Introduction.

Halotolerant bacteria improve plant adaptability to high salt concentrations in soils, making it essential to study isolates inhabiting vulnerable agroecosystems. Objective. To identify halotolerant bacteria isolated from soils of the Ciénaga de Zapata, Cuba, and to characterize them as plant growth-promoting bacteria in plants tolerant to high salinity levels. Materials and methods. The research was conducted in the laboratories of the Instituto de Investigaciones Fundamentales en Agricultura Tropical Alejandro de Humboldt, Cuba, and the Centro Nacional de Recursos Genéticos, Mexico. Five isolates capable of tolerating 200 mM NaCl were selected and phylogenetically identified through 16S rRNA gene sequencing. Laboratory experiments were performed under a completely randomized design, with the five isolates as treatments. Nitrogen fixation, phosphate solubilization, and the production of ammonium, siderophores, indolic compounds, and lytic enzymes were evaluated as response variables. Plant assays were conducted between June and November 2023 under a randomized block design with six treatments (five bacterial strains and an uninoculated control), with three replicates, assessing plant growth and salinity tolerance indicators. Data were subjected to one-way analysis of variance and Duncan’s test at 5 % significance. Results. The isolates belonged to the genera Bacillus and Cupriavidus. All fixed atmospheric nitrogen and solubilized calcium phosphate; four produced siderophores; two generated ammonium; two solubilized potassium; two synthesized indolic compounds and lytic enzymes; and one solubilized aluminum. In plant assays, strains CZ1 and CZ6 stood out, showing significant differences compared to the other strains and the control. Conclusions. The isolated halotolerant bacteria possess traits that support their use as microbial inoculants in saline environments.