9728297 Finkelstein The plant hormone abscisic acid (ABA) regulates many aspects of plant growth and development affecting crop productivity, including embryogenesis, water relations and tolerance of a variety of environmental stresses. Our long term goal is to study the function and interaction of elements involved in responses to ABA. Dr. Finkelstein has recently cloned a gene required for seed responses to ABA, AB14, and found it to encode a protein with homology to a class of transcription factors. The experiments outlined in this proposal will characterize the location and timing of AB14 synthesis within the plant, its biochemical function, and investigate its interactions with other gene products in coordinating seed development. Our hypothesis is that AB14 is a seed-specific member of a small family of transcription factors, at least one of which (AB14) participates in seed- and/or ABA-regulation of gene expression, possibly in combination with other transcription factors. The PI expects these studies to have general relevance to understanding the activities of the other members of this gene family. Furthermore, they may have practical significance for potential manipulation of seed nutritional and storage qualities.