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Transcript markers of herbicide stress in Arabidopsis and their 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. A. Gutierrez. Transcript markers of herbicide stress in Arabidopsis and their cross-species extrapolation to Brassica. Presented at 2008 American Society of Plant Biology, Merida, MEXICO, June 26 - July 01, 2008.
Impact/Purpose:
Low concentrations and short environmental persistence times of some herbicides make it difficult to develop analytical methods to detect herbicide residues in plants or soils.
Description:
Low concentrations and short environmental persistence times of some herbicides make it difficult to develop analytical methods to detect herbicide residues in plants or soils. In contrast, genomics may provide tools to identify herbicide exposure to plants in field settings. Using whole genome microarray technology (Affymetrix ATH1 GeneChip), a set of 101 candidate markers was identified that provided composite diagnostic signatures that differentiated the transcriptional responses of Arabidopsis thaliana to five important, high potency herbicides. To address the specificity of these markers, quality-controlled and highly replicated expression data were extracted for a wide range of abiotic and biotic stresses, and also chemical compounds inhibiting diverse physiological processes. Only experiments perfomed with ATH1 array, Col-0 genetic background and leaf/seedling tissues as in our epxression data were considered, and these revealed in principal component analyses a clear distinction for the herbicide transcript signature. The individual herbicide replica experiments and the extracted stress datasets were also subjected to correlation analyses. Correlations between individual samples of different treatment groups are considerably lower than within group correlations. Orthologs of these markers were predicted for Brassica, and eight such candidates were tested for Primisulfuron and Sulfometuron methyl in B. napus at 24h and 72h post treatment. Expression patterns observed B. rapa were similar to Arabidopsis, which indicates that true orthologous genes have been identified. Efforts are underway to develop a custom array to detect herbicide drift exposure to Brassica.