Towards a better understanding of copper tolerance mechanisms in the model plant species Arabidopsis thaliana
(2011)
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Details
- Authors
- Supervisors
- Abstract
- (en) Copper (Cu) is an essential micronutrient for all living organisms but it becomes highly toxic when present in excess. To cope with high levels of Cu supply, plants have evolved tightly regulated tolerance networks. This project aims to contribute to the understanding of Cu tolerance mechanisms by using the model plant species Arabidopsis thaliana. First, we showed that Cu2+ excess is responsible for a reorganization of the root system architecture (RSA) characterized by a primary root growth inhibition and an increase in the lateral root density. Several metabolic processes are associated with this RSA remodeling, including changes in the mineral homeostasis, hormonal status and lignin deposition. A classical genetic approach was then undertaken to tackle the components of this response. In a screen for mutants altered in their response to Cu2+ excess, one Cu2+-sensitive mutant (named cop29) was selected because it exhibited a severe root growth inhibition upon Cu2+ excess. Through a map-based cloning combined with genomic approaches, we identified the At3g14190 gene as the mutated gene responsible for the cop29 phenotype. This gene encodes a protein that has never been characterized before. The cop29 phenotypic characterization revealed that the mutant is also sensitive to Zn2+, Mn2+, and Na+ excess. We also noticed significant lower K+ concentrations in mutant tissues compared to WT upon Cu2+ or Na+ excess. We started the characterization of the COP29 gene/protein and underlined, by using genomic and proteomic databases, that the COP29 protein could have a role as a regulator of the cell cycle. In agreement with this hypothesis, a homologue of the COP29 protein has been recently characterized in rice and maintains meristematic activity under stress conditions. Perspectives will involve additional experiments to confirm a similar role of the COP29 protein in Arabidopsis.
- Affiliations
UCLouvain SST/ELI/ELIA - Agronomy
Citations
Lequeux, H. (2011). Towards a better understanding of copper tolerance mechanisms in the model plant species Arabidopsis thaliana. https://hdl.handle.net/2078.5/94150