Independent experiments were carried out in the present study. Firstly, an autochthonous bacteria, isolated from the semi- arid experimental soil from the province of Murcia (Spain), was identified using molecular methods and in an in vitro assay, we determined changes on maintenance of growth of the bacterial cells in axenic culture medium under non stress and stress osmotic conditions [by 40% polyethylene glycol (PEG) application] and their abilities to produce proline, lipid peroxidation (MDA) or poly-ß-hydroxybutyrate (PHB) and PGPB characteristics tested as
-ketobutyrate (ACC deaminase), indole acetic acid (IAA) produc- tion and phosphate solubilization under such non-stress and stress conditions. Secondary, a microcosm experiment under drought conditions analyzed the effectiveness of five autochthonous AM fungal species single or in consortium inoculated and the impact of autochthonous bacteria in improving plant growth, physiology, nutrition and antioxidant activities as indexes of drought tolerance.