Molecular analysis of phosphite induced responses in Arabidopsis thaliana
Berkowitz, O., Jost, R., Fenske, R., Hardy, G.E.S.J. and O'Brien, P.A. (2011) Molecular analysis of phosphite induced responses in Arabidopsis thaliana. In: XVIII International Botanical Congress IBC2011, 23 - 30 July, Melbourne, Australia.
Phosphite (H2PO3 -) is a phosphate analog that is not metabolised by plants but can interfere with the phosphate signalling pathway. It inhibits the plant’s phosphate starvation response, e.g. the up-regulation of high-affinity phosphate transporters, and thus has constrictive effects on plant growth under low phosphate supply. Phosphite has also been used widely to protect plants from oomycete pathogens such as Phytophthora and Phytium. Phytophthora species are prominent pathogens in agriculture, e.g. Phytophthora infestans being the causing agent of potato blight (Irish potato femine). Phytophthora cinnamomi has devastating effects ('dieback disease') on native ecosystems with over 3000 plant species at risk in Western Australia alone. Phosphite is the only known protectant of plants and exhibits a complex mode of action. At elevated concentrations it directly inhibits the pathogen’s growth by interference with its phosphate-dependent metabolism and/or phosphate signalling which is paralleled in plants grown on high phosphite concentrations. In addition to these direct effects phosphite also induces some of the plant’s defence responses, e.g. treatment of plants leads to increased expression of defence genes. However, the underlying mechanism of this indirect effect is not understood. We have started to characterise the impact of phosphite on plant defence responses by analyses of phenotypic changes, gene expression and metabolic pathways in the model plant species Arabidopsis thaliana. Transgenic plants have been generated that express a microbial phosphite dehydrogenase which converts phosphite into phosphate. These plants are a valuable tool to dissect direct from indirect phosphite effects.
|Publication Type:||Conference Item|
|Murdoch Affiliation:||Centre for Phytophthora Science and Management
School of Biological Sciences and Biotechnology
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