Here we report that Cupriavidus metallidurans bacteria increase sodium (Na+) accumulation in Arabidopsis thaliana and quinoa (Chenopodium quinoa). Given the metal mobilizing feature of the bacteria, we tested this hypothesis that the bacteria can increase the uptake of Na+, a metal ion, by plants. In agar plate assays under salinity conditions, the bacterial inoculation significantly decreased plant biomass by 280% and 20% in Arabidopsis and quinoa, respectively. In pot experiments under the salinity conditions, the bacterial inoculation resulted in about 60% loss of the quinoa plant biomass. We detected a significant high accumulation of Na+ in the leaf and stem tissues of the bacteria-inoculated quinoa plants, suggesting an association between increased Na+ accumulation and bacteria-mediated growth retardation in the plants. Altogether we report a novel phenomenon, in which bacteria increase Na+ uptake by plants.

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