Poster: Bioinformatics

Abs # 912: Integrated genomic and metabolic analyses of Arabidopsis thaliana physiology

Presenter:	Klapa, Maria I., mklapa@eng.umd.edu
Authors	Klapa, Maria I. (A)   Vantoai, Tara  (B) (C)  Moy, Linda  (B)   Linford, Lara  (B)   Kanani, Harin  (A)   Dutta, Bhaskar  (A)   Sushak, Kinjal  (A)   Hasseman, Jeremy  (B)   Quackenbush, John  (B)
Affiliations:	(A): Department of Chemical Engineering, University of Maryland (B): The Institute for Genomic Research (TIGR) (C): Department of Food, Agricultural, and Biological Engineering, Ohio State University
Web Site:	http://www.glue.umd.edu/~mklapa

It is presently clear that the analysis of a biological system requires the integration of all fingerprints of cellular function: gene expression, total protein production and in vivo enzymatic activity. The value of knowing one of the three is undermined without equally detailed information about the others. Integration of all profiles of a systematically perturbed cellular system can provide insight about the function of unknown genes, the relationship between gene and metabolic regulation and even the reconstruction of the gene regulation network.

In this context, we will demonstrate an integrated analysis of the Arabidopsis thaliana physiology, in which the response of the plant to increased CO₂ concentration in its environment was measured simultaneously at the genomic and metabolic level. Specifically, two sets of plants, grown for 12 days under constant light in liquid cultures, were fed continuously for a day with air of ambient composition and 1% CO₂ concentration, respectively. In both cases CO₂ was 10% labeled. Plants were harvested at various time points and their average gene expression profile was measured using full-genome DNA microarrays, while their metabolic profile using Gas Chromatography - Mass Spectrometry (GC-MS). The metabolic profile comprises the intracellular concentrations of sugars, organic acids and amino acids, while, when possible, measurements of the distribution of label in the various metabolite pools provided additional information about the in vivo enzymatic activity. Comparison of the two cellular profiles unraveled similarities and differences between the genomic and metabolic response of the plants to the external stress, while the derived conclusions proved beneficial for the design of new more specific experiments.