This research is directed towards an eventual understanding of the metabolic regulation of the polyamine pathway and the genes encoding the enzymes of the pathway in Nicotiana (tobacco). Molecular probes (antibodies or cDNA clones) will be obtained for 3 of the enzymes of the pathway: ornithine, arginine, and SAM decarboxylases. The methods used will be standard protein purification and antibody production, coupled with the possible use of heterologous probes for some enzymes that have been cloned from mammalian systems. These probes will be used to study the regulation of the pathway by polyamines and by environmental factors. Tobacco cell cultures are a favorable system because they can grow on a minimal defined medium, and also be regenerated into whole plants. This research will also examine the genomic DNA corresponding to any cDNA clones, as examples of genes encoding metabolic enzymes, a category of plant genes that are relatively understudied. The proposed research is important to an understanding of how polyamines affect plant growth. Polyamines are thought to be involved in a number of important aspects of plant growth including flower development (the subject of this proposal), seed formation, senescence (plant death) and many aspects of plant responses to stress (salt, drought, pathogens).***//
