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Trade-offs in immunity in the metal hyperaccumulator Noccaea caerulescens (TRADEOFF METAL)
Date du début: 1 oct. 2013, Date de fin: 30 sept. 2015 PROJET  TERMINÉ 

Metal hyperaccumulating plants are able to accumulate exceptionally high concentrations of metals, such as Zinc, Nickel, and Cadmium, in their shoots to levels that would be toxic to most other plant species. The trait of metal hyperaccumulation has evolved independently multiple times in the plant kingdom. Since this trait is of high importance to bioremediation and biofortification strategies, intensive research efforts aim to decipher the underlying molecular processes. However, although our understanding of the molecular mechanisms involved in metal uptake and tolerance has improved, not much is known about the processes that have led to the evolution of metal hyperaccumulation in plants. Recent studies have provided new insight into the ecological and evolutionary significance of this trait by showing that the metal hyperaccumulating plant Noccaea caerulescens can use high concentrations of accumulated metals to defend itself against attack by pathogenic microorganisms. Interestingly, infected N. caerulescens plants show none of the inducible defence responses that are used by most plants to provide protection against infection, which suggests that it relies on accumulated metal for disease resistance. The fact that these plants have evolved the ability to uptake and store metals in their shoot tissue, but have in turn lost defences common to most plants suggests a trade-off in expressing both traits. This project aims to study the evolutionary, ecological and functional processes involved in the gain of metal hyperaccumulation and loss of other defensive traits in N. caerulescens. Responsible genes will be identified using phenotyping and RNAseq technology and these candidate genes will be further analysed through evolutionary approaches. The project will provide new insights into the evolution and ecology of metal hyperaccumulation and contribute to the understanding of how plant responses to biotic and abiotic stress may be connected on the molecular level.