Agronomy and Crop Sciences Commons^™

T-Phylloplanin And Cis-Abienol, Two Natural Products From Tobacco Have Broad Spectrum, Anti-Fungal Activities, Brian Christopher King

University of Kentucky Doctoral Dissertations

Tobacco phylloplanins (T-phylloplanin) are a group of closely-related glycoproteins that are formed and disposed at the interface between the plant aerial surface (the phylloplane) and the atmosphere. They are synthesized in short procumbent trichomes and are secreted to aerial surfaces where they are thought to serve the plant as a first line of defense against fungal pathogens. Here it is shown using in vitro and in planta assays that tobacco and sunflower phylloplanins have broad-spectrum antifungal activities against spores - and also hyphae for two species - of several true fungi. Field tests show that T-phylloplanin reduces diseases caused by …

Using Manual Defoliation To Simulate Soybean Rust: Effect On Growth And Yield Formation, Abdullah Mohammad Aqeel

University of Kentucky Doctoral Dissertations

Field experiments were conducted in Kentucky and Louisiana in 2008 and 2009 (split-plot in a randomized complete block design with four replications) to investigate it is possible to simulate with manual defoliation the effect of soybean rust (SBR) (Phakopsora pachyrhizi Syd. and P. Syd) injury on a healthy soybean [Glycine max, (L.) Merr.] canopy, understand how defoliation affects the growth dynamics and canopy light interception, and if defoliation affectsleaf senescence and nitrogen remobilization during the seed-filling period. Two manual defoliation treatments based on changes in effective leaf area index (ELAI) (calculated as the reduction in leaf area …

Restoration Of Tall Fescue Pastures To Native Warm Season Grasslands: Does A Fungal Endophyte Symbiosis Play A Role In Restoration Success?, Sarah Lynn Hall

University of Kentucky Doctoral Dissertations

Tall fescue, a cool-season grass native to Europe, central Asia, and northern Africa, has been widely distributed throughout the U.S. for use as turf and forage. Following its widespread planting, its ability to associate with a toxic fungal endophyte, Neotyphodium coenophialum, was discovered. Research has linked this fescue-endophyte association with increased biotic and abiotic stress resistance in endophyte-infected (E+) versus endophyte-free (E-) plants, and these differences may affect the ability of land managers to eradicate tall fescue and restore native grasslands. I conducted three studies to examine whether E+ tall fescue plants respond differently to management than E- plants, …

Phylloplanins: Novel Antifungal Proteins On Plant Leaf Surfaces, Ryan William Shepherd

University of Kentucky Doctoral Dissertations

Secreted surface proteins are an innate immune defense component employed by animals to inhibit invading microbes. Surface proteins have not been documented in plants, even though the aerial leaf surface, or phylloplane, is a major site of pathogen ingress. We have discovered novel proteins, termed phylloplanins, which accumulate on leaf surfaces of Nicotiana tabacum, and we have isolated the gene Phylloplanin that is unique in gene databases. Natural and E. coli-expressed phylloplanins inhibit spore germination and limit leaf infection by the oomycete pathogen Peronospora tabacina.

We investigated the site of phylloplanin biosynthesis using biochemical techniques. These techniques …

Grazing Evaluation Of A Novel Endophyte Tall Fescue Developed For The Upper Transition Zone, Jennifer Michelle Johnson

University of Kentucky Doctoral Dissertations

A wild-type endophyte (Neotyphodium coenophialum [(Morgan-Jones & Gams) Glen Bacon & Hanlin]) that infects tall fescue [Lolium arundinaceum (Schreb.) Darbysh. = Schedonorous arundinaceum (Schreb.) Dumort.] imparts tolerances to moisture, heat, and grazing stresses, but also produces ergot alkaloids that adversely affect performance and physiology of cattle. Novel endophytes, developed by AgResearch Ltd. NZ, can sustain fescue persistence and productivity, but do not produce toxic ergot alkaloids. University of Kentucky Plant Breeder, T. D. Phillips Ph.D, developed a tall fescue experimental population (KYFA9301) for the upper transition zone. A 2-yr grazing experiment was conducted with steers to evaluate steer …

Evaluating The Effects Of Organic And Conventional Inputs On Soil Chemical And Biological Properties In A Four-Year Vegetable Rotation And The Investigation Of Soil Microbial Properties On Plant Gene Expression, Audrey Law

University of Kentucky Doctoral Dissertations

The objective of this research was to determine the effects of conventional inputs on soil chemical and biological properties compared to organic systems in a four year vegetable rotation. Tillage and cover crops were the same in all treatments to avoid confounding factors often present in similar research. Additional experiments investigated plant gene expression in organic and conventional management systems and in soils with decreased microbial diversity. Experimental plots were prepared in the spring of 2004; four replications of three management treatments, organic, low-input and conventional, were arranged in a randomized complete block design. The rotation consisted of edamame soybean, …

Map-Based Cloning Of An Anthracnose Resistance Gene In Medicago Truncatula, Shengming Yang

University of Kentucky Doctoral Dissertations

Anthracnose, caused by the fungal pathogen Colletotrichum trifolii, is one of the most destructive diseases of alfalfa worldwide. Cloning and characterization of the host resistance (R) genes against the pathogen will improve our knowledge of molecular mechanisms underlying host resistance and facilitate the development of resistant alfalfa cultivars. However, the intractable genetic system of cultivated alfalfa, owing to its tetrasomic inheritance and outcrossing nature, limits the ability to carry out genetic analysis in alfalfa. Nonetheless, the model legume Medicago truncatula, a close relative of alfalfa, provides a surrogate for cloning the counterparts of many agronomically important genes in …