CONICET | Buscador de Institutos y Recursos Humanos

Introduction Great part of problems that humanity faces are due to the degradation and loss of arable land and organic carbon content, the loss of structural stability, the decrease in soil biological activity, and the increase risk of erosion and salinization. It is well known that a considerable number of bacterial species, mostly those associated with the plant rhizosphere, are able to exert a beneficial effect upon plant growth. Therefore, their use as biofertilizers or control agents for agriculture improvement has been a focus of numerous researchers, possible solution to these problems is the use of rhizosphere bacteria that stimulate plant growth as bioinoculants. Objective Isolate and identify potential plant growth promoting rhizobacteria stems of saline soils and biochemically characterization as them. Materials and Methods Root samples were from Argentine Salinas, Salinas Grandes of Santiago del Estero and Antinaco Valley of La Rioja. The isolation was based on differences in the morphology of their colonies. Isolates were identified by sequencing the 16S gene and their characterization was carried out by determining the ability of solubilizing the inorganic phosphate by growing on solid medium with tricalcium phosphate (NBRIP supplemented), total indol production was determined by the colorimetric reaction with the reagent Salkowsky, and resistance to 1.2 M NaCl was analyzed in solid LB medium. Pseudomonas putida was used as positive control. Results A total of 25 strains were isolated, 20 of them were able to solubilized phosphate with an efficiency between 3.33 to 4.02%, compared to the control that was 2.92%. There were 14 strains producing siderophores, one of them have a greater efficiency of 350% compared to 217% of control. The other aislates had similar values to the control. The total production of indoles were between 0.17 to 24 ug/mL. Finally, 9 strains grown optimally with NaCl (mass and isolated colonies), 8 only grown on ground and the other were not able. Conclusion Potentially promoting plant growth rhizosphere strains were isolated. Strains 2, 17S, 22S, 33S, 34S from the Salinas Grandes and 41S from Antinaco Valley, are those with increased activity in all biochemical tests and resistance to NaCl.