Rhizosphere bacteria have a decisive influence on plant ionic adjustment, as well as in ameliorating plant growth under an array of stress situations. Plant growth-promoting rhizobacteria (PGPR) colonize the rhizosphere of plants and promote plant growth through mechanisms such as solubilization of mineral phosphates, biological N2 fixation, production of siderophores and phytohormones, and can induce systemic resistance in the plant. This can be of extreme importance when considering the restoration of salinized grounds by halophytic species. This present work aims to evaluate the physiological fitness and phytoprotection improvement by salt marsh PGPR in Halimione portulacoides under mild and severe salt stress. Plants inoculated with PGPR-consortium showed higher photochemical performances, improved antioxidant response, and promotion of osmotic balance traits, that boosted the individual’s ability to cope with mild salt stress. All these changes are also in line with the differential elemental profiles (Na, K, and Ca) observed in the different plant tissues. Even under severe salt stress, some physiological traits were improved when compared to the non-inoculated individuals. The results developed under this work, point out an important role of bioaugmentation in promoting plant fitness and improving salt tolerance, with a great potential for applications in seawater agriculture, restoration, and bio-reclamation of salinized soils.

Halophytic plants are, by definition, well adapted to saline soils. However, even halophytes can face nutritional imbalance and accumulation of high levels of compounds such as oxalic acid (OA), and nitrate (NO₃^¯). These compounds compromise the potential nutritional health benefits associated with salt tolerant plants such as Portulaca oleracea. Thus, preventing the accumulation of non-nutritional compounds will allow plants to be grown in saline conditions as crops. To this end, two ecotypes (ET and RN) of Portulaca oleracea plants were grown under growth room conditions with two levels of salinity (0, 50 mM NaCl) and three ratios of nitrate: ammonium (0:100%; 33:66%; 25:75% NO₃^¯:NH₄⁺). The results showed that both ecotypes exposed to elevated NO₃^¯, showed severe leaf chlorosis, high levels of OA, citric acid, and malic acid, while plants of ecotype ET exposed to elevated NH₄⁺ concentrations (33% and 75%) and 50 mM NaCl displayed a marked reduction in OA content, increased total chlorophyll and carotenoid contents, crude protein content, total fatty acid (TFA) and α-Linolenic acid (ALA) thus enhancing leaf quality. This opens the potential to grow high biomass, low OA P. oleracae crops. Lastly, our experiments suggest that ecotype ET copes with saline conditions and elevated NH₄⁺ through shifts in leaf metabolites.