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Articles 31 - 56 of 56
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Plant Calcium Content: Ready To Remodel, Jian Yang, Tracy Punshon, Mary Lou Guerinot, Kendal D. Hirschi
Plant Calcium Content: Ready To Remodel, Jian Yang, Tracy Punshon, Mary Lou Guerinot, Kendal D. Hirschi
Dartmouth Scholarship
By identifying the relationship between calcium location in the plant cell and nutrient bioavailability, the plant characteristics leading to maximal calcium absorption by humans can be identified. Knowledge of plant cellular and molecular targets controlling calcium location in plants is emerging. These insights should allow for better strategies for increasing the nutritional content of foods. In particular, the use of preparation-free elemental imaging technologies such as synchrotron X-ray fluorescence (SXRF) microscopy in plant biology may allow researchers to understand the relationship between subcellular location and nutrient bioavailability. These approaches may lead to better strategies for altering the location of calcium …
Evolution Of Plant Sucrose Uptake Transporters, Anke Reinders, Alicia B. Sivitz, John M. Ward
Evolution Of Plant Sucrose Uptake Transporters, Anke Reinders, Alicia B. Sivitz, John M. Ward
Dartmouth Scholarship
In angiosperms, sucrose uptake transporters (SUTs) have important functions especially in vascular tissue. Here we explore the evolutionary origins of SUTs by analysis of angiosperm SUTs and homologous transporters in a vascular early land plant, Selaginella moellendorffii, and a non-vascular plant, the bryophyte Physcomitrella patens, the charophyte algae Chlorokybus atmosphyticus, several red algae and fission yeast, Schizosaccharomyces pombe. Plant SUTs cluster into three types by phylogenetic analysis. Previous studies using angiosperms had shown that types I and II are localized to the plasma membrane while type III SUTs are associated with vacuolar membrane. SUT homologs were …
The Role Of Cax1 And Cax3 In Elemental Distribution And Abundance In Arabidopsis Seed, Tracy Punshon, Kendall Hirschi, Jian Yang, Antonio Lanzirotti, Barry Lai, Mary Lou Guerinot
The Role Of Cax1 And Cax3 In Elemental Distribution And Abundance In Arabidopsis Seed, Tracy Punshon, Kendall Hirschi, Jian Yang, Antonio Lanzirotti, Barry Lai, Mary Lou Guerinot
Dartmouth Scholarship
The ability to alter nutrient partitioning within plants cells is poorly understood. In Arabidopsis (Arabidopsis thaliana), a family of endomembrane cation exchangers (CAXs) transports Ca2+ and other cations. However, experiments have not focused on how the distribution and partitioning of calcium (Ca) and other elements within seeds are altered by perturbed CAX activity. Here, we investigate Ca distribution and abundance in Arabidopsis seed from cax1 and cax3 loss-of-function lines and lines expressing deregulated CAX1 using synchrotron x-ray fluorescence microscopy. We conducted 7- to 10-μm resolution in vivo x-ray microtomography on dry mature seed and 0.2-μm resolution x-ray …
Empirical Geographic Modeling Of Switchgrass Yields In The United States, Henriette I. Jager, Latha M. Baskaran, Craig C. Brandt, Ethan B. Davis
Empirical Geographic Modeling Of Switchgrass Yields In The United States, Henriette I. Jager, Latha M. Baskaran, Craig C. Brandt, Ethan B. Davis
Dartmouth Scholarship
Switchgrass (Panicum virgatum L.) is a perennial grass native to the United States that has been studied as a sustainable source of biomass fuel. Although many field‐scale studies have examined the potential of this grass as a bioenergy crop, these studies have not been integrated. In this study, we present an empirical model for switchgrass yield and use this model to predict yield for the conterminous United States. We added environmental covariates to assembled yield data from field trials based on geographic location. We developed empirical models based on these data. The resulting empirical models, which account for spatial …
Ethylene Receptors Function As Components Of High-Molecular-Mass Protein Complexes In Arabidopsis, Yi-Feng Chen, Zhiyong Gao, Robert J. Kerris, Wuyi Wang, Brad M. Binder, G. Eric Schaller
Ethylene Receptors Function As Components Of High-Molecular-Mass Protein Complexes In Arabidopsis, Yi-Feng Chen, Zhiyong Gao, Robert J. Kerris, Wuyi Wang, Brad M. Binder, G. Eric Schaller
Dartmouth Scholarship
Background: 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 …
Mir319a Targeting Of Tcp4 Is Critical For Petal Growth And Development In Arabidopsis, Anwesha Nag, Stacey King, Thomas Jack
Mir319a Targeting Of Tcp4 Is Critical For Petal Growth And Development In Arabidopsis, Anwesha Nag, Stacey King, Thomas Jack
Dartmouth Scholarship
In a genetic screen in a drnl-2 background, we isolated a loss-of-function allele in miR319a (miR319a129). Previously, miR319a has been postulated to play a role in leaf development based on the dramatic curled-leaf phenotype of plants that ectopically express miR319a (jaw-D). miR319a129 mutants exhibit defects in petal and stamen development; petals are narrow and short, and stamens exhibit defects in anther development. The miR319a129 loss-of-function allele contains a single-base change in the middle of the encoded miRNA, which reduces the ability of miR319a to recognize targets. Analysis of the expression patterns of the …
Disruption Of Osysl15 Leads To Iron Inefficiency In Rice Plants, Sichul Lee, Jeff C. Chiecko, Sun A. Kim, Elsbeth L. Walker, Youngsook Lee, Mary Lou Guerinot, Gyhheung An
Disruption Of Osysl15 Leads To Iron Inefficiency In Rice Plants, Sichul Lee, Jeff C. Chiecko, Sun A. Kim, Elsbeth L. Walker, Youngsook Lee, Mary Lou Guerinot, Gyhheung An
Dartmouth Scholarship
Uptake and translocation of metal nutrients are essential processes for plant growth. Graminaceous species release phytosiderophores that bind to Fe3+; these complexes are then transported across the plasma membrane. We have characterized OsYSL15, one of the rice (Oryza sativa) YS1-like (YSL) genes that are strongly induced by iron (Fe) deficiency. The OsYSL15 promoter fusion to β-glucuronidase showed that it was expressed in all root tissues when Fe was limited. In low-Fe leaves, the promoter became active in all tissues except epidermal cells. This activity was also detected in flowers and seeds. The OsYSL15:green …
The Leaf Ionome As A Multivariable System To Detect A Plant's Physiological Status, Ivan R. Baxter, Olga Vitek, Brett Lahner, Balasubramaniam Muthukumar, Monica Borghi, Joe Morrissey, Mary Lou Guerinot, David E. Salt
The Leaf Ionome As A Multivariable System To Detect A Plant's Physiological Status, Ivan R. Baxter, Olga Vitek, Brett Lahner, Balasubramaniam Muthukumar, Monica Borghi, Joe Morrissey, Mary Lou Guerinot, David E. Salt
Dartmouth Scholarship
The contention that quantitative profiles of biomolecules contain information about the physiological state of the organism has motivated a variety of high-throughput molecular profiling experiments. However, unbiased discovery and validation of biomolecular signatures from these experiments remains a challenge. Here we show that the Arabidopsis thaliana (Arabidopsis) leaf ionome, or elemental composition, contains such signatures, and we establish statistical models that connect these multivariable signatures to defined physiological responses, such as iron (Fe) and phosphorus (P) homeostasis. Iron is essential for plant growth and development, but potentially toxic at elevated levels. Because of this, shoot Fe concentrations are …
Nectar Secondary Compounds Affect Self-Pollen Transfer: Implications For Female And Male Reproduction, Rebecca E. Irwin, Lynn S. Adler
Nectar Secondary Compounds Affect Self-Pollen Transfer: Implications For Female And Male Reproduction, Rebecca E. Irwin, Lynn S. Adler
Dartmouth Scholarship
Pollen movement within and among plants affects inbreeding, plant fitness, and the spatial scale of genetic differentiation. Although a number of studies have assessed how plant and floral traits influence pollen movement via changes in pollinator behavior, few have explored how nectar chemical composition affects pollen transfer. As many as 55% of plants produce secondary compounds in their nectar, which is surprising given that nectar is typically thought to attract pollinators. We tested the hypothesis that nectar with secondary compounds may benefit plants by encouraging pollinators to leave plants after visiting only a few flowers, thus reducing self-pollen transfer. We …
Chloroplast Fe(Iii) Chelate Reductase Activity Is Essential For Seedling Viability Under Iron Limiting Conditions, Jeeyon Jeong, Christopher Cohu, Loubna Kerkeb, Marinus Pilon, Erin L. Connolly, Mary Lou Guerinot
Chloroplast Fe(Iii) Chelate Reductase Activity Is Essential For Seedling Viability Under Iron Limiting Conditions, Jeeyon Jeong, Christopher Cohu, Loubna Kerkeb, Marinus Pilon, Erin L. Connolly, Mary Lou Guerinot
Dartmouth Scholarship
Photosynthesis, heme biosynthesis, and Fe-S cluster assembly all take place in the chloroplast, and all require iron. Reduction of iron via a membrane-bound Fe(III) chelate reductase is required before iron transport across membranes in a variety of systems, but to date there has been no definitive genetic proof that chloroplasts have such a reduction system. Here we report that one of the eight members of the Arabidopsis ferric reductase oxidase (FRO) family, FRO7, localizes to the chloroplast. Chloroplasts prepared from fro7 loss-of-function mutants have 75% less Fe(III) chelate reductase activity and contain 33% less iron per microgram of chlorophyll than …
The Mads-Domain Transcriptional Regulator Agamous-Like15 Promotes Somatic Embryo Development In Arabidopsis And Soybean, Dhiraj Thakare, Weining Tang, Kristine Hill, Sharyn E. Perry
The Mads-Domain Transcriptional Regulator Agamous-Like15 Promotes Somatic Embryo Development In Arabidopsis And Soybean, Dhiraj Thakare, Weining Tang, Kristine Hill, Sharyn E. Perry
Dartmouth Scholarship
The MADS-domain transcriptional regulator AGAMOUS-LIKE15 (AGL15) has been reported to enhance somatic embryo development when constitutively expressed. Here we report that loss-of-function mutants of AGL15, alone or when combined with a loss-of-function mutant of a closely related family member, AGL18, show decreased ability to produce somatic embryos. If constitutive expression of orthologs of AGL15 is able to enhance somatic embryo development in other species, thereby facilitating recovery of transgenic plants, then AGL15 may provide a valuable tool for crop improvement. To test this idea in soybean (Glycine max), a full-length cDNA encoding a putative ortholog of AGL15 was isolated from …
Systems Approach Identifies An Organic Nitrogen-Responsive Gene Network That Is Regulated By The Master Clock Control Gene Cca1, Rodrigo A. Gutierrez, Trevor L. Stokes, Karen Thum, Xiaodong Xu, Mariana Obertello, Manpreet S. Katari, Milos Tanurdzic, Alexis Dean, Damion C. Nero, C Robertson Mcclung, Gloria M. Coruzzi
Systems Approach Identifies An Organic Nitrogen-Responsive Gene Network That Is Regulated By The Master Clock Control Gene Cca1, Rodrigo A. Gutierrez, Trevor L. Stokes, Karen Thum, Xiaodong Xu, Mariana Obertello, Manpreet S. Katari, Milos Tanurdzic, Alexis Dean, Damion C. Nero, C Robertson Mcclung, Gloria M. Coruzzi
Dartmouth Scholarship
Understanding how nutrients affect gene expression will help us to understand the mechanisms controlling plant growth and development as a function of nutrient availability. Nitrate has been shown to serve as a signal for the control of gene expression in Arabidopsis. There is also evidence, on a gene-by-gene basis, that downstream products of nitrogen (N) assimilation such as glutamate (Glu) or glutamine (Gln) might serve as signals of organic N status that in turn regulate gene expression. To identify genome-wide responses to such organic N signals, Arabidopsis seedlings were transiently treated with ammonium nitrate in the presence or absence of …
Variation In Molybdenum Content Across Broadly Distributed Populations Of Arabidopsis Thaliana Is Controlled By A Mitochondrial Molybdenum Transporter (Mot1), Ivan Baxter, Balasubramaniam Muthukumar, Hyeong Cheol Park, Peter Buchner, Brett Lahner, John Danku, Keyan Zhao, Joohyun Lee, Malcolm J. Hawkesford, Mary Lou Guerinot, David E. Salt
Variation In Molybdenum Content Across Broadly Distributed Populations Of Arabidopsis Thaliana Is Controlled By A Mitochondrial Molybdenum Transporter (Mot1), Ivan Baxter, Balasubramaniam Muthukumar, Hyeong Cheol Park, Peter Buchner, Brett Lahner, John Danku, Keyan Zhao, Joohyun Lee, Malcolm J. Hawkesford, Mary Lou Guerinot, David E. Salt
Dartmouth Scholarship
Molybdenum (Mo) is an essential micronutrient for plants, serving as a cofactor for enzymes involved in nitrate assimilation, sulfite detoxification, abscisic acid biosynthesis, and purine degradation. Here we show that natural variation in shoot Mo content across 92 Arabidopsis thaliana accessions is controlled by variation in a mitochondrially localized transporter (Molybdenum Transporter 1 - MOT1) that belongs to the sulfate transporter superfamily. A deletion in the MOT1 promoter is strongly associated with low shoot Mo, occurring in seven of the accessions with the lowest shoot content of Mo. Consistent with the low Mo phenotype, MOT1 expression in low Mo accessions …
A Strong Constitutive Ethylene-Response Phenotype Conferred On Arabidopsis Plants Containing Null Mutations In The Ethylene Receptors Etr1 And Ers1, Xiang Qu, Brenda P. Hall, Zhiyong Gao, G. Eric Schaller
A Strong Constitutive Ethylene-Response Phenotype Conferred On Arabidopsis Plants Containing Null Mutations In The Ethylene Receptors Etr1 And Ers1, Xiang Qu, Brenda P. Hall, Zhiyong Gao, G. Eric Schaller
Dartmouth Scholarship
The ethylene receptor family of Arabidopsis consists of five members, falling into two subfamilies. Subfamily 1 is composed of ETR1 and ERS1, and subfamily 2 is composed of ETR2, ERS2, and EIN4. Although mutations have been isolated in the genes encoding all five family members, the only previous insertion allele of ERS1 (ers1-2) is a partial loss-of-function mutation based on our analysis. The purpose of this study was to determine the extent of signaling mediated by subfamily-1 ethylene receptors through isolation and characterization of null mutations.
A Subset Of Arabidopsis Ap2 Transcription Factors Mediates Cytokinin Responses In Concert With A Two-Component Pathway, Aaron M. Rashotte, Michael G. Mason, Claire E. Hutchison, Fernando J. Ferreira, G. Eric Schaller, Joseph J. Kieber
A Subset Of Arabidopsis Ap2 Transcription Factors Mediates Cytokinin Responses In Concert With A Two-Component Pathway, Aaron M. Rashotte, Michael G. Mason, Claire E. Hutchison, Fernando J. Ferreira, G. Eric Schaller, Joseph J. Kieber
Dartmouth Scholarship
The plant hormone cytokinin regulates numerous growth and developmental processes. A signal transduction pathway for cytokinin has been elucidated that is similar to bacterial two-component phosphorelays. In Arabidopsis, this pathway is comprised of receptors that are similar to sensor histidine kinases, histidine-containing phosphotransfer proteins, and response regulators (ARRs). There are two classes of response regulators, the type-A ARRs, which act as negative regulators of cytokinin responses, and the type-B ARRs, which are transcription factors that play a positive role in mediating cytokinin-regulated gene expression. Here we show that several closely related members of the Arabidopsis AP2 gene family of …
Ecological Costs And Benefits Of Defenses In Nectar, Lynn S. Adler, Rebecca E. Irwin
Ecological Costs And Benefits Of Defenses In Nectar, Lynn S. Adler, Rebecca E. Irwin
Dartmouth Scholarship
The nectar of many plant species contains defensive compounds that have been hypothesized to benefit plants through a variety of mechanisms. However, the relationship between nectar defenses and plant fitness has not been established for any species. We experimentally manipulated gelsemine, the principal alkaloid of Carolina jessamine (Gelsemium sempervirens), in nectar to determine its effect on pollinator visitation, nectar robber visitation, and male and female plant reproduction. We found that nectar robbers and most pollinators probed fewer flowers and spent less time per flower on plants with high compared to low nectar alkaloids. High alkaloids decreased the donation of fluorescent …
Phylogenetic Relationships Within Cation Transporter Families Of Arabidopsis, Pascal Mäser, Sébastien Thomine, Julian I. Schroeder, John M. Ward, Kendal Hirschi, Heven Sze, Ina N. Talke, Anna Amtmann, Frans J.M. Maathuis, Dale Sanders, Jeff F. Harper, Jason Tchieu, Michael Gribskov, Michael W. Persans, David E. Salt, Sun A. Kim, Mary Lou Guerinot
Phylogenetic Relationships Within Cation Transporter Families Of Arabidopsis, Pascal Mäser, Sébastien Thomine, Julian I. Schroeder, John M. Ward, Kendal Hirschi, Heven Sze, Ina N. Talke, Anna Amtmann, Frans J.M. Maathuis, Dale Sanders, Jeff F. Harper, Jason Tchieu, Michael Gribskov, Michael W. Persans, David E. Salt, Sun A. Kim, Mary Lou Guerinot
Dartmouth Scholarship
Uptake and translocation of cationic nutrients play essential roles in physiological processes including plant growth, nutrition, signal transduction, and development. Approximately 5% of the Arabidopsis genome appears to encode membrane transport proteins. These proteins are classified in 46 unique families containing approximately 880 members. In addition, several hundred putative transporters have not yet been assigned to families. In this paper, we have analyzed the phylogenetic relationships of over 150 cation transport proteins. This analysis has focused on cation transporter gene families for which initial characterizations have been achieved for individual members, including potassium transporters and channels, sodium transporters, calcium antiporters, …
Networking Senescence-Regulating Pathways By Using Arabidopsis Enhancer Trap Lines, Yuehui He, Weining Tang, Johnnie D. Swain, Anthony L. Green, Thomas P. Jack, Susheng Gan
Networking Senescence-Regulating Pathways By Using Arabidopsis Enhancer Trap Lines, Yuehui He, Weining Tang, Johnnie D. Swain, Anthony L. Green, Thomas P. Jack, Susheng Gan
Dartmouth Scholarship
The last phase of leaf development, generally referred to as leaf senescence, is an integral part of plant development that involves massive programmed cell death. Due to a sharp decline of photosynthetic capacity in a leaf, senescence limits crop yield and forest plant biomass production. However, the biochemical components and regulatory mechanisms underlying leaf senescence are poorly characterized. Although several approaches such as differential cDNA screening, differential display, and cDNA subtraction have been employed to isolate senescence-associated genes (SAGs), only a limited number of SAGs have been identified, and information regarding the regulation of these genes is …
An Enhancer Trap Line Associated With A D-Class Cyclin Gene In Arabidopsis, Kankshita Swaminathan, Yingzhen Yang, Natasha Grotz, Lauren Campisi, Thomas Jack
An Enhancer Trap Line Associated With A D-Class Cyclin Gene In Arabidopsis, Kankshita Swaminathan, Yingzhen Yang, Natasha Grotz, Lauren Campisi, Thomas Jack
Dartmouth Scholarship
In yeast and animals, cyclins have been demonstrated to be important regulators of cell cycle progression. In recent years, a large number of A-, B-, and D-class cyclins have been isolated from a variety of plant species. One class of cyclins, the D-class cyclins, is important for progression through G1 phase of the cell cycle. In Arabidopsis, four D-class cyclins have been isolated and characterized (CYCLIN-D1;1, CYCLIN-D2;1,CYCLIN-D3;1, and CYCLIN-D4;1). In this report we describe the characterization of a fifth D-class cyclin gene,CYCLIN-D3;2 (CYCD3;2), from Arabidopsis. An enhancer trap line, line 5580, …
Integrated Temporal Regulation Of The Photorespiratory Pathway. Circadian Regulation Of Two Arabidopsis Genes Encoding Serine Hydroxymethyltransferase, C Robertson Mcclung, Meier Hsu, Janet E. Painter, Jennifer M. Gagne, Sharon D. Karlsberg, Patrice A. Salome
Integrated Temporal Regulation Of The Photorespiratory Pathway. Circadian Regulation Of Two Arabidopsis Genes Encoding Serine Hydroxymethyltransferase, C Robertson Mcclung, Meier Hsu, Janet E. Painter, Jennifer M. Gagne, Sharon D. Karlsberg, Patrice A. Salome
Dartmouth Scholarship
The photorespiratory pathway is comprised of enzymes localized within three distinct cellular compartments: chloroplasts, peroxisomes, and mitochondria. Photorespiratory enzymes are encoded by nuclear genes, translated in the cytosol, and targeted into these distinct subcellular compartments. One likely means by which to regulate the expression of the genes encoding photorespiratory enzymes is coordinated temporal control. We have previously shown in Arabidopsis that a circadian clock regulates the expression of the nuclear genes encoding both chloroplastic (Rubisco small subunit and Rubisco activase) and peroxisomal (catalase) components of the photorespiratory pathway. To determine whether a circadian clock also regulates the expression of genes …
Identification Of A Family Of Zinc Transporter Genes From Arabidopsis That Respond To Zinc Deficiency, Natasha Grotz, Tama Fox, Erin Connolly, Walter Park, Mary Lou Guerinot, David Eide
Identification Of A Family Of Zinc Transporter Genes From Arabidopsis That Respond To Zinc Deficiency, Natasha Grotz, Tama Fox, Erin Connolly, Walter Park, Mary Lou Guerinot, David Eide
Dartmouth Scholarship
Millions of people worldwide suffer from nutritional imbalances of essential metals like zinc. These same metals, along with pollutants like cadmium and lead, contaminate soils at many sites around the world. In addition to posing a threat to human health, these metals can poison plants, livestock, and wildlife. Deciphering how metals are absorbed, transported, and incorporated as protein cofactors may help solve both of these problems. For example, edible plants could be engineered to serve as better dietary sources of metal nutrients, and other plant species could be tailored to remove metal ions from contaminated soils. We report here the …
Iron Uptake By Symbiosomes From Soybean Root Nodules., Kristin Levier, David A. Day, Mary Lou Guerinot
Iron Uptake By Symbiosomes From Soybean Root Nodules., Kristin Levier, David A. Day, Mary Lou Guerinot
Dartmouth Scholarship
To identify possible iron sources for bacteroids in planta, soybean (Glycine max L. Merr.) symbiosomes (consisting of the bacteroid-containing peribacteroid space enclosed by the peribacteroid membrane [PBM]) and bacteroids were assayed for the ability to transport iron supplied as various ferric [Fe(III)]-chelates. Iron presented as a number of Fe(III)-chelates was transported at much higher rates across the PBM than across the bacteroid membranes, suggesting the presence of an iron storage pool in the peribacteroid space. Pulse-chase experiments confirmed the presence of such an iron storage pool. Because the PBM is derived from the plant plasma membrane, we reasoned that it …
A Novel Iron-Regulated Metal Transporter From Plants Identified By Functional Expression In Yeast., David Eide, Margaret Broderius, Jeanette Fett, Mary Lou Guerinot
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, …
Molecular Basis Of The Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Activase Mutation In Arabidopsis Thaliana Is A Guanine-To-Adenine Transition At The 5'-Splice Junction Of Intron 3, Beverly M. Orozco, C Robertson Mcclung, Jeffrey M. Werneke, William L. Ogren
Molecular Basis Of The Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Activase Mutation In Arabidopsis Thaliana Is A Guanine-To-Adenine Transition At The 5'-Splice Junction Of Intron 3, Beverly M. Orozco, C Robertson Mcclung, Jeffrey M. Werneke, William L. Ogren
Dartmouth Scholarship
Analysis of the ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase gene and gene products from Arabidopsis thaliana wild-type plants and the Rubisco activase-deficient mutant strain showed that the rca mutation caused GT to be changed to AT at the 5[prime]-splice junction of intron 3 in the six-intron pre-mRNA. Northern blot analysis, genomic and cDNA sequencing, and primer extension analysis indicated that the mutation causes inefficient and incomplete splicing of the pre-mRNA, resulting in the accumulation of three aberrant mRNAs. One mutant mRNA was identical with wild-type mRNA except that it included intron 3, a second mRNA comprised intron 3 and exons 4 through …
Porphyrin Accumulation And Export By Isolated Barley (Hordeum Vulgare) Plastids (Effect Of Diphenyl Ether Herbicides), Judith M. Jacobs, Nicholas J. Jacobs
Porphyrin Accumulation And Export By Isolated Barley (Hordeum Vulgare) Plastids (Effect Of Diphenyl Ether Herbicides), Judith M. Jacobs, Nicholas J. Jacobs
Dartmouth Scholarship
We have investigated the formation of porphyrin intermediates by isolated barley (Hordeum vulgare) plastids incubated for 40 min with the porphyrin precursor 5-aminolevulinate and in the presence and absence of a diphenylether herbicide that blocks protoporphyrinogen oxidase, the enzyme in chlorophyll and heme synthesis that oxidizes protoporphyrinogen IX to protoporphyrin IX. In the absence of herbicide, about 50% of the protoporphyrin IX formed was found in the extraplastidic medium, which was separated from intact plastids by centrifugation at the end of the incubation period. In contrast, uroporphyrinogen, an earlier intermediate, and magnesium protoporphyrin IX, a later intermediate, were located mainly …
Physiological Basis For Differential Sensitivities Of Plant Species To Protoporphyrinogen Oxidase-Inhibiting Herbicides, Timothy D. Sherman, José M. Becerril, Hiroshi Matsumoto, Mary V. Duke, Judy M. Jacobs, Nicholas J. Jacobs, Stephen O. Duke
Physiological Basis For Differential Sensitivities Of Plant Species To Protoporphyrinogen Oxidase-Inhibiting Herbicides, Timothy D. Sherman, José M. Becerril, Hiroshi Matsumoto, Mary V. Duke, Judy M. Jacobs, Nicholas J. Jacobs, Stephen O. Duke
Dartmouth Scholarship
With a leaf disc assay, 11 species were tested for effects of the herbicide acifluorfen on porphyrin accumulation in darkness and subsequent electrolyte leakage and photobleaching of chlorophyll after exposure to light. Protoporphyrin IX (Proto IX) was the only porphyrin that was substantially increased by the herbicide in any of the species. However, there was a wide range in the amount of Proto IX accumulation caused by 0.1 millimolar acifluorfen between species. Within species, there was a reduced effect of the herbicide in older tissues. Therefore, direct quantitative comparisons between species are difficult. Nevertheless, when data from different species and …