1Managed by UT-Battelle for the Department of Energy Molecular signatures characterize plant response to single and multiple environmental stresses Contact: Stan Wullschleger, DOE/Office of Science/Biological & Environmental Research  Gene expression profiles provide an approach to classify plant response to stress according to the architecture of the transcriptome.  Such a capability would be valuable as scientists seek to identify mechanisms that underlie plant response to single and multiple environmental factors.  A framework is described that translates patterns of gene expression into highly diagnostic genomic signatures for plants exposed to high air temperatures and drought, both alone and in combination.  Plant scientists at ORNL and BNL confirm that molecular signatures can be used to describe the physiological state of an organism when plants are exposed to a single stress or when stresses (e.g., heat and drought) are imposed simultaneously.  In nature, departure from homeostatic equilibrium, or stress, is most often caused by multiple environmental factors. The approach developed here should provide an improved understanding of how plants respond to stress in complex environments such as those that will likely occur due to global climate change.

2Managed by UT-Battelle for the Department of Energy  Background: Gene expression profiles can provide a mechanistic understanding of the processes by which genetic change translates to phenotypic variation and the resultant appearance of distinct physiological traits. Progress has been made in this area, particularly in biomedicine, but ecology currently lacks an analogous approach where genomic information is used to characterize the response of an organism to stress and then predict phenotypic outcomes (e.g., stress tolerance, fitness).  Results: Microarrays were used to classify the physiological state of an organism according to the architecture of the transcriptome. This information was linked with coexpression network analysis to determine the underlying genes governing the particular response. We identified several unique stress responsive pathways for Arabidopsis plants exposed to temperature, osmotic, salt, drought stress, and UV-B.  Conclusions: Linking the concept of genomic signatures to gene coexpression analysis provides a unique method of relating an observed plant phenotype to changes in gene expression that underlie that phenotype. Such information is critical to current and future investigations in plant biology and, in particular, to population biology and ecology, where mechanistic insights derived at the resolution of the genome can help researchers understand the dynamic response of individuals and populations to climatic change. Molecular signatures characterize plant response to single and multiple environmental stresses Contact: Stan Wullschleger, DOE/Office of Science/Biological & Environmental Research Weston DJ, Gunter LE, Rogers A, and Wullschleger SD Connecting genes, coexpression modules, and molecular signatures to environmental stress phenotypes in plants. BMC Systems Biology 2: 16 (doi: / )