Analysis of gene expression in wheat upon treatment with a novel plant activator

Plant activators are an exciting alternative to modern day plant pathogen control procedures. Yet research on plant activators and the mechanisms involved in their action remains limited. The plant activator used during this study, SS, is a purified fraction from the commercial product ComCat® with known positive effects in field trials. The main aims of the study was to confirm the action of SS on a molecular level in wheat, identify genes involved in the process and examine the possible mode of action of the activator. Leaf rust resistant Thatcher+Lr34 and susceptible Thatcher wheat cultivars were treated with SS and water. SSH was performed on pooled Thatcher+Lr34 RNA resulting in 562 putatively induced cDNA clones. Of these, 51 were sequenced. The sequenced clones shared homology with a variety of genes mostly encoding photosynthetic and metabolic products, as well as one plant defence related gene encoding Ptr ToxA binding protein1. Expression analysis confirmed a characteristic two step induction pattern in Thatcher+Lr34 confirming the induced gene expression It was concluded that SS application in wheat increases photosynthetic and metabolic capacity on a molecular level thereby confirming field results. The induction of expression of TaThf1 (Ptr ToxA Binding protein1) by SS suggested a possible unique role in plant defence against pathogens.