniana. In growth chamber experiments, C3 inhibited conidial germination on leaf surfaces and reduced lesion frequency and percent diseased leaf area compared with nontreated controls. The amount of leaf spot suppression was related to the C3 dose applied. The highest dose tested, 10⁹ CFU/ml, prevented nearly all B. sorokiniana conidia from germinating on treated leaf surfaces and provided nearly complete suppression of lesion development. When colloidal chitin was added to C3 cell suspensions of 10⁷ or …

Dnak And The Heat Stress Response Of Pseudomonas Syringae Pv. Glycinea, Lisa M. W. Keith, James E. Partridge, Carol L. Bender

Department of Plant Pathology: Faculty Publications

The dnaK gene from Pseudomonas syringae pv. glycinea PG4180 was cloned and sequenced. The dnaK coding region was 1,917 bp and contained a putative O³² heat shock promoter 86 bp upstream of the translational start site. grpE, another heat shock gene, was found immediately upstream of the putative dnaK promoter. The predicted amino acid sequence of dnaK showed relatedness to the ATPase and substrate binding domains commonly found in heat shock proteins, as well as the highly conserved signature sequence motifs belonging to the Hsp70 protein family. Furthermore, the PG4180 dnaK gene complemented an Escherichia coli dnaK mutant …

An Engineered Closterovirus Rna Replicon And Analysis Of Heterologous Terminal Sequences For Replication, Satyanarayana Tatineni, Siddarame Gowda, V. P. Boyko, Maria R. Albiach-Marti, Munir Mawassi, J. Navas-Castillo, Alexander V. Karasev, V. Dolja, Mark E. Hilf, D. J. Lewandowski, P. Moreno, Moshe Bar-Joseph, S. M. Garnsey, William O. Dawson

Department of Plant Pathology: Faculty Publications

Citrus tristeza virus (CTV) populations in citrus trees are unusually complex mixtures of viral genotypes and defective RNAs developed during the long-term vegetative propagation of the virus and by additional mixing by aphid transmission. The viral replication process allows the maintenance of minor amounts of disparate genotypes and defective RNAs in these populations. CTV is a member of the Closteroviridae possessing a positive-stranded RNA genome of ≈20 kilobases that expresses the replicase-associated genes as an ≈400-kDa polyprotein and the remaining 10 3' genes through subgenomic mRNAs. A full-length cDNA clone of CTV was generated from which RNA transcripts capable of …

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 …

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 …

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 …

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 …

Characterization Of The Large (L) Rna Of Peanut Bud Necrosis Tospovirus, S. Gowda, Satyanarayana Tatineni, R. A. Naidu, A. Mushegian, W. O. Dawson, D. V. R. Reddy

Department of Plant Pathology: Faculty Publications

The nucleocapsids purified from peanut plants systemically infected with peanut bud necrosis virus (PBNV), a member of the genus Tospovirus, contained both viral(v) and viral complementary(vc) sense L RNAs. Defective forms of L RNA containing ‘core polymerase region’ were observed. The full length L RNA of PBNV was sequenced using overlapping cDNA clones. The 8911 nucleotide L RNA contains a single open reading frame (ORF) in the vc strand, and encodes a protein of 330 kDa. At the 50 and 30 termini of the v sense RNA there were 247 and 32 nt untranslated regions, respectively, containing an 18 …

Peanut Yellow Spot Virus Is A Member Of A New Serogroup Of Tospovirus Genus Based On Small (S) Rna Sequence And Organization, Satyanarayana Tatineni, S. Gowda, K. Lakshminarayana Reddy, S. E. Mitchell, W. O. Dawson, D. V. R. Reddy

Department of Plant Pathology: Faculty Publications

Peanut yellow spot virus (PYSV) represents a distinct tospovirus species based on serology and nucleic acid hybridization. The sequence of the S RNA was 2 970 nucleotides with 22 nucleotide long inverted repeats (with three mismatches) at the termini. The coding was ambisense with a long open reading frame (ORF) in each strand. The 5'-large ORF (1 440 nucleotides in the viral sense (v) strand) encoded a protein with a predicted size of 53.2 kDa that was identified as the nonstructural (NSs) protein based on 16–21% sequence identity and 42– 48% sequence similarity with other tospoviruses. A 3' ORF (741 …

Identification Of The Wheat Curl Mite As The Vector 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

Wheat with virus-like symptoms (extracts containing a 33-kDa protein in sodium dodecyl sulfate- polyacrylamide gel electrophoresis, negative in enzyme-linked immunosorbent assay to wheat streak mosaic virus, and not infectious in a backassay to other wheat) reacted positively to antiserum made against a protein purified from symptomatic corn infected with the High Plains virus (HPV), indicating a serological relationship between the corn and wheat pathogens. The wheat curl mite (WCM, Aceria tosichella Keifer) was identified as the vector of the virus and caused persistent infection of barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) in greenhouse experiments. The …

Comparison Of Avrd Alleles From Pseudomonas Syringae Pv. Glycinea, Lisa Wolfson Keith, Carol Boyd, Noel T. Keen, J. E. Patridge

Department of Plant Pathology: Faculty Publications

Avirulence gene D alleles resided on indigenous plasmids in races 0, 2, 3, 4, 5, and 6 of Pseudomonas syringae pv. glycinea (Psg), but the allele in race 1 appeared to be chromosomal. These were all nonfunctional avirulence genes because they neither induced the avirulence phenotype on Rpg4 soybean cultivars nor directed the production of syringolide elicitors when expressed in Escherichia coli cells. The predicted proteins encoded by the seven Psg avrD genes were very similar to that of a functional class II allele from P. syringae pv. phaseolicola G50 race 2, but contained mutations collectively …

Genetic Variability Among Maize Inbred Lines For Resistance To The High Plains Virus–Wheat Streak Mosaic Virus Complex, A. Marçon, S. M. Kaeppler, S. G. Jensen

Department of Plant Pathology: Faculty Publications

High plains virus (HPV) is a pathogen that causes a severe disease, especially in susceptible corn genotypes. The virus is transmitted by the eriophyid mite Aceria tosichella, which also transmits wheat streak mosaic virus (WSMV). This often results in a mixed infection by these two viruses. Genetic variability for resistance to the HPV exists among maize inbred lines but has not been characterized. The disease reaction of 30 maize inbred lines to the mixed infection and to WSMV alone was characterized in this study. Evaluation was based on symptom expression and virus titer (HPV and WSMV), as measured by …