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Arabidopsis transcriptional responses differentiating closely related chemicals (herbicides) and cross-species extrapolation to Brassica
Citation:
Das, M., M. T. Mader, G. Haberer, A. R. Schaffner, J. R. REICHMAN, L. S. WATRUD, T. G. PFLEEGER, D. M. OLSZYK, F. F. Aceituno, AND R. Gutierrez. Arabidopsis transcriptional responses differentiating closely related chemicals (herbicides) and cross-species extrapolation to Brassica. Presented at 19th International Conference on Arabidopsis Research, Montreal, QC, CANADA, July 23 - 28, 2008.
Impact/Purpose:
Using whole genome Affymetrix ATH1 GeneChips we characterized the transcriptional response of Arabidopsis thaliana Columbia 24 hours after treatment with five different herbicides.
Description:
Using whole genome Affymetrix ATH1 GeneChips we characterized the transcriptional response of Arabidopsis thaliana Columbia 24 hours after treatment with five different herbicides. Four of them (chloransulam, imazapyr, primisulfuron, sulfometuron) inhibit acetolactate synthase (ALS), while one (glyphosate) inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). The ALS-inhibiting herbicides affected the expression of numerous genes, particularly those related to protein metabolism and amino acid biosynthesis; they also led to altered transcription of genes involved in C-metabolism, secondary metabolism, abiotic stress response, cell wall modification and growth. In contrast, glyphosate affected the expression of much fewer genes. Interestingly, a set of 101 markers could be compiled which provided a composite diagnostic signature that reliably differentiated the transcriptional responses of Arabidopsis to the five herbicides tested, although the ALS-inhibitors encompassed two highly similar chemical structures (sulfonylurea compounds). These herbicide-specific expression patterns were also distinct from responses to major biotic and abiotic stressors and to series of reference chemicals for which data had been carefully selected from quality controlled public ATH1 microarray experiments. Orthologs of selected markers were predicted for Brassicaceae, and several such candidates were tested in B. napus for responses to the sulfonylurea compounds sulfometuron methyl and primisulfuron methyl. Similar expression patterns were observed as in Arabidopsis, indicating that true ortholous genes had been identified.