Life Sciences Commons^™

Lake Mead National Recreation Area Vegetation Monitoring And Management: Quarterly Progress Report, Period Ending December 31, 2006, Margaret N. Rees

Vegetation Monitoring

Executive Summary

• Two new Weed Sentry research assistants were hired.
• Weed Sentry staff surveyed for exotic species on 89 miles of roads on NPS and BLM land and treated more than 21,000 exotic plants in incipient populations.
• A grid-based rare plant monitoring method was tested this quarter.
• A manuscript detailing vegetation succession on a water pipeline at Lake Mead NRA was submitted for review to the journal Crossosoma.
• New integrative projects undertaken this quarter included establishing a competition study between a native grass and the exotic Sahara mustard, salvaging plants for research purposes from private sites with permission from landowners, …

Nuclec Acds Encoding Pseudomonas Hop Proteins And Use Thereof, Alan Collmer, James R. Alfano, Xiaoyan Tang, C. Robin Buell, Gregory B. Martin

Department of Plant Pathology: Faculty Publications

The present invention relates to isolated nucleic acid mol ecules encoding a type III—secreted bacterial protein capable of modifying a cell death pathway in a plant cell. One aspect of the present invention involves an isolated nucleic acid molecule having a nucleotide sequence that encodes the HopPtol)2 protein of Pseudomonas syringae pv. syringae DC 3000. Expression vectors, host cells, and transgenic plants which include the DNA molecules of the present invention are also disclosed. The nucleic acid mol ecules of the present invention can be used to impart disease resistance to a plant and to make a plant hypersusceptible to …

Whole-Genome Expression Profiling Defines The Hrpl Regulon Of Pseudomonas Syringae Pv. Tomato Dc3000, Allows De Novo Reconstruction Of The Hrp Cis Element, And Identifies Novel Coregulated Genes, Adriana O. Ferreira, Christopher R. Myers, Jeffrey S. Gordon, Gregory B. Martin, Monica Vencato, Alan Collmer, Misty D. Wehling, James R. Alfano, Gabriel Moreno-Hagelsieb, Warren F. Lamboy, Geneviene Declerck, David J. Schneider, Samuel W. Cartinhour

Department of Plant Pathology: Faculty Publications

Pseudomonas syringae pv. tomato DC3000 is a model pathogen of tomato and Arabidopsis that uses a hypersensitive response and pathogenicity (Hrp) type III secretion system (T3SS) to deliver virulence effector proteins into host cells. Expression of the Hrp system and many effector genes is activated by the HrpL alternative sigma factor. Here, an open reading frame-specific whole-genome microarray was constructed for DC3000 and used to comprehensively identify genes that are differentially expressed in wild-type and ΔhrpL strains. Among the genes whose differential regulation was statistically significant, 119 were upregulated and 76 were downregulated in the wild-type compared with the ΔhrpL …

Microbial Content Of Abattoir Wastewater And Its Contaminated Soil In Lagos, Nigeria, A. O. Adesemoye, B. O. Opere, S. C. O. Makinde

Department of Plant Pathology: Faculty Publications

Microbial content of wastewater in two abattoirs and the impact on microbial population of receiving soil was studied in Agege and Ojo Local Government Areas in Lagos State, Nigeria. Wastewater samples were collected from each of the abattoirs over three months period and examined for microbial content. Soil samples contaminated with the wastewaters were also collected and analyzed for microbial content as compared to soil without wastewater contamination in the neighborhood (control). Some physico-chemical parameters of the samples such as total dissolved solid, chemical oxygen demand, etc., were examined. The wastewater samples from both abattoirs were highly contaminated; Agege abattoir …

Lake Mead National Recreation Area Vegetation Monitoring And Management: Final Close-Out Report, Time Period: October 1, 2005 To September 30, 2006, Margaret N. Rees

Vegetation Monitoring

The National Park Service (NPS) at Lake Mead National Recreation Area (LAME) entered into a cooperative agreement with the University of Nevada, Las Vegas (UNLV) to accomplish vegetation monitoring and management activities. This report summarizes activities that took place by UNLV under this task agreement between October 1, 2005, and September 30, 2006. The activities included:

• Weed Sentry mapping and treating incipient populations of exotic invasive plants throughout Clark County, including along shorelines of Lakes Mead and Mohave;
• Monitoring of targeted rare native plant species;
• Sahara mustard research; and
• Providing technical assistance upon request to the NPS vegetation manager.

In …

Inducible Yeast System For Viral Rna Recombination Reveals Requirement For An Rna Replication Signal On Both Parental Rnas, Hernan Garcia-Ruiz, Paul Ahlquist

Department of Plant Pathology: Faculty Publications

To facilitate RNA recombination studies, we tested whether Saccharomyces cerevisiae, which supports brome mosaic virus (BMV) replication, also supports BMV RNA recombination. Yeast strains expressing BMV RNA replication proteins 1a and 2a^pol were engineered to transiently coexpress two independently inducible, overlapping, nonreplicating derivatives of BMV genomic RNA3. B33' lacked the coat protein gene and negative-strand RNA promoter. B35' lacked the positive-strand RNA promoter and had the coat gene replaced by the selectable URA3 gene. After 12 to 72 h of induction, B33' and B35' transcription was repressed and Ura⁺ yeast cells were selected. All Ura⁺ cells …

Pseudomonas SyringaeHrpj Is A Type Iii Secreted Protein That Is Required For Plant Pathogenesis, Injection Of Effectors,And Secretion Of The Hrpz1 Harpin, Zheng Qing Fu, Ming Guo, James R. Alfano

Center for Plant Science Innovation: Faculty and Staff Publications

The bacterial plant pathogen Pseudomonas syringae requires a type III protein secretion system (TTSS) to cause disease. The P. syringae TTSS is encoded by the hrp-hrc gene cluster. One of the genes within this cluster, hrpJ, encodes a protein with weak similarity to YopN, a type III secreted protein from the animal pathogenic Yersinia species. Here, we show that HrpJ is secreted in culture and translocated into plant cells by the P. syringae pv. tomato DC3000 TTSS. A DC3000 hrpJ mutant, UNL140, was greatly reduced in its ability to cause disease symptoms and multiply in Arabidopsis thaliana …

Effects Of Ultraviolet-B Radiation On Leaf Morphology Of Arabidopsis Thaliana (L.) Heynh. (Brassicaceae), Maria Regina Torres Boeger, Mary E. Poulson

Biology Faculty Scholarship

Reduction of the ozone layer results in the increase in ultraviolet radiation reaching the earth's surface, especially the ultraviolet-B (UV-B). The increase of radiation may induce structural and physiological changes in plants, influencing their growth and development. This paper evaluates the effects of ambient UV-B radiation upon to the leaf morphology of Arabidopsis thaliana developed under controlled conditions. The seeds of A. thaliana grown in environmental chamber, with 300 µmol m^-2s^-1 de photosynthetically active radiation (PAR) with and without 6 kJ m^-2 s^-1 of radiation UV-B_be (UV-B_be; UV-B biologically effective). After 21 …

Effects Of Smoke And Fire-Related Cues On Panstemon Barbatus Seeds, Scott R. Abella

Public Policy and Leadership Faculty Publications

Previous research has found that exposure to fire-related cues enhances germination of some plant species, and such species may exist in frequent-fire southwestern United States Pinus ponderosa forests. I performed four greenhouse experiments with Penstemon barbatus, a perennial forb common in P. ponderosa forests, testing seed responses to liquid and air smoke, charred P. ponderosa wood and leachate, heat and emergence substrates. Liquid smoke increased P. barbatus emergence to as high as 63%, 44% greater than controls, and enhanced emergence in all 4 experiments. Air smoke produced by burning P. ponderosa litter for 15 min appeared to increase emergence similar …

Bacillus Species Nrrl B-30212 For Reducing Fusarium Head Blight In Cereals, David A. Schisler, Naseem L. Khan, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Four yeasts (NRRL Y-30213, NRRL Y-30214, NRRL Y-30215, and NRRL Y-30216) and 1 bacterium (NRRL B-30212) have been identified as being superior antagonists capable of suppressing Fusarium head blight (head scab) in cereals, particularly in wheat and barley. Fusarium head blight is primarily caused by the fungus Gibberella zeae (anamorph=Fusarium graminearum).

Crop Updates 2006 - Weeds, Alexandra Douglas, Thomas M. Wolf, Harm Van Rees, Bill Gordon, Peter Newman, Glenn Adam, Aik Lee, Siew Lee, Katherine Hollaway, Brad Rayner, John Peirce, Rick Llewellyn, Frank D'Emden, Michelle Owen, Stephen Powles, Michael Walsh, Emma Glasfurd, Kathryn Steadman, David Ferris, Bevan Addison, Aik Cheam, Dave Nicholson, Ruben Vargas, Shahab Pathan, Abul Hashem, Nerys Wilkins, Catherine Borger, Bob French, Kari-Lee Falconer, Martin Harries, Chris Matthews, Vikki Osten, Harnohinder Dhammu, David Nicholson, Richard Quinlan, Debbie Allen, Mark Seymour, Pam Burgess, Owen Coppen, Chris Roberts, Christiaan Valentine, A. K. Basandrai, W. J. Macleod, John Moore, Neil Rothnie, Russell Speed, John Simons, Ted Spadek, Daya Patabendige, Michael Renton, Sally Peltzer, Art Diggle

Crop Updates

This session covers thirty seven papers from different authors:

1. ACKNOWLEDGEMENTS, Alexandra Douglas, CONVENOR – WEEDS DEPARTMENT OF AGRICULTURE

SPRAY TECHNOLOGY

2. Meeting the variable application goals with new application technology, Thomas M. Wolf, Agriculture and Agri-Food Canada, Saskatoon Research Centre

3. Spray nozzles for grass weed control, Harm van Rees, BCG (Birchip Cropping Group)

4. Boom sprayer setups – achieving coarse droplets with different operating parameters, Bill Gordon, Bill Gordon Consulting

5. Complying with product label requirements, Bill Gordon, Bill Gordon Consulting

6. IWM a proven performer over 5 years in 33 focus paddocks, Peter Newman and …

Crop Updates 2006 - Oilseeds, Graham Walton, Fiona Martin, Anne Wilkins, Nathan Hancock, Matthew Nelson, Marieclaire Castello, Linda Thompson, Anouska Cousin, Guijun Yan, Wallace Cowling, Moin Salam, Bill Mcloud, Ravjit Khangura, Jean Galloway, Art Diggle, R. F. Brennan, M. D. A. Bolland, P. M. Damon, Z. Rengel, Terry Rose, Qifu Ma, Dave Eksteen

Crop Updates

This session covers thirteen papers from different authors:

1. INTRODUCTION, Graham Walton, CONVENOR, Department of Agriculture

2. The performance of new TT canola varieties in National Variety Testing (NVT) WA, Fiona Martin, Research Agronomist, Agritech Crop Research

3. Comparison of TT Canola Varieties in Oilseeds WA Trials – 2005, Collated by G.H. Walton, Department of Agriculture, WA, from a collaboration between Oilseeds WA, Seed Companies, Agronomists and Growers

4. An overview of the potential for a Biofuels Industry in Western Australia, Anne Wilkins and Nathan Hancock, Department of Agriculture

5. Retrieval of fertile progeny from interspecific …

Bioinformatics-Enabled Identification Of The Hrpl Regulon And Type Iii Secretion System Effector Proteins Of Pseudomonas Syringae Pv. Phaseolicola 1448a, Monica Vencato, Fang Tian, James R. Alfano, C. Robin Buell, Samuel Cartinhour, Genevieve A. Declerck, David S. Guttman, John Stavrinides, Vinita Joardar, Magdalen Lindeberg, Philip A. Bronstein, John W. Mansfield, Christopher R. Myers, Alan Collmer, David J. Schneider

Department of Plant Pathology: Faculty Publications

The ability of Pseudomonas syringae pv. phaseolicola to cause halo blight of bean is dependent on its ability to translocate effector proteins into host cells via the hypersensitive response and pathogenicity (Hrp) type III secretion system (T3SS). To identify genes encoding type III effectors and other potential virulence factors that are regulated by the HrpL alternative sigma factor, we used a hidden Markov model, weight matrix model, and type III targeting-associated patterns to search the genome of P. syringae pv. phaseolicola 1448A, which recently was sequenced to completion. We identified 44 high-probability putative Hrp promoters upstream of genes encoding the …

Regulation Of Hyphal Morphogenesis And The Dna Damage Response By The Aspergillus Nidulans Atm Homolog Atma, Iran Malavazi, Camile P. Semighini, Marcia Regina Von Zeska Kress, Steven D. Harris, Gustavo H. Goldman

Department of Plant Pathology: Faculty Publications

Ataxia telangiectasia (A-T) is an inherited disorder characterized by progressive loss of motor function and susceptibility to cancer. The most prominent clinical feature observed in A-T patients is the degeneration of Purkinje motor neurons. Numerous studies have emphasized the role of the affected gene product, ATM, in the regulation of the DNA damage response. However, in Purkinje cells, the bulk of ATM localizes to the cytoplasm and may play a role in vesicle trafficking. The nature of this function, and its involvement in the pathology underlying A-T, remain unknown. Here we characterize the homolog of ATM (AtmA) in the filamentous …

First Report Of Leaf Spot Of Smooth Bromegrass Caused By Pithomyces Chartarum In Nebraska, C. Eken, C. C. Jochum, G. Y. Yuen

Department of Plant Pathology: Faculty Publications

Smooth bromegrass (Bromus inermis Leyss.) is the most common perennial grass species cultivated for forage in North America. During late fall of 2004, smooth bromegrass plants in Lincoln, NE were observed to have brown lesions on leaf midveins that were several centimeters long. Symptomatic leaves were surface disinfested for 1 min in 2% NaOCl and incubated at 25°C on potato dextrose agar (PDA) and water agar. The fungus, Pithomyces chartarum (Berk. & Curt) Ellis, was isolated consistently and identified on the basis of morphological characteristics (1). Colonies were effused and black on PDA. Conidiophores measured 3.5 to 8 …

Fungicide Sensitivity Of Sclerotinia Homoeocarpa From Golf Courses In Ohio, Young-Ki Jo, Amy L. Niver, Joseph W. Rimelspach, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Managing dollar spot, the most common and chronic disease on intensively cultivated turfgrass, relies on the judicious use of fungicides. The heavy use of fungicides has led to the development of isolates of Sclerotinia homoeocarpa insensitive to several classes of fungicides, including benzimidazoles, demethylation-inhibitors, and dicarboximides. In vitro fungicide sensitivity assays using single discriminatory concentrations of thiophanate-methyl, propiconazole, and iprodione were developed in this study for evaluating field efficacy of these fungicides and the prevalence of fungicide insensitivity within S. homoeocarpa isolated from golf courses throughout Ohio. Discriminatory concentrations for these fungicides were determined to be: thiophanate-methyl = 1,000 μg …

Ethylene Stimulates Nutations That Are Dependent On The Etr1 Receptor, Brad M. Binder, Ronan C. O'Malley, Wuyi Wang, Tobias C. Zutz, Anthony B. Bleeker

Faculty Publications and Other Works -- Biochemistry, Cellular and Molecular Biology

Ethylene influences a number of processes in Arabidopsis (Arabidopsis thaliana) through the action of five receptors. In this study, we used high-resolution, time-lapse imaging to examine the long-term effects of ethylene on growing, etiolated Arabidopsis seedlings. These measurements revealed that ethylene stimulates nutations of the hypocotyls with an average delay in onset of over 6 h. The nutation response was constitutive in ctr1-2 mutants maintained in air, whereas ein2-1 mutants failed to nutate when treated with ethylene. Ethylene-stimulated nutations were also eliminated in etr1-7 loss-of-function mutants. Transformation of the etr1-7 mutant with a wild-type genomic ETR1 transgene rescued the nutation …

2006 Wildflower Of The Year: Spicebush, Lindera Benzoin, W. John Hayden

Biology Faculty Publications

Spicebush is a multistemmed deciduous shrub that grows to a height of one to three meters. Young stems are delicate and may be smooth or finely hairy. Leaves are alternate and simple, with an elliptic to obovate blade that tapers at both the base and apex and is bounded by a smooth margin. Examined closely, the margin will reveal a series of fine hairs that project directly out from the leaf edge. In size, leaves are neither remarkably large nor small; they range from one to six inches in length and up to about two and a half inches wide, …

Avenacin Production In Creeping Bentgrass (Agrostis Stolonifera) And Its Influence On The Host Range Of Gaeumannomyces Graminis, S. L. Thomas, P. Bonello, P. E. Lipps, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Avenacinase activity has been shown to be a key factor determining the host range of Gaeumannomyces graminis on oats (Avena sativa). G. graminis var. avenae produces avenacinase, which detoxifies the oat root saponin avenacin, enabling it to infect oats. G. graminis var. tritici does not produce avenacinase and is unable to infect oats. G. graminis var. avenae is also reported to incite take-all patch on creeping bentgrass (Agrostis stolonifera). It is unknown whether creeping bentgrass produces avenacin and if the avenacin-avenacinase interaction influences G. graminis pathogenicity on creeping bentgrass. The root extracts of six creeping bentgrass …

Carbon-To-Nitrogen Ratio And Carbon Loading Of Production Media Influence Freeze-Drying Survival And Biocontrol Efficacy Of Cryptococcus Nodaensis Oh 182.9, Shouan Zhang, David A. Schisler, Michael J. Boehm, Patricia J. Slininger

Department of Plant Pathology: Faculty Publications

Fusarium head blight (FHB), caused by Gibberella zeae, is a devastating disease of wheat worldwide. Cryptococcus nodaensis OH 182.9 is an effective biocontrol agent for this disease. Development of a dried product of OH 182.9 would have potential advantages of ease of handling, favorable economics, and acceptance by end users. Isolate OH 182.9 was grown for 48 and 72 h in semi-defined complete liquid (SDCL) medium with carbon-to-nitrogen (C/N) ratios of 6.5:1, 9:1, 11:1, 15:1, and 30:1, and in SDCL C/N 30:1 media with varied carbon loadings of 7, 14, 21, and 28 g/liter. Total biomass production and cell …

First Report Of Sudden Death Syndrome Of Soybean Caused By Fusarium Solani F. Sp. Glycines In Nebraska, A. D. Ziems, L. J. Giesler, G. Y. Yuen

Department of Plant Pathology: Faculty Publications

During August of 2004, soybean (Glycine max (L.) Merr.) plants exhibiting symptoms typical of sudden death syndrome (SDS) caused by Fusarium solani (Mart.) Sacc. f. sp. glycines (= Fusarium virguliforme Akoi, O'Donnell, Homma, & Lattanzi) (1) were observed in Nemaha and Pierce counties in eastern Nebraska. Leaf symptoms ranged from small chlorotic spots to prominent interveinal necrosis on plants at R5-R6 growth stages. Taproots of symptomatic plants were plated on potato dextrose agar (PDA) amended with hymexazol, ampicillin, and rifampicin (HAR). Resulting fungal isolates grew slowly and developed masses of blue macroconidia, characteristic of F. solani f. sp. glycines …

Evaluation Of The Single Kernel Characterization System (Skcs) For Measurement Of Sorghum Grain Attributes, S. R. Bean, O. K. Chung, M. R. Tuinstra, Jeffrey F. Pedersen, J. Erpelding

Department of Agronomy and Horticulture: Faculty Publications

The single kernel characterization system (SKCS) has been widely used in the wheat industry, and SKCS parameters have been linked to end-use quality in wheat. The SKCS has promise as a tool for evaluating sorghum grain quality. However, the SKCS was designed to analyze wheat, which has a different kernel structure from sorghum. To gain a better understanding of the meaning of SKCS predictions for grain sorghum, individual sorghum grains were measured for length, width, thickness (diameter), and weight by laboratory methods and by the SKCS. SKCS predictions for kernel weight and thickness were highly correlated to laboratory measurements. However, …

Chemical Composition And Response To Dilute-Acid Pretreatment And Enzymatic Saccharification Of Alfalfa, Reed Canarygrass, And Switchgrass, Bruce S. Dien, Hans-Joachim G. Jung, Kenneth P. Vogel, Michael D. Casler, Joann F. S. Lamb, Loren Iten, Robert C. Mitchell, Gautum Sarath

Department of Agronomy and Horticulture: Faculty Publications

Alfalfa stems, reed canarygrass, and switchgrass; perennial herbaceous species that have potential as biomass energy crops in temperate regions; were evaluated for their bioconversion potential as energy crops. Each forage species was harvested at two or three maturity stages and analyzed for carbohydrates, lignin, protein, lipid, organic acids, and mineral composition. The biomass samples were also evaluated for sugar yields following pretreatment with dilute sulfuric followed by enzymatic saccharification using a commercial cellulase preparation. Total carbohydrate content of the plants varied from 518 to 655 g kg^-1 dry matter (DM) and cellulose concentration from 209 to 322 g kg …

Mutations In Arabidopsis Yellow Stripe-Like1 And Yellow Stripe-Like3 Reveal Their Roles In Metal Ion Homeostasis And Loading Of Metal Ions In Seeds, Brian M. Waters, Heng-Hsuan Chu, Raymond J. Didonato, Louis A. Roberts, Robynn B. Eisley, Brett Lahner, David E. Salt, Elsbeth L. Walker

Department of Agronomy and Horticulture: Faculty Publications

Here, we describe two members of the Arabidopsis (Arabidopsis thaliana) Yellow Stripe-Like (YSL) family, AtYSL1 and AtYSL3. The YSL1 and YSL3 proteins are members of the oligopeptide transporter family and are predicted to be integral membrane proteins. YSL1 and YSL3 are similar to the maize (Zea mays) YS1 phytosiderophore transporter (ZmYS1) and the AtYSL2 iron (Fe)-nicotianamine transporter, and are predicted to transport metal-nicotianamine complexes into cells. YSL1 and YSL3 mRNAs are expressed in both root and shoot tissues, and both are regulated in response to the Fe status of the plant. β-Glucuronidase reporter expression, driven by …

Application Of Machine Learning In Snp Discovery, Lakshmi K. Matukumalli, John J. Grefenstette, David L. Hyten, Ik-Young Choi, Perry B. Cregan, Curtis P. Van Tassell

Department of Agronomy and Horticulture: Faculty Publications

Background: Single nucleotide polymorphisms (SNP) constitute more than 90% of the genetic variation, and hence can account for most trait differences among individuals in a given species. Polymorphism detection software PolyBayes and PolyPhred give high false positive SNP predictions even with stringent parameter values. We developed a machine learning (ML) method to augment PolyBayes to improve its prediction accuracy. ML methods have also been successfully applied to other bioinformatics problems in predicting genes, promoters, transcription factor binding sites and protein structures. Results: The ML program C4.5 was applied to a set of features in order to build a SNP classifier …

Snp-Phage – High Throughput Snp Discovery Pipeline, Lakshmi K. Matukumalli, John J. Grefenstette, David L. Hyten, Ik-Young Choi, Perry B. Cregan, Curt P. Van Tassell

Department of Agronomy and Horticulture: Faculty Publications

Background: Single nucleotide polymorphisms (SNPs) as defined here are single base sequence changes or short insertion/deletions between or within individuals of a given species. As a result of their abundance and the availability of high throughput analysis technologies SNP markers have begun to replace other traditional markers such as restriction fragment length polymorphisms (RFLPs), amplified fragment length polymorphisms (AFLPs) and simple sequence repeats (SSRs or microsatellite) markers for fine mapping and association studies in several species. For SNP discovery from chromatogram data, several bioinformatics programs have to be combined to generate an analysis pipeline. Results have to be stored in …

Impacts Of Genetic Bottlenecks On Soybean Genome Diversity, D. L. Hyten, Qijian Song, Youlin Zhu, Ik-Young Choi, Randall L. Nelson, Jose M. Costa, James E. Specht, Randy C. Shoemaker, Perry B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

Soybean has undergone several genetic bottlenecks. These include domestication in Asia to produce numerous Asian landraces, introduction of relatively few landraces to North America, and then selective breeding over the past 75 years. It is presumed that these three human-mediated events have reduced genetic diversity. We sequenced 111 fragments from 102 genes in four soybean populations representing the populations before and after genetic bottlenecks. We show that soybean has lost many rare sequence variants and has undergone numerous allele frequency changes throughout its history. Although soybean genetic diversity has been eroded by human selection after domestication, it is notable that …

Soybean Cultivars Resulted From More Recombination Events Than Unselected Lines In The Same Population, T. R. Stefaniak, D. L. Hyten Jr., V. R. Pantalone, A. Klarer, T. W. Pfeiffer

Department of Agronomy and Horticulture: Faculty Publications

The selection of superior adapted cultivars has contributed to the doubling of soybean [Glycine max (L.) Merr.] yields in the USA since 1930. Genetic variation was required for this selection to be effective. The objective of this study was to evaluate the importance of homologous chromosome meiotic recombination in the creation of soybean cultivars. A set of 10 adapted high-yielding cultivars selected from the cross ‘Williams’ × ‘Essex’ was com-pared with a set of 156 random recombinant inbred lines (RILs) from the same population. Crossover events were identified using 143 simple sequence repeat (SSR) markers span-ning all 20 soybean …

Ethylene Could Influence Ferric Reductase, Iron Transporter, And H+-Atpase Gene Expression By Affecting Fer (Or Fer-Like) Gene Activity, Carlos Lucera, Brian M. Waters, Francisco Javier Romera, María José García, María Morales, Esteban Alcántara, Rafael Pérez-Vicente

Department of Agronomy and Horticulture: Faculty Publications

In previous works, it has been shown, by using ethylene inhibitors and precursors, that ethylene could participate in the regulation of the enhanced ferric reductase activity of Fe-deficient Strategy I plants. However, it was not known whether ethylene regulates the ferric reductase gene expression or other aspects related to this activity. This paper is a study of the effects of ethylene inhibitors and precursors on the expression of the genes encoding the ferric reductases and iron transporters of Arabidopsis thaliana (FRO2 and IRT1) and Lycopersicon esculentum (= Solanum lycopersicum) (FRO1 and IRT1) plants. The effects …

Influence Of Nutrient Availability, Stand Age, And Canopy Structure On Isoprene Flux In A Eucalyptus Saligna Experimental Forest, Jennifer L. Funk, Christian P. Giardina, Alexander Knohl, Manuel T. Lerdau

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Eucalyptus plantations occupy approximately 10 million ha of land in the tropics and, increasingly, afforestation and reforestation projects are relying on this genus to provide rapid occupation of degraded sites, large quantities of high-quality wood products, and high rates of carbon sequestration. Members of the genus Eucalyptus are also very high emitters of isoprene, the dominant volatile organic compound emitted by trees in tropical ecosystems, which significantly influences the oxidative capacity of the atmosphere. While fertilization growth response of these trees has been intensively studied, little is known about how fertilization and tree age alter isoprene production from plantations of …