Cytokin are a group of plant hormones which play an important role in cell division and differentiation. The mechanisms controlling the appropriate levels of cytokinins in plants are poorly understood. The long term goal of the research project is to identify regulatory elements controlling cytokinin metabolism in the genus Phaseolus. Recent findings led to the discovery of genetic differences in cytokinin metabolism in Phaseolus embryos, identification of novel zeatin metabolites and isolation of three cytokinin specific enzymes. As the activities of these enzymes are species specific and the resulting metabolites display higher biological activity than the parent compound, selective expression of key metabolic enzymes may be a significant mechanism of regulating active cytokinin levels. To elucidate the metabolic control mechanisms, we propose to further characterize the enzymes, to generate mononclonal anti bodies for detection of enzyme activity at different developmental stages and to conduct molecular analyses of the regulation and expression of these enzymes. The proposed work is important to the formulation of a working model governing the overall controls of hormone metabolism in higher plants. Cytokinins are a group of hormones which regulate plant growth and cell division. The proposal work is designed to isolate and identify aspects of these plant hormones and their functioning to better understand plant growth.
