Changes In Nutritionally Important Metabolites In Brassica Related to Differential Gene Expression Induced by Selenium

Abiotic factors often induce physiological responses as a result of differential genetic expression within plant metabolic pathways.  Plant physiologists have developed analytical techniques (HPLC, GC, and MS) to measure these impacts in terms of the concentrations of metabolites in plants at the biochemical level. There have been many studies on genotypic and environmental regulation of plant metabolites. However, few studies present data on their regulation at the molecular level.  Functional genomics can provide information about intermediate steps involving gene expression and signal transduction that occur between initial environmental stimuli and eventual plant physiological responses.  DNA microarrays offer a powerful technology to assess how a large number of genes and gene products (RNA and proteins) interact within specific metabolic pathways.  We made use of DNA microarray technology to help elucidate differential gene expression within important metabolite pathways of Brassica and Arabidopsis and to confirm previous analytical results on the impact of selenium on production of glucosinolate and carotenoid compounds within these species.  DNA microarray data identified specific expression of key enzymes within these pathways and helped explain the results of our biochemical analyses.  This technology offers an economical and effective technique to plant physiologists for the quantitative measurement of metabolic responses in specialty crops to biotic or abiotic stimuli, or genetic modifications.