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Biofertilization with plant-growth-promoting rhizobacteria (PGPR) can positively affect the growth and health of host plants and reinforce their tolerance of stressors. Here, we investigate the use of isolated PGPR consortia from halophytes to improve strawberry growth and flowering performance under saline and elevated CO2 and temperature conditions. Growth, flower bud production, and the photosynthetic apparatus response were determined in strawberry plants grown at 0 and 85 mmol L−1 NaCl and in two atmospheric CO2-temperature combinations (400/700 ppm and 25/+4 °C, respectively). Biofertilization improved strawberry plant growth and flower bud production, independently of salinity conditions, at ambient CO2 and 25 °C, while bacterial inoculation only had a positive effect on plant growth in the presence of salt in high CO2 and at +4 °C. Biofertilizers 1 and 3 generated the largest biomass of strawberries at 400 ppm CO2 and 0 and 85 mmol L−1 NaCl, respectively, while biofertilizer 1 did so in the presence of salt and in an atmosphere enriched with CO2 and at +4 °C. The effect of the consortia was mediated by bacterial strain PGP properties, rather than by an improvement in the photosynthetic rate of the plants. Furthermore, biofertilizers 1 and 2 increased the number of flower buds in the absence of salt, while biofertilizers 3 and 4 did so for salt-inoculated plants at 400 ppm CO2 and at 25 °C. There was no effect of inoculation on flower bud production of plants grown at high CO2 and at +4 °C. Finally, we concluded that the effect of bacterial inoculation on strawberry growth and flowering depended on the type of bacterial strain and growth conditions. This highlights the importance of developing studies considering stress interaction to assess the real potential of biofertilizers. [ABSTRACT FROM AUTHOR]

In a scenario of climate change and growing population, halophyte root microbiota interactions may be a sustainable solution to improve alternative crop production while combating abiotic stress. In this work, seeds of the cash crop halophyte Salicornia ramosissima were inoculated with five different plant growth-promoting rhizobacteria consortia, isolated from the rhizosphere of five halophytes in southwestern Spain salt marshes. For the first time, we recorded seed germination response to three interactive abiotic stressors, CO2 (400 and 700 ppm), temperature (25 and 29 ℃) and salinity (171, 510 and 1030 mM NaCl), all of them related to climate change. Salinity played a decisive role, as no significant differences were registered between treatments at 171 mM NaCl and no germination took place at 1030 mM NaCl. At 510 mM NaCl, one rhizobacterial consortium improved seed parameters notably, increasing up to 114% germination percentage and 65% seedlings biomass. These first findings encourage us to think that cash crop halophytes like S. ramosissima and halophyte root microbiota may be valuable resources for human or animal feeding in a future climate reality. [ABSTRACT FROM AUTHOR]