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Plant Sciences

Theses/Dissertations

2018

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Articles 1 - 19 of 19

Full-Text Articles in Genetics and Genomics

Investigating The Role Of Brachypodium Distachyon Cellulose Synthase 8 In Gluconacetobacter Diazotrophicus Colonization, Xuan Yang Dec 2018

Investigating The Role Of Brachypodium Distachyon Cellulose Synthase 8 In Gluconacetobacter Diazotrophicus Colonization, Xuan Yang

Electronic Thesis and Dissertation Repository

Nitrogen is an essential nutrient for plant growth. Significant amount of nitrogen fertilizer is applied to crop field to maintain high yield. Alternatives to chemical nitrogen fertilizer are needed to reduce the costs of crop production and offset environmental damage. Gluconacetobacter diazotrophicus is a nitrogen fixing bacterium that was originally isolated from sugarcane and has been proposed as a possible biofertilizer for monocot crop production. However, the colonization of G. diazotrophicus in most monocot crops is limited and deep understanding of the response of the host plants to G. diazotrophicus colonization is still lacking. In this study, research was conducted …


Sip-428, A Sir2 Deacetylase Enzyme And Its Role In Biotic Stress Signaling Pathway, Bal Krishna Chand Thakuri Dec 2018

Sip-428, A Sir2 Deacetylase Enzyme And Its Role In Biotic Stress Signaling Pathway, Bal Krishna Chand Thakuri

Electronic Theses and Dissertations

SABP2 (Salicylic Acid Binding Protein 2) plays a vital role in the salicylic acid signaling pathway of plants both regarding basal resistance and systemic acquired resistance against pathogen infection. SIP-428 (SABP2 Interacting Protein-428) is a Silent information regulator 2 (SIR2) like deacetylase enzyme that physically interacts with SABP2 in a yeast two-hybrid interaction and confirmed independently by a GST pull-down assay. We demonstrated that SIP- 428 is an NAD+ dependent SIR2 deacetylase enzyme. Transgenic tobacco plants silenced in SIP- 428 expression via RNAi showed enhanced basal resistance to microbial pathogens. Moreover, these SIP-428-silenced lines also exhibited a robust induction of …


A Plant Pathology View Of Signaling: A Computational Study Of Fusarium Oxysporum Kinomes And Downy Mildew Resistance In Sweet Basil, Gregory Deiulio Nov 2018

A Plant Pathology View Of Signaling: A Computational Study Of Fusarium Oxysporum Kinomes And Downy Mildew Resistance In Sweet Basil, Gregory Deiulio

Doctoral Dissertations

This dissertation is composed of two projects that focus on pathogen and plant signaling within the framework of plant pathology. The first project targets protein kinases within the species complex Fusarium oxysporum based on genomic information and tracks their presence/absence and copy number variation across evolutionary time. We have predicted the kinomes of 19 Ascomycete fungi using the kinase annotating software Kinannote. Among Fusaria, kinases related to the perception of the environment, such as Histidine kinases, are proliferated. Similarly, I observed the expansion of Target of Rapamycin (TOR) kinase that regulates cell growth and development in responding to environmental cues. …


Variation And Evolution Of Fruit Ripening Traits In Tomato Species, Ian M. Gillis Oct 2018

Variation And Evolution Of Fruit Ripening Traits In Tomato Species, Ian M. Gillis

Doctoral Dissertations

As angiosperm seeds mature within their ovaries, ovary tissue tends to grow and transform itself into fruit, which aids the success of the seeds. Fruits that are fleshy provide numerous ways to aid in the protection and the dispersal of seeds. First, they keep seeds hidden, encased in hard walls, surrounded by poisons and unpalatable compounds, and second, they undergo developmental changes that facilitate seeds’ release. Tomatoes, a model fleshy fruit, have all these protective traits, and over the course of ripening they become the familiar fruit that is a staple crop around the world. The wild relatives of cultivated …


Genome Wide Association Studies For Identification Of Markers Linked To Sucrose Traits In Sugarcane, Nathanael Darrell Fickett Oct 2018

Genome Wide Association Studies For Identification Of Markers Linked To Sucrose Traits In Sugarcane, Nathanael Darrell Fickett

LSU Doctoral Dissertations

Sugarcane, being a complex aneu-polyploid, poses unique challenges to fine mapping of quantitative trait loci (QTL) controlling agronomic traits of interest. Genome-wide association studies (GWAS) could be a better alternative to identify molecular markers associated with specific traits due to high linkage disequilibrium in sugarcane. In the first study, marker-trait associations (MTAs) were evaluated for three sucrose traits, Brix, total recoverable sugar (TRS), and percent sucrose on 48 elite and historic Louisiana breeding clones using 1,062 alleles. These sucrose traits were highly correlated (P-value < 0.0001) at >0.96. TASSEL 5.1 and JMP Genomics 8.0 were compared with eight models run in each program. …


Grapevine Vein Clearing Virus: Epidemiological Patterns And Construction Of A Clone, Cory Von Keith Aug 2018

Grapevine Vein Clearing Virus: Epidemiological Patterns And Construction Of A Clone, Cory Von Keith

MSU Graduate Theses

Grapevine vein clearing virus (GVCV) is a recently discovered virus belonging to the Badnavirus genus. Characteristic to its name, the virus is associated with a disease where symptoms manifest as pronounced vein-clearing, resulting in severe berry deformation and vine decline in susceptible grape varieties. Sustainable production of wine is dependent on healthy plants. The associated disease is mainly found in Midwest vineyards. Attempts were made in this thesis to provide evidence of causality of the virus to the associated disease and to infer the historical path and migration pattern of GVCV. Conclusions and discussions will provide grape producers with the …


Defective Aba-Mediated Sugar Signalling Pathway In An Established Arabidopsis Thaliana Cell Suspension Culture Explains Its Stay-Green Phenotype At High Sugar Concentrations, Avery Mccarthy Jun 2018

Defective Aba-Mediated Sugar Signalling Pathway In An Established Arabidopsis Thaliana Cell Suspension Culture Explains Its Stay-Green Phenotype At High Sugar Concentrations, Avery Mccarthy

Electronic Thesis and Dissertation Repository

An unusual sugar insensitive phenotype was identified in an established cell suspension culture of Arabidopsis thaliana. We characterized the physiology, biochemistry and genetics of the sugar insensitive cell culture, in order to identify factors contributing to the phenotype. Chlorophyll levels of the cell suspension culture were insensitive to high sucrose (6-15% w/v) and maintained a green phenotype. Immunoblotting indicated that levels of key photosynthetic proteins (PsaA, Lhcb2 and Rubisco) increased as a function of external sucrose concentration. The green cell culture was photosynthetically competent based on light-dependent, CO2-saturated rates of O2 evolution as well as Fv/Fm …


The Role Of Ferric Reduction Oxidases In Plant Anti-Herbivore Defense., Virginia C. Nunamaker May 2018

The Role Of Ferric Reduction Oxidases In Plant Anti-Herbivore Defense., Virginia C. Nunamaker

College of Arts & Sciences Senior Honors Theses

Iron is an essential element required for plants to carry out metabolic functions such as photosynthesis, heme biosynthesis, and chlorophyll biosynthesis. Within Arabidopsis thaliana, eight ferric reduction oxidase (FRO) genes function in iron uptake and homeostasis with tissue specific expression. However, little else is known regarding the biological role of FROs. Recent studies identify the FRO gene family as particularly responsive to the green leaf plant derived volatile (GLV) cis-3-hexenyl acetate (z3HAC). Since z3HAC acts as a wound signal and cues unaffected parts of the plant to prime defenses prior to herbivory, an increase in FRO activity in response …


A Contribution Toward A Global Monograph Of Gyroporus: Taxonomy, Phylogeny, Biogeography, Naveed Davoodian May 2018

A Contribution Toward A Global Monograph Of Gyroporus: Taxonomy, Phylogeny, Biogeography, Naveed Davoodian

Dissertations, Theses, and Capstone Projects

Gyroporus (Sclerodermatineae, Boletales, Agaricomycetes, Basidiomycota, Fungi) is a genus of ectomycorrhizal mushroom-forming fungi distributed throughout the world in suitable habitats. Previous attempts to untangle the diversity of this genus proved difficult due to the presence of semi-cryptic species and equivocal results from phylogenetic analysis of ribosomal RNA markers. To overcome these obstacles, a combined taxonomic and phylogenetic (emphasizing protein-coding genes) approach is used here to delimit species and elucidate geographic and evolutionary patterns of Gyroporus. Careful study of relevant literature and herbarium specimens was augmented by field work in North America, Australia, and East Asia for observation and collection …


The Determinants Of Nucleosome Patterns And The Impact Of Phosphate Starvation On Nucleosome Patterns And Gene Expression In Rice, Qi Zhang Mar 2018

The Determinants Of Nucleosome Patterns And The Impact Of Phosphate Starvation On Nucleosome Patterns And Gene Expression In Rice, Qi Zhang

LSU Doctoral Dissertations

In eukaryotic cells, DNA is a large molecule that must be greatly condensed to fit within the nucleus. DNA is wrapped around histone proteins to form nucleosomes, which facilitate DNA condensation, but on the other hand, may limit DNA processes. Organisms must respond to environmental stress in order to survive, and one strategy is by remodeling nucleosomes to promote changes in DNA accessibility to alter gene expression. Studies have demonstrated a clear correlation between nucleosome dynamics and transcriptional change in some eukaryotes, however factors that affect nucleosome positioning in plants are largely unknown, and the correlation between nucleosome dynamics and …


Characterization Of A Novel Vps26c-Retromer Complex And Its Interaction With An Endosomal Trafficking Pathway Regulated By The Snare Vti13 In Controlling Polarized Growth And Cell Wall Organization In Arabidopsis Thaliana, Suryatapa Ghosh Jha Jan 2018

Characterization Of A Novel Vps26c-Retromer Complex And Its Interaction With An Endosomal Trafficking Pathway Regulated By The Snare Vti13 In Controlling Polarized Growth And Cell Wall Organization In Arabidopsis Thaliana, Suryatapa Ghosh Jha

Graduate College Dissertations and Theses

The endosomal trafficking system is a network of highly coordinated cellular pathways that control the growth and function of cells. The coordination of secretion and endocytosis in cells is one of the primary drivers of polarized growth, where new plasma membrane and cell wall components are deposited at the growing apex. In plants, one of the cell types exhibiting polarized growth are the root hairs. Root hairs are regulated extensions of epidermal cells called trichoblasts and are essential for anchorage, absorption of water and nutrients, and plant-microbe interactions. In this thesis, I characterize a previously undescribed protein involved in retromer …


Bacterial Inoculants, Endophytic Bacteria And Their Influence On Nicotiana Physiology, Development And Microbiome, Andrea Marisa Sanchez Barrios Jan 2018

Bacterial Inoculants, Endophytic Bacteria And Their Influence On Nicotiana Physiology, Development And Microbiome, Andrea Marisa Sanchez Barrios

Theses and Dissertations--Plant and Soil Sciences

Soil and root microbial communities have been studied for decades, and the incorporation of high-throughput techniques and analysis has allowed the identification of endophytic/non-culturable organisms. This has helped characterize and establish the core microbiome of many model plant species which include underground and aboveground organs. Unfortunately, the information obtained from some of these model plants is not always transferable to other agronomic species. In this project, we decided to study the microbiome of the Nicotiana genus because of its importance in plant physiological and plant-microbe interactions studies. The data obtained was used as baseline information that allowed us to better …


Chemical Topping Burley Tobacco, Mitchell D. Richmond Jan 2018

Chemical Topping Burley Tobacco, Mitchell D. Richmond

Theses and Dissertations--Plant and Soil Sciences

The act of topping tobacco (Nicotiana tabacum L.) involves the removal of the terminal bud or inflorescence of the tobacco plant. This practice ordinarily is accomplished by manually removing the top of each tobacco plant in an entire field which is labor intensive and costly. Chemical topping utilizes sucker control products to inhibit the terminal bud and axillary bud growth without manually removing the top of the tobacco plant. There were several research objectives in order to determine the utility of a chemical topping system: 1) determine if burley tobacco could be chemically topped with currently registered suckercide products …


Quantifying Genetic Responses Of Plants To Drought Stress With A Comparative Transcriptome Approach, Jessica K. Devitt Jan 2018

Quantifying Genetic Responses Of Plants To Drought Stress With A Comparative Transcriptome Approach, Jessica K. Devitt

Electronic Theses and Dissertations

Mentzelia section Bartonia (Loasaceae) commonly occurs in some of the hottest and driest places in North America, but we poorly understand the mechanisms that allow them to tolerate such extreme environments. Morphological and physiological adaptations are well studied in model organisms. The underlying genetic responses to drought stress in non-model organisms like Mentzelia is unknown. To better understand and identify differences and similarities in genetic responses to drought stress between species existing in different habitats with differing water availability, three species from the genus Mentzelia were compared. Species of section Bartonia occur across an environmental gradient, from temperate to arid …


Investigating Phosphorylation Patterns And Their Effect On The Activity Of Transcription Factor Taabf1 In Imbibing Cereal Grains, Grace Uwase Jan 2018

Investigating Phosphorylation Patterns And Their Effect On The Activity Of Transcription Factor Taabf1 In Imbibing Cereal Grains, Grace Uwase

Honors Theses

The wheat transcription factor TaABF1 plays an important role in hormone-mediated regulation of seed dormancy and germination of cereal grains. Evidence shows that TaABF1 activity is regulated by phosphorylation, and previous work in our lab showed that when serine residues in its conserved regions; S36, S37, S113, S115 were altered to phosphomimetic aspartate, the 4xD TaABF1 mutant had increased activity as a transcription factor. However, when only S113 was altered, TaABF1’s activity was greatly reduced. The work presented here explored whether the S36D/S37D/S115D mutant would have stronger activity than the 4xD mutant. Using the particle bombardment technique to introduce the …


Floral Symmetry Genes Elucidate The Development And Evolution Of Oil-Bee Pollinated Flowers Of Malpighiaceae And Krameriaceae, Farahnoz N. Khojayori Jan 2018

Floral Symmetry Genes Elucidate The Development And Evolution Of Oil-Bee Pollinated Flowers Of Malpighiaceae And Krameriaceae, Farahnoz N. Khojayori

Theses and Dissertations

Specialization on insect and animal pollinators is thought to be the driving force for the evolution of floral traits. Specifically in the New World (NW), the oil-bee pollination syndrome has led to the convergence of floral characters in two distantly related families of core eudicots, Malpighiaceae and Krameriaceae. Both families display a flag-like structure that establishes a zygomorphic flower and floral oil rewards in epithelial elaiophores. These traits work concomitantly to attract and reward female oil-bees that help fertilize these flowers and in return receive oils. The underlying genetics of floral zygomorphy were studied in several clades of core eudicots, …


Quantitative And Molecular Analysis Of Habituation At The Maize R1 Locus, Robert C. Lindsay Jan 2018

Quantitative And Molecular Analysis Of Habituation At The Maize R1 Locus, Robert C. Lindsay

Theses and Dissertations

Epigenetics is the study of heritable changes in phenotypes that are not the result of changes in DNA sequence. Examples of epigenetic affecters include methylation changes, chromatin modifications, transcription factors, and RNA-based changes. The molecular mechanisms behind epigenetic changes are not fully understood. Canalization is the buffering of gene expression against environmental changes over time, while habituation is semi-stable expression change over time due to selection. This work characterized the molecular changes associated with the kernel color changes of the R-sc:86-17pale allele at the maize red color1 (r1) locus to determine if the changes are epigenetic in nature. …


Natural And Anthropogenic Drivers Of Tree Evolutionary Dynamics, Brandon M. Lind Jan 2018

Natural And Anthropogenic Drivers Of Tree Evolutionary Dynamics, Brandon M. Lind

Theses and Dissertations

Species of trees inhabit diverse and heterogeneous environments, and often play important ecological roles in such communities. As a result of their vast ecological breadth, trees have become adapted to various environmental pressures. In this dissertation I examine various environmental factors that drive evolutionary dynamics in threePinusspecies in California and Nevada, USA. In chapter two, I assess the role of management influence of thinning, fire, and their interaction on fine-scale gene flow within fire-suppressed populations of Pinus lambertiana, a historically dominant and ecologically important member of mixed-conifer forests of the Sierra Nevada, California. Here, I find evidence …


The Transcriptional Response Of Trametes Versicolor To Growth On Maple Chips And Miscanthus Straw, Maha Alanazi Jan 2018

The Transcriptional Response Of Trametes Versicolor To Growth On Maple Chips And Miscanthus Straw, Maha Alanazi

Masters Theses

This thesis research explored the transcriptional response of Trametes versicolor, a white-rot fungus, in response to fundamentally different types of lignocellulosic biomass (miscanthus and maple) and rich medium (malt extract agar). After five weeks of growth by the fungus on the biomass, the fungal RNA was extracted from three biological replicates per biomass type and mRNA was sequenced (approximately 30 million reads per sample). The reads were processed using ArrayStar to covert to RPKM and annotated using JGI's T. versicolor GO annotation file along with NCBI's BLAST. Comparisons were made between average gene expression of the fungus grown on …