## 4. Discussion  
Salinity is a major factor limiting plant growth and productivity. Based on their adaptive evolution, some plants, especially halophytes, can resist salinity compared to glycopytes that cannot resist and die. Therefore, the microorganisms associated with these halophytes were able to tolerate, survive and proliferate in the soil and rhizosphere of this hostile environment [20]. The beneficial bacteria associated with these plants colonized the rhizosphere and have an important role in the resistance of plants to saline stress. Plants inoculated with these bacteria induced biochemical and morphological changes leading to increased tolerance to abiotic stress. The current research focused primarily on microorganisms associated with the rhizosphere of halophytes, with PGP activities and high salt tolerance, they are therefore the most suitable candidate for the growth and improvement of the yield of glycolytic plants in areas affected by salt [21]. In this study, 98 strains were isolated from the rhizosphere and endosphere of two species of halophytes (_Sueda mollis_ and _Salsola tetrendra_) and salt soils were located in three different Chotts in eastern Algeria. The physico-chemical characteristics of the sampling sites showed that these soils were highly saline (Ec ranging from 22.95 to 30.34 mS/cm) and had a slightly basic pH (pH 7.99 to 8.05). Of these isolates, 44.89% were rhizosphere bacteria, the number of cultivable bacteria isolated from the rhizosphere soil of the halophyte was higher than the number of non-rhizosphere and endophytic bacteria. This high number of bacteria in the rhizosphere was related to the richness of this zone in secreted root exudates. Such results were observed by [PERSON] et al. [22], where the _Salicornia_ rhizosphere appeared to be a very rich habitat of bacterial communities in comparison with non-rhizosphere soil. This comes back to the rhizosphere effect which was described by several authors [3; 22; 23]. Many authors have specified that mucilage and exudates are the most important sources of organic matter brought to the soil and assimilated by telluric microflora [23]. Bacteria isolated from these areas also had plant growth-promoting properties [20]. In our study of the isolates tested, 73.46% showed nitrogen fixation activity. Nitrogen (N) isone of the main nutrients through which the plant benefits from the microbial association. The inoculation of rhizobacteria in agricultural soil to replace the use of nitrogen fertilizers had shown a marked improvement in crop yield [24]. The mineral phosphate supply was also one of the main activities for improving plant growth. Data from this study showed that 26.53% of strains were capable of solubilizing phosphate. They can be considered as biofertilizers because they could release a quantity of soluble \(p\) which can be assimilated by plants. The percentage of strains obtained was low compared to other works. It was generally accepted that the nature of the soil had an impact on the performance of strains [3]. The synthesis of plant growth hormones, including IAA, is a very common faculty in PGPR. All strains isolated were capable of producing IAA at levels varying from 2.25 ug/mL to 13.83 ug/mL. The highest values were obtained by the rhizospheric isolates of Oum Bouaghi OR16 (12.67 ug/mL), OR15 (13.83 ug/mL), OR14 (10.06 ug/mL). Among the phytohormones, most salt-tolerant PGPR induced IAA biosynthesis. The variation in the amount of IAA produced by the PGPR was, however, species-specific. A high level of IAA produced by halotolerant rhizobacteria was responsible for increased root growth in saline soils. Phytohormones are essential for regulating plant responses and maintaining normal plant physiology to confer tolerance to salinity and other environmental stresses [23]. The responses of plants to salinity induce various alterations in molecular, biochemical and physiological aspects. Modulating the hormonal balance of plants is one of the strategies that PGPR adapted to improve plant growth.