Finkelstein Lab

Figure 1

My laboratory research focuses on the cellular and molecular mechanisms controlling growth and development in plants. Regulation of plant growth is largely coordinated by the action of a small number of hormone classes, all of which have a wide variety of effects throughout the plant's life. We have focused our efforts on signal transduction in response to abscisic acid (ABA), a hormone that affects many agronomically important features of plant growth: embryo development, seed and bud dormancy, water relations, tolerance of a variety of environmental stresses, and senescence. We are using a genetic approach to investigate the mechanism of ABA action by studying mutants of Arabidopsis with reduced sensitivity to ABA. Physiological and genetic characterization of these mutants suggests that the products of the ABA-insensitive (ABI) and other ABA response loci operate in a web of interconnected recognition/response pathways that includes "cross-talk" with signaling in response to other hormones, nutrient status, abiotic stresses, light and developmental cues.

Figure 2

Our major goal is to identify the molecular details of ABA signal transduction. We have used a map-based cloning strategy to identify two novel transcription factors (ABI4 and ABI5) and a third gene (ABI8) that encodes a protein of unknown biochemical function. We are broadening our studies of the network by identifying additional genes that interact with or regulate these loci and investigating their function in ABA and/or stress signaling. These studies have shown that some of the ABI genes are members of gene families with overlapping functions that may be either synergistic or antagonistic, and that there is substantial cross-regulation of expression among some ABI genes and their homologs. We have also identified strong interactions with another novel family of proteins that attenuates function of ABI5 and related transcription factors in early seedling growth. Many, but not all, of the proteins we study are components of the recently identified "core signaling pathway" for ABA response. By integrating molecular, genetic and physiological data, we hope to develop a coherent model of ABA action that could have applications in modifying seed quality and yield or stress tolerance of plants.