Calcium-permeable cation channels are involved in uranium uptake in Arabidopsis thaliana

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Dynamics of the membrane proteome of Arabidopsis thaliana roots in response to uranium stress

Uranium (U) is a non-essential and toxic metal to living plants. Yet, plants are able to take up U naturally present in the soil and accumulate uranyl ions preferentially in the root cell wall and the apoplast. However, molecular targets of U are still poorly identified, and proteomic analyses have only focused on the soluble proteome of plants. To gain a more complete picture of the plant proteome dynamics, here we studied effects of U (i.e. 5 µM and 50 µM) on root membrane proteins from Arabidopsis thaliana using a label free quantitative proteomic workflow based on a nanoLC-MS/MS approach. By this method, we identified 466 differentially regulated proteins after U exposure. Data interpretation revealed that U primarily interferes with membrane-bound enzymes and transporters associated with amino acid metabolism, water transport, intercellular junction assembly and endosome organization. These results provide new insights into the phytotoxic action of U

Dynamics of the membrane proteome of Arabidopsis thaliana roots in response to uranium stress

Uranium (U) is a non-essential and toxic metal to living plants. Yet, plants are able to take up U naturally present in the soil and accumulate uranyl ions preferentially in the root cell wall and the apoplast. However, molecular targets of U are still poorly identified, and proteomic analyses have only focused on the soluble proteome of plants. To gain a more complete picture of the plant proteome dynamics, here we studied effects of U (i.e. 5 µM and 50 µM) on root membrane proteins from Arabidopsis thaliana using a label free quantitative proteomic workflow based on a nanoLC-MS/MS approach. By this method, we identified 466 differentially regulated proteins after U exposure. Data interpretation revealed that U primarily interferes with membrane-bound enzymes and transporters associated with amino acid metabolism, water transport, intercellular junction assembly and endosome organization. These results provide new insights into the phytotoxic action of U

Characterization of a uranium-tolerant green microalga of the genus Coelastrella with high potential for the remediation of metal-polluted waters

International audienceUranium (U) contamination of terrestrial and aquatic ecosystems poses a significant threat to the environment and human health due to the chemotoxicity of this actinide. The characterization of organisms that tolerate and accumulate U is crucial to decipher the mechanisms evolved to cope with the radionuclide and to propose new effective strategies for the bioremediation of U-contaminated environments. Here, we isolated a unicellular green microalga of the genus Coelastrella from U-contaminated wastewater. We showed that Coelastrella sp. PCV is much more tolerant to U than Chlamydomonas reinhardtii and Chlorella vulgaris. Coelastrella sp. PCV is able to accumulate U very rapidly and then gradually release it into the medium, behaving as an excluder to limit the toxic effects of U. The ability of Coelastrella sp. PCV to accumulate U is remarkably high, with up to 240 mg of tightly bound U per g of dry biomass. Coelastrella sp. PCV is able to grow and maintain high photosynthesis in natural metal-contaminated waters from a wetland near a reclaimed U mine. In a single one-week growth cycle, Coelastrella sp. PCV is able to capture 25-55% of the U from the contaminated waters and shows lipid droplet accumulation. Coelastrella sp. PCV is a very promising microalga for the remediation of polluted waters with valorization of algal biomass that accumulates lipids