Digital Commons Network^™

Characterization Of Natural Variants Of Local Wild Bananas & Seed Progeny Of Musa Acuminata, Muhammad Asif Javed

Student Works (2000-2009)

The purpose of this study was to characterize the variation pattern that exists in the wild Musa acuminata (AA) populations. widely distributed in Malaysia. Fourteen populations of Musa acuminata, which included subspecies malaccensis, siamea and truncata were collected from different locations including Selangor, Pahang, Perak, Kelantan, Kedah and Terengganu for studies on variation within and between populations, based on morphological characters, biochemical, ploidy and genomic DNA content. Techniques of numerical taxonomy were employed to determine the variation pattern and these included use of the clustering method and principal component analysis. Ploidy level and genomic DNA content were determined by flow …

Early Evaluation Of Banana Cultivars For Fusarium Wilt Tolerance, Abdulkadir Aden Mohamed

Student Works (2000-2009)

Field evaluation of banana plants for disease tolerance in soil infested with Fusarium oxysporum f. sp. cubense is commonly used. The process is slow as disease expression usually takes 4-5 months, while inoculum concentration, edaphic conditions, temperature and other variables that may affect disease expression are difficult to control. An alternative method of screening plantlets at the nursery stage was developed. The technique consisted of a double tray set up; a perforated inner tray containing sterilized river sand or a sand-clay mixture (4 sand : I clay) on which hardened tissue-cultured plantlets were grown, and a larger outer containment tray …

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 …

Pseudomonas Syringae Hrp Type Iii Secretion System And Effector Proteins, Alan Collmer, Jorge L. Badel, Amy O. Charkowski, Wen-Ling Deng, Derrick E. Fouts, Adela R. Ramos, Amos H. Rehm, Deborah M. Anderson, Olaf Schneewind, Karin V. Van Dijk, James R. Alfano

Center for Plant Science Innovation: Faculty Publications

Pseudomonas syringae is a member of an important group of Gram-negative bacterial pathogens of plants and animals that depend on a type III secretion system to inject virulence effector proteins into host cells. In P. syringae, hrpyhrc genes encode the Hrp (type III secretion) system, and avirulence (avr) and Hrpdependent outer protein (hop) genes encode effector proteins. The hrpyhrc genes of P. syringae pv syringae 61, P. syringae pv syringae B728a, and P. syringae pv tomato DC3000 are flanked by an exchangeable effector locus and …

Nuclear Localization Of Turnip Crinkle Virus Movement Protein P8, Yuval Cohen, Feng Qu, Andreas Gisel, Thomas Jack Morris, Patricia Zambryski

Department of Plant Pathology: Faculty Publications

Turnip crinkle virus (TCV) is a single-stranded positive-sense RNA virus of the Carmovirus genus. Two of its five open reading frames (ORFs), encoding proteins of 8 and 9 kDa, are required for cell-to-cell movement of the virus. These movement proteins (MPs) were fused to green fluorescent protein (GFP) to determine their cellular localization. In protoplasts, p9-GFP, like GFP itself, is found throughout the cytoplasm, as well as in cell nuclei. In contrast, p8-GFP was confined to the cell nucleus. Similar localization patterns were observed when specific small peptide epitopes were fused to p8 and p9 proteins instead of GFP. The …

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 …

A Plant Virus Vector For Systemic Expression Of Foreign Genes In Cereals, Il-Ryong Choi, Drake C. Stenger, Thomas Jack Morris, Roy C. French

Department of Plant Pathology: Faculty Publications

Inserts bearing the coding sequences of NPTll and P-glucuronidase (GUS) were placed between the nuclear inclusion b (Nlb) and coat protein (CP) domains of the wheat streak mosaic virus (WSMV) polyprotein ORF. The WSMV Nlb-CP junction containing the nuclear inclusion a (Nla) protease cleavage site was duplicated, permitting excision of foreign protein domains from the viral polyprotein. Wheat, barley, oat and maize seedlings supported systemic infection of WSMV bearing NPTII. The NPTII insert was stable for at least 18-30 days post-inoculation and had little effect on WSMV CP accumulation. Histochemical assays indicated the presence of functional GUS protein in systemically …

The Open Reading Frame 5a Of Foxtail Mosaic Virus Is Expressed In Vivo And Is Dispensable For Systemic Infection, N.L. Robertson, Roy C. French, Thomas Jack Morris

Department of Plant Pathology: Faculty Publications

Infectious transcripts were successfully derived from full-length cDNA clones of foxtail mosaic potexvirus (FoMV). Full-length clones were constructed by RT-PCR whereby 50 and 30 genomic segments of 2.7 and 3.4 kb, respectively, were ligated into Bluescript II KS. The in vitro RNA transcripts were infectious to moncotyledonous (barley) and dicotyledonous (Chenopodium amaranticolor) plant species. Individual mutation studies on clones of each of the five major ORFs confirmed predicted gene function for the polymerase, TGB (triple gene block), and coat protein (CP) genes. Protoplast studies on expression of a unique open reading frame, ORF 5A, which initiates 143 nts …

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 …

Characterization Of North American Armillaria Species By Nuclear Dna Content And Rflp Analysis, Mee-Sook Kim, Ned Klopfenstein, Geral I. Mcdonald, Kathiravetpillai Arumuganathan, Anne K. Vidaver

Department of Plant Pathology: Faculty Publications

Twenty-six isolates representing nine North American Armillaria species were investigated with flow cytometry and RFLP (restriction fragment length polymorphism) analyses to determine their nuclear DNA content and RFLP profile. Three putatively diploid isolates of A. ostoyae, A. gemina, A. calvescens, A. sinapina, A. mellea, A. gallica, A. nabsnona, and North American Biological Species (NABS) X were analyzed, and two putatively diploid isolates of NABS XI also were analyzed. Nuclear DNA contents of Armillaria species were 0.11-0.17 pg per nucleus (55-84 X 10" bp/C), depending on species. Among the nine North American Armillaria species tested, A. ostoyae, A. gemirza, and …

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. …

Crop Updates 2000 - Cereals Part 1, Timothy G. Reeves, Sanjaya Rajaram, Maarten Van Ginkel, Richard Trethowan, Hans-Joachim Braun, Kelly Cassaday, R. A. Mcintosh, Rob Loughman, Ross Brennan, Mike Bolland, Zed Rengel, David Isbister, Paul Blackwell, Derk Bakker, Greg Hamilton, David Houlbrooke, Cliff Spann, Doug Rowe, Patrick Gethin, Stephen Loss, Frank Boetel, Tim O'Dea, Noeleen Edwards, Wayne Pluske, Ross Brennan, M. T. F. Wong, K. Wittwer, H. Zhang

Crop Updates

This session covers eleven papers from different authors:

PLENARY PAPERS

1. New Wheat for a Secure, Sustainable Future, Timothy G. Reeves, Sanjaya Rajaram, Maarten van Ginkel, Richard Trethowan, Hans-Joachim Braun, and Kelly Cassaday, International Maize and Wheat Improvement Centre (CIMMYT)

2. Managing Cereal Rusts - a National Perspective, R.A. McIntosh, University of Sydney Plant Breeding Institute, New South Wales

3. Managing Cereal Rusts in 2000 - a regional imperative, R. Loughman, Agriculture Western Australia

4. Is nutrition the answer to wheat after canola problems?Ross Brennan¹, Bill Bowden¹, Mike Bolland¹, Zed Rengel^{2 …}

An Efficient Wheat Transformation Procedure: Transformed Calli With Long-Term Morphogenic Potential For Plant Regeneration, Lingyu Zhang, J.J. Rybczynski, W.G. Langenberg, Amitava Mitra, Roy C. French

Department of Plant Pathology: Faculty Publications

A method for producing large numbers of transgenic wheat plants has been developed. With this approach, an average of 9.7% of immature embryo explants were transformed and generated multiple self-fertile, independently transformed plants. No untransformed plants, or escapes, were regenerated. This transformation procedure uses morphogenic calli derived from scutellum tissue of immature embryos of Triticum aestivum cv. Bobwhite co-bombarded with separate plasmids carrying a selectable marker gene (bar) and a gene of interest, respectively. Transformed wheat calli with a vigorous growth phenotype were obtained by extended culture on media containing 5.0 mg/l bialaphos. These calli retained morphogenic potential …

The Pseudomonas Syringae Hrp Pathogenicity Island Has A Tripartite Mosaic Structure Composed Of A Cluster Of Type Iii Secretion Genes Bounded By Exchangeable Effector And Conserved Effector Loci That Contribute To Parasitic Fitness And Pathogenicity In Plants, James R. Alfano, Amy O. Charkowski, Wen-Ling Deng, Jorge L. Badel, Tanja Petnicki- Ocwieja, Karin Van Dijk, Alan Collmer

Center for Plant Science Innovation: Faculty Publications

The plant pathogenic bacterium Pseudomonas syringae is divided into pathovars differing in host specificity, with P. syringae pv. syringae (Psy) and P. syringae pv. tomato (Pto) representing particularly divergent pathovars. P. syringae hrp/hrc genes encode a type III protein secretion system that appears to translocate Avr and Hop effector proteins into plant cells. DNA sequence analysis of the hrp/hrc regions in Psy 61, Psy B728a, and Pto DC3000 has revealed a Hrp pathogenicity island (Pai) with a tripartite mosaic structure. The hrp/hrc gene cluster is conserved in all three strains and is flanked by a unique exchangeable …

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 …

The Role Of Chitinase Production By Stenotrophomonas Maltophilia Strain C3 In Biological Control Of Bipolaris Sorokiniana, Zhongge Zhang, Gary Y. Yuen

Department of Plant Pathology: Faculty Publications

The role of chitinase production by Stenotrophomonas maltophilia strain C3 in biological control of leaf spot on tall fescue (Festuca arundinacea), caused by Bipolaris sorokiniana, was investigated in vitro and in vivo. The filtrate of a broth culture of C3, with chitin as the carbon source, was separated into fractions. A high molecular-weight fraction (>8 kDa) was chitinolytic and more inhibitory than a low-molecularweight, nonchitinolytic fraction to conidial germination and hyphal growth by B. sorokiniana and to leaf spot development. A protein fraction derived by ammonium sulfate precipitation and a chitinase fraction purified by chitin affinity …

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 …

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 …

Fully Biologically Active In Vitro Transcripts Of The Eriophyid Mite-Transmitted Wheat Streak Mosaic Tritimovirus, Il-Ryong Choi, Roy C. French, Gary L. Hein, Drake C. Stenger

Department of Plant Pathology: Faculty Publications

Infectious RNA of wheat streak mosaic virus (WSMV) has been produced using a full-length cDNA clone as a template for in vitro transcription with SP6 RNA polymerase. Infectivity was dependent on the use of template plasmid DNA that had not undergone spontaneous rearrangement during amplification in Escherichia coli. The presence of WSMV in systemically infected wheat plants inoculated with in vitro transcripts was confirmed by reverse-transcription polymerase chain reaction of the WSMV P3 gene and by accumulation of WSMV coat protein as detected by immunoblotting. Maintenance of the full-length WSMV cDNA in the high copy number plasmid pUC18 was problematic …

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 …

The Avr (Effector) Proteins Hrma (Hoppsya) And Avrpto Are Secreted In Culture From Pseudomonas Syringae Pathovars Via The Hrp (Type Iii) Protein Secretion System In A Temperature- And Ph-Sensitive Manner, Karin V. Van Dijk, Derrick E. Fouts, Amos H. Rehm, Angela R. Hill, Alan Collmer, James R. Alfano

Center for Plant Science Innovation: Faculty Publications

We present here data showing that the Avr proteins HrmA and AvrPto are secreted in culture via the native Hrp pathways from Pseudomonas syringae pathovars that produce these proteins. Moreover, their secretion is strongly affected by the temperature and pH of the culture medium. Both HrmA and AvrPto were secreted at their highest amounts when the temperature was between 18 and 22°C and when the culture medium was pH 6.0. In contrast, temperature did not affect the secretion of HrpZ. pH did affect HrpZ secretion, but not as strongly as it affected the secretion of HrmA. This finding suggests that …

Agriculture Western Australia's Centre For Cropping Systems - Northam, Agriculture Western Australia

Grain and other field crops published reports

Agriculture Western Australia's Centre for Cropping Systems in York Road, Northam, was established as a centre of excellence for research, development and extension into cropping systems.

Its role is to stimulate the contribution of ideas from individuals, groups and organisations with an interest in research, development, and extension relating to innovative, profitable and sustainable crop-based farming systems.

The Centre for Cropping Systems is part of a regional network with strong links to Agriculture Western Australia's Crop Improvement Institute based at South Perth, the Dryland Research Institute at Merredin and the Avondale Research Fann at Beverley. It also links with universities …

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 …

Morphogenesis Is Coordinated With Nuclear Division In Germinating Aspergillus Nidulans Conidiospores, Steven D. Harris

Department of Plant Pathology: Faculty Publications

Germinating Aspergillus nidulans conidiospores switch to polarized apical growth following an initial period of isotropic expansion. At the same time, they re-enter the nuclear division cycle. The relationship between spore polarization and nuclear division was investigated by testing the effect of cell cycle inhibitors and temperature-sensitive cell cycle mutations on spore morphogenesis. On rich media, it was found that spore polarization is delayed if completion of the first mitosis is blocked. The observed delay may be dependent upon the activity of the mitosis-promoting NIMA kinase. An additional mechanism appears to prevent polarization as the spore progresses through its first S …

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 …

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 …

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 …

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 …