Plant Biology Commons^™

Census And Mapping Of Chorro Creek Bog Thistle In Reservoir Canyon, San Luis Obispo, Ca, Tyler Michael Lutz

Biological Sciences

Chorro Creek bog thistle (Cirsium fontinale var. obispoense) is a federally endangered variety of Fountain thistle endemic to western San Luis Obispo County. The U.S. Fish and Wildlife Service knows of nineteen populations, many with multiple colonies. A population was discovered in the Reservoir Canyon Natural Reserve in 2001, but has not been monitored or described since the time of its discovery. In fall of 2013, a census of the population was performed, the four colonies were mapped, and a floristic survey was conducted. A field experiment was initiated to determine if reducing the riparian canopy coverage can …

Molecular And Biochemical Mechanisms Of Pathogenesis In The Maize Foliar Pathogen Cercospora Zeae-Maydis, Winfred-Peck Dorleku

Graduate Theses and Dissertations

GLS is a serious foliar disease of maize, a major staple crop grown commercially in the USA for both human and animal feed production, and increasingly, for ethanol production. The disease is caused by two Cercospora species, C. zeae-maydis and C. zeina, both of which infect maize in the USA and in other parts of the world, with yield losses potentially greater than 50%, depending on local conditions. In culture, C. zeae-maydis produces a phytotoxic, host non-specific perylenequinone, cercosporin, and abscisic acid (ABA), for which there is no known pathological or physiological function in the fungus. Experimental evidence indicates …

The Influence Of Hydrogeomorphology, Soil Redox Conditions, And Salinity On The Spatial Zoning Of Saltgrass, Salt Rush, And Cattails In Scotts Creek Marsh, Swanton Pacific Ranch, Ca, Mark D. Gormley

Master's Theses

Scotts Creek Marsh (SCM) is a small coastal wetland ecosystem in Davenport, CA. The vegetation of SCM is dominated by three halophytic zones comprised of saltgrass, salt rush, cattails. The objectives of the study were (i) to investigate the variables that influence the zoning of the three dominant halophyte communities in SCM and (ii) to the test the effectiveness of Indicator of Reduction in Soil (IRIS) tubes to indicate the reduction of S. The study examined the following parameters from April 6 to July 21, 2013: (i) the HGM of Scotts Creek Marsh, (ii) soil oxidation and reduction (redox) conditions, …

Optimal Copper Supply Is Required For Normal Plant Iron Deficiency Responses, Brian M. Waters, Laura C. Armbrust

Department of Agronomy and Horticulture: Faculty Publications

Iron (Fe) and copper (Cu) homeostasis are tightly linked across biology. Understanding crosstalk between Fe and Cu nutrition could lead to strategies for improved growth on soils with low or excess metals, with implications for agriculture and phytoremediation. Here, we show that Cu and Fe nutrition interact to increase or decrease Fe and/or Cu accumulation in leaves and Fe uptake processes. Leaf Cu concentration increased under low Fe supply, while high Cu lowered leaf Fe concentration. Ferric reductase activity, an indicator of Fe demand, was inhibited at insufficient or high Cu supply. Surprisingly, plants grown without Fe were more susceptible …

Mechanisms For Regulation Of Plant Kinesins, Anindya Ganguly, Ram Dixit

Biology Faculty Research

Throughout the eukaryotic world, kinesins serve as molecular motors for the directional transport of cellular cargo along microtubule tracks. Plants contain a large number of kinesins that have conserved as well as specialized functions. These functions depend on mechanisms that regulate when, where and what kinesins transport. In this review, we highlight recent studies that have revealed conserved modes of regulation between plant kinesins and their non-photosynthetic counterparts. These findings lay the groundwork for understanding how plant kinesins are differentially engaged in various cellular processes that underlie plant growth and development.

Remote Estimation Of Nitrogen And Chlorophyll Contents In Maize At Leaf And Canopy Levels, Michael Schlemmer, Anatoly A. Gitelson, James S. Schepers, Richard B. Ferguson, Y. Peng, J. Shanahan, Donald Rundquist

Department of Agronomy and Horticulture: Faculty Publications

Leaf and canopy nitrogen (N) status relates strongly to leaf and canopy chlorophyll (Chl) content. Remote sensing is a tool that has the potential to assess N content at leaf, plant, field, regional and global scales. In this study, remote sensing techniques were applied to estimate N and Chl contents of irrigated maize (Zea mays L.) fertilized at five N rates. Leaf N and Chl contents were determined using the red-edge chlorophyll index with R2 of 0.74 and 0.94, respectively. Results showed that at the canopy level, Chl and N contents can be accurately retrieved using green and red-edge Chl …

Ceratobasidium Root Rot: A New Disease Of Watermelon In Arizona, Claudia Nischwitz

All Current Publications

No abstract provided.

Arabidopsis 56–Amino Acid Serine Palmitoyltransferase- Interacting Proteins Stimulate Sphingolipid Synthesis, Are Essential, And Affect Mycotoxin Sensitivity, Athen N. Kimberlin, Saurav Majumder, Gongshe Han, Ming Chen, Rebecca E. Cahoon, Julie M. Stone, Teresa M. Dunn, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty Publications

Maintenance of sphingolipid homeostasis is critical for cell growth and programmed cell death (PCD). Serine palmitoyltransferase (SPT), composed of LCB1 and LCB2 subunits, catalyzes the primary regulatory point for sphingolipid synthesis. Small subunits of SPT (ssSPT) that strongly stimulate SPT activity have been identified in mammals, but the role of ssSPT in eukaryotic cells is unclear. Candidate Arabidopsis thaliana ssSPTs, ssSPTa and ssSPTb, were identified and characterized. Expression of these 56–amino acid polypeptides in a Saccharomyces cerevisiae SPT null mutant stimulated SPT activity from the Arabidopsis LCB1/LCB2 heterodimer by >100-fold through physical interaction with LCB1/LCB2. ssSPTa transcripts were …

Response Of Near-Isogenic Sorghum Lines, Differing At The P Locus For Plant Colour, To Grain Mould And Head Smut Fungi, Deanna L. Funnell-Harris, L. K. Prom, Scott E. Sattler, Jeffrey F. Pedersen

Department of Plant Pathology: Faculty Publications

Leaves and stalks of many sorghum genotypes accumulate dark red or purple pigments upon wounding while some plants, called ‘tan,’ do not. Grains with unpigmented ‘white’ pericarps grown on tan plants are more desirable for food. The hypothesis tested was that pigments in plants protected grain against the panicle diseases grain mould and head smut. Near-isogenic tan or purple plant color genotypes with white grain were planted at Lincoln and Ithaca, NE and Corpus Christi, TX. The field grown grain was plated onto semi-selective media to detect the presence of grain colonisation by mould genera Alternaria, Fusarium and Curvularia. …

Differences In Temperature Responses Of Achene Types In Centaurea Melitensis, Kandee L. Bain

LUX: A Journal of Transdisciplinary Writing and Research from Claremont Graduate University

Southern California has a Mediterranean climate with wet winters and hot dry summers. This type of environment is associated with irregular temperature patterns and rainfall, which can be unpredictable. Unpredictable environments, can threaten the germination and survival of plants like Centaurea melitensis. To ensure germination and survival under unpredictable environmental conditions, some plants may develop characteristic structures like cleistogamous flower heads, and in some cases they will develop heteromorphic achenes. Morphological differences between peripheral and center achenes may indicate variable responses to temperature. Additionally, unpredictable environmental conditions may lead to differences in the number of peripheral to center achenes …

Wheat Streak Mosaic Virus Infects Systemically Despite Extensive Coat Protein Deletions: Identification Of Virion Assembly And Cell-To-Cell Movement Determinants, Satyanarayana Tatineni, Frank A. Kovacs, Roy C. French

Department of Plant Pathology: Faculty Publications

Viral coat proteins function in virion assembly and virus biology in a tightly coordinated manner with a role for virtually every amino acid. In this study, we demonstrated that the coat protein (CP) of Wheat streak mosaic virus (WSMV) (genus Tritimovirus; family Potyviridae) is unusually tolerant of extensive deletions with continued virion assembly and/or systemic infection. A series of deletion and point mutations were created in the CP cistron of wild-type and/or GFP-tagged WSMV and examined the effects of these mutations on cell-to-cell and systemic transport and virion assembly of WSMV. Mutants with overlapping deletions comprising N-terminal amino …

Microtubule Severing At Crossover Sites By Katanin Generates Ordered Cortical Microtubule Arrays In Arabidopsis, Quan Zhang, Erica Fishel, Tyler Bertroche, Ram Dixit

Biology Faculty Research

Highlights

• Severing primarily depolymerizes the overlying CMT at crossover sites
• Severing probability increases nonlinearly with crossover time
• Katanin localizes to crossover sites and is required for severing
• Loss of katanin activity prevents the formation of coaligned CMT arrays

Summary
The noncentrosomal cortical microtubules (CMTs) of land plants form highly ordered parallel arrays that mediate cell morphogenesis by orienting cellulose deposition [1, 2 and 3]. Since new CMTs initiate from dispersed cortical sites at random orientations [4], parallel array organization is hypothesized to require selective pruning of CMTs that are not in the dominant orientation. Severing of CMTs at crossover sites …

Calmodulin-Mediated Signal Transduction Pathways In Arabidopsis Are Fine-Tuned By Methylation, Joydeep Banerjee, Roberta Magnani, Meera Nair, Lynnette M. Dirk, Seth Debolt, Indu B. Maiti, Robert L. Houtz

Department of Plant Pathology: Faculty Publications

Calmodulin N-methyltransferase (CaM KMT) is an evolutionarily conserved enzyme in eukaryotes that transfers three methyl groups to a highly conserved lysyl residue at position 115 in calmodulin (CaM). We sought to elucidate whether the methylation status of CaM plays a role in CaM-mediated signaling pathways by gene expression analyses of CaM KMT and phenotypic characterization of Arabidopsis thaliana lines wherein CaM KMT was overexpressed (OX), partially silenced, or knocked out. CaM KMT was expressed in discreet spatial and tissue-specific patterns, most notably in root tips, floral buds, stamens, apical meristems, and germinating seeds. Analysis of transgenic plants with genetic dysfunction …

Botrytis Neck Rot Of Onion, Claudia Nischwitz

All Current Publications

No abstract provided.

Quantitative Relationship Of Soil Texture With The Observed Population Density Reduction Of Heterodera Glycines After Annual Corn Rotation In Nebraska, Oscar Perez-Hernandez, Loren J. Giesler

Department of Plant Pathology: Faculty Publications

Soil texture has been commonly associated with the population density of Heterodera glycines (soybean cyst nematode: SCN), but such an association has been mainly described in terms of textural classes. In this study, multivariate analysis and a generalized linear modeling approach were used to elucidate the quantitative relationship of soil texture with the observed SCN population density reduction after annual corn rotation in Nebraska. Forty-five commercial production fields were sampled in 2009, 2010, and 2011 and SCN population density (eggs/100 cm3 of soil) for each field was determined before (Pi) and after (Pf) annual corn rotation from ten 3 3 …

The System I And System Iii Holocytochrome C Synthases In Cytochrome C Biogenesis, Brian San Francisco

All Theses and Dissertations (ETDs)

Cytochromes c are proteins that are involved in important redox reactions in organisms from every kingdom of life. C-type cytochromes, uniquely, possess a covalently bound heme. Since cytochromes c are assembled at their site(s) of function: outside of the cytoplasmic membrane in bacteria, in the chloroplast lumen, or in the mitochrondrial intermembrane space), their assembly poses unique challenges to heme trafficking and post translational modification. Three major systems exist in nature for cytochrome c assembly, termed systems I, II, and III. Using recombinant Escherichia coli, aspects of systems I and III were analyzed, with an emphasis on the synthase protein(s) …

Forward Genetic Screen Of Trichomes For Discovery Of Cytoskeleton-Based Mutants, Adam M. Fessenden, Samuel Belteton, Daniel B. Szymanski

The Summer Undergraduate Research Fellowship (SURF) Symposium

Understanding plant cell development and what genes influence cell growth can lead to breakthroughs in beneficial areas such as bioremediation, agricultural production, and biofuels. However, information on many of the genes that control plant cell growth is either unknown or severely limited. Further research to fully comprehend the genetic pathways within the cells will enable the genetic engineering of plants to further benefit society. One approach is the combined use of a forward genetic screen, sophisticated growth analysis, and gene identification. Using Arabidopsis thaliana trichomes, leaf hairs, as a model system, the mutagenized population of thousands of plants was screened …

Streptomycin Resistance Of Erwinia Amylovora Isolated From Apple (Malus Domesticus) In Utah, Claudia Nischwitz

All Current Publications

No abstract provided.

Impact Of Mid-Successional Dominant Species On The Diversity And Progress Of Succession In Regenerating Temperate Grasslands, Sandor Bartha, Szilard Szentes, Andras Horvath, Judit Hazi, Zita Zimmerman, Csaba Molnar, Istvan Dancza, Katalin Margoczi, Robert Pal, Dragica Purger, David Schmidt, Miklos Ovari, Cecelia Komoly, Zsuszanna Sutyinszki, Gabor Szabo, Andras Istvan Csatho, Melinda Juhasz, Karoly Penksza, Zsolt Molnar

Biological Sciences

(i) Which species dominate mid-successional old-fields in Hungary? How does the identity of these species relate to local (patch-scale) diversity and to the progress of succession? (ii) Which species have the strongest negative impact on diversity in spontaneous old-field succession and what generalizations are possible about traits of these species? (iii) Are these species dominant or subordinate components in mature target communities? (iv) Do native or alien species have stronger effects on the diversity and progress of succession?

Functional Characterization Of Metallothioneins In Arabidopsis And Barley, Nimnara Yookongkaew

Open Access Dissertations

Metalothioneins (MTs) are metal binding proteins that can bind metals such as Cu, Zn, and Cd but the functions of MTs in plants are largely unknown. To understand the function of MTs in Arabidopsis, T-DNA insertion mutants lacking 4 MT genes including MT1a, MT2a, MT2b and MT3 were developed. The quadruple mutant (mt1a/mt2a/mt2b/mt3) showed no visible phenotype under standard growth conditions. However, it accumulated higher Cu in leaves compared to wild type but lower Cu in seeds. Further analysis showed that triple mutants lacking both MT1a and MT2b, which are highly expressed in vascular tissues, had similar …