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Laboratory of Physiology and Molecular Genetics of Plants

Person in charge of the Unit : Oui

Our objective is to identify and to characterize the molecular basis of plant responses to abiotic stresses. A better understanding of those mechanisms will allow to enhance plant tolerance to stress. In particular, we focus our research on tolerance and hyperaccumulation of heavy metals, as well as on mineral deficiency.


Nutrition of plants in major mineral elements

Understanding how plants regulate ion uptake and transport could have significant implications for plant nutrition and human health. For example, by modifying ion uptake and transport, it is possible to develop crops that grow efficiently on nutrient-poor soils, which will reduce the need for fertilizers, increase productivity and better nutritional value. The main research theme is centered on magnesium deficiency in two model plants: Arabidopsis thaliana and Beta vulgaris (sugar beet). The overall goal is to understand how these plants acquire, distribute and regulate their internal Mg level. In a physiological approach, mineral profile, photosynthetic activity and sugar transport are analyzed during Mg deficiency. In a molecular approach, transcriptome changes are identified in response to Mg deficiency. The transcriptional profiling allows the identification of genes involved in rapid responses to external Mg deprivation. In addition, we are identifying limiting steps in sucrose loading from source organs (his transport being often modified upon major elements deficiency). We are characterizing changes in sucrose transport activity by direct transport measurements in purified membrane vesicles, and changes in the expression of sucrose transporter genes, as well as protein abundance are examined. We also investigate the processes by which mineral nutrients, depending on their availability, can have positive and negative effects on the development and growth of roots. We make use of a forward genetic approach to identify Arabidopsis mutant plants that have lost their ability to respond to external mineral supply.

Identification of Molecular Mechanisms Involved in Plant Tolerance to elements metallic tracks

Our research is centered on the identification and characterization of genes implicated in the tolerance and accumulation of cadmium. This identification is based on the study of two close relatives of Arabidopsis thaliana, the model species in plant molecular biology, (which are Thlaspi caerulescens and Arabidopsis halleri). Several genetic approaches have been designed in the laboratory or in collaboration. The study of genes encoding heavy metal transporter or heavy metal binding proteins is in progress. Functional studies include the study of mutant (where the expression of the candidate gene was silenced or enhanced by genetic engineering), tissular cellular localisation, and the study of affinity for heavy metals.  This research wil provide tools to better understand and to modify tolerance and flux of metals through the plant.