Genomics of Plant Stress Tolerance

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The long-term goal of this proposal is to identify and determine the role of all the genes involved in a plants response to salt and water stress. Over the last decade, it has become clear that responses to water deficit and ion imbalance are governed by complex molecular and biochemical signal transduction processes, which coordinately act to determine tolerance or sensitivity at the whole-plant levet. Within the last five years, however, advances in genomics, informatics, and functional genomics have made it technically feasible to gain a global understanding of the gene complement or set that becomes integrated to effect abiotic stress tolerance. To tackle the genetic basis of this tolerance in higher plants in the most efficient, comprehensive, and integrative way possible Drs. R. Bressan, P. Hasegawa ( Purdue University), R. Burnap, J. Cushman, R. Prade (Oklahoma State University) and H. Bohnert, D. Gaibraith, J-K. Zhu (University of Arizona) have formed a consortium. Each participant has a documented and extensive experience in this research area with a proven record of productivity and in many instances past or present collaborations.This team will employ three distinct, yet complementary approaches to isolate, characterize, and assess the function of the core set of stress-related genes that provide the basis for the water and salt stress tolerance phenotype in plants.The first approach will encompass the functional identification of genes important to stress tolerance by random and targeted mutagenesis strategies in well-studied model organisms (Synechocystis PCC6803, Saccharomyces cerevisiae, Aspergillus nidulans, and Arabidopsis thaliana). For Arabidopsis, they will identify, map and clone genetic Ioci from a large set of mutants defective in stress tolerance or signaling. The resulting sets of mutants will be used for complementation studies using genes from higher plant sources.The second approach aims to define the core set of stress-related transcripts from both sensitive plants (Arabidopsis thaliana and rice) and resistant plants (Dunaliella salina and ice plant) using EST sequendng and microarray analysis. This approach will focus on the comparative study of gene expression patterns in salt and drought sensitive and resistant organisms, since recent studies of resistant organisms have revealed the existence of mechanisms of stress tolerance not present or not appropriately expressed in sensitive organisms.The third approach will extend the functional analysis of stress-related transcripts by monitoring in situ Iocalizations by using promoter trapping approaches and gain-of-function studies.These approaches represent logical extensions of ongoing work in individual groups within this center. They will foster interaction and integration of Consortium activities through daily interactions, workshops/meetings and extended work periods in member laboratories for their students and postdoctoral fellows to ensure a new generation of researchers trained in multi-faceted and interdisciplinary problem solving. The impact of abiotic stress on crop productivity is remarkable according to USDA statistics and amounts to two-thirds of all yield reductions in agriculture. This proposal is exceptionally timely, combines unique expertise, is hypothesis-driven and culminates in a dearly defined goal - understanding the number, nature and networking of genes and physiological mechanisms that constitute plant abiotic stress tolerance.