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Plant Biology

2004

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Articles 1 - 30 of 41

Full-Text Articles in Life Sciences

Systematics Of Dirca (Thymelaeaceae) Based On Its Sequences And Issr Polymorphisms, James A. Schrader, William R. Graves Dec 2004

Systematics Of Dirca (Thymelaeaceae) Based On Its Sequences And Issr Polymorphisms, James A. Schrader, William R. Graves

Horticulture Publications

The genus Dirca consists of three disjunct species of shrubs. Dirca palustris is found in the eastern United States and adjacent Canada; D, occidcntahs is Umited to six counties near the San Francisco Bay in California; and the recently discovered D, mcxicana is known from one isolated population in northeastern Mexico. The three species have been described and classified according to morphological characters, but the morphological evidence does not provide a clear assessment of the relationships among the species. Morphologically D. mexicana most closely resembles D. occidenlalis., but known biogeographical trends raise doubt regarding how the three species are interrelated ...


In Vitro Propagation, Regeneration, Attempted Tetraploid Induction, And Agrobacterium-Mediated Transformation Of Euphorbia Pulchurrima ‘Winter Rose’™, Kimberly Ann Pickens Dec 2004

In Vitro Propagation, Regeneration, Attempted Tetraploid Induction, And Agrobacterium-Mediated Transformation Of Euphorbia Pulchurrima ‘Winter Rose’™, Kimberly Ann Pickens

Doctoral Dissertations

Poinsettia, Euphorbia pulchurrima, is the number one potted flowering plant in the United States. ‘Winter Rose’™ is a very popular cultivar with more than one million plants sold each year. To further improve this cultivar, particularly for larger flower heads and free branching, this research aimed at establishing some in vitro systems for application of biotechnology to poinsettia genetic improvement.

A protocol was established for in vitro axillary bud proliferation using greenhouse grown terminal buds. Buds were placed on Murashige-Skoog (MS) basal medium supplemented with benzlyaminopurine (BA). Explants produced the greatest number of axillary buds on medium containing between 2 ...


Rice Contains Two Disparate Ent-Copalyl Diphosphate Synthases With Distinct Metabolic Functions, Sladjana Prisic, Meimei Xu, P. Ross Wilderman, Reuben J. Peters Dec 2004

Rice Contains Two Disparate Ent-Copalyl Diphosphate Synthases With Distinct Metabolic Functions, Sladjana Prisic, Meimei Xu, P. Ross Wilderman, Reuben J. Peters

Biochemistry, Biophysics and Molecular Biology Publications

Rice (Oryza sativa) produces ent-copalyl diphosphate for both gibberellin (GA) phytohormone and defensive phytoalexin biosynthesis, raising the question of how this initial biosynthetic step is carried out for these distinct metabolic processes. Here, a functional genomics approach has been utilized to identify two disparate ent-copalyl diphosphate synthases from rice (OsCPS1ent and OsCPS2ent). Notably, it was very recently demonstrated that only one of these (OsCPS1ent) normally operates in GA biosynthesis as mutations in this gene result in severely impaired growth. Evidence is presented here strongly indicating that the other (OsCPS2ent) is involved in related secondary ...


Collaborative Research: Developing Methods To Study Age-Related Changes In The Physiology Of Forest Trees, Michael S. Greenwood Nov 2004

Collaborative Research: Developing Methods To Study Age-Related Changes In The Physiology Of Forest Trees, Michael S. Greenwood

University of Maine Office of Research Administration: Grant Reports

Trees continue to increase in size and complexity over life spans that may last many centuries, and each year the growing regions of their shoots produce new foliage and reproductive structures. As they grow older and larger, forest trees appear to grow more slowly, produce thicker foliage and more reproductive structures. These changes are likely to be associated with age-related declines in the growth rates of forest stands, which occur before the mid-point of the lifespan of important timber species. Although similar patterns of age- and size-related change in the morphology and physiology of foliage have been described for numerous ...


Can Solid Matrix Priming With Ga3 Break Seed Dormancy In Eastern Gamagrass?, C. Rogis, L. R. Gibson, A. D. Knapp, R. Horton Nov 2004

Can Solid Matrix Priming With Ga3 Break Seed Dormancy In Eastern Gamagrass?, C. Rogis, L. R. Gibson, A. D. Knapp, R. Horton

Agronomy Publications

Development of methods for breaking seed dormancy in eastern gamagrass (Tripsacum dactyloides, L.) could increase its use. Solid matrix priming, the controlled hydration of seed in a system of solid carrier and water, has been used with some success to enhance germination in warm-season grasses. gibberellic acid (ga3), a known promoter of eastern gamagrass germination, can be added to solid matrix priming systems. In this study, systems were evaluated for conditioning eastern gamagrass seeds using the solid carriers Agro-Lig, MicroCel E, and Vermiculite #5. GA3 was added in 0.01 M concentration solutions to systems with water potentials of −0 ...


Short-Term Growth Responses To Ethylene In Arabidopsis Seedlings Are Ein3/Eil1 Independent, Brad Binder, Laura Mortimore, Anna Stepanova, Joseph Ecker, Anthony Bleecker Sep 2004

Short-Term Growth Responses To Ethylene In Arabidopsis Seedlings Are Ein3/Eil1 Independent, Brad Binder, Laura Mortimore, Anna Stepanova, Joseph Ecker, Anthony Bleecker

Brad M. Binder

Kinetic studies indicate there are two phases to growth inhibition by ethylene for the hypocotyls of etiolated Arabidopsis seedlings. Phase I is transient, while phase II results in sustained growth inhibition. The EIN2 membrane protein is required for both the first and second phases of growth inhibition by ethylene, while the transcription factors EIN3 and EIL1 are required for the second phase but not the first phase. The first phase lasts no more than 2 h. It is less sensitive to the ethylene response inhibitor 1-methylcyclopropene and more sensitive to ethylene than the second phase. The first phase shows adaptation ...


Disabling Surveillance: Bacterial Type Iii Secretion System Effectors That Suppress Innate Immunity, Avelina Espinosa, James R. Alfano Aug 2004

Disabling Surveillance: Bacterial Type Iii Secretion System Effectors That Suppress Innate Immunity, Avelina Espinosa, James R. Alfano

Faculty Publications from the Center for Plant Science Innovation

Many Gram-negative bacterial pathogens of plants and animals are dependent on a type III protein secretion system (TTSS). TTSSs translocate effector proteins into host cells and are capable of modifying signal transduction pathways. The innate immune system of eukaryotes detects the presence of pathogens using specific pathogen recognition receptors (PRRs). Plant PRRs include the FLS2 receptor kinase and resistance proteins. Animal PRRs include Tolllike receptors and nucleotide-binding oligomerization domain proteins. PRRs initiate signal transduction pathways that include mitogen-activated protein kinase (MAPK) cascades that activate defencerelated transcription factors. This results in induction of proinflammatory cytokines in animals, and hallmarks of defence ...


Identification Of Syn-Pimara-7,15-Diene Synthase Reveals Functional Clustering Of Terpene Synthases Involved In Rice Phytoalexin/Allelochemical Biosynthesis, P. Ross Wilderman, Meimei Xu, Yinghua Jin, Robert M. Coates, Reuben J. Peters Aug 2004

Identification Of Syn-Pimara-7,15-Diene Synthase Reveals Functional Clustering Of Terpene Synthases Involved In Rice Phytoalexin/Allelochemical Biosynthesis, P. Ross Wilderman, Meimei Xu, Yinghua Jin, Robert M. Coates, Reuben J. Peters

Biochemistry, Biophysics and Molecular Biology Publications

Rice (Oryza sativa) produces momilactone diterpenoids as both phytoalexins and allelochemicals. Accordingly, the committed step in biosynthesis of these natural products is catalyzed by the class I terpene synthase that converts syn-copalyl diphosphate to the corresponding polycyclic hydrocarbon intermediate syn-pimara-7,15-diene. Here, a functional genomics approach was utilized to identify a syn-copalyl diphosphate specific 9β-pimara-7,15-diene synthase (OsDTS2). To our knowledge, this is the first identified terpene synthase with this particular substrate stereoselectivity and, by comparison with the previously described and closely related ent-copalyl diphosphate specific cassa-12,15-diene synthase (OsDTC1), provides a model system ...


Promoters From Chlorella Virus Genes Providing For Expression Of Genes In Prokaryotic And Eukaryotic Hosts, Amitava Mitra, James L. Van Etten Jun 2004

Promoters From Chlorella Virus Genes Providing For Expression Of Genes In Prokaryotic And Eukaryotic Hosts, Amitava Mitra, James L. Van Etten

Papers in Plant Pathology

The invention is directed to novel promoters or mutants thereof from Chlorella virus DNA methyltansferase genes. A Chlorella Virus gene promoter is operably linked to a first and/or Second DNA sequence encoding a gene that is different from the Chlorella virus to form an expression cassette. An expression cassette can be introduced into prokaryotic and/or eukaryotic cells and can provide for a high level of expression of the gene encoded by the first and/or Second DNA sequence. The invention also provides a method for Screening other Chlorella virus genes for promoters that can function to express a ...


The Pseudomonas Syringae Hopptov Protein Is Secreted In Culture And Translocated Into Plant Cells Via The Type Iii Protein Secretion System In A Manner Dependent On The Shcv Type Iii Chaperone, Misty D. Wehling, Ming Guo, Zheng Qing Fu, James R. Alfano Jun 2004

The Pseudomonas Syringae Hopptov Protein Is Secreted In Culture And Translocated Into Plant Cells Via The Type Iii Protein Secretion System In A Manner Dependent On The Shcv Type Iii Chaperone, Misty D. Wehling, Ming Guo, Zheng Qing Fu, James R. Alfano

Faculty Publications from the Center for Plant Science Innovation

The bacterial plant pathogen Pseudomonas syringae depends on a type III protein secretion system and the effector proteins that it translocates into plant cells to cause disease and to elicit the defense-associated hypersensitive response on resistant plants. The availability of the P. syringae pv. tomato DC3000 genome sequence has resulted in the identification of many novel effectors. We identified the hopPtoV effector gene on the basis of its location next to a candidate type III chaperone (TTC) gene, shcV, and within a pathogenicity island in the DC3000 chromosome. A DC3000 mutant lacking ShcV was unable to secrete detectable amounts of ...


Does Seed Size Affect The Rate Of Germination And Early Seedling Growth In Hairy Vetch?, Joy Ekpo May 2004

Does Seed Size Affect The Rate Of Germination And Early Seedling Growth In Hairy Vetch?, Joy Ekpo

McCabe Thesis Collection

Size is an important characteristic of seed quality because larger seeds with larger volume contain more resources and are likely to exhibit greater vigor than smaller seeds (Ellis, 1992). In a range of plant species, seed size has been shown to affect germination rate, emergence rate, success of establishment, and growth (Black 1957; Bentley et al. 1980; Sanderson et al. 2002). Hairy vetch is an annual legume that is used for improvement of soil for pasture and to provide ground cover protecting against erosion (Duke 1981; Undersander 2002; Sattell et al 1988). Problems facing the establishment of hairy vetch are ...


Cattle As Grazing Management And Seed Dispersal Tools For Increasing Native Species Diversity On Great Basin Rangelands, Marina K. Whitacre May 2004

Cattle As Grazing Management And Seed Dispersal Tools For Increasing Native Species Diversity On Great Basin Rangelands, Marina K. Whitacre

All Graduate Theses and Dissertations

A series of experiments evaluated: 1) the influence of seed intake and gut

retention time on seed passage , recovery , and germinability; 2) fecal seeding and

broadcast /trampling as techniques to incorporate seeds into a well-established

Agropyron desertorum (Fisch.) Schult. stand in Skull Valley , Utah; 3) intensive

grazing as a means to reduce Agropyron biomass and increase establishment and

survival of seeded species; and 4) the recovery and germinability of seed extracted

from dung collected from the field. Two shrubs (Artemisia tridentata Nutt. ssp.

wyomingensis Beetle & Young and Atriplex confertifolia Torr. & Frem.), a grass

(Elymus elymoides (Raf.) Swezey) , and a forb (Sphaeralcea grossulariaefolia (H. &

A.) Rydb.) were selected as representative native species. Holstein heifers were fed

15,000 , 30 ,000 , and 60,000 seeds of Artemisia , Sphaeralcea, and Elymus. Elymus

recovery was negatively correlated to seed intake. Sphaeralcea had the highest

percentage of recovered, undamaged seed, followed by Elymus and Artemisia.

Sphaeralcea and Artemisia seed passage was highest on Day 1 then dropped sharply.

Elymus passage and recovery were more consistent through time. Post-passage

germjnability was highest for Elymus and Sphaeralcea on Day 1. Artemisia

germjnation was neghgible.

In the fall seeding, Sphaeralcea emerged in 6% of the subplots (half were

volunteers). Overall seedling mortality was 93%. Elymus emerged in 63% of the

dung pats, with 86% mortality. No Artemisia emerged. Drought and Anabrus

simplex herbivory contributed to low seedling emergence and survival. In April

2003, similar treatments were applied, except Atriplex seed was substituted for

Artemisia, and a third treatment was added (broadcast seeding/raking). No

emergence was observed. Sphaeralcea had the highest seed recovery from dung

collected in the field trials, followed by Elymus, Atriplex, and Artemisia.

Sphaeralcea germinability was similar for seeds collected from both trials (11 %) and

Elymus germination was highest in the fall seeding (13%).

These studies indicate that: 1) physical seed properties (size, shape, density,

seed coat) influence seed passage , recovery, and germination; 2) intensive grazing

can reduce Agropyron biomass by 50% for 2 years; 3) broadcast/trampling ...


The Effect Of Water And Nitrogen On The Response Of Sorghum Cultivars With Contrasting Nitrogen Use Efficiency, Teshome Regassa Apr 2004

The Effect Of Water And Nitrogen On The Response Of Sorghum Cultivars With Contrasting Nitrogen Use Efficiency, Teshome Regassa

Teshome H. Regassa

Water and nitrogen (N) are important environmental factors limiting sorghum production. Information is lacking on the combined effects of water and N for cultivars with different degrees of water and/or N stress tolerance. Sorghum cultivars known for N and water stress tolerance difference were evaluated to identify plant characteristics contributing to N use efficiency (NUE). Cultivars San Chi San and CK-60 were evaluated at Mead, NE on a Sharpsburg silty clay loam soil under water (stress and non-stress), and N (0, 40, 80, and 120 kg ha−1) rates. Experimental units were arranged in split-split plot and treatments were ...


Crop Updates 2004 - Cereals, Wal Anderson, Vivian Vanstone, Robert Loughman, Vanessa Stewart, Darshan Sharma, Christine Zaicou-Kunesch, Brenda Shackley, Mohammad Amjad, Steve Penny Jr, Glen Riethmuller, Jeromy Lemon, Mario D'Antuono, Veronika Reck, Ben Curtis, Judith Devenish, Melaine Kupsch, Anne Smith, Blakely Paynter, Roslyn Jetter, Leanne Schulz, Jocelyn Ball, Tom Sweeny, Stephen Loss, Ashleigh Brooks, Justin Fuery, Geoff Anderson, Zed Rengel, Paul Damon, Eddy Pol, Narelle Hill, Ray Tugwell, Ron Mctaggart, Nathan Moyes, John Majewski, Manisha Shanker, James Piotrowski, Ciara Beard, Kithsiri Jayasena, Kazue Tanaka, Grey Poulish, Debbie Thackray, Rohan Prince, Roger Jones, Peter Nelson, Nigel Metz, Leisa Armstrong, Yee Leong (Alex) Yung, Moin Salam, David Tennant Feb 2004

Crop Updates 2004 - Cereals, Wal Anderson, Vivian Vanstone, Robert Loughman, Vanessa Stewart, Darshan Sharma, Christine Zaicou-Kunesch, Brenda Shackley, Mohammad Amjad, Steve Penny Jr, Glen Riethmuller, Jeromy Lemon, Mario D'Antuono, Veronika Reck, Ben Curtis, Judith Devenish, Melaine Kupsch, Anne Smith, Blakely Paynter, Roslyn Jetter, Leanne Schulz, Jocelyn Ball, Tom Sweeny, Stephen Loss, Ashleigh Brooks, Justin Fuery, Geoff Anderson, Zed Rengel, Paul Damon, Eddy Pol, Narelle Hill, Ray Tugwell, Ron Mctaggart, Nathan Moyes, John Majewski, Manisha Shanker, James Piotrowski, Ciara Beard, Kithsiri Jayasena, Kazue Tanaka, Grey Poulish, Debbie Thackray, Rohan Prince, Roger Jones, Peter Nelson, Nigel Metz, Leisa Armstrong, Yee Leong (Alex) Yung, Moin Salam, David Tennant

Crop Updates

This session covers twenty eight papers from different authors:

PLENARY

1. Declining profitability in continuous cropping systems. Is more wheat the answer on Duplex soil? Dr Wal Anderson, Department of Agriculture

2. Disease implications of extending the wheat phase in low-medium rainfall areas, Dr Vivian Vanstone and Dr Robert Loughman, Department of Agriculture

3. Prolonged wheat phase on duplex soils – where do weeds set the boundary? Vanessa Stewart, Department of Agriculture

WHEAT AGRONOMY

4. Management of small grain screenings in wheat, Dr Wal Anderson and Dr Darshan Sharma, Department of Agriculture

5. Agronomic responses of new wheat varieties, Christine Zaicou-Kunesch ...


Closterovirus Bipolar Virion: Evidence For Initiation Of Assembly By Minor Coat Protein And Its Restriction To The Genomic Rna 5' Region, Satyanarayana Tatineni, Siddarame Gowda, Maria A. Ayllon, William O. Dawson Jan 2004

Closterovirus Bipolar Virion: Evidence For Initiation Of Assembly By Minor Coat Protein And Its Restriction To The Genomic Rna 5' Region, Satyanarayana Tatineni, Siddarame Gowda, Maria A. Ayllon, William O. Dawson

Papers in Plant Pathology

The long flexuous virions of the Closteroviridae have a unique bipolar architecture incorporating two coat proteins, with most of the helical nucleocapsid encapsidated by the major coat protein (CP) and a small portion of one end encapsidated by the minor coat protein (CPm). It is not known whether CPm encapsidates the genomic RNA and, if so, which end and what effects transition between the two coat proteins. Two other virus-encoded proteins, an HSP70 homolog (HSP70h) and an = 61-kDa protein, are required to augment virion assembly. In this work, we examine the in vivo encapsidation of Citrus tristeza virus by its ...


Clonal Propagation Of Dalbergia Sissoo Roxb. By Softwood Nodal Cuttings: Effects Of Genotypes, Application Of Iba And Position Of Cuttings On Shoots, Azamal Husen Dr. Jan 2004

Clonal Propagation Of Dalbergia Sissoo Roxb. By Softwood Nodal Cuttings: Effects Of Genotypes, Application Of Iba And Position Of Cuttings On Shoots, Azamal Husen Dr.

Dr. Azamal Husen

No abstract provided.


Growth Performance Of Datura Innoxia Mill. Under The Stress Of Coal-Smoke Pollution, Azamal Husen, Muhammad Iqbal Jan 2004

Growth Performance Of Datura Innoxia Mill. Under The Stress Of Coal-Smoke Pollution, Azamal Husen, Muhammad Iqbal

Dr. Azamal Husen

One-year-old plants of Datura innoxia growing in natural condition in the Hamdard University campus, New Delhi (normal site) and around the Badarpur thermal power plant, New Delhi (polluted site), were studied and compared for their vegetative growth and pollen viability. The power plant emits 1450 tonnes fly ash and 100 tonnes sulphur dioxide per day. Significant variation was found in plant growth, biomass and pollen viability of the two population. The shoot growth was reduced at the polluted site but the root length, the number of branches and the plant biomass were increased, compared to the control. Pollen viability declined ...


Topcrop W.A. State Focus 2002-2003 Wheat Protein, Alison Slade, Jeremy Lemon Jan 2004

Topcrop W.A. State Focus 2002-2003 Wheat Protein, Alison Slade, Jeremy Lemon

Bulletins 4000 -

The State Focus program is supported by the Grains Research and Development Corporation (GRDC) in conjunction with TOPCROP to provide grower groups with a new learning concept. The concept was developed in Victoria and has been adopted by South Australia and Western Australia.

Wheat protein was selected as the Western Australian State Focus in response to a wide-ranging consultation of grower groups, researchers and the TOPCROP West management group. As crop yield potential increases through matching varieties to growing season length, weed and disease control, and timely sowing systems, the crop’s demand for nitrogen increases. Unless the demand is ...


Effects Of Choline, Betaine, And Wheat Floral Extracts On Growth Of Fusarium Graminearum, Jessica S. Engle, Patrick E. Lipps, Terry L. Graham, Michael J. Boehm Jan 2004

Effects Of Choline, Betaine, And Wheat Floral Extracts On Growth Of Fusarium Graminearum, Jessica S. Engle, Patrick E. Lipps, Terry L. Graham, Michael J. Boehm

Papers in Plant Pathology

Fusarium head blight has been more severe when infection occurs during anthesis, indicating that floral organs may be important infection courts. Choline acetate and glycinebetaine have been extracted from wheat and reported to be growth stimulants of Fusarium graminearum. They are hypothesized to enhance infection and tissue colonization. Growth of F. graminearum was examined on media amended with extracts from floral parts of nine wheat genotypes with various Fusarium head blight resistance levels. Results indicated no significant effect of anther, palea, or lemma extracts on radial growth when compared with unamended controls. Effects on spore germination and hyphal growth of ...


Vascular Plant Species Inventory Of Richardson Bottoms Wildlife Viewing Area, Travis D. Marsico Jan 2004

Vascular Plant Species Inventory Of Richardson Bottoms Wildlife Viewing Area, Travis D. Marsico

Journal of the Arkansas Academy of Science

No abstract provided.


Seed Mass And Morphology In Outcrossing And Selfing Species Of Clarkia (Onagraceae): An Sem Study, Jennifer L. Knies, Veronique A. Delesalle, A. R. Cavaliere Jan 2004

Seed Mass And Morphology In Outcrossing And Selfing Species Of Clarkia (Onagraceae): An Sem Study, Jennifer L. Knies, Veronique A. Delesalle, A. R. Cavaliere

Biology Faculty Publications

Seeds from three pairs of outcrossing-selfing sister taxa from the genus Clarkia (farewell-to-spring, Onagraceae)—Clarkia unguiculata, Clarkia exilis, Clarkia xantiana ssp. xantiana and ssp. parviflora, and Clarkia concinna ssp. concinna and ssp. automixa—were studied to assess the effects of contrasting mating systems on seed mass and seed morphology. For each outcrossing-selfing comparison, the seed mass of the selfing taxon was less than that of the outcrossing taxon. Seed mass typically differed significantly among populations within a taxon. Scanning electron microscopy showed that the seeds from all these taxa share several characteristics: a bullet to shield shape, a reticulate exotesta ...


Aerobic Stability Of Heat And Orchardgrass Round-Bale Silage, Robert T. Rhein, Wayne K. Coblentz, Charles F. Rosenkrans Jr., D. Wayne Kellog Jan 2004

Aerobic Stability Of Heat And Orchardgrass Round-Bale Silage, Robert T. Rhein, Wayne K. Coblentz, Charles F. Rosenkrans Jr., D. Wayne Kellog

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

In Arkansas, silage is typically stored as balage in long rows of round bales wrapped in plastic film. It is important to evaluate the aerobic stability of this fermented forage when it is exposed to air, especially during the winter months when most of it is fed to livestock or sold as a cash crop. Two types of forage, orchardgrass (Dactylis glomerata) and wheat (Triticum aestivum), were harvested in May 2002 and stored as balage. Twenty-one bales of each balage type were unwrapped and exposed to air on 10 Dec. 2002 for 0, 2, 4, 8, 16, 24, or 32 ...


Confirmation That Dirca Spp. (Thymelaeaeae) Reproduce From Rhizomes, William R. Graves Jan 2004

Confirmation That Dirca Spp. (Thymelaeaeae) Reproduce From Rhizomes, William R. Graves

Horticulture Publications

There are three North American species of deciduous shrubs in the genus Dirca L. Dirca palustris L. occurs in the eastern United States and in southeastern Canada (Vogelmann 1953). Although its distribution is broad, D. palustris typically is obscure locally and is restricted to moist soils as an understory species along wooded slopes (Kurz 1997). Dirca occidentalis Gray also occurs on slopes (McMinn and Forderhase 1935), but its distribution is narrowly restricted to six counties of California near the San Francisco Bay. Within this area, D. occidentalis inhabits cool niches with frequent fog and relatively uniform soil moisture (Johnson 1994 ...


Pseudomonas Syringae Type Iii Secretion System Targeting Signals And Novel Effectors Studied With A Cya Translocation Reporter, Lisa M. Schechter, Kathy A. Roberts, Yashitola Jamir, James R. Alfano, Alan Collmer Jan 2004

Pseudomonas Syringae Type Iii Secretion System Targeting Signals And Novel Effectors Studied With A Cya Translocation Reporter, Lisa M. Schechter, Kathy A. Roberts, Yashitola Jamir, James R. Alfano, Alan Collmer

Faculty Publications from the Center for Plant Science Innovation

Pseudomonas syringae pv. tomato strain DC3000 is a pathogen of tomato and Arabidopsis. The hrp-hrcencoded type III secretion system (TTSS), which injects bacterial effector proteins (primarily called Hop or Avr proteins) into plant cells, is required for pathogenicity. In addition to being regulated by the HrpL alternative sigma factor, most avr or hop genes encode proteins with N termini that have several characteristic features, including (i) a high percentage of Ser residues, (ii) an aliphatic amino acid (Ile, Leu, or Val) or Pro at the third or fourth position, and (iii) a lack of negatively charged amino acids ...


The Hopptof Locus Of Pseudomonas Syringae Pv. Tomato Dc3000 Encodes A Type Iii Chaperone And A Cognate Effector, Libo Shan, Hye-Sook Oh, Jianfu Chen, Ming Guo, Jianmin Zhou, James R. Alfano, Alan Collmer, Xu Jia, Xiaoyan Tang Jan 2004

The Hopptof Locus Of Pseudomonas Syringae Pv. Tomato Dc3000 Encodes A Type Iii Chaperone And A Cognate Effector, Libo Shan, Hye-Sook Oh, Jianfu Chen, Ming Guo, Jianmin Zhou, James R. Alfano, Alan Collmer, Xu Jia, Xiaoyan Tang

Papers in Plant Pathology

Type III secretion systems are highly conserved among gram-negative plant and animal pathogenic bacteria. Through the type III secretion system, bacteria inject a number of virulence proteins into the host cells. Analysis of the whole genome sequence of Pseudomonas syringae pv. tomato DC3000 strain identified a locus, named HopPtoF, that is homologous to the avirulence gene locus avrPphF in P. syringae pv. phaseolicola. The HopPtoF locus harbors two genes, ShcFPto and HopFPto, that are preceded by a single hrp box promoter. We present evidence here to show that ShcFPto and HopFPto encode a type III chaperone ...


Molecular Differentiation Of Two Sibling Species Of The Black Fly Simulium Vittatum (Diptera: Simuliidae) Based On Random Amplified Polymorphic Dna, G. A. Duncan, P. H. Adler, K. P. Pruess, Thomas O. Powers Jan 2004

Molecular Differentiation Of Two Sibling Species Of The Black Fly Simulium Vittatum (Diptera: Simuliidae) Based On Random Amplified Polymorphic Dna, G. A. Duncan, P. H. Adler, K. P. Pruess, Thomas O. Powers

Papers in Plant Pathology

Larvae of the black fly morphospecies Simulium vittatum from Colorado, Montana, Nebraska, and New Hampshire were cytologically identified as either the IS-7 or the IIIL-1 cytospecies. DNA was PCR amplified from cytotyped larvae using eight 10-mer primers, labeled with 33P, and run on polyacrylamide gels. The entire data set of 96 amplicons produced incomplete separation of the two cytospecies when subjected to neighbor-joining and maximum parsimony analyses. However, when analyzed within geographical regions, separate species status was supported. Boot- strap support for distinctness of the two cytospecies was best in Colorado where they were collected in true sympatry. The ...


Type Iii Secretion System Effector Proteins: Double Agents In Bacterial Disease And Plant Defense, James R. Alfano, Alan Collmer Jan 2004

Type Iii Secretion System Effector Proteins: Double Agents In Bacterial Disease And Plant Defense, James R. Alfano, Alan Collmer

Papers in Plant Pathology

Many phytopathogenic bacteria inject virulence effector proteins into plant cells via a Hrp type III secretion system (TTSS). Without the TTSS, these pathogens cannot defeat basal defenses, grow in plants, produce disease lesions in hosts, or elicit the hypersensitive response (HR) in nonhosts. Pathogen genome projects employing bioinformatic methods to identify TTSS Hrp regulon promoters and TTSS pathway targeting signals suggest that phytopathogenic Pseudomonas, Xanthomonas, and Ralstonia spp. harbor large arsenals of effectors. The Hrp TTSS employs cus- tomized cytoplasmic chaperones, conserved export components in the bacterial en- velope (also used by the TTSS of animal pathogens), and a more ...


Nematode Molecular Diagnostics: From Bands To Barcodes, Tom Powers Jan 2004

Nematode Molecular Diagnostics: From Bands To Barcodes, Tom Powers

Papers in Plant Pathology

Nematodes are considered among the most difficult animals to identify. DNA-based diagnostic methods have already gained acceptance in applications ranging from quarantine determinations to assessments of biodiversity. Researchers are currently in an information-gathering mode, with intensive efforts applied to accumulating nucleotide sequence of 18S and 28S ribosomal genes, internally transcribed spacer regions, and mitochondrial genes. Important linkages with collateral data such as digitized images, video clips and specimen voucher web pages are being established on GenBank and NemATOL, the nematode-specific Tree of Life database. The growing DNA taxonomy of nematodes has lead to their use in testing specific short sequences ...


Carbohydrate Partitioning And Photosynthesis In Arabidopsis Thaliana , Dan Joseph Stessman Jan 2004

Carbohydrate Partitioning And Photosynthesis In Arabidopsis Thaliana , Dan Joseph Stessman

Retrospective Theses and Dissertations

To characterize carbohydrate partitioning and photosynthesis in Arabidopsis thaliana we examined three different lines: wild type Columbia ecotype, immutans, and T-DNA knockouts of vacuolar acid invertase. Wild type plants displayed decreasing photosynthesis from the beginning of leaf expansion through senescence. Chlorophyll, total soluble protein, and expression of LhcB also declined in a similar fashion. Pulse-label feeding of 14C showed a peak flux into glucose and fructose coincident with full leaf expansion a large decrease in LhcB expression. However, flux of 14C into the different carbohydrate fractions did not reflect carbohydrate pool sizes. The conclusion was that flux into the different ...


Age And Sex-Specific Rates Of Leaf Regeneration In The Mojave Desert Moss Syntrichia Caninervis, Lloyd Stark, L. Nichols, Nicholas N. Mcletchie, S. D. Smith, C. Zundel Jan 2004

Age And Sex-Specific Rates Of Leaf Regeneration In The Mojave Desert Moss Syntrichia Caninervis, Lloyd Stark, L. Nichols, Nicholas N. Mcletchie, S. D. Smith, C. Zundel

Life Sciences Faculty Publications

The extremely skewed female-biased sex ratio in the desert moss Syntrichia caninervis was investigated by assessing the regeneration capacity of detached leaves. Juvenile, green, yellow-green, and brown leaves equating to approximately 0, 2, 6, and 12 yr of age, respectively, were detached from individuals of S. caninervis collected from 10 field populations and grown in a growth chamber for 58 d at a light intensity of 33–128 µmol · m–2 · s–1. Younger leaves (0–2 yr old) tended to have a greater viability, regenerate more quickly, extend their protonemal filaments farther, produce shoots (gametophores) more quickly, produce more ...