Life Sciences Commons^™

Abiotic Stress Responses In Photosynthetic Organisms, Joseph Msanne

School of Natural Resources: Dissertations, Theses, and Student Research

Cellular and molecular aspects of abiotic stress responses in Arabidopsis thaliana subjected to cold, drought, and high salinity and in two photosynthetic green alga, Chlamydomonas reinhardtii and Coccomyxa sp. C-169, subjected to nitrogen deprivation were investigated. Cold, drought, and high salinity can negatively affect plant growth and crop production. The first research aimed at determining the physiological functions of the stress-responsive Arabidopsis thaliana RD29A and RD29B genes. Cold, drought, and salt induced both genes; the promoter of RD29Awas found to be more responsive to drought and cold stresses, whereas the promoter of RD29B was highly responsive to salt stress. …

Effects Of Nitrogen Deposition And Empirical Nitrogen Critical Loads For Ecoregions Of The United States, Linda H. Pardo, Mark E. Fenn, Christine L. Goodale, Linda H. Geiser, Charles T. Driscoll, Edith B. Allen, Jill S. Baron, Roland Bobbink, William D. Bowman, Christopher M. Clark, Bridget Emmett, Frank S. Gilliam, Tara L. Greaver, Sharon J. Hall, Erik A. Lilleskov, Lingli Liu, Jason A. Lynch, Knute J. Nadelhoffer, Steven S. Perakis, Molly J. Robin-Abbott, John L. Stoddard, Kathleen C. Weathers, Robin L. Dennis

Biological Sciences Faculty Research

Human activity in the last century has led to a significant increase in nitrogen (N) emissions and atmospheric deposition. This N deposition has reached a level that has caused or is likely to cause alterations to the structure and function of many ecosystems across the United States. One approach for quantifying the deposition of pollution that would be harmful to ecosystems is the determination of critical loads. A critical load is defined as the input of a pollutant below which no detrimental ecological effects occur over the long-term according to present knowledge. The objectives of this project were to synthesize …

No Accession-Specific Effect Of Rhizosphere Soil Communities On The Growth And Competition Of Arabidopsis Thaliana Accessions, Anna G. Aguilera, Adán Colón-Carmona, Rick Kesseli, Jeffrey S. Dukes

Biology Faculty Publication Series

Soil communities associated with specific plant species affect individual plants' growth and competitive ability. Limited evidence suggests that unique soil communities can also differentially influence growth and competition at the ecotype level. Previous work with Arabidopsis thaliana has shown that accessions produce distinct and reproducible rhizosphere bacterial communities, with significant differences in both species composition and relative abundance. We tested the hypothesis that soil communities uniquely affect the growth and reproduction of the plant accessions with which they are associated. Specifically, we examined the growth of four accessions when exposed to their own soil communities and the communities generated by …

Heritable Epigenetic Variation Among Maize Inbreds, Steve R. Eichten, Ruth A. Swanson, James C. Schnable, Amanda J. Waters, Peter J. Hermanson, Sanzhen Liu, Cheng-Ting Yeh, Yi Jia, Karla Gendler, Michael Freeling, Patrick S. Schnable, Matthew W. Vaughn, Nathan M. Springer

Department of Agronomy and Horticulture: Faculty Publications

Epigenetic variation describes heritable differences that are not attributable to changes in DNA sequence. There is the potential for pure epigenetic variation that occurs in the absence of any genetic change or for more complex situations that involve both genetic and epigenetic differences. Methylation of cytosine residues provides one mechanism for the inheritance of epigenetic information. A genome-wide profiling of DNA methylation in two different genotypes of Zea mays (ssp. mays), an organism with a complex genome of interspersed genes and repetitive elements, allowed the identification and characterization of examples of natural epigenetic variation. The distribution of DNA methylation …

Transcriptomic Characterization Of A Synergistic Genetic Interaction During Carpel Margin Meristem Development In Arabidopsis Thaliana, April N. Wynn, Elizabeth E. Rueschhoff, Robert G. Franks

Biological Sciences Research

In flowering plants the gynoecium is the female reproductive structure. In Arabidopsis thalianaovules initiate within the developing gynoecium from meristematic tissue located along the margins of the floral carpels. When fertilized the ovules will develop into seeds. SEUSS (SEU) and AINTEGUMENTA (ANT) encode transcriptional regulators that are critical for the proper formation of ovules from the carpel margin meristem (CMM). The synergistic loss of ovule initiation observed in the seu ant double mutant suggests that SEU and ANT share overlapping functions during CMM development. However the molecular mechanism underlying this synergistic interaction is unknown. Using …

Miscanthus 3 Giganteus Productivity: The Effects Of Management In Different Environments, Matt Maughan, German Bollero, D.K. Lee, Robert Darmody, Stacy Bonos, Laura Cortese, James Murphy, Roch E. Gaussoin, Matthew Sousek, David Williams, Linda Williams, Fernando Miguez, Thomas Voigt

Department of Agronomy and Horticulture: Faculty Publications

Miscanthus 9 giganteus is a C4 perennial grass that shows great potential as a high-yielding biomass crop. Scant research has been published that reports M. 9 giganteus growth and biomass yields in different environments in the United States. This study investigated the establishment success, plant growth, and dry biomass yield of M. 9 giganteus during its first three seasons at four locations (Urbana, IL; Lexington, KY; Mead, NE; Adelphia, NJ) in the United States. Three nitrogen rates (0, 60, and 120 kg ha -1) were applied at each location each year. Good survival of M. 9 giganteus during its first …

Rna-Mediated Silencing In Algae: Biological Roles And Tools For Analysis Of Gene Function, Heriberto Cerutti, Xinrong Ma, Joseph Msanne, Timothy Repas

Center for Plant Science Innovation: Faculty and Staff Publications

Algae are a large group of aquatic, typically photosynthetic, eukaryotes that include species from very diverse phylogenetic lineages, from those similar to land plants to those related to protist parasites. The recent sequencing of several algal genomes has provided insights into the great complexity of these organisms. Genomic information has also emphasized our lack of knowledge of the functions of many predicted genes, as well as the gene regulatory mechanisms in algae. Core components of the machinery for RNA-mediated silencing show widespread distribution among algal lineages, but they also seem to have been lost entirely from several species with relatively …

Single Molecule Analysis Of The Arabidopsis Fra1 Kinesin Shows That It Is A Functional Motor Protein With Unusually High Processivity, Chuanmei Zhu, Ram Dixit

Biology Faculty Publications & Presentations

The Arabidopsis FRA1 kinesin contributes to the organization of cellulose microfibrils through an unknown mechanism. The cortical localization of this kinesin during interphase raises the possibility that it transports cell wall-related cargoes along cortical microtubules that either directly or indirectly influence cellulose microfibril patterning. To determine whether FRA1 is an authentic motor protein, we combined bulk biochemical assays and single molecule fluorescence imaging to analyze the motor properties of recombinant, GFP-tagged FRA1 containing the motor and coiled-coil domains (designated as FRA1(707)–GFP). We found that FRA1(707)–GFP binds to microtubules in an ATP-dependent manner and that its ATPase activity is dramatically stimulated …

A New Species Of Diploid Quillwort (Isoetes, Isoetaceae, Lycophyta) From Lebanon, Jay F. Bolin, Rebecca D. Bray, Lytton John Musselman

Biological Sciences Faculty Publications

A new species, Isoetes libanotica Musselman, Bolin & B. D. Bray (Isoetaceae, Lycophyta), is described from Akkar District of northern Lebanon. It is a seasonal terrestrial species of basaltic soils, diploid (2n = 22), with complete velum coverage. Megaspore diameter ranges from 338 to 477 mu m with remote, low tuberculate ornamentation and a low to obsolete equatorial girdle; microspore length ranges from 25 to 30 mu m, with echinate ornamentation. At the type locality of I. libanotica, two other Isoetes L. species occur sympatrically. These superficially similar Isoetes species can be differentiated from I. libanotica using megaspore …

Muts Homolog1 Is A Nucleoid Protein That Alters Mitochondrial And Plastid Properties And Plant Response To High Light, Ying-Zhi Xu, Maria P. Arrieta-Montiel, Kamaldeep S. Virdi, Wilson B. M. De Paula, Joshua R. Widhalm, Gilles J. Basset, Jaime I. Davila, Thomas Elthon, Christian G. Elowsky, Shirley J. Sato, Thomas E. Clemente, Sally Ann Mackenzie

Center for Plant Science Innovation: Faculty and Staff Publications

Mitochondrial-plastid interdependence within the plant cell is presumed to be essential, but measurable demonstration of this intimate interaction is difficult. At the level of cellular metabolism, several biosynthetic pathways involve both mitochondrial- and plastid-localized steps. However, at an environmental response level, it is not clear how the two organelles intersect in programmed cellular responses. Here, we provide evidence, using genetic perturbation of the MutS Homolog1 (MSH1) nuclear gene in five plant species, that MSH1 functions within the mitochondrion and plastid to influence organellar genome behavior and plant growth patterns. The mitochondrial form of the protein participates in DNA recombination …

Relationships Among Rubus (Rosaceae) Species Used In Traditional Chinese Medicine, Yinu Wang

Masters Theses & Specialist Projects

Traditional Chinese medicine has a long history of using plants therapeutically including multiple species of the genus Rubus (Rosaceae). Fruits and other parts of Rubus plants have had a significant effect on human health and nutrition in both ancient and modern times. The pharmacological effects of Rubus include anti-inflammatory, antibacterial, anti-stress, anti-cancer and anti-aging properties. One of the current challenges limiting further development of Rubus resources in traditional Chinese medicine is a poor understanding of phylogenetic relationships among Rubus species in general and especially among Asian species, and also the need for additional studies of phytochemicals. Several confounding factors are …

Gata-Family Transcription Factors In Magnaporthe Oryzae, Cristian F. Quispe

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The filamentous fungus, Magnaporthe oryzae, responsible for blast rice disease, destroys around 10-30% of the rice crop annually. Infection begins when the specialized infection structure, the appressorium, generates enormous internal turgor pressure through the accumulation of glycerol. This turgor acts on a penetration peg emerging at the base of the cell, causing it to breach the leaf surface allowing its infection.

The enzyme trehalose-6- phosphate synthase (Tps1) is a central regulator of the transition from appressorium development to infectious hyphal growth. In the first chapter we show that initiation of rice blast disease requires a regulatory mechanism involving an …

Documenting Effects Of Urbanization On Flora Using Herbarium Records, Rebecca W. Dolan, Marcia E. Moore, Jessica Stephens

Scholarship and Professional Work - LAS

1. As human populations increasingly live in cities, urban floras and the ecosystem services they provide are under increasing threat. Understanding the effects of urbanization on plants can help to predict future changes and identify ways to preserve biological diversity. Relatively few studies document changes through time in the flora of a focal region and those that do primarily address European floras. They often rely on contemporary spatial gradient studies as surrogates for changes with time.

2. We compare historical species records (prior to 1940) with the current flora for Marion County, Indiana, USA, home to Indianapolis, the 13th largest city in …

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Oak Galls: A Strange Biology Indeed!, W. John Hayden

Biology Faculty Publications

Anyone who takes the time to look closely at several branches of oak will soon find one or another peculiar anomaly among the leaves and twigs. One can easily find structures resembling Ping-Pong balls, hard knots, fluffy tufts, horns—either single or clustered, or irregular thickenings, to mention just a few possibilities. These abnormal growths are galls, structures caused by the presence of small insect larvae living inside the tissue of the plant. Galls can be found on a wide variety of plants. They are common, for example, on the stems of goldenrods, and the leaves of maples, but oaks are …

Herbicide-Resistant Risk Assessment: Response Of Common Nebraska Weeds To Dicamba Dose, Roberto J. Crespo

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Dicamba-resistant soybeans are being developed to provide an additional herbicide mechanism of action that can be used in soybean, and to provide a tool to help manage or mitigate the evolution of other herbicide-resistant weed populations. The objectives of this thesis were to assess the risk of common Nebraska weeds developing resistance to dicamba, quantify baseline dose-response to dicamba of high-risk weed species, and survey the variability in dicamba dose-response among populations of those species. Twenty-five weed scientists were asked to estimate the risk likelihood of ten weed species evolving resistance to dicamba following the commercialization of dicamba-resistant soybean. Palmer …

Sphingolipids Containing Very-Long-Chain Fatty Acids Define A Secretory Pathway For Specific Polar Plasma Membrane Protein Targeting In Arabidopsis, Jennifer E. Markham, Diana Molino, Lionel Gissot, Yannick Bellec, Kian Hématy, Jessica Marion, Katia Belcram, Jean-Christophe Palauqui, Béatrice Satiat-Jeunemaître, Jean-Denis Faure

Department of Biochemistry: Faculty Publications

Sphingolipids are a class of structural membrane lipids involved in membrane trafficking and cell polarity. Functional analysis of the ceramide synthase family in Arabidopsis thaliana demonstrates the existence of two activities selective for the length of the acyl chains. Very-long-acyl-chain (C > 18 carbons) but not long-chain sphingolipids are essential for plant development. Reduction of very-long-chain fatty acid sphingolipid levels leads in particular to auxin-dependent inhibition of lateral root emergence that is associated with selective aggregation of the plasma membrane auxin carriers AUX1 and PIN1 in the cytosol. Defective targeting of polar auxin carriers is characterized by specific aggregation of Rab-A2a– …

Generation Of Transgenic Medicago Sativa Overexpressing "Osmotin-Chitinase" Gene Chimera, Jahnavi Reddy Kancharla

Masters Theses & Specialist Projects

Medicago is widely used as a forage crop. It is often susceptible to various pathogenic infections and exhibits low growth in drought and extreme climatic conditions. In the current study, a strategy was developed for over-expressing an “Osmotin-Chitinase” gene chimera in transgenic Medicago that could potentially confer resistance to different biotic and abiotic stresses. Seed germination of several cultivars of Medicago (M. sativa ssp. sativa, M. sativa ssp. falcata, M. sativa ssp. caerulea, M. truncatula, and M. Rugosa) was tested to determine the cultivars with good germination rates. Among these, M. sativa ssp. sativa showed an …

Screening Synteny Blocks In Pairwise Genome Comparisons Through Integer Programming, Haibao Tang, Eric Lyons, Brent S. Pedersen, James C. Schnable, Andrew H. Paterson, Michael Freeling

Department of Agronomy and Horticulture: Faculty Publications

Background:

It is difficult to accurately interpret chromosomal correspondences such as true orthology and paralogy due to significant divergence of genomes from a common ancestor. Analyses are particularly problematic among lineages that have repeatedly experienced whole genome duplication (WGD) events. To compare multiple “subgenomes” derived from genome duplications, we need to relax the traditional requirements of “one-to-one” syntenic matchings of genomic regions in order to reflect “one-to-many” or more generally “many-to-many” matchings. However this relaxation may result in the identification of synteny blocks that are derived from ancient shared WGDs that are not of interest. For many downstream analyses, we …

A First Insight Into Population Structure And Linkage Disequilibrium In The U.S. Peanut Minicore Collection, Vikas Belamkar, Michael Gomez Selvaraj, Jamie L. Ayers, Paxton R. Payton, Naveen Puppala, Mark D. Burow

Department of Agronomy and Horticulture: Faculty Publications

Knowledge of genetic diversity, population structure, and degree of linkage disequilibrium (LD) in target association mapping populations is of great importance and is a prerequisite for LD-based mapping. In the present study, 96 genotypes comprising 92 accessions of the US peanut minicore collection, a component line of the tetraploid variety Florunner, diploid progenitors A. duranensis (AA) and A. ipaënsis (BB), and synthetic amphidiploid accession TxAG-6 were investigated with 392 simple sequence repeat (SSR) marker bands amplified using 32 highly-polymorphic SSR primer pairs. Both distance- and model-based (Bayesian) cluster analysis revealed the presence of structured diversity. In general, the wild-species accessions …

Genes Identified By Visible Mutant Phenotypes Show Increased Bias Toward One Of Two Subgenomes Of Maize, James C. Schnable, Michael Freeling

Department of Agronomy and Horticulture: Faculty Publications

Not all genes are created equal. Despite being supported by sequence conservation and expression data, knockout homozygotes of many genes show no visible effects, at least under laboratory conditions. We have identified a set of maize (Zea mays L.) genes which have been the subject of a disproportionate share of publications recorded at MaizeGDB. We manually anchored these ‘‘classical’’ maize genes to gene models in the B73 reference genome, and identified syntenic orthologs in other grass genomes. In addition to proofing the most recent version 2 maize gene models, we show that a subset of these genes, those that …

Dose–Sensitivity, Conserved Non-Coding Sequences, And Duplicate Gene Retention Through Multiple Tetraploidies In The Grasses, James C. Schnable, Brent S. Pedersen, Sabarinath Subramaniam, Michael Freeling

Department of Agronomy and Horticulture: Faculty Publications

Whole genome duplications, or tetraploidies, are an important source of increased gene content. Following whole genome duplication, duplicate copies of many genes are lost from the genome. This loss of genes is biased both in the classes of genes deleted and the subgenome from which they are lost. Many or all classes are genes preferentially retained as duplicate copies are engaged in dose sensitive protein–protein interactions, such that deletion of any one duplicate upsets the status quo of subunit concentrations, and presumably lowers fitness as a result. Transcription factors are also preferentially retained following every whole genome duplications studied. This …

Sphingolipids In The Root Play An Important Role In Regulating The Leaf Ionome In Arabidopsis Thaliana, Dai-Yin Chao, Kenneth Gable, Ming Chen, Ivan Baxter, Charles R. Dietrich, Edgar B. Cahoon, Mary Lou Guerinot, Brett Lahner, Shiyu Lu, Jennifer E. Markham, Joe Morrissey, Gongshe Han, Sita Gupta, Jeffrey M. Harmon, Jan G. Jaworski, Teresa M. Dunn, David E. Salt

Department of Biochemistry: Faculty Publications

Sphingolipid synthesis is initiated by condensation of Ser with palmitoyl-CoA producing 3-ketodihydrosphinganine (3-KDS), which is reduced by a 3-KDS reductase to dihydrosphinganine. Ser palmitoyltransferase is essential for plant viability. Arabidopsis thaliana contains two genes (At3g06060/TSC10A and At5g19200/TSC10B) encoding proteins with significant similarity to the yeast 3-KDS reductase, Tsc10p. Heterologous expression in yeast of either Arabidopsis gene restored 3-KDS reductase activity to the yeast tsc10D mutant, confirming both as bona fide 3-KDS reductase genes. Consistent with sphingolipids having essential functions in plants, double mutant progeny lacking both genes were not recovered from crosses of single tsc10A and tsc10B …

Hybrid Oaks: Full Of Vexation And Wonder, W. John Hayden

Biology Faculty Publications

Distinguishing different species of oak in the forests of eastern North America can be challenging. For one thing, there are simply a lot of different species to sort out. A recent reference (Stein et al. 2003), describes 50 species in the genus Quercusoccurring naturally east of the 100th meridian, and 90 species are distinguished for all of North America north of Mexico (Nixon 1997). With so many species to parse, confident identification requires careful study of leaves, stem and leaf hairiness, and fully mature acorns with their caps. But care is not always enough, because in addition to the …

Crop Updates 2011 - Nutrition, Precision Agriculture & Climate And Forecasting, Deb Archdeacon, Andrew Gulliver, David Cullen, Qifu Ma, Richard Bell, Ross Brennan, Craig Scanlan, Wen Chen, Geoff Anderson, Mike Bolland, Peter Rees, Sandy Alexander, Frank D'Emden, Stephen Davies, Breanne Best, Louise Barton, Klaus Butterbach-Bahl, Ralph Kiese, Daniel Murphy, Peter Newman, Roger Mandel, Roger Lawes, Michael Robertson, Derk Bakker, Jeremy Lemon, Alison Lacey, John Paul Collins, Glen Riethmuller, Fiona H. Evans, David Stephens, Caroline Peek, Tim Scanlon

Crop Updates

This session covers sixteen papers from different authors:

Nutrition

1. Balance® used in conventional cropping practice with half of the upfront fertiliser rate can sustain crop yield and build soil biological fertility, Deb Archdeacon1, Andrew Gulliver2 and David Cullen2, 1Agronomica, Wellington Mill, WA, 2Custom Composts, Nambeelup, WA

2. Effects of potassium (K) supply on plant growth, potassium uptake and grain Yield in wheat grown in grey sand, Qifu Ma1, Richard Bell1, Ross Brennan2 and Craig Scanlan2, 1School of Environmental Science, Murdoch University, 2Department of Agriculture and Food

3. Improving fertiliser management: redefining the …

Crop Updates 2011 - Cereals, David Bowran, Bill Crabtree, Peter Carberry, Peter Burges, Bevan Buirchell, Ben Curtis, Sarah Ellis, Brenda Shackley, Christine Zaicou, Siva Sivapalan, Penny Goldsmith, Gae Plunkett, Darshan Sharma, Mario D'Antuono, Art Diggle, Peter Mangano, Sally Peltzer, Michael Renton, Bill Macleod, Fumie Horiuchi, George Wyatt, Geoff Anderson, Richard Bell, Ross Brennan, Wen Chen, Penny Riffkin

Crop Updates

This session covers eleven papers from different authors:

OPENING, NEW CROP VARIETIES & DECISION SUPPORT

Opening

1. Overview of the 2010 season, David Bowran, Director, Practice and Systems Innovation, Department of Agriculture and Food,

2. My experience in a drought as a farmer and consultant, Bill Crabtree, Morawa, Western Australia

3. Meeting the productivity and sustainability challenges to Australian agriculture until 2030, Peter Carberry, CSIRO Sustainable Agriculture Flagship

New Crop Varieties

4. National Variety Trials (NTV) wheat variety performance – captivity vs broadacre, Peter Burgess, Kalyx Agriculture

5. WALAN2289 – a new lupin variety to replace …

Crop Updates 2011 - Farming Systems, Janette Drew, Rob Grima, Bob French, Raj Malik, Mark Seymour, Christine Zaicou-Kunesch, Glenn Mcdonald, Brendon Nicholas, Dennis Van Gool, James Fisher, Peter Tozer, Doug Abrecht, Michael Robertson, Cameron Weeks, Michael O'Conner, Peter Newman, Mike Clarke, Andrew Blake, Gordon Macaulay, Vijay Jayasena, Syed M. Nasar-Abbas, Larisa Cato, Robert Loughman, Ken Quail

Crop Updates

This session covers twelve papers from different authors:

1. Fallowing 50% of the farm each year – does it pay? Janette Drew and Rob Grima

Department of Agriculture and Food

2. How crop sequences affect the productivity and resilience of cropping systems in two Western Australian environments, Bob French, Raj Malik, Mark Seymour, Department of Agriculture and Food

3. When is continuous wheat or barley sustainable? Christine Zaicou-Kunesch and Rob Grima Department of Agriculture and Food

4. Identifying constraints to bridging the yield gap, Glenn McDonald, Department of Agriculture and Food

5. Land constraints limiting wheat yields in …

The N-Terminal Region Of Wheat Streak Mosaic Virus Coat Protein Is A Host- And Strain-Specific Long-Distance Transport Factor, Satyanarayana Tatineni, David H. Van Winkle, Roy French

Department of Plant Pathology: Faculty Publications

Understanding the genetics underlying host range differences among plant virus strains can provide valuable insights into viral gene functions and virus-host interactions. In this study, we examined viral determinants and mechanisms of differential infection of Zea mays inbred line SDp2 by Wheat streak mosaic virus (WSMV) isolates. WSMV isolates Sidney 81 (WSMV-S81) and Type (WSMV-T) share 98.7% polyprotein sequence identity but differentially infect SDp2: WSMV-S81 induces a systemic infection, but WSMV-T does not. Coinoculation and sequential inoculation of SDp2 with WSMV-T and/or WSMV-S81 did not affect systemic infection by WSMV-S81, suggesting that WSMV-T does not induce a restrictive defense response …

Delivery Of Prolamins To The Protein Storage Vacuole In Maize Aleurone Cells, Francisca C. Reyes, Taijoon Chung, David Holding, Rudolf Jung, Richard Vierstra, Marisa S. Otegui

Center for Plant Science Innovation: Faculty and Staff Publications

Zeins, the prolamin storage proteins found in maize (Zea mays), accumulate in accretions called protein bodies inside the endoplasmic reticulum (ER) of starchy endosperm cells. We found that genes encoding zeins, a-globulin, and legumin-1 are transcribed not only in the starchy endosperm but also in aleurone cells. Unlike the starchy endosperm, aleurone cells accumulate these storage proteins inside protein storage vacuoles (PSVs) instead of the ER. Aleurone PSVs contain zeinrich protein inclusions, a matrix, and a large system of intravacuolar membranes. After being assembled in the ER, zeins are delivered to the aleurone PSVs in atypical prevacuolar compartments …

Plant Targets For Pseudomonas Syringae Type Iii Effectors: Virulence Targets Or Guarded Decoys?, Anna Block, James R. Alfano

Center for Plant Science Innovation: Faculty and Staff Publications

The phytopathogenic bacterium Pseudomonas syringae can suppress both pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) by the injection of type III effector (T3E) proteins into host cells. T3Es achieve immune suppression using a variety of strategies including interference with immune receptor signaling, blocking RNA pathways and vesicle trafficking, and altering organelle function. T3Es can be recognized directly or indirectly by resistance proteins monitoring specific T3E targets resulting in ETI. It is presently unclear whether the monitored targets represent bona fide virulence targets or guarded decoys. Extensive overlap between PTI and ETI signaling suggests that T3Es may suppress …

Systematics And Biogeography Of The Clusioid Clade (Malpighiales), Brad R. Ruhfel

Biological Sciences Faculty and Staff Research

The clusioids are a clade of flowering plants in the diverse rosid order Malpighiales. It includes five families (i.e., Bonnetiaceae, Calophyllaceae, Clusiaceae sensu stricto, Hypericaceae, and Podostemaceae) that form a conspicuous element of tropical forests worldwide and are economically important. Their phylogenetic and biogeographical history has remained uncertain, however, which has hindered our understanding of their evolution. I conducted the first taxon-rich multigene analysis of this important clade to clarify their phylogenetic relationships (Chapter 1). Plastid (cp:matK, ndhF, and rbcL) and mitochondrial (mt: matR) nucleotide sequence data from nearly 200 taxa produced a well-resolved clusioid phylogeny and indicate that several …