E-GEOD-5718 - Transcription profiling of Arabidopsis to investigate protective role of silicon in the Arabidopsis-powdery mildew pathosystem
Submitted on 1 September 2006, released on 14 June 2008, last updated on 4 May 2014
The role and essentiality of silicon (Si) in plant biology has been debated for over 150 years in spite of numerous reports describing its beneficial properties. To obtain unique insights regarding the effect of Si on plants, we performed a complete transcriptome analysis of both control and powdery mildew-stressed Arabidopsis plants, with or without Si application, using a 44K microarray. Surprisingly, the expression of all but two genes was unaffected by Si in control plants, a result contradicting reports of possible direct effect of Si as a fertilizer. In contrast, inoculation of plants, treated or not with Si, altered the expression of a set of nearly 4,000 genes. Following functional categorization, many of the up-regulated genes were defense-related whereas a large proportion of down-regulated genes were involved in primary metabolism. Regulated defense genes included R genes, stress-related transcription factors, genes involved in signal transduction, the biosynthesis of stress hormones (SA, JA, ethylene), and the metabolism of reactive oxygen species. In inoculated plants treated with Si, the magnitude of down-regulation was attenuated by over 25%, an indication of stress alleviation. Our results demonstrate that Si treatment had no effect on the metabolism of unstressed plants suggesting a non essential role for the element, but that it has beneficial properties attributable to modulation of a more efficient response to pathogen stress. Experiment Overall Design: A loop design with complete dye-swap was used as experimental design for comparing plants submitted to four treatments and three biological replicates for a total of 24 Agilent Arabidopsis 3 microarrays. Two factors experimental factors : response to a compound (Silicon, treated or not treated) and disease state (Erysiphe cichoracearum, normal vs. diseased). Each factor had two levels. For each of the four combinations of factors, three plants were randomly selected. Thus a total of 12 plants were used for the experiment. RNA was extracted from rosette leaves.
transcription profiling by array, unknown experiment type
The protective role of silicon in the Arabidopsis-powdery mildew pathosystem. François Fauteux, Florian Chain, François Belzile, James G Menzies, Richard R Bélanger. Proc Natl Acad Sci U S A 103(46):17554-9 (2006)