J. G. Menzies,3 and
R. R. Bélanger1
1Département de Phytologie--Faculté des Sciences de l'agriculture et de l'alimentation, Centre de Recherche en Horticulture, and 2Département de Phytologie--Faculté des Sciences de l'agriculture et de l'alimentation, Université Laval, Pavillon Charles-Eugène-Marchand, Québec, QC G1V 0A6, Canada; 3Agriculture and Agri-Food Canada, 195 Dafoe Road, Winnipeg, MB R3T 2M9, Canada
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Accepted 29 May 2009.
The supply of soluble silicon (Si) to plants has been associated with many benefits that remain poorly explained and often contested. In this work, the effect of Si was studied on wheat plants under both control and pathogen stress (Blumeria graminis f. sp. tritici) conditions by conducting a large transcriptomic analysis (55,000 unigenes) aimed at comparing the differential response of plants under four treatments. The response to the supply of Si on control (uninfected) plants was limited to 47 genes of diverse functions providing little evidence of regulation of a specific metabolic process. Plants reacted to inoculation with B. graminis f. sp. tritici by an upregulation of many genes linked to stress and metabolic processes and a downregulation of genes linked to photosynthesis. Supplying Si to inoculated plants largely prevented disease development, a phenotypic response that translated into a nearly perfect reversal of genes regulated by the effect of B. graminis f. sp. tritici alone. These results suggest that Si plays a limited role on a plant's transcriptome in the absence of stress, even in the case of a high-Si-accumulating monocot such as wheat. On the other hand, the benefits of Si in the form of biotic stress alleviation were remarkably aligned with a counter-response to transcriptomic changes induced by the pathogen B. graminis f. sp. tritici.
© 2009 The American Phytopathological Society