Plant Biology Commons^™

Effects Of Modification Of The Transcription Initiation Site Context On Citrus Tristeza Virus Subgenomic Rna Synthesis, Maria A. Ayllon, Siddarame Gowda, Satyanarayana Tatineni, Alexander V. Karasev, Scott Adkins, Munir Mawassi, Jose Guerri, Pedro Moreno, William O. Dawson

Department of Plant Pathology: Faculty Publications

Citrus tristeza virus (CTV), a member of the Closteroviridae, has a positive-sense RNA genome of about 20 kb organized into 12 open reading frames (ORFs). The last 10 ORFs are expressed through 3'-coterminal subgenomic RNAs (sgRNAs) regulated in both amounts and timing. Additionally, relatively large amounts of complementary sgRNAs are produced. We have been unable to determine whether these sgRNAs are produced by internal promotion from the full-length template minus strand or by transcription from the minus-stranded sgRNAs. Understanding the regulation of 10 sgRNAs is a conceptual challenge. In analyzing commonalities of a replicase complex in producing so many …

Induced Resistance As A Mechanism Of Biological Control By Lysobacter Enzymogenes Strain C3, Ozlem Kilic-Ekici, Gary Y. Yuen

Department of Plant Pathology: Faculty Publications

Induced resistance was found to be a mechanism for biological control of leaf spot, caused by Bipolaris sorokiniana, in tall fescue (Festuca arundinacea) using the bacterium Lysobacter enzymogenes strain C3. Resistance elicited by C3 suppressed germination of B. sorokiniana conidia on the phylloplane in addition to reducing the severity of leaf spot. The pathogen-inhibitory effect could be separated from antibiosis by using heat-inactivated cells of C3 that retained no antifungal activity. Application of live or heat-killed cells to tall fescue leaves resulted only in localized resistance confined to the treated leaf, whereas treatment of roots resulted in …

Crop Updates - 2003 Oilseeds, Peter Nelson, Graham Walton, Hasan Zaheer, Paul Carmody, J. A. Fortescue, D. W. Turner, Janet Wroth, Wallace Cowling, Anh-Van Pham, R. F. Brennan, Glen Riethmuller, Greg Hamilton, Jo Hawksley, C. M. Zaicou-Kunesch, D. Eksteen, Françoise A. Berlandier, Christiaan Valentine, Owain Edwards, Roger Jones, Brenda Coutts, Lisa Smith, Jenny Hawkes, Ravjit Khangura, Moin Salam, Art J. Diggle, Martin J. Barbetti, Kevin Walden

Crop Updates

This session covers fifteen papers from different authors

ACKNOWLEDGMENTS

VARIETIES

1. Large scale canola varietal evaluation in WA, Peter Nelson, Oilseeds WA

2. Performance of IT and TT canola varieties in the medium and high rainfall agzones of WA 2001-02, Graham Walton, Hasan Zaheer and Paul Carmody, Department of Agriculture

QUALITY

1. Reproductive biology, cotyledon development and oil accumulation in canola, J.A. Fortescue and D.W. Turner, School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia

2. Plant and environmental factors affecting oil concentration in canola – a mini-review, D.W. Turner, School of Plant Biology, …

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Crop Updates 2003 - Cereals, Graham Crosbie, Robert Loughman, Collin Wellings, Greg Shea, Simon Mckirdy, Neil C. Turner, Brenda Shackley, Wal Anderson, Darshan Sharma, Mohammad Amjad, Steve Penny Jr, Melanie Kupsch, Anne Smith, Veronika Reck, Pam Burgess, Glenda Smith, Elizabeth Tierney, Peter Burges, Moin U. Salam, Megan Collins, Art Diggle, Blakely Paynter, Roslyn J. Jettner, Kevin Young, Jocelyn Ball, Natasha Littlewood, Lucy Anderton, Irene Waters, Tim Setter, Jeff Russell, Reg Lance, Chengdao Li, Sue Broughton, Michael Jones, Grace Zawko, Keith Gregg, Stephen Loss, Frank Ripper, Ryan Guthrie, Daniel Bell, Patrick Gethin, Narelle Hill, Laurence Caeslake, Vivien Vanstone, Sean Kelly, Helen Hunter, Christopher R. Newman

Crop Updates

This session covers twenty one papers from different authors:

PLENARY

1. Recognising and responding to new market opportunities in the grains industry, Graham Crosbie, Manager, Grain Products Research, Crop Breeding, Plant Industries, Department of Agriculture

2. Stripe rust – where to now for the WA wheat industry? Robert Loughman¹, Colin Wellings² and Greg Shea¹¹Department of Agriculture, ²University of Sydney Plant Breeding Institute, Cobbitty (on secondment from NSW Agriculture)

3. Benefits of a Grains Biosecurity Plan, Dr Simon McKirdy, Plant Health Australia, Mr Greg Shea, Department of Agriculture

4. Can we improve …

The Pseudomonas Syringae Type Iii-Secreted Protein Hopptod2 Possesses Protein Tyrosine Phosphatase Activity And Suppresses Programmed Cell Death In Plants, Avelina Espinosa, Ming Guo, Vincent C. Tam, Zheng Qing Fu, James R. Alfano

Center for Plant Science Innovation: Faculty Publications

The bacterial plant pathogen Pseudomonas syringae possesses a type III protein secretion system that delivers many virulence proteins into plant cells. A subset of these proteins (called Avr proteins) is recognized by the plant’s innate immune system and triggers defences. One defence-associated response is the hypersensitive response (HR), a programmed cell death (PCD) of plant tissue. We have previously identified HopPtoD2 as a type III secreted protein from P. s. pv. tomato DC3000. Sequence analysis revealed that an N-terminal domain shared homology with Avr- PphD and a C-terminal domain was similar to protein tyrosine phosphatases (PTPs). We demonstrated that purified …

Chitosanase May Enhance Anti-Fungal Defense Responses In Transgenic Tobacco, Bill L. Hendrix

Inquiry: The University of Arkansas Undergraduate Research Journal

Fungicides are expensive, dangerous, and can be harmful to the environment, but they are often necessary for profitable farming operations. New technologies may soon allow farmers to replace these chemicals with genetically engineered plants producing antifungal enzymes that degrade fungal cell walls. To explore this option, a Paenbacillus chitosanase gene was cloned, sequenced, and modified for plant expression. The modified gene was delivered to tobacco (Nicotiana tabacum L cv. Xanthine) leaf disks via Agrobacterium tumenfaciens-mediated transformation. The putative GMOs were tested for transgene integration, transcription, and translation. Confirmed transformants were then screened for enhanced responses to a Rhizoctonia solani cell …

The Role Of Natural Calcium Oxalate Crystals In Plant Defense Against Chewing Insects, Sarah J. Doege

Inquiry: The University of Arkansas Undergraduate Research Journal

Calcium oxalate is the most abundant insoluble mineral found in plants and it is common among many plant families. Calcium oxalate crystals in plants can appear as irregular rectangles, spiked balls, or needles. The formidable appearance of these crystals has lead to speculation that they might serve as a form of pest control by deterring chewing insects. We utilized mutant plant lines to assess the effects of plant calcium oxalate crystals on the survival and feeding habits of chewing insects. We have taken advantage of calcium oxalate-deficient (cod) mutants of the barrel medic, Medicago truncatula Calcium oxalate crystals accumulate in …

Fungal Biology And Agriculture: Revisiting The Field, O. Yarden, D. J. Ebbole, S. Freeman, R. J. Rodriguez, M. B. Dickman

Department of Plant Pathology: Faculty Publications

Plant pathology has made significant progress over the years, a process that involved overcoming a variety of conceptual and technological hurdles. Descriptive mycology and the advent of chemical plant-disease management have been followed by biochemical and physiological studies of fungi and their hosts. The later establishment of biochemical genetics along with the introduction of DNA-mediated transformation have set the stage for dissection of gene function and advances in our understanding of fungal cell biology and plant–fungus interactions. Currently, with the advent of high-throughput technologies, we have the capacity to acquire vast data sets that have direct relevance to the numerous …

Transcription Strategy In A Closterovirus: A Novel 5'-Proximal Controller Element Of Citrus Tristeza Virus Produces 5'- And 3'-Terminal Subgenomic Rnas And Differs From 3' Open Reading Frame Controller Elements, Siddarame Gowda, Maria A. Ayllon, Satyanarayana Tatineni, Moshe Bar-Joseph, William O. Dawson

Department of Plant Pathology: Faculty Publications

Citrus tristeza virus (CTV) produces more than thirty 3'- or 5'-terminal subgenomic RNAs (sgRNAs) that accumulate to various extents during replication in protoplasts and plants. Among the most unusual species are two abundant populations of small 5'-terminal sgRNAs of approximately 800 nucleotides (nt) termed low-molecular-weight tristeza (LMT1 and LMT2) RNAs. Remarkably, CTV replicons with all 10 3' genes deleted produce only the larger LMT1 RNAs. These 5'-terminal positive-sense sgRNAs do not have corresponding negative strands and were hypothesized to be produced by premature termination during plus-strand genomic RNA synthesis. We characterized a cis-acting element that controls the production …

Evaluation Of Resistance Screening Methods For Sclerotinia Stem Rot Of Soybean And Dry Bean, Linda S. Kull, Tri D. Vuong, Kris S. Powers, Kent M. Eskridge, James R. Steadman, Glen L. Hartman

Department of Plant Pathology: Faculty Publications

Three methods to identify levels of resistance to Sclerotinia sclerotiorum in soybean (Glycine max) and dry bean (Phaseolus vulgaris) were compared using multiple data analyses. The three methods were mycelial plug inoculations of cotyledons, cut stems, and detached leaves. Six S. sclerotiorum isolates of known relative aggressiveness were inoculated on each of three soybean and dry bean cultivars with varied response to S. sclerotiorum. For soybean, all three inoculation methods accurately identified isolate aggressiveness irrespective of cultivar, but identification of susceptible and partially resistant soybean cultivars was influenced by isolate. For dry bean, the cotyledon and cut …

The Shca Protein Is A Molecular Chaperone That Assists In The Secretion Of The Hoppsya Effector From The Type Iii (Hrp) Protein Secretion System Of Pseudomonas Syringae, Karin V. Van Dijk, Vincent C. Tam, Angela R. Records, Tanja Petnicki-Ocwieja, James R. Alfano

Center for Plant Science Innovation: Faculty Publications

Pseudomonas syringae uses a type III protein secretion system encoded by the Hrp pathogenicity island (Pai) to translocate effector proteins into plant cells. One of these effector proteins is HopPsyA. A small open reading frame (ORF), named shcA, precedes the hopPsyA gene in the Hrp Pai of P. s. syringae 61. The predicted amino acid sequence of shcA shares general characteristics with chaperones used in type III protein secretion systems of animal pathogens. A functionally non-polar deletion of shcA in P. s. syringae 61 resulted in the loss of detectable HopPsyA in supernatant fractions, consistent with ShcA acting as a …

Crop Updates 2002 - Lupins, Amelia Mclarty, Bob French, Laurie Wahlsten, Martin Harries, Paul Blackwell, Mike Collins, Bill Crabtree, Geoff Fosbery, Angie Roe, Matt Beckett, Abul Hashem, Nerys Wilkins, Geoff Thomas, Ken Adcock, Debbie Thackray, Jenny Hawkes, Roger Jones, Brenda Coutts, Manisha Shankar, Mark Sweetingham, Bevan Buirchell, Nichole Burges, Dominie Wright, Susan J. Barker, Jairo A. Palta, Neil C. Turner, Matt Evans, Brett Glencross, John Curnow, Wayne Hawkins, Jon C. Clements

Crop Updates

This session covers twenty four papers from different authors:

LUPIN INDUSTRY ISSUES AND RESEARCH DIRECTIONS

ACKNOWLEDGMENTS Amelia McLarty LUPIN CONVENOR DEPARTMENT OF AGRICULTURE

VARIETIES

1. Evaluation of lupinus mutabilis in Western Australia, Bob French, Laurie Wahlsten and Martin Harries, Department of Agriculture

2. Adaption of restricted-branching lupins in short-growing season environments, Bob French, Laurie Wahlsten, Department of Agriculture

ESTABLISHMENT

3. Moisture delving for better lupin establishment, Dr Paul Blackwell, Department of Agriculture

4. Lupins, tramlines, 600mm rows, rolling and shield spraying … a good result in a dry season! Paul Blackwell and Mike Collins, Department of Agriculture

5. Lupin …

Genomewide Identification Of Pseudomonas Syringae Pv.Tomato Dc3000 Promoters Controlled By The Hrpl Alternative Sigma Factor, Derrick E. Fouts, Robert B. Abramovitch, James R. Alfano, Angela M. Baldo, C. Robin Buell, Samuel Cartinhour, Arn K. Chatterjee, Mark D'Ascenzo, Michelle L. Gwinn, Sondra G. Lazarowitz, Na-Chun Lin, Gregory B. Martin, Amos H. Rehm, David J. Schneider, Karin V. Van Dijk, Xiaoyan Tang, Alan Collmer

Center for Plant Science Innovation: Faculty Publications

The ability of Pseudomonas syringae pv. tomato DC3000 to parasitize tomato and Arabidopsis thaliana depends on genes activated by the HrpL alternative sigma factor. To support various functional genomic analyses of DC3000, and specifically, to identify genes involved in pathogenesis, we developed a draft sequence of DC3000 and used an iterative process involving computational and gene expression techniques to identify virulence-implicated genes downstream of HrpLresponsive promoters. Hypersensitive response and pathogenicity (Hrp) promoters are known to control genes encoding the Hrp (type III protein secretion) machinery and a few type III effector proteins in DC3000. This process involved (i) identification of …

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

Inquiry: The University of Arkansas Undergraduate Research Journal

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

Selected Soybean Plant Introductions With Partial Resistance To Sclerotinia Sclerotiorum, D. D. Hoffman, B. W. Diers, G. L. Hartman, C. D. Nickell, R. L. Nelson, W. L. Pedersen, E. R. Cober, George L. Graef, J. R. Steadman, C. R. Grau, B. D. Nelson, L. E. Del Rio, T. Helms, T. Anderson, V. Poysa, University Of Guelph, W. C. Stienstra

Department of Plant Pathology: Faculty Publications

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a major soybean (Glycine max) disease in north-central regions of the United States and throughout the world. Current sources of resistance to Sclerotinia stem rot express partial resistance, and are limited in number within soybean germ plasm. A total of 6,520 maturity group (MG) 0 to IV plant introductions (PIs) were evaluated for Sclerotinia stem rot resistance in the United States and Canada in small plots or in the greenhouse from 1995 to 1997. Selected PIs with the most resistance were evaluated for resistance in the United States and …

Greenhouse And Field Evaluation Of Biological Control Of Fusarium Head Blight On Durum Wheat, D. A. Schisler, N. I. Khan, Michael J. Boehm, P. J. Slininger

Department of Plant Pathology: Faculty Publications

Fusarium head blight (FHB) is a devastating disease that causes extensive yield and quality losses to wheat and barley. In durum wheat, the pathogen-produced toxin deoxynivalenol (DON) is retained in semolina at ~50%, and the causal agent of FHB, Gibberella zeae, has a strong adverse effect on pasta color. Two bacteria and two yeast strains with known efficacy against G. zeae on hexaploid wheats were produced in liquid culture and assayed on two cultivars of durum wheat in greenhouse bioassays. All antagonists reduced FHB severity on cultivar Renville, and three of the four reduced severity on cultivar Ben, with …

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

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

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

The P23 Protein Of Citrus Tristeza Virus Controls Asymmetrical Rna Accumulation, Satyanarayana Tatineni, Siddarame Gowda, Maria A. Ayllon, Maria R. Albiach-Marti, Shailaja Rabindran, William O. Dawson

Department of Plant Pathology: Faculty Publications

Citrus tristeza virus (CTV), a member of the Closteroviridae, has a 19.3-kb positive-stranded RNA genome that is organized into 12 open reading frames (ORFs) with the 10 3' genes expressed via a nested set of nine or ten 3'-coterminal subgenomic mRNAs (sgRNAs). Relatively large amounts of negative-stranded RNAs complementary to both genomic and sgRNAs accumulate in infected cells. As is characteristic of RNA viruses, wild-type CTV produced more positive than negative strands, with the plus-to-minus ratios of genomic and sgRNAs estimated at 10 to 20:1 and 40 to 50:1, respectively. However, a mutant with all of the 3' genes …

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

Dissertations and Theses

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

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

Department of Plant Pathology: Faculty Publications

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

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

Crop Updates

This session covers twenty six papers from different authors:

INTRODUCTION,

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

VARIETIES

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

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

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

NUTRITION

5. Banding manganese fertiliser below the seed increases seed …

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 …

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 …

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 …