Keywords: Potassium, disease, pest, defence, signalling, metabolism, crops, Arabidopsis thaliana.

Recent advances in plant science have identified potential gene targets for biotechnological efforts to improve nutrient usage and disease resistance in crops. If we want to further exploit the inherent potential of plants to manage nutrient resources and defend themselves against pest and pathogens we have to understand the molecular interactions between nutrition and defence. In this paper we review existing data on how potassium deficiency affects a number of physiological and metabolic processes that impact on plant susceptibility to pathogens and insect pests. Furthermore we describe recent results from our laboratory concerning potassium-deficiency induced changes in gene expression, total enzyme activities, metabolites and signalling pathways in the model plant Arabidopsis thaliana. The data provide a comprehensive picture of how potassium nutrition modulates metabolic and hormonal pathways. It is hoped that this work will lead towards the identification of crucial genes that integrate plant potassium status with metabolism and defence, which in future can be targeted to manipulate crop susceptibility to pathogens and pests under specific conditions of mineral nutrition.

Anna Amtmann, Stephanie Troufflard and Patrick Armengaud, Plant Science Group, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK

20 pages, 1 figure, 87 references.