The focus of research interests of my laboratory is to investigate genes and metabolites of lipid-based biochemical and signal transduction pathways and the role they play in plant development and survival in response to pathogens. Key regulatory components of these pathways are lipases, lipoxygenases (LOX), 12-oxo-phytodienoate reductases (OPR). One of the greatest scientific challenges that we face currently in this field is to understand the physiological function of individual genes and isozymes, pathways they initiate and their metabolites. Although we are interested in most aspects of these pathways, our current emphasis is to elucidate functions of individual members of the multigene families of LOXs and OPRs in corn. Using genomics tools we have identified and cloned all members of maize LOX gene family. RNA profiling and other expression data strongly suggest their involvement in disease resistance mechanisms. By using reverse genetics strategy, a project is underway to identify maize mutants in which function of all LOX genes is interrupted by insertions of Mutator transposable elements. To assess function of these genes in defense-responses these mutants will undergo vigorous disease resistance screening, oxylipin profiling via HPLC, GC-MS and other biochemical techniques. The most harmful corn diseases worldwide are those caused by pathogens Fusarium verticillioides and Aspergillus flavus, that produce mycotoxins that are extremely harmful to humans and animals. Therefore, these and other corn diseases are the primary targets of our research program.

PLPA 617: Principles and Concepts of Plant Pathogenesis (4 hours with lab). Critical review of the most current literature on molecular and biochemical mechanisms of plant responses to pathogen invasion; overview of disease resistance genes, major classes of defense-related proteins, phytoalexins and antibacterial secondary metabolites and signal-transduction pathways such as those mediated by salicylic acid-, ethylene- and lipid-derived compounds. Laboratory exercises include cloning of resistance and defense-related genes by reverse and forward genetics approaches (genomic and plasmid DNA extraction, RNA extraction, Southern and Northern blotting, PCR amplification, PCR product cloning, co-segregation analysis).

PLPA 301: Will focus on the nature of disease causing agents, the outcomes of theinteraction between plants and pathogens, and the methods we use to control the diseases. The course will conclude with a review of specific subdisciplines, such as epidemiology, the genetics of plant disease, physiological aspects of the disease process, and recent advances in biotechnolgy for better understanding and controlling plant diseses.

The course is designed to parallel the information being covered in PLPA 303/Plant Patholgy Laboratory. The content of PLPA 303 will help in understanding the principles in PLPA 301 by allowing you to directly examine and manipulate plant pathogens as well as diseased symptomatic plants. This experiential perspective is essential to a thorough understanding of plant pathology.