Plant Sciences Commons^™

Dynamics Of Redox-Driven Molecular Processes In Local And Systemic Plant Immunity, Philip Berg

Theses and Dissertations

The work here presents two main parts. In the first part, chapters 1 – 3 focus on dynamical systems modeling in plant immunity, whereas chapters 4 – 6 describe contributions to computational modeling and analysis of proteomics and genomics data. Chapter 1 investigates dynamical and biochemical patterns of reversibly oxidized cysteines (RevOxCys) during effector-triggered immunity (ETI) in Arabidopsis, examines the regulatory patterns associated with Arabidopsis thimet oligopeptidase 1 and 2’s (TOP1 and TOP2), roles in the RevOxCys events during ETI, and analyzes the redox phenotype of the top1top2 mutant. The second chapter investigates the peptidome dynamics during ETI …

Dissecting The Regulatory Network Of Sphingolipid Biosynthesis In Plants, Ariadna Gonzalez-Solis

Department of Biochemistry: Dissertations, Theses, and Student Research

Sphingolipids are a diverse group of lipids recognized as important components of cellular membranes and regulators of processes during development and in response to environmental stresses. Serine palmitoyltransferase (SPT) catalyzes the first step in sphingolipid biosynthesis and is a primary regulatory point for homeostasis. ORM proteins have been identified as negative regulators of SPT activity, however the mechanistic details of the regulation are only beginning to be understood. In this work, we show that ORM1 and ORM2 are essential for life cycle completion in Arabidopsis thaliana. Furthermore, the study of a structural ORM1 variant provided information about a transmembrane …

Characterizing The Role Of Β-Amylase3 In Cold Stress Response And Recovery In Arabidopsis Thaliana, Isabelle G. Houston

Senior Honors Projects, 2020-current

Starch is a polymer of glucose that is used as an energy store in plants. Mobilization of starch has implications in abiotic stress survival and recovery. While the importance of carbon and energy allocation in plant survival has been explored, the specific roles of starch degrading enzymes in plant responses to stress are still unclear. β-Amylase3, or BAM3, is the principle starch degrading enzyme at night and is transcriptionally upregulated in response to cold stress in the plant Arabidopsis thaliana. Using single and quadruple knockout mutant plants, I aimed to clarify the role of BAM3 in the response to …

Examining The Role Of Grp And Lik1 In Wall Associated Kinase (Wak) Perception Of Pectin In The Plant Cell Wall, Jack Ryan Mitchell

Honors Projects

Wall associated kinases (WAKs) are cell membrane bound receptor kinases that bind pectin and pectin fragments (OGs).The binding of WAKs to pectin sends a growth signal required for cell elongation and plant development. WAKs bind OGs with higher affinity than native pectin and instead activate a stress response. Glycine rich proteins (GRPs) are secreted cell wall proteins of unknown function. Seven GRPs with 65% sequence similarity are coded on a 90kb locus of Arabidopsis chromosome 2. GRP3 and WAK1 have been shown to bind in vitro, but single null mutations have no discernible phenotype, suggesting that the GRPs are redundant. …

Purification Of 26s Proteasomes And Their Subcomplexes From Plants, Richard S. Marshall, David C. Gemperline, Richard D. Vierstra

Biology Faculty Publications & Presentations

The 26S proteasome is a highly dynamic, multisubunit, ATP-dependent protease that plays a central role in cellular housekeeping and many aspects of plant growth and development by degrading aberrant polypeptides and key cellular regulators that are first modified by ubiquitin. Although the 26S proteasome was originally enriched from plants over 30 years ago, only recently have significant advances been made in our ability to isolate and study the plant particle. Here, we describe two robust methods for purifying the 26S proteasome and its subcomplexes from Arabidopsis thaliana; one that involves conventional chromatography techniques to isolate the complex from wild-type …

Identification Of N-Acylethanolamine Hydrolyzing Enzyme In Solanum Lycopersicum, Derek A. Stuffle

Undergraduate Honors Theses

N-acylethanolamines (NAEs) are fatty acid derivatives that occur naturally in plant and animal systems. In mammals, they regulate physiological functions, including neurotransmission, immune responses, vasodilation, embryo development and implantation, feeding behavior, and cell proliferation. NAEs are metabolized by fatty acid amide hydrolase (FAAH), which belongs to the amidase signature family. It is hypothesized that putative FAAH functions as the catalyst in the metabolism of N-acylethanolamine in tomato plants. To test the hypothesis, FAAH protein homologs were identified in tomato via in silico analysis. Among the six homologs identified, FAAH1 and FAAH2 were selected for further validation. This study …

The Role Of Protein Kinases Rog1 And Srf6 In The Wak Stress Response Pathway, Jaepil Eric Yoon

Jaepil Eric Yoon

The wall-associated kinases (WAKs) are receptor kinases that bind cell wall pectin to activate expansion and stress response pathways in Arabidopsis thaliana. When bound to pectin polymers, WAKs initiate expansion by inducing the expression of vacuolar invertases that increase cellular turgor pressure, which pushes out against the cell wall. WAKs also bind pathogen or wounding induced pectin fragments called oligogalacturonic acids (OGs). When bound to OGs, WAKs induce a stress response, which leads to the activation of MAP kinases, MPK3 and MPK6. Phosphoproteomics and mass spectrometry identified receptor kinase SRF6, cytoplasmic kinase ROG1, and nuclear DNA binding protein REM2 to …

The Role Of Protein Kinases Rog1 And Srf6 In The Wak Stress Response Pathway, Jaepil E. Yoon

Honors Projects

No abstract provided.

Bacterial Expression Of Plant Pyruvate Kinase, Kristina Fuller

STAR Program Research Presentations

Pyruvate kinases serve an important role in regulating glycolysis pathways. Different pyruvate kinase isozymes can dictate which of several different products will be formed during the final step of glycolysis. Being able to reliably copy active pyruvate kinases (PK) would allow study of the different isozymes, with the goal of eventually creating plants that are more nutritionally beneficial for humans. This study focused on improving the protocol for replicating each of two isolated PK isozymes from the model plant Arabidopsis thaliana. Previous attempts had resulted in the PK denaturing and consequently precipitating out of solution and so we manipulated the …

Acyl-Lipid Metabolism, Younghua Li-Beisson, Basil Shorrosh, Fred Beisson, Mats X. Andersson, Vincent Arondel, Philip D. Bates, Sébastien Baud, David Bird, Allan Debono, Timothy P. Durrett, Rochus B. Franke, Ian A. Graham, Kenta Katayama, Amélie A. Kelly, Tony Larson, Jonathan E. Markham, Martine Miquel, Isabel Molina, Ikuo Nishida, Owen Rowland, Lacey Samuels, Katherine M. Schmid, Hajime Wada, Ruth Welti, Changcheng Xu, Rémi Zallot, John Ohlrogge

Scholarship and Professional Work - LAS

Acyl lipids in Arabidopsis and all other plants have a myriad of diverse functions. These include providing the core diffusion barrier of the membranes that separates cells and subcellular organelles. This function alone involves more than 10 membrane lipid classes, including the phospholipids, galactolipids, and sphingolipids, and within each class the variations in acyl chain composition expand the number of structures to several hundred possible molecular species. Acyl lipids in the form of triacylglycerol account for 35% of the weight of Arabidopsis seeds and represent their major form of carbon and energy storage. A layer of cutin and cuticular waxes …

Functions Of The Arabidopsis Kinesin Superfamily Of Microtubule-Based Motor Proteins, Chuanmei Zhu, Ram Dixit

Biology Faculty Publications & Presentations

Plants possess a large number of microtubule-based kinesin motor proteins. While the kinesin-2, 3, 9, and 11 families are absent from land plants, the kinesin-7 and 14 families are greatly expanded. In addition, some kinesins are specifically present only in land plants. The distinctive inventory of plant kinesins suggests that kinesins have evolved to perform specialized functions in plants. Plants assemble unique microtubule arrays during their cell cycle, including the interphase cortical microtubule array, preprophase band, anastral spindle and phragmoplast. In this review, we explore the functions of plant kinesins from a microtubule array viewpoint, focusing mainly on Arabidopsis kinesins. …

Host Pathogen Interactions: Is Arabidopsis Thaliana Remembered By Its Nemesis Pseudomonas Syringae?, Daniel Z. Kreiser

Lawrence University Honors Projects

Plants contain innate immune systems that deter pathogen infection. Pattern recognition receptors bind microbe-associated molecular patterns (MAMPs), triggering immunity. MAMPs are proteins exclusive to pathogens that are typically indispensable for their survival. For this reason, MAMPs cannot be mutated or removed without causing pathogen death. However, this does not necessitate constitutive expression of MAMPs. In this study, the MAMP response of Arabidopsis thaliana was utilized to determine differential detection of MAMPs expressed by Pseudomonas syringe pv. tomato DC3000 when pretreated with A. thaliana. Results demonstrated that more MAMPs are detected when P. syringae had previously encountered A. thaliana, …

Elucidating The Mechanism Of Organelle Trafficking In Arabidopsis Thaliana: The Mya2 Globular Tail Interacts With Atrabc2a., Su Ji Jeong

Chancellor’s Honors Program Projects

No abstract provided.

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 …

Ethylene Receptors Function As Components Of High-Molecular-Mass Protein Complexes In Arabidopsis, Yi-Feng Chen, Zhiyong Gao, Robert J. Kerriss Iii, Wuyi Wang, Brad M. Binder, G. Eric Schaller

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

The gaseous plant hormone ethylene is perceived in Arabidopsis thaliana by a five-member receptor family composed of ETR1, ERS1, ETR2, ERS2, and EIN4. Methodology/Principal Findings

Gel-filtration analysis of ethylene receptors solubilized from Arabidopsis membranes demonstrates that the receptors exist as components of high-molecular-mass protein complexes. The ERS1 protein complex exhibits an ethylene-induced change in size consistent with ligand-mediated nucleation of protein-protein interactions. Deletion analysis supports the participation of multiple domains from ETR1 in formation of the protein complex, and also demonstrates that targeting to and retention of ETR1 at the endoplasmic reticulum only requires the first 147 amino acids of …

Ethylene Receptors Function As Components Of High-Molecular-Mass Protein Complexes In Arabidopsis, Yi-Feng Chen, Zhiyong Gao, Robert J. Kerriss Iii, Wuyi Wang, Brad M. Binder, G. Eric Schaller

Brad M. Binder

The gaseous plant hormone ethylene is perceived in Arabidopsis thaliana by a five-member receptor family composed of ETR1, ERS1, ETR2, ERS2, and EIN4. Methodology/Principal Findings Gel-filtration analysis of ethylene receptors solubilized from Arabidopsis membranes demonstrates that the receptors exist as components of high-molecular-mass protein complexes. The ERS1 protein complex exhibits an ethylene-induced change in size consistent with ligand-mediated nucleation of protein-protein interactions. Deletion analysis supports the participation of multiple domains from ETR1 in formation of the protein complex, and also demonstrates that targeting to and retention of ETR1 at the endoplasmic reticulum only requires the first 147 amino acids of …

Functional Analysis Of Receptor-Like Kinases In Pollen-Pistil Interactions In Arabidopsis Thaliana, Mini Aggarwal

Masters Theses 1911 - February 2014

Rac/Rop GTPases are molecular switches in plants that control the growth of polarized cells such as pollen tubes and root hairs, differentiation, development, actin dynamics, production of reactive oxygen species (ROS) and disease resistance. These small GTPases are activated by guanine nucleotide exchange factors (GEFs) that replace GDP for GTP and are referred to as RopGEFs in plants. To identify upstream components of the RopGEF regulated signaling pathways, GEF1 from Arabidopsis thaliana was used as a bait to screen a seedling cDNA library in a yeast two-hybrid system. This yielded members of a small family of the Catharanthus roseus Receptor-like …

A Novel Iron-Regulated Metal Transporter From Plants Identified By Functional Expression In Yeast., David Eide, Margaret Broderius, Jeanette Fett, Mary Lou Guerinot

Dartmouth Scholarship

Iron is an essential nutrient for virtually all organisms. The IRT1 (iron-regulated transporter) gene of the plant Arabidopsis thaliana, encoding a probable Fe(II) transporter, was cloned by functional expression in a yeast strain defective for iron uptake. Yeast expressing IRT1 possess a novel Fe(II) uptake activity that is strongly inhibited by Cd. IRT1 is predicted to be an integral membrane protein with a metal-binding domain. Data base comparisons and Southern blot analysis indicated that IRT1 is a member of a gene family in Arabidopsis. Related sequences were also found in the genomes of rice, yeast, nematodes, and humans. In Arabidopsis, …