97-23171 Sun Gibberellins are a large family of diterpenoid compounds, many of which are growth regulators in plants which affect diverse developmental processes, such as germination, stem elongation, leaf expansion, or flower and fruit or seed development. The proposed work focuses on the perception of gibberellins by cells and the signal transduction pathway that leads to the known responses of the hormone resulting in changes in gene expression and the developmental and physiological reactions that are well described. Little, in contrast, is known about gibberellin perception and signaling. The proposed will characterize the gene, RGA, which very likely encodes a gibberellin receptor, and study mutants in Arabidopsis which are defective in different aspects of gibberellin signal transduction. The work includes genetic analysis, gene cloning and the traditional techniques for characterizations of genes, cell-specificity of expression and, finally, biochemical analyses for a functional description of genes. While the work is principally designed for obtaining an understanding of hormone signaling, the application aspects of the work for crop improvement, for example, are considerable.
