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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 …

Reproductive Biology Of Melilotus Officinalis (L.) Lam (Fabaceae: Papilionoideae): Morphology, Seed/Ovule Ratios And Ovule Abortion Patterns, Susan Lee Schouten

Dissertations and Theses

Melilotus officinalis, an introduced herbaceous species within the Papilionoideae, has a fixed ovule abortion pattern. In its primarily single-seeded, indehiscent fruits, with an average of 6.98 ovules/fruit, this species matured the basal-most ovule in 67.63% and the second basal-most ovule in 24.22% of the fruits studied. This pattern contrasts with other legumes studied, which abort the basal-most ovules or those at either end of the fruit. Workers propose interaction between two opposing gradients--that of maternal resources from the basal end of the fruit and of fertilization from the stylar end. Several lines of evidence indicate that all ovules are …

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 …

Horticulture Research Report 1994 - 1998, Frank Wise Institute, Kununurra, Department Of Agriculture, Western Australia, D. Robinson, M. Howes, R. Randell

Horticulture research reports

This report summarises horticultural research, development and extension activities undertaken by staff from the Kununurra District Office during the period 1993 to 1998 and reported annually at the Frank Wise Institute Horticultural Research Review. The range and extent of activities presented and supported by Agriculture Western Australia with industry collaboration indicates the importance of horticulture in the economies of the Kimberley Region and Western Australia. Further support by funding bodies and agribusiness, and collaboration with other research organizations is also acknowledged. Since the early 1980's, horticultural output and value of production from the Ord River Irrigation Area (ORIA) have risen …

Internal Temperature Of Douglas-Fir Buds Is Altered At Elevated Temperature, Martha E. Apple, Melissa S. Lucash, David M. Olszyk, David T. Tingey, Donald L. Phillips

Environmental Science and Management Faculty Publications and Presentations

Pseudotsuga menziesii (Douglas-fir) saplings were grown in sun-lit controlled environment chambers at ambient or elevated (4°C above ambient) temperature. We measured internal temperatures of vegetative buds with thermocouple probes and compared temperatures of normal buds and abnormal buds with loosened, rosetted outer scales in elevated temperature chambers. The abnormal buds had higher and earlier peak daily temperatures than normal buds. Elevated temperature may influence the internal temperature of buds and contribute to the development of abnormal, rosetted buds with loosened outer scales. Abnormal bud development may alter branching patterns and allometry of Douglas-fir trees subjected to climatic change.

Screening Pinus Sylvestris Grown For The Production Of Christmas Trees For Resistance To Western Gall Rust Peridermium Harknessii Using Different Sources Of Aeciospores, Todd A. Burnes, Jennifer Juzwik, Robert A. Blanchette

Journal of the Minnesota Academy of Science

Results showed a moderate to high susceptibility of Pinus sylvestris to western gall rust Peridermium harknessii from Pinus sylvestris in Michigan and Pinus banksiana in Minnesota. In general, Pinus sylvestris seed sources were more susceptible to aeciospores collected from Pinus sylvestris than aeciospores collected from Pinus banksiana.

Effect Of Atmospheric Co2 Enrichment On Root Growth And Carbohydrate Allocation Of Phaseolus Spp., Katrina J. Salsman, Dean N. Jordan, S. D. Smith, D. S. Neuman

Life Sciences Faculty Research

A glasshouse experiment was conducted with plants of Phaseolus grown in liquid culture. Root growth parameters (biomass, diameter, length, growth rate, zone of cell division), root rheological components (wall extensibility, water potential yield threshold, water potential), shoot growth, carbon allocation, and abscisic acid (ABA) concentration were measured in Phaseolus acutifolius A. Gray at ambient (550 μmol mol−1) and elevated (700 μmol mol−1) atmospheric CO2 concentrations. For contrast, measurements of above‐ and belowground growth were conducted on Phaseolus vulgaris L. in the same treatments. Under nonlimiting conditions of water and nutrients, elevated CO2 increased root and shoot growth of P. acutifolius …

A Vegetation Analysis Of Plant Communities In And Around Selected Holding Ponds At Mcclintic Wildlife Management Area, Mason County, West Virginia, Russell Bowman Shrader

Theses, Dissertations and Capstones

This study was conducted as an analysis of vegetation in and around four ponds at McClintic Wildlife Management Area (MWMA), located in Mason County, West Virginia. The MWMA is the former West Virginia Ordnance Works (WVOW), having served as a trinitrotoluene (TNT) manufacturing site from 1941-1946. Such history presents the area with unique conditions resulting in diverse types and amounts of plants, since any type of forest disturbance, regardless of cause, alters ecosystem functions. This project was originally designed as part of a groundwater pump-and-treat plan for MWMA, where potential impacts of groundwater removal to ponds and the associated plant …

Notes: Evaluation Of A Filter Bag System For Ndf, Adf, And Ivdmd Forage Analysis, Kenneth P. Vogel, Jeffrey F. Pedersen, Steven D. Masterson, John J. Toy

Department of Agronomy and Horticulture: Faculty Publications

A new method of determining in vitro dry matter digestibility (IVDMD) as recently developed in which the digestion is conducted with the forage samples in filter bags. Our objective was to compare the filter bag and conventional IVDMD analysis methods using smooth bromegrass (Bromus inermis Leyss.), switchgrass (Panicum virgatum L.), and forage sorghum [Sorghum bicolor (L.) Moench] samples. In addition, the filter bag analysis systems for determining non-sequential neutral and acid detergent fiber (NDF and ADF), respectively, were compared with the non-sequential conventional analysis systems. In the filter bag systems, the forage samples are sealed in filter bags and the …

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 …

Effect Of Leaf Phosphorus And Potassium Concentration On Chlorophyll Meter Reading In Rice, Shaobing Peng, Arnel L. Sanico, Felipe V. Garcia, Rebecca C. Laza, Romeo M. Visperas, Josue P. Descalsota, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

Chlorophyll meter (SPAD) is a convenient tool to estimate leaf nitrogen (N) concentration of rice plants. There is no information on the effects of leaf phosphorus (P) and potassium (K) concentration on SP AD readings and on the relationship between SPAD values and leaf N concentration in the literature. In 1996 dry season, cv IR72 was grown at the International Rice Research Institute (IRRI) and the Philippine Rice Research Institute (PhilRice) under various N, P and K fertilizer combinations. SPAD measurements were made on the topmost fully expanded leaves at mid-tillering and panicle initiation. The leaves were then detached, dried …

Loci Controlling Resistance To High Plains Virus And Wheat Streak Mosaic Virus In A B73 × Mo17 Population Of Maize, A. Marçon, S. M. Kaeppler, S. G. Jensen, L. Senior, C. Stuber

Department of Agronomy and Horticulture: Faculty Publications

High Plains disease has the potential to cause significant yield loss in susceptible corn (Zea mays L.) and wheat (Triticum aestivum L.) genotypes, especially in the central and western USA. The primary causal agent, High Plains virus (HPV), is vectored by wheat curl mite (WCM; Aceria tossicheila Keifer), which is also the vector of wheat streak mosaic virus (WSMV). In general, the two diseases occur together as a mixed infection in the field. The objective of this research was to characterize the inheritance of HPV and WSMV resistance using B73 (resistant to HPV and WSMV) × Mo17 (moderately …

Bulletin 4397 - Stone Fruit From Western Australia - At A Glance, Glynn Ward, Geraldine Pasqual, Eleanor Melvin-Carter

Bulletins 4000 -

Western Australia produces a range of horticultural commodities including fruit, vegetables, flowers, nursery products and wine as part of its fast growing $400 million horticultural industry. Natural advantages such as climate and clean environment, soils and water make Western Australia an ideal place to supply a variety of high quality produce to domestic and international markets.

The stone fruit industry in Western Australia is booming with large production increases predicted. Production from well established plum, peach and nectarine orchards in 1996/97 is estimated at $17 million and exports have doubled in the past five years to $10 million in 1998/99. …

Measurement Of Sorghum Stalk Strength Using The Missouri-Modified Electronic Rind Penetrometer, Jeffrey F. Pedersen, J. J. Toy

Department of Agronomy and Horticulture: Faculty Publications

Resistance to lodging is critical in sorghum [Sorghum bicolor (L.) Moench] grown for grain, yet adequate tools for plant breeders to assess this character at or before anthesis have not been developed. The objective of this study was to evaluate whether an electronic penetrometer previously shown to be an effective tool for measuring stalk strength in maize (Zea mays L.) could be usedd to differentiate among grain sorghum hybrids. Entries in three commercial grain sorghum hybrid trials were evaluated for rind penetrometer resistance (RPR) of the peduncle, the lower stalk anthesis and the lower stalk at maturity. Actual …

Comparison Of Common Cytotypes Of Andropogon Gerardii (Andropogoneae, Poaceae), Kathleen H. Keeler, Geoffrey A. Davis

School of Biological Sciences: Faculty Publications

Many plant species contain populations with more than one polyploid cytotype, but little is known of the mechanisms maintaining several cytotypes in a population. Andropogon gerardii cytotypes were compared to evaluate different models of autopolyploid cytotype coexistence. The enneaploid (90 chromosome, 9x) cytotype was found to be larger and taller than the hexaploid (60 chromosome, 6x) cytotype. Seed production is significantly more efficient in hexaploids, but seed production per area was not significantly different. The two cytotypes are not exomorphologically separable in the field because of great plasticity in response to environmental variation and wide variation …

Amanoa, W. John Hayden

Biology Faculty Publications

Monoecious or dioecious trees or shrubs, latex absent. Leaves alternate, distichous, evergreen, simple, coriaceous, glabrous; stipules intrapetiolar, paired, or confluent across the leaf axil; margins entire; venation pinnate. Inflorescence axillary and/or terminal, of densely bracteate clusters (reduced cymules), in the axils of ordinary foliage leaves, in nonleafy pseudoterminal aggregates that revert to vegetative growth, or (in neotropical species) in the axils of alternate, reduced, crescentiform stipular bracts of determinate deciduous spiciform axes borne in groups of 1-several per branch apex; axes straight or sinuous; floral bracts minute, deltate, with abaxially pubescent midribs. Staminate flowers sessile or pedicellate, regular; perianth biseriate; …

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

Center for Plant Science Innovation: Faculty Publications

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

Morphogenesis Of Douglas Fir Buds Is Altered At Elevated Temperature But Not At Elevated Co2, Martha E. Apple, Melissa S. Lucash, David M. Olszyk, David T. Tingey

Environmental Science and Management Faculty Publications and Presentations

Global climatic change as expressed by increased CO₂ and temperature has the potential for dramatic effects on trees. To determine what its effects may be on Pacific Northwest forests, Douglas-fir (Pseudotsuga menziesii ) seedlings were grown in sun-lit controlled environment chambers at ambient or elevated (+4°C above ambient) temperature, and at ambient or elevated (+200 ppm above ambient) CO₂. In 1995–1996 and 1996–1997, elevated CO₂ had no effect on vegetative bud morphology, while the following unusual morphological characteristics were found with greater frequency at elevated temperature than at ambient: rosetted buds with reflexed and loosened outer …

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 …

The Effects Of Rose Bengal Application On The Production Of Salicylic Acid In Nahg Tobacco Plants, Nicole Christine Ott

Honors Theses

Plants have the ability to develop resistance to a wide range of pathogens following exposure to a single bacterium, fungus, or virus. This resistance occurs in all tissues, not only those that were previously infected. This mechanisms is termed systemic acquired resistance (SAR). The phenolic compound salicylic acid (SA) has been linked to SAR in tobacco, arabidopsis, and cucumber plants. Oxidative stress also causes SA production, which leads to SAR. An engineered tobacco plant (nahG) that does not have the ability to accumulate SA has been used as a research tool in investigations concerning SA activity. Rose Bengal …

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

Biological Sciences Theses & Dissertations

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

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

In …

Bowen Ratio Estimates Of Evapotranspiration For Stands On The Virgin River In Southern Nevada, Dale A. Devitt, A. Sala, S. D. Smith, J. Cleverly, L. K. Shaulis, R. Hammett

Life Sciences Faculty Research

A Bowen ratio energy balance was conducted over a Tamarix ramosissima (saltcedar) stand growing in a riparian corridor along the Virgin River in southern Nevada. Measurements in two separate years were compared and contrasted on the basis of changes in growing conditions. In 1994, a drought year, record high temperatures, dry winds, and a falling water table caused partial wilt of outer smaller twigs in the canopy of many trees in the stand around the Bowen tower. Subsequently, evapotranspiration (ET) estimates declined dramatically over a 60‐day period (11 mm d−1 tod−1). In 1995, the Virgin River at the Bowen tower …

Demographic Viability Of Populations Of Silene Regis In Midwestern Prairies: Relationships With Fire Management, Genetic Variation, Geographic Location, Population Size And Isolation, Eric S. Menges, Rebecca W. Dolan

Scholarship and Professional Work - LAS

1. We studied the demographic viability of populations of a long-lived iteroparous prairie perennial, Silene regia, in relation to management regimes, population sizes, geographical region (Ohio and Indiana vs. Missouri and Arkansas), degree of isolation and amount of genetic variation. Demographic data were collected from 16 populations for up to 7 years.

2. This species has high survivorship, slow growth, frequent flowering and episodic seedling recruitment. Matrix projection methods were used to summarize population performance with and without recruitment. Median finite rates of increase by population varied from 0.57 to 1.82 and from 0.44 to 0.99, respectively.

3. Populations with the highest rates …

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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 …

Intrapopulation Sex Ratio Variation In The Salt Grass Distichlis Spicata, Sarah M. Eppley, Maureen L. Stanton, Richard K. Grosberg

Biology Faculty Publications and Presentations

In many dioecious plant populations, males and females appear to be spatially segregated, a pattern that is difficult to explain given its potentially high costs. However, in asexually propagating species, spatial segregation of the sexes may be indistinguishable from superficially similar patterns generated by random establishment of a few genets followed by extensive clonal spread and by gender-specific differences in rates of clonal spread. In populations where a significant fraction of individuals are not flowering and gender cannot be assigned to this fraction, apparent spatial segregation of the sexes may be due to differential flowering between the sexes. We confirm …