A combined biochemical, molecular and computational approach to understanding the regulation of gibberellin biosynthesis in Arabidopsis

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Valerie M. Sponsel (PI), Jianhua Ruan (Co-PI), Garry Sunter (Co-PI).Proposal number IOS-0848135A combined biochemical, molecular and computational approach to understanding the regulation of gibberellin biosynthesis in Arabidopsis.The gibberellin group of plant hormones regulate many phases of a plant's life cycle from seed germination to flowering and fruit development. The amount of bioactive gibberellin that is present in particular cells, or tissues, at specific stages of development is finely regulated, and will determine whether plant growth and development are optimal. Defining the factors that regulate gibberellin metabolism and signaling is necessary in order to understand the molecular mechanisms that establish gibberellin homeostasis. The project brings together three scientists with backgrounds in plant physiology, molecular biology and bioinformatics to examine the transcriptional regulation of genes encoding enzymes in the gibberellin biosynthetic pathway in the model plant, Arabidopsis thaliana. It focuses on how 2-oxoglutarate-dependent dioxygenase enzymes are regulated by internal factors including gibberellins (metabolic regulation) and other plant hormones, such as auxin. Transcriptional regulation of some of these enzymes appears to be set in place in a hierarchical manner, and the premise of this research is that elucidating the means whereby this regulation is applied will be instrumental in understanding gibberellin homeostasis. Integrated computational analysis of promoter sequences and of publicly-available large-scale microarray data will be performed to determine if particular motifs are shared between 2-oxoglutarate-dependent dioxygenases that have common regulation (temporal, spatial, feed-back, auxin etc), and to construct quantitative, predictive models of transcriptional regulation using those motifs. It is then proposed to test whether these motifs define cis-regulatory elements that are responsible for timing, location and hormonal regulation of transcriptional activity in Arabidopsis seedlings. The interdisciplinary research will be conducted at the University of Texas at San Antonio, a Hispanic-serving, predominantly undergraduate institution with 75% first generation students. It brings together students from the Computer Science and Biology Departments and will train students from groups traditionally underrepresented in science and technology.