Plant Breeding and Genetics Commons^™

Osmotic Stress Induces Phosphorylation Of Histone H3 At Threonine 3 In Pericentromeric Regions Of Arabidopsis Thaliana, Zhen Wang, Juan Casas-Mollano, Jianping Xu, Jean-Jack Riethoven, Chi Zhang, Heriberto D. Cerutti

Center for Plant Science Innovation: Faculty Publications

Histone phosphorylation plays key roles in stress-induced transcriptional reprogramming in metazoans but its function(s) in land plants has remained relatively unexplored. Here we report that an Arabidopsis mutant defective in At3g03940 and At5g18190, encoding closely related Ser/Thr protein kinases, shows pleiotropic phenotypes including dwarfism and hypersensitivity to osmotic/salt stress. The double mutant has reduced global levels of phosphorylated histone H3 threonine 3 (H3T3ph), which are not enhanced, unlike the response in the wild type, by drought-like treatments. Genome-wide analyses revealed increased H3T3ph, slight enhancement in trimethylated histone H3 lysine 4 (H3K4me3), and a modest decrease in histone H3 occupancy …

Biochemical And Proteomic Profiling Of Maize Endosperm Texture And Protein Quality, Kyla J. Morton

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

The research described herein, focuses on the biochemical and proteomic analysis of the maize endosperm and what influences kernel texture. Quality Protein Maize (QPM) is a hard endosperm version of the high-lysine opaque2 (o2) mutant but the genes involved in modifying the soft o2 endosperm are unknown. Pyrophosphate (PPi)-dependent fructose 6-phosphate 1-phosphotransferase (PFP) catalyzes the ATP-independent conversion of fructose 6-phosphate to fructose 1, 6-bisphosphate in glycolysis. We found a large increase in transcript and protein levels of the alpha regulatory subunit of PFP (PFPα) in QPM endosperm. In vitro enzyme assays show a significant increase in forward PFP …

Association Mapping For Elemental Concentration Resulting From Vegetative Stage Soil Waterlogging Stress In Wheat (Triticum Aestivum L.), Maria Nelly Arguello-Blanco

Graduate Theses and Dissertations

Soil waterlogging (WL) affects wheat production worldwide, including the southern of the U.S. Little is known about the genetics of tolerance mechanisms to WL, particularly of potentially toxic elements such as aluminum, iron and sodium. The objectives of this study were to use association mapping (AM) to identify SNP associated with the EC in the vegetative tissue of a set of 240 diverse soft winter wheat genotypes (AM panel) grown under field WL and to determine the impact of WL on wheat yield (GY) and yield components in a set 28 adapted cultivars (YT)

YT study showed reductions in GY …

Physiological Responses Of Cotton Genotypes To Water-Deficit Stress During Reproductive Development, Cristiane Pilon

Graduate Theses and Dissertations

Drought stress is one of the major abiotic factors affecting crop growth and limiting production worldwide. Cotton genotypes vary in drought tolerance, and the effects of drought stress on the anatomy and physiology of cotton leaves and roots have been reported. However, information on physiological and metabolic processes of leaves and flowers of modern cotton cultivars under water-deficit stress during reproductive development is not well elucidated. It was hypothesized that water-deficit stress during squaring and flowering stages would impair stomatal conductance and photosynthetic efficiency of leaves, which consequently would result in osmotic adjustment through accumulation of compatible solutes, increased activity …

Alternative Restoration Treatments To Maximize Growth And Survival Of Tamaulipan Thornscrub Species During Seeding Establishment, Jennifer Lynn Vela

Theses and Dissertations - UTB/UTPA

Anthropogenic activities that destroy, degrade, or fragment terrestrial ecosystems have long-lasting detrimental impacts on ecosystem function, services, and biodiversity. The Tamaulipan thornscrub ecoregion of south Texas and northeastern Mexico has sustained considerable loss, degradation, and fragmentation due land conversion for agriculture, urbanization, and introduction of invasive flora and fauna. In an attempt to restore habitat for endangered and migratory animals, United States Fish and Wildlife Service has undertaken a large-scale thornscrub revegetation effort in south Texas. The goal of this study was to develop effective restoration techniques to promote growth and survival of Tamaulipan thornscrub species during seedling establishment. Beginning …

Combinatorial Effects Of Fatty Acid Elongase Enzymes On Nervonic Acid Production In Camelina Sativa, Dongxin Huai, Yuanyuan Zhang, Chunyu Zhang, Edgar B. Cahoon, Yongming Zhou

Center for Plant Science Innovation: Faculty Publications

Very long chain fatty acids (VLCFAs) with chain lengths of 20 carbons and longer provide feedstocks for various applications; therefore, improvement of VLCFA contents in seeds has become an important goal for oilseed enhancement. VLCFA biosynthesis is controlled by a multi-enzyme protein complex referred to as fatty acid elongase, which is composed of β-ketoacyl-CoA synthase (KCS), β-ketoacyl-CoA reductase (KCR), β-hydroxyacyl-CoA dehydratase (HCD) and enoyl reductase (ECR). KCS has been identified as the ratelimiting enzyme, but little is known about the involvement of other three enzymes in VLCFA production. Here, the combinatorial effects of fatty acid elongase enzymes on VLCFA production …

Genetic Diversity Of Miscanthus In The Us Naturalized Populations Based On Molecular Marker, Suma Basak

College of Agriculture, Environment and Nutrition Sciences Graduate Theses and Dissertations

ABSTRACT

Miscanthus is a fast growing bioenergy grass, tolerant of adverse conditions and has high biomass production, and is increasingly attractive as a potential source of cellulosic ethanol. An understanding of genetic variation in naturalized populations of Miscanthus in the US may help in selecting appropriate parents for breeding superior cultivars that are adapted in the wide-ranging and changing environments. The molecular marker analysis of Miscanthus is an important tool towards the genetic improvement program of this bioenergy grass. As sugarcane is closely related to Miscanthus, we employed its DNA markers as probes to explore genetic diversity within and among …

Anaerobic Detoxification Of Acetic Acid In A Thermophilic Ethanologen, A Joe Shaw, Bethany B. Miller, Stephen R. Rogers, William Robert Kenealy, Alex Meola, Ashwini Bhandiwad, W Ryan Sillers, Indraneel Shikhare, David Hogsett, Christopher Herring

Dartmouth Scholarship

The liberation of acetate from hemicellulose negatively impacts fermentations of cellulosic biomass, limiting the concentrations of substrate that can be effectively processed. Solvent-producing bacteria have the capacity to convert acetate to the less toxic product acetone, but to the best of our knowledge, this trait has not been transferred to an organism that produces ethanol at high yield. We have engineered a five-step metabolic pathway to convert acetic acid to acetone in the thermophilic anaerobe Thermoanaerobacterium saccharolyticum.

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Genetic Mapping Of Yield And Normalized Difference Vegetative Index In Soft Red Winter Wheat (Triticum Aestivum L.), Christopher Keith Addison

Graduate Theses and Dissertations

Wheat is the most widely cultivated cereal crop, being grown on 17% of the global crop land and as such must be adapted to an array of environmental stresses. In order to become a variety, wheat breeding lines must be tested across a range of environments for both high productivity and stability. Quantitative trait loci (QTL) mapping and indices are tools that can aid plant breeders in the selection of superior lines. Soft red winter wheat accounts for 20% of the total wheat production in the United States, being grown in the southeastern U.S. predominantly along the Mississippi River. However, …

Heritabilitas, Variabilitas Dan Analisis Kekerabatan Genetik Pada 15 Genotip Pisang (Musa Paradisiaca) Varietas Ambon Asal Jawa Barat Berdasarkan Karakter Morfologi Di Jatinangor, Ade Ismail, Noladhi Wicaksana, Z. Daulati

Jurnal Kultivasi

Heritabilitas, variabilitas, dan kekerabatan dari suatu populasi sangat penting dalam pera-kitan kultivar unggul pisang. Parameter genetik tersebut merupakan langkah awal dalam suatu kegiatan seleksi pada populasi pisang ambon ini. Tujuan dari penelitian ini adalah mengestimasi nilai hertitabilitas, variabilitas, dan hubungan kekerabatan 15 genotip pisang ambon. Adapun metode penelitian yang digunakan merupakan metode eksperimen dengan tata ruang Rancangan Acak Kelompok (RAK) dengan ulangan dua kali. Penelitian ini dilakukan di Kebun Percobaan Ciparanje, Unpad Jatinangor, dengan ketinggian 753 m di atas permukaan laut (dpl). Waktu penelitian dilaksanakan pada bulan Mei 2013 sampai dengan bulan Februari 2014. Hasil penelitian menunjukkan bahwa nilai heritabilitas …

Sumoylation By A Stress-Specific Small Ubiquitin-Like Modifier E2 Conjugase Is Essential For Survival Of Chlamydomonas Reinhardtii Under Stress Conditions, Amy R. Knobbe, Kempton M. Horken, Thomas M. Plucinak, Eniko Balassa, Heriberto Cerutti, Donald P. Weeks

Center for Plant Science Innovation: Faculty Publications

Posttranslational modification of proteins by small ubiquitin-like modifier (SUMO) is required for survival of virtually all eukaryotic organisms. Attachment of SUMO to target proteins is catalyzed by SUMO E2 conjugase. All haploid or diploid eukaryotes studied to date possess a single indispensable SUMO conjugase. We report here the unanticipated isolation of a Chlamydomonas reinhardtii (mutant5 [mut5]), in which the previously identified SUMO conjugase gene C. reinhardtii ubiquitin-conjugating enzyme9 (CrUBC9) is deleted. This surprising mutant is viable and unexpectedly displays a pattern of protein SUMOylation at 25°C that is essentially identical to wild-type cells. However, unlike wild-type …

Toward Production Of Jet Fuel Functionality In Oilseeds: Identification Of Fatb Acyl-Acyl Carrier Protein Thioesterases And Evaluation Of Combinatorial Expression Strategies In Camelina Seeds, Hae Jin Kim, Jillian E. Silva, Hieu Sy Vu, Keithanne Mockaitis, Jeong-Won Nam, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty Publications

Seeds of members of the genus Cuphea accumulate medium-chain fatty acids (MCFAs; 8:0–14:0). MCFA- and palmitic acid- (16:0) rich vegetable oils have received attention for jet fuel production, given their similarity in chain length to Jet A fuel hydrocarbons. Studies were conducted to test genes, including those from Cuphea, for their ability to confer jet fuel-type fatty acid accumulation in seed oil of the emerging biofuel crop Camelina sativa. Transcriptomes from Cuphea viscosissima and Cuphea pulcherrima developing seeds that accumulate >90% of C8 and C10 fatty acids revealed three FatB cDNAs (CpuFatB3, CvFatB1, and CpuFatB4 …

Fungal Morphogenesis, Xiaorong Lin, J. Andrew Alspaugh, Haoping Liu, Steven D. Harris

Center for Plant Science Innovation: Faculty Publications

Morphogenesis in fungi is often induced by extracellular factors and executed by fungal genetic factors. Cell surface changes and alterations of the microenvironment often accompany morphogenetic changes in fungi. In this review, we will first discuss the general traits of yeast and hyphal morphotypes and how morphogenesis affects development and adaptation by fungi to their native niches, including host niches. Then we will focus on the molecular machinery responsible for the two most fundamental growth forms, yeast and hyphae. Last, we will describe how fungi incorporate exogenous environmental and host signals together with genetic factors to determine their morphotype and …

Gene Silencing In Microalgae: Mechanisms And Biological Roles, Eun-Jeong Kim, Xinrong Ma, Heriberto Cerutti

Center for Plant Science Innovation: Faculty Publications

Microalgae exhibit enormous diversity and can potentially contribute to the production of biofuels and high value compounds. However, for most species, our knowledge of their physiology, metabolism, and gene regulation is fairly limited. In eukaryotes, gene silencing mechanisms play important roles in both the reversible repression of genes that are required only in certain contexts and the suppression of genome invaders such at transposons. The recent sequencing of several algal genomes is providing insights into the complexity of these mechanisms in microalgae. Collectively, glaucophyte, red, and green microalgae contain the machineries involved in repressive histone H3 lysine methylation, DNA cytosine …

Sirna-Directed Dna Methylation In Plants, Meng Xie, Bin Yu

Center for Plant Science Innovation: Faculty Publications

DNA cytosine methylationis an important epigenetic process that is correlated with transgene silencing, transposon suppression, and gene imprinting. In plants, small interfering RNAs (siRNAs) can trigger DNA methylation at loci containing their homolog sequences through a process called RNAdirected DNA methylation (RdDM). In canonical RdDM, 24 nucleotide (nt) siRNAs (ra-siRNAs) will be loaded into their effector protein called ARGONAUTE 4 (AGO4) and subsequently targeted to RdDM loci through base-pairing with the non-coding transcripts produced by DNA-directed RNA Polymerase V. Then, the AGO4-ra-siRNA will recruit the DNA methyltransferase to catalyze de novo DNA methylation. Recent studies also identified non-canonical RdDM pathways …

The Role Of Ethylene In Plant Responses To K+ Deficiency, Daniel P. Schachtman

Center for Plant Science Innovation: Faculty Publications

Potassium is an essential macronutrient that is involved in regulating turgor , in driving plant growth, and in modulating enzyme activation. The changes in root morphology, root function, as well as cellular and molecular responses to low potassium conditions have been studied in the model plant Arabidopsis and in other plant species. In Arabidopsis ethylene plays a key role in roots in the transduction of the low potassium signal, which results in altered root function and growth. The first clues regarding the role of ethylene were detected through transcriptional profiling experiments showing changes in the expression of genes related to …

Redirection Of Metabolic Flux For High Levels Of Omega-7 Monounsaturated Fatty Acid Accumulation In Camelina Seeds, Huu Tam Nguyen, Hyunwoo Park, Karen L. Koster, Rebecca E. Cahoon, Hanh Nguyen, John Shanklin, Thomas E. Clemente, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty Publications

Seed oils enriched in omega-7 monounsaturated fatty acids, including palmitoleic acid (16:1Δ9) and cis-vaccenic acid (18:1Δ11), have nutraceutical and industrial value for polyethylene production and biofuels. Existing oilseed crops accumulate only small amounts (<2%) of these novel fatty acids in their seed oils. We demonstrate a strategy for enhanced production of omega-7 monounsaturated fatty acids in camelina (Camelina sativa) and soybean (Glycine max) that is dependent on redirection of metabolic flux from the typical Δ9 desaturation of stearoyl (18:0)-acyl carrier protein (ACP) to Δ9 desaturation of palmitoyl (16:0)-acyl carrier protein (ACP) and coenzyme A (CoA). This was achieved by seed-specific co-expression of a mutant Δ9-acyl-ACP and an acyl-CoA desaturase with high specificity for 16:0-ACP and CoA substrates, respectively. This strategy was most effective in camelina where seed oils with ~17% omega-7 monounsaturated fatty acids were obtained.

Further increases in omega-7 fatty acid accumulation to 60–65% of the total fatty acids in camelina seeds were achieved by inclusion of seed-specific suppression of 3-keto-acyl-ACP synthase II and the FatB 16:0-ACP thioesterase genes to increase substrate pool sizes of 16:0-ACP for the Δ9-acyl-ACP desaturase and by blocking C18 fatty acid elongation. Seeds from these lines also had total saturated fatty acids reduced to ~5% of …

Production Of High Levels Of Poly-3-Hydroxybutyrate In Plastids Of Camelina Sativa Seeds, Meghna R. Malik, Wenyu Tang, Nii Patterson, Jihong Tang, Rachel L. Wellinghoff, Mary L. Preuss, Claire Burkitt, Nirmala Sharma, Yuanyuan Ji, Joseph M. Jez, Oliver P. Peoples, Jan G. Jaworski, Edgar B. Cahoon, Kristi D. Snell

Center for Plant Science Innovation: Faculty Publications

Poly-3-hydroxybutyrate (PHB) production in plastids of Camelina sativa seeds was investigated by comparing levels of polymer produced upon transformation of plants with five different binary vectors containing combinations of five seed-specific promoters for expression of transgenes. Genes encoding PHB biosynthetic enzymes were modified at the N-terminus to encode a plastid targeting signal. PHB levels of up to 15% of the mature seed weight were measured in single sacrificed T1 seeds with a genetic construct containing the oleosin and glycinin promoters.

A more detailed analysis of the PHB production potential of two of the best performing binary vectors in a Camelina …

Toward Production Of Jet Fuel Functionality In Oilseeds: Identification Of Fatb Acyl-Acyl Carrier Protein Thioesterases And Evaluation Of Combinatorial Expression Strategies In Camelina Seeds, Hae Jin Kim, Jillian E. Silva, Hieu Sy Vu, Keithanne Mockaitis, Jeong-Won Nam, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty Publications

Seeds of members of the genus Cuphea accumulate medium-chain fatty acids (MCFAs; 8:0–14:0). MCFA- and palmitic acid- (16:0) rich vegetable oils have received attention for jet fuel production, given their similarity in chain length to Jet A fuel hydrocarbons. Studies were conducted to test genes, including those from Cuphea, for their ability to confer jet fuel-type fatty acid accumulation in seed oil of the emerging biofuel crop Camelina sativa. Transcriptomes from Cuphea viscosissima and Cuphea pulcherrima developing seeds that accumulate >90% of C8 and C10 fatty acids revealed three FatB cDNAs (CpuFatB3, CvFatB1, and CpuFatB4) …

Microrna Biogenesis, Degradation And Activity In Plants, Meng Xie, Shuxin Zhang, Bin Yu

Center for Plant Science Innovation: Faculty Publications

microRNAs (miRNAs) are important regulators of gene expression. After excised from primary miRNA transcript by dicer-like1 (DCL1, an RNAse III enzyme), miRNAs bind and guide their effector protein named argonaute 1 (AGO1) to silence the expression of target RNAs containing their complementary sequences in plants. miRNA levels and activities are tightly controlled to ensure their functions in various biological processes such as development, metabolism and responses to abiotic and biotic stresses. Studies have identified many factors that involve in miRNA accumulation and activities. Characterization of these factors in turn greatly improves our understanding of the processes related to miRNAs. Here, …