Life Sciences Commons^™

A Unique Role For The Host Escrt Proteins In Replication Of Tomato Bushy Stunt Virus, Daniel Barajas, Yi Jiang, Peter D. Nagy

Plant Pathology Faculty Publications

Plus-stranded RNA viruses replicate in infected cells by assembling viral replicase complexes consisting of viral- and host-coded proteins. Previous genome-wide screens with Tomato bushy stunt tombusvirus (TBSV) in a yeast model host revealed the involvement of seven ESCRT (endosomal sorting complexes required for transport) proteins in viral replication. In this paper, we show that the expression of dominant negative Vps23p, Vps24p, Snf7p, and Vps4p ESCRT factors inhibited virus replication in the plant host, suggesting that tombusviruses co-opt selected ESCRT proteins for the assembly of the viral replicase complex. We also show that TBSV p33 replication protein interacts with Vps23p ESCRT-I …

Remote Sensing To Detect The Movement Of Wheat Curl Mites Through The Spatial Spread Of Virus Symptoms, And Identification Of Thrips As Predators Of Wheat Curl Mites, Abby R. Stilwell

Department of Entomology: Dissertations, Theses, and Student Research

The wheat curl mite (WCM), Aceria tosichella Keifer, transmits three viruses to winter wheat: wheat streak mosaic virus, High Plains virus, and Triticum mosaic virus. This virus complex causes yellowing of the foliage and stunting of plants. WCMs disperse by wind, and an increased understanding of mite movement and subsequent virus spread is necessary in determining the risk of serious virus infections in winter wheat. These risk parameters will help growers make better decisions regarding WCM management. The objectives of this study were to evaluate the capabilities of remote sensing to identify virus infected plants and to establish the potential …

Education In Plant Pathology Present Status And Future Challenges, James Macdonald, Caitilyn Allen, David Gadoury, William Jacobi, Segenet Kelemu, James Moyer, Tim Murray, Kevin Ong, Charles Pearson, John Sherwood, Ann Vidaver

Department of Plant Pathology: Faculty Publications

Plant pathology is largely a mission driven discipline that seeks to increase the fundamental understanding of host–pathogen interactions and the etiology of plant diseases for the purpose of preventing or mitigating crop loss. This is an important mission because all nations face serious challenges in their efforts to prevent disease on plants cultivated for food, fiber, ornamental use, timber, and fuel, as well as those growing in native ecosystems. In 1994, it was estimated that global losses due to plant diseases ranged from 9.7 to 14.2% of potential yield (12).

Viral Vectors Useful In Soybean And Methods Of Use, Said A. Ghabrial, Chunquan Zhang, Honcgang Gu

Plant Pathology Faculty Patents

The invention provides Bean pod mottle virus (BPMV) vectors useful for expression of heterologous proteins in plants such as soybean. The BPMV vectors are also useful for virus-induced gene silencing. The invention also provides methods for expressing a heterologous polypeptide in a plant such as soybean. The invention additionally provides methods for virus-induced gene silencing, particularly in a soybean plant, which can be used to determine the function of a gene of interest.

Defective Interfering Rnas: Foes Of Viruses And Friends Of Virologists, Kunj Bihari Pathak, Peter D. Nagy

Plant Pathology Faculty Publications

Defective interfering (DI) RNAs are subviral RNAs produced during multiplication of RNA viruses by the error-prone viral replicase. DI-RNAs are parasitic RNAs that are derived from and associated with the parent virus, taking advantage of viral-coded protein factors for their multiplication. Recent advances in the field of DI RNA biology has led to a greater understanding about generation and evolution of DI-RNAs as well as the mechanism of symptom attenuation. Moreover, DI-RNAs are versatile tools in the hands of virologists and are used as less complex surrogate templates to understand the biology of their helper viruses. The ease of their …

Inhibition Of Rna Recruitment And Replication Of An Rna Virus By Acridine Derivatives With Known Anti-Prion Activities, Zsuzsanna Sasvari, Stéphane Bach, Marc Blondel, Peter D. Nagy

Plant Pathology Faculty Publications

BACKGROUND: Small molecule inhibitors of RNA virus replication are potent antiviral drugs and useful to dissect selected steps in the replication process. To identify antiviral compounds against Tomato bushy stunt virus (TBSV), a model positive stranded RNA virus, we tested acridine derivatives, such as chlorpromazine (CPZ) and quinacrine (QC), which are active against prion-based diseases.

METHODOLOGY/PRINCIPAL FINDINGS: Here, we report that CPZ and QC compounds inhibited TBSV RNA accumulation in plants and in protoplasts. In vitro assays revealed that the inhibitory effects of these compounds were manifested at different steps of TBSV replication. QC was shown to have an effect …

The Genome Of Nectria Haematococca: Contribution Of Supernumerary Chromosomes To Gene Expansion, Jeffrey J. Coleman, Steve D. Rounsley, Marianela Rodriguez-Carres, Alan Kuo, Catherine C. Wasmann, Jane Grimwood, Jeremy Schmutz, Masatoki Taga, Gerard J. White, Shiguo Zhou, David C. Schwartz, Michael Freitag, Li-Jun Ma, Etienne G. J. Danchin, Bernard Henrissat, Pedro M. Coutinho, David R. Nelson, Dave Straney, Carolyn A. Napoli, Bridget M. Barker, Michael Gribskov, Martijn Rep, Scott Kroken, István Molnár, Christopher Rensing, John C. Kennell, Jorge Zamora, Mark L. Farman, Eric U. Selker, Asaf Salamov, Harris Shapiro, Jasmyn Pangilinan, Erika Lindquist, Casey Lamers, Igor V. Grigoriev, David M. Geiser, Sarah F. Covert, Esteban Temporini, Hans D. Vanetten

Plant Pathology Faculty Publications

The ascomycetous fungus Nectria haematococca, (asexual name Fusarium solani), is a member of a group of >50 species known as the "Fusarium solani species complex". Members of this complex have diverse biological properties including the ability to cause disease on >100 genera of plants and opportunistic infections in humans. The current research analyzed the most extensively studied member of this complex, N. haematococca mating population VI (MPVI). Several genes controlling the ability of individual isolates of this species to colonize specific habitats are located on supernumerary chromosomes. Optical mapping revealed that the sequenced isolate has 17 chromosomes ranging from 530 …

Triticum Mosaic Virus: A Distinct Member Of The Family Potyviridae With An Unusually Long Leader Sequence, Satyanarayana Tatineni, Amy D. Ziems, Stephen N. Wegulo, Roy French

Department of Plant Pathology: Faculty Publications

The complete genome sequence of Triticum mosaic virus (TriMV), a member in the family Potyviridae, has been determined to be 10,266 nucleotides (nt) excluding the 3′ polyadenylated tail. The genome encodes a large polyprotein of 3,112 amino acids with the “hall-mark proteins” of potyviruses, including a small overlapping gene, PIPO, in the P3 cistron. The genome of TriMV has an unusually long 5′ nontranslated region of 739 nt with 12 translation initiation codons and three small open reading frames, which resemble those of the internal ribosome entry site containing 5′ leader sequences of the members of Picornaviridae. Pairwise …

Effect Of Growth Stage On The Relationship Between Tan Spot And Spot Blotch Severity And Yield In Winter Wheat, Stephen N. Wegulo, Julie A. Breathnach, P. Stephen Baenziger

Department of Plant Pathology: Faculty Publications

Foliar fungal diseases frequently cause significant economic losses in the hard red winter wheat production areas of the Great Plains of the United States. In 2007, field experiments were conducted in four environments in Nebraska, USA to determine the crop growth stage at which severity of tan spot and spot blotch was most strongly related to yield in winter wheat. Secondary objectives were to evaluate the efficacy of fungicides in controlling tan spot and spot blotch and to determine the effect of fun¬gicide application timing on disease intensity and yield. Disease severity assessed at Zadoks growth stage (ZGS) 60 (flower¬ing) …

Diseases Of Floriculture Crops In South Carolina: Evaluation Of A Pre-Plant Sanitation Treatment And Identification Of Species Of Phytophthora, Ernesto Robayo Camacho

All Theses

This project was composed of two separate studies. In one study, the species of Phytophthora that have been found associated with diseased floriculture crops in South Carolina and four other states were characterized and identified using molecular (RFLP fingerprints and DNA sequences for ITS regions and cox I and II genes), morphological (sporangia, oogonia, antheridia, oospores, and chlamydospores), and physiological (mating behavior and cardinal temperatures) characters. In addition, sensitivity to the fungicide mefenoxam was determined. In all, 87 isolates from 63 host plants that were collected over a 13-year period (1996 through 2008) were examined. Host plants came from 46 …

Evolution Of A Subtilisin-Like Protease Gene Family In The Grass Endophytic Fungus Epichloë Festucae, Michelle K. Bryant, Christopher L. Schardl, Uljana Hesse, Barry Scott

Plant Pathology Faculty Publications

BACKGROUND: Subtilisin-like proteases (SLPs) form a superfamily of enzymes that act to degrade protein substrates. In fungi, SLPs can play either a general nutritive role, or may play specific roles in cell metabolism, or as pathogenicity or virulence factors.

RESULTS: Fifteen different genes encoding SLPs were identified in the genome of the grass endophytic fungus Epichloë festucae. Phylogenetic analysis indicated that these SLPs belong to four different subtilisin families: proteinase K, kexin, pyrolysin and subtilisin. The pattern of intron loss and gain is consistent with this phylogeny. E. festucae is exceptional in that it contains two kexin-like genes. Phylogenetic analysis …

Enhanced Disease Susceptibility 1 And Salicylic Acid Act Redundantly To Regulate Resistance Gene-Mediated Signaling, Srivathsa C. Venugopal, Rae-Dong Jeong, Mihir Kumar Mandal, Shifeng Zhu, A. C. Chandra-Shekara, Ye Xia, Matthew Hersh, Arnold J. Stromberg, Duroy Navarre, Aardra Kachroo, Pradeep Kachroo

Plant Pathology Faculty Publications

Resistance (R) protein-associated pathways are well known to participate in defense against a variety of microbial pathogens. Salicylic acid (SA) and its associated proteinaceous signaling components, including enhanced disease susceptibility 1 (EDS1), non-race-specific disease resistance 1 (NDR1), phytoalexin deficient 4 (PAD4), senescence associated gene 101 (SAG101), and EDS5, have been identified as components of resistance derived from many R proteins. Here, we show that EDS1 and SA fulfill redundant functions in defense signaling mediated by R proteins, which were thought to function independent of EDS1 and/or SA. Simultaneous mutations in EDS1 and the SA-synthesizing enzyme SID2 compromised hypersensitive response and/or …

An Icosahedral Algal Virus Has A Complex Unique Vertex Decorated By A Spike, Mickaël V. Cherrier, Victor A. Kostyuchenko, Chuan Xiao, Valorie D. Bowman, Anthony J. Battisti, Xiaodong Yan, Paul R. Chipman, Timothy S. Baker, James L. Van Etten, Michael G. Rossmann

Department of Plant Pathology: Faculty Publications

Paramecium bursaria Chlorella virus-1 is an icosahedrally shaped, 1,900-Å-diameter virus that infects unicellular eukaryotic green algae. A 5-fold symmetric, 3D reconstruction using cryoelectron microscopy images has now shown that the quasiicosahedral virus has a unique vertex, with a pocket on the inside and a spike structure on the outside of the capsid. The pocket might contain enzymes for use in the initial stages of infection. The unique vertex consists of virally coded proteins, some of which have been identified. Comparison of shape, size, and location of the spike with similar features in bacteriophages T4 and P22 suggests that the spike …

Phylogenetic Analyses Reveal Monophyletic Origin Of The Ergot Alkaloid Gene Dmaw In Fungi, Miao Liu, Daniel G. Panaccione, Christopher L. Schardl

Plant Pathology Faculty Publications

Ergot alkaloids are indole-derived mycotoxins that are important in agriculture and medicine. Ergot alkaloids are produced by a few representatives of two distantly related fungal lineages, the Clavicipitaceae and the Trichocomaceae. Comparison of the ergot alkaloid gene clusters from these two lineages revealed differences in the relative positions and orientations of several genes. The question arose: is ergot alkaloid biosynthetic capability from a common origin? We used a molecular phylogenetic approach to gain insights into the evolution of ergot alkaloid biosynthesis. The 4-γ,γ-dimethylallyltryptophan synthase gene, dmaW, encodes the first step in the pathway. Amino acid sequences deduced …

A Nonsense Mutation In A Cinnamyl Alcohol Dehydrogenase Gene Is Responsible For The Sorghum Brown Midrib6 Phenotype1[W][Oa], Scott E. Sattler, Aaron J. Saathoff, Eric J. Haas, Nathan A. Palmer, Deanna L. Funnell-Harris, Gautam Sarath, Jeffrey F. Pedersen

Department of Plant Pathology: Faculty Publications

brown midrib6 (bmr6) affects phenylpropanoid metabolism, resulting in reduced lignin concentrations and altered lignin composition in sorghum (Sorghum bicolor). Recently, bmr6 plants were shown to have limited cinnamyl alcohol dehydrogenase activity (CAD; EC 1.1.1.195), the enzyme that catalyzes the conversion of hydroxycinnamoyl aldehydes (monolignals) to monolignols. A candidate gene approach was taken to identify Bmr6. Two CAD genes (Sb02g024190 and Sb04g005950) were identified in the sorghum genome based on similarity to known CAD genes and through DNA sequencing a nonsense mutation was discovered in Sb04g005950 that results in a truncated protein lacking the NADPH-binding and C-terminal …

Plant Growth-Promoting Rhizobacteria Allow Reduced Application Rates Of Chemical Fertilizers, A. O. Adesemoye, H. A. Torbert, J. W. Kloepper

Department of Plant Pathology: Faculty Publications

The search for microorganisms that improve soil fertility and enhance plant nutrition has continued to attract attention due to the increasing cost of fertilizers and some of their negative environmental impacts. The objectives of this greenhouse study with tomato were to determine (1) if reduced rates of inorganic fertilizer coupled with microbial inoculants will produce plant growth, yield, and nutrient uptake levels equivalent to those with full rates of the fertilizer and (2) the minimum level to which fertilizer could be reduced when inoculants were used. The microbial inoculants used in the study were a mixture of plant growth-promoting rhizobacteria …

Chlorella Viruses Prevent Multiple Infections By Depolarizing The Host Membrane, Timo Greiner, Florian Frohns, Ming Kang, James L. Van Etten, Anja Käsmann, Anna Moroni, Brigitte Hertel, Gerhard Thiel

Department of Plant Pathology: Faculty Publications

Previous experiments established that when the unicellular green alga Chlorella NC64A is inoculated with two viruses, usually only one virus replicates in a single cell. That is, the viruses mutually exclude one another. In the current study, we explore the possibility that virus- induced host membrane depolarization, at least partially caused by a virus-encoded K+ channel (Kcv), is involved in this mutual exclusion. Two chlorella viruses, PBCV-1 and NY-2A, were chosen for the study because (i) they can be distinguished by real-time PCR and (ii) they exhibit differential sensitivity to Cs+, a well-known K+ channel blocker. PBCV-1-induced host membrane depolarization, …

Crop Updates - 2009 Katanning, Murray Scholz, Peter Newman, Glenn Adam, Trevor Bell, Michael Whitehead, W. K. Anderson, C. Gazey, J. Andrew, R. Pearce, Bill Bowden, Wayne Pluske, Jeremy Lemon, D. C. Edmeades, J. J. Russell, B. H. Paynter, David Ferris, Abul Hashem, Catherine Borger, Stephen B. Powels, Qin Yu, Mechelle Owen, Roberto Busi, Sudheesh Manalil, Sally Peltzer, David Minkey, Raj Malik

Crop Updates

This session covers seventeen papers from different authors

1. GM canola – How will it affect the way I farm? Murray Scholz, 2008 Nuffield scholar, Southern NSW

2. Eight years of IWM smashes tyegrass seed banks by 98% over 31 focus paddocks, Peter Newman, Glenn Adam & Trevor Bell, Department of Agriculture and Food

3. The global economic climate and impacts on agriculture, profile on Michael Whitehead Rabobank New York

4. Lessons from five years of cropping systems research, W.K. Anderson, Department of Agriculture and Food

5. Case study of a 17year old agricultural lime trial, C. Gazey, Department of Agriculture …

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A Discontinuous Rna Platform Mediates Rna Virus Replication: Building An Integrated Model For Rna-Based Regulation Of Viral Processes, Baodong Wu, Judit Pogany, Hong Na, Beth L. Nicholson, Peter D. Nagy, K. Andrew White

Plant Pathology Faculty Publications

Plus-strand RNA viruses contain RNA elements within their genomes that mediate a variety of fundamental viral processes. The traditional view of these elements is that of local RNA structures. This perspective, however, is changing due to increasing discoveries of functional viral RNA elements that are formed by long-range RNA-RNA interactions, often spanning thousands of nucleotides. The plus-strand RNA genomes of tombusviruses exemplify this concept by possessing different long-range RNA-RNA interactions that regulate both viral translation and transcription. Here we report that a third fundamental tombusvirus process, viral genome replication, requires a long-range RNA-based interaction spanning approximately 3000 nts. In vivo …

First Report Of Columbia Root-Knot Nematode (Meloidogyne Chitwoodi) In Potato In Turkey, A. Ozarslandan, Z. Devran, N. Mutlu, I. H. Elekcioglu

Department of Plant Pathology: Faculty Publications

Columbia root-knot nematode, Meloidogyne chitwoodi Golden et al., was identified from potatoes, Solanum tuberosum L., collected from Nigde Province, Turkey in September 2006. Seed potatoes are the most likely source for this introduction. The nematode is currently found to be infecting potatoes grown in the Netherlands, Portugal, Belgium, Germany, the United States, Mexico, South Africa, and Argentina. M. chitwoodi acquired a quarantine status in Europe (1) because of its potential to become established worldwide and its high damage probability. Some countries prohibit import of both seed and table stock potatoes originating in states known to harbor M. chitwoodi. Lesions …

Crop Updates 2009 - Farming Systems, Derk Bakker, Grey Poulish, Steve Lacy, Svetlana Micic, Peter Mangano, Tony Dore, Alan Lord, Vivien Vanstone, Helen Hunter, Sean Kelly, W. K. Anderson, Gary Lang, David Mccarthy, Ruhi Ferdowsian, Ian Rose, Andrew Van Burgel, David Ferris, Rob Grima, Natalie Hogg, John Davis, Jarrad Martin, Pippa Michael, Robert Belford, Kawsar P. Salam, Roy Murray-Prior, David Bowran, Moin U. Salam, Tim Scanlon, Len Wade, Megan Ryan, Megan Abrahams, Chad Reynolds, Caroline Peek, Dennis Van Gool, Kari-Lee Falconer, Daniel Gardiner, Geoff Anderson, Siva Sivapalan, Tim Mcclelland, James Hunt, Zvi Hochman, Bill Long, Dean Holzworth, Anthony Whitbread, Stephen Van Rees, Peter Devoil, Yvette Oliver, Michael Robertson, Peter Stone

Crop Updates

This session covers nineteen papers from different authors:

Decision support technology

1. The use of high resolution imagery in broad acre cropping, Derk Bakker and Grey Poulish, Department of Agriculture and Food

2. Spraywise decisions – online spray applicatiors planning tool, Steve Lacy, Nufarm Australia Ltd

3. Testing for redlegged earthmite resistance in Western Australia, Svetlana Micic, Peter Mangano, Tony Dore and Alan Lord, Department of Agriculture and Food

4. Screening cereal, canola and pasture cultivars for Root Lesion Nematode (Pratylenchus neglectus), Vivien Vanstone, Helen Hunter and Sean Kelly,Department of Agriculture and Food

Farming Systems Research

5. …

Crop Updates 2009 - Weeds, Catherine Borger, Abul Hashem, Mike Clarke, Aik Cheam, Michael Walsh, Harmohinder Dhammu, Vince Lambert, Chris Roberts, Russell Quartermaine, David Nicholson, Mike Jackson, Bill Campbell, John Moore, Mario D'Antuono, Paul Matson, Peter Newman, Sally Peltzer, Dave Minkey, Stephen B. Powles, Qin Yu, Mechelle Owen, Roberto Busi, Sudheesh Manalil, Leigh Smith, Peter White, Fiona Evans, Art Diggle, Catherine Borger, Pippa Michael, Siew Lee, Rob Grima, Glenn Adam, Trevor Bell, Steve Davies, Glen Riethmuller

Crop Updates

This session covers twenty three papers from different authors:

Herbicides

1. New pre-seeding grass selective herbicides – How well do they work in zero or no-till systems? Dr Catherine Borgerand Dr Abul Hashem, Department of Agriculture and Food

2. Velocity®—An alternate mode of action for the control of wild radish in cereals, Mike Clarke, Bayer Cropscience Pty Ltd, Dr Aik Cheam, Department of Agriculture and Food, Dr Michael Walsh, WAHRI, University of Western Australia

3. Herbicide tolerance of new barley varieties, Harmohinder Dhammu, Vince Lambert, Chris Roberts and Russell Quartermaine, Department of Agriculture and Food

4. Herbicide tolerance of …

Crop Updates 2009 - Cereals, Jeff Baldock, Doug Edmeades, Mark Seymour, Paul Carmody, Ian Pritchard, Alan Meldrum, Michael Robertson, Roger Lawes, Rob Sands, Peter White, Felicity Byrne, Andrew Bathgate, Kedar Adhikari, Tanveer Khan, Stuart Morgan, Alan Harris, P. Gaur, K. M. H. Siddique, H. Clarke, N. C. Turner, W. Macleod, S. Morgan, Chris Veitch, Tony Leonforte, Kith Jayasena, Geoff Thomas, Rob Loughman, Kazue Tanaka, Ravjit Khangura, M. Amjad, Richard Oliver, Dusty Severtson, Peter Mangano, John Botha, Brenda Coutts, Manisha Shankar, Kasia Rybak, Michael Baker, Andrea Hills, Shahajahan Miyan, Peter Portmann, Nicole Rice, Robert Henry, Jeff J. Russell, B. H. Paynter, Linda Price, Brenda Shackley, Vicki Scanlan, Darshan Sharma, Christine Zaicou-Kunesch

Crop Updates

This session covers twenty seven papers from different authors:

PLENARY

1. Building soil carbon for productivity and implications for carbon accounting, Jeff Baldock, CSIRO Land and Water, Adelaide, SA

2. Fact or Fiction: Who is telling the truth and how to tell the difference, Doug Edmeades, agKnowledge Ltd, Hamilton

3. Four decades of crop sequence trials in Western Australia, Mark Seymour,Department of Agriculture and Food

BREAK CROPS

4. 2008 Break Crops survey Report, Paul Carmody,Development Officer, Department of Agriculture and Food

5. Attitudes of Western Australian wheatbelt growers to ‘Break Crops’, Paul Carmody and Ian …

Evaluating Pseudomonas Aeruginosa As Plant Growth–Promoting Rhizobacteria In West Africa, Anthony O. Adesemoye, Esther O. Ugoji

Department of Plant Pathology: Faculty Publications

Some parameters of growth were examined in three test crops as indices of plant growth–promoting rhizobacteria (PGPR) ability of Pseudomonas aeruginosa. Crops include Abelmoschus esculentus L. (okra), Lycopersicon esculentum L. (tomato), and Amaranthus sp. (African spinach). This study aimed to examine the effectiveness of PGPR in West Africa and determine whether the inoculation method has an impact on PGPR’s effectiveness. Bacterium was isolated from topsoil in the Botanical Garden, University of Lagos, Nigeria. Inoculation with bacteria was done by soaking seeds in 10⁶ cfu/ml of bacterial suspension, and coating was done using 10% starch (w/v) as seed adhesive …

Rathayibacter Iranicus Isolated From Symptomless Wheat Seeds In Turkey, E. Postnikova, Irina V. Agarkova, S. Altundag, F. Eskandari, A. Sechler, A. Karahan, A. K. Vidaver, W. Schneider, M. Ozakman, N. W. Schaad

Department of Plant Pathology: Faculty Publications

Rathayibacter iranicus (Ri), originally reported in Iran in 1961 (Sharif, 1961), has not been reported outside Iran and only one strain is known to exist. Like R. tritici (Rt), Ri causes a gumming disease of wheat in association with the nematode Anguina tritici (Paruthi et al., 1989). During 2003, a survey of wheat seed for Rathayibacter species (RS) in Turkey using samples from 799 farmers in six provinces in Central Anatolia was conducted. The samples showed neither the brown to black galls typical of A. tritici infection nor the yellowish galls typical of Ri and Rt. To determine the presence …

Severity Of Root Rot In Mature Subterranean Clover And Associated Fungal Pathogens In The Wheatbelt Of Western Australia, Tim Scanlon, Tiernan A. O’Rourke, Martin J. Barbetti, Megan H. Ryan, Len J. Wade, Alan C. Mckay, Ian T. Riley, Hua Li, Krishnapillai Sivasithamparam

Journal articles

Pasture decline is considered to be a serious challenge to agricultural productivity of subterranean clover across southern Australia. Root disease is a significant contributing factor to pasture decline. However, root disease assessments are generally carried out in the early part of the growing season and in areas predominantly sown to permanent pastures. For this reason, in spring 2004, a survey was undertaken to determine the severity of root disease in mature subterranean clover plants in pastures located in the wheatbelt of Western Australia. DNA-based soil assays were used to estimate population density in the soil of a variety of soil-borne …

Effects Of Increased Pco2 And Temperature On The North Atlantic Spring Bloom. Iii. Dimethylsulfoniopropionate, Peter A. Lee, Jamie R. Rudisill, Aimee R. Neeley, Jennifer M. Maucher, David A. Hutchins, Yuanyuan Feng, Clinton E. Hare, Karine Leblanc, Julie M. Rose, Steven W. Wilhelm, Janet M. Rowe, Giacomo R. Ditullio

Department of Plant Pathology: Faculty Publications

The CLAW hypothesis argues that a negative feedback mechanism involving phytoplankton- derived dimethylsulfoniopropionate (DMSP) could mitigate increasing sea surface temperatures that result from global warming. DMSP is converted to the climatically active dimethylsulfide (DMS), which is transferred to the atmosphere and photochemically oxidized to sulfate aerosols, leading to increases in planetary albedo and cooling of the Earth’s atmosphere. A shipboard incubation experiment was conducted to investigate the effects of increased temperature and pCO₂ on the algal community structure of the North Atlantic spring bloom and their subsequent impact on particulate and dissolved DMSP concentrations (DMSP_p and DMSP_{d …}

Participation Of Leaky Ribosome Scanning In Protein Dual Targeting By Alternative Translation Initiation In Higher Plants, Yashitola Wamboldt, Saleem Mohammed, Christian Elowsky, Chris Wittgren, Wilson B. M. De Paula, Sally Ann Mackenzie

Center for Plant Science Innovation: Faculty and Staff Publications

Postendosymbiotic evolution has given rise to proteins that are multiply targeted within the cell. Various mechanisms have been identified to permit the expression of proteins encoding distinct N termini from a single gene. One mechanism involves alternative translation initiation (aTI). We previously showed evidence of aTI activity within the Arabidopsis thaliana organellar DNA polymerase gene POLg2. Translation initiates at four distinct sites within this gene, two non-AUG, to produce distinct plastid and mitochondrially targeted forms of the protein. To understand the regulation of aTI in higher plants, we used Polg2 as a model to investigate both cis- and trans …

Characterization Of The 5′- And 3′-Terminal Subgenomic Rnas Produced By A Capillovirus: Evidence For A Cp Subgenomic Rna, Satyanarayana Tatineni, Mohammad R. Afunian, Siddarame Gowda, Mark E. Hilf, Moshe Bar-Joseph, William O. Dawson

Department of Plant Pathology: Faculty Publications

The members of Capillovirus genus encode two overlapping open reading frames (ORFs): ORF1 encodes a large polyprotein containing the replication-associated proteins plus a coat protein (CP), and ORF2 encodes a movement protein (MP), located within ORF1 in a different reading frame. Organization of the CP sequence as part of the replicase ORF is unusual in capilloviruses. In this study, we examined the capillovirus genome expression strategy by characterizing viral RNAs produced by Citrus tatter leaf virus (CTLV), isolate ML, a Capillovirus. CTLV-ML produced a genome-length RNA of ∼6.5-kb and two 3′-terminal sgRNAs in infected tissue that contain the MP …

Dollar Spot Fungus Sclerotinla Homoeocarpa Produces Oxalic Acid, R. C. Venu, Robert A. Beaulieu, Terrance L. Graham, Ainhoa Martinez Medina, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Dollar spot, caused by Sclerotinia homoeocarpa,. is one of the most devastating diseases of turfgrass worldwide. Many fungi belonging to the genus Sclerotinia produce oxalic acid along with pectolytic cell wall-degrading enzymes. A series of in vitro experiments showed the relationships among temperature, pH, mycelial growth and acid production. Mycelial growth and acid production were most abundant when S. homoeocarpa was grown between 20 and 30°C. Acid production by S. homoeocarpa appeared to be dependent upon the pH of the environment in which it was grown. High performance liquid chromatography analysis of spent broth revealed the presence of oxalic acid. …