USDA-Hatch, USDA-Hatch. The genetics and geography of new polyploid species origin in nature. Factors leading to the origin of polyploid species in their original, wild situations are largely unknown. This project will lead to identifying molecular profiles for diploid progenitors of polyploid species and result in a study of the geography and ecology of the origin of these polyploids. This year we were able to use the chloroplast DNA markers trnL-F spacer and rbcL to identify chloroplast genome contributions to known hybrids from nature. We also explored the single-copy nuclear gene LEAFY. We were successful in isolating and sequencing the gene, but it turned out to have insufficient variability to identify ancestral genomes in polyploids. Crop developers can use the information we develop as they design new polyploid crop plants. (D. Barrington, H. Driscoll, L. Weiss)
National Science Foundation. Determinants of molecular recognition between pheromone receptors and lipopeptide pheromones of Schizophyllum commune. Recognizing external factors, including signals from other members of the same species, requires specific molecular receptors. This work explores how pheromone receptors of a mushroom fungus distinguish among many signals made by other members of the species. A new receptor gene and several pheromone genes have been isolated. Changes have been made in pheromones and receptors to understand what constitutes an effective signal. This receptor class is found in animals and fungi, and includes many receptors that respond to pharmaceuticals. These studies explore how this class of receptors works. (T. Fowler, C. Baker, J. Pare, G. Robertson, J. Kaye, B. Farley)
USDA-Hatch,. Molecular approach to the visualization of lateral root development in the model legume, Medicago truncatula. As a result of a symbiosis with nitrogen-fixing rhizobium bacteria, legumes are relieved of a dependence on additional fertilizer. Only legumes can form this symbiosis. What changes distinguish legume development and allow the interaction with rhizobium? Altered lateral root development may have predisposed legumes to form a symbiosis with rhizobia. We found that regulation of root architecture in legumes differs from that of non-legumes. Understanding what unique aspects of legume development allow them to interact with nitrogen-fixing rhizobium bacteria, might allow us to improve the ability of non-legumes to grow in the absence of commercial fertilizer. (J. Harris)
National Science Foundation. The Cdc42-Cdc24 molecular switch. The long-term goal of this project is to understand what controls the growth of cells and how this regulation interfaces with cell division. The specific aim is to understand the functions of several proteins that control cell growth in the yeast Saccharomyces cerevisiae. In these experiments, researchers showed that the Cdc42p oncogene homolog and its regulator Cdc24p co-localize to sites of polarized growth in the cell, and specific amino acid domain in each protein are responsible for this localization. The research will be useful in cancer research as these proteins have human counterparts that are defective in certain human cancers. (D. Johnson, K. Toenjes, K. Cole, J. Koster, E. Alexander, K. Shaw)
National Institutes of Health/NIDCR. Molecular interactions of oral bacteria and matrix proteins. Actinobacillus actinomycetemcomitans (Aa) is a causative agent of periodontitis and other serious human infections. Little is known about the tropisms used by this organism to maintain itself within the oral cavity and to infiltrate and disseminate in tissues. The purpose of this proposal is to identify the genes and determine the amino acid sequences of Aa matrix binding proteins. Matrix protein binding mutants and the corresponding genes have been identified. Identification of binding factors will be used to develop therapies to prevent the onset and progression of periodontal diseases. (K. Mintz)
National Institutes of Health. Lentivirus-host interactions during assembly and release. Human Immunodeficiency Virus (HIV) is the etiological agent of AIDS and thus is responsible for a worldwide epidemic. The goal of this project is to better understand how HIV is assembled in and released from infected cells. We have characterized the subcellular compartment towards which HIV components are targeted for viral assembly and egress. Our findings may identify novel targets for intervention with the infectious cycle. (M. Thali)
USDA-Hatch. Analysis of Arabidopsis mutants altered in biofilm formation. The interaction between beneficial bacteria and plant roots that results in plant resistance to pathogens is initiated on the root cell wall surface. The purpose of this study is to identify plant genes that are important for the binding of P. fluorescens to plant roots. Screening of arabidopsis T-DNA lines did not result in the identification of mutant plants altered in P. fluorescens binding. Therefore, we initiated a new approach, involving the generation of synthetic matrix proteins, to further characterize root cell wall structure. These studies will enhance our abilities to control plant microbe interactions in the field in a manner that will be beneficial for plant growth. (M. Tierney, C. Johnson, Anne Dougherty)
National Science Foundation. Function of AtPRPs in root hairs and guard cells of Arabidopsis. The ability of plants to control their nutrient and water status has a major impact on plant health, nutrition, and crop yield. This project examines the roles of a family of cell wall proteins (PRPs) that function in root hairs and guard cells, two cell types that function in maintaining nutrient and water status during plant growth. Mutants lacking one or both PRPs expressed in root hairs were found to grow poorly under nutrient-limiting conditions. Molecular analysis of these proteins showed that these PRPs function in different regions of the root hair cell wall and primary sequences responsible for their localization and crosslinking were identified. These studies will help in our understanding of how cell wall structure controls specific aspects of root hair physiology important for plant growth. (M. Tierney, X. Zhang)
National Institutes of Health. Small molecule approaches to studying Toxoplasma gondii invasion. Toxoplasma gondii is a protozoan parasite of significant medical and veterinary importance. Using high-throughput screening techniques, we have undertaken a search for novel compounds that are able to block the invasion of T. gondii into cells of its hosts. We have identified 24 such inhibitors and are currently characterizing their mechanisms of action. This work will provide important new insights into the mechanisms of invasion, as well as new opportunities for anti-parasitic drug development. (G. Ward, K. Carey, A. Heaslip, J. Haraldsen)
USDA-Other Grant, USDA-Other Grant, National Institutes of Health (NINDS). Different Notch receptors in Drosophila development. The cell surface receptor Notch performs different functions during Drosophila development. We are determining whether the different Notch forms perform the different functions. We have shown that (1) Delta functions both as a ligand for Notch and a receptor, (2) that the Notch and Delta binding strength regulate the rate of Notch signaling, and (3) have shown that the Notch amino terminal region regulate receptor clustering, thereby rate of signaling and down-regulation. Notch and Delta are associated with numerous developmental defects and diseases. Our data will lead to better understanding of development and therapeutic strategies. (C. Wesley, B. Bardot, A. Ahimou, L-P. Mok, M. LeComte)
10 projects