Haloalkaliphilic bacteria have plant growth promoting characteristics that can be used to deal with different environmental stresses. To study the effect of haloalkaliphilic bacteria to reduce salinity and alkalinity stress in wheat, 48 isolates were isolated and grouped into halophiles, alkaliphiles and haloalkaliphiles based on growth characteristics. The ammonia, 3-indole acetic acid and ACC (1-aminocyclopropane-1-carboxylate) deaminase production were studied. Wheat yield was evaluated in the presence of six plant growth promoting activity superior isolates in the greenhouse condition. Definitive identification was performed by 16S rRNA gene sequencing. All three groups had plant growth promoting characteristics. Halophilic, alkaliphilic and haloalkaliphilic strains increased wheat yield about 20.6%, 42.7% and 58.2% in comparison with the control, respectively. The economic grain yield was maximum in H7 (3366 Kg ha-1), A11 (5530 Kg ha-1) and HA6 (2672 Kg ha-1) strains. The 16S rRNA gene sequencing indicated that all of them were owned to Bacillaceae family. These bacteria belonged to four genera including, Alkalibacillus, Bacillus, Haloalkalibacillus and Virgibacillus. H1 and H7 belonged to Virgibacillus genera and Virgibacillus pantothenticus species, respectively. Both superior alkaliphilic isolates were classified to Bacillus clausii. The haloalkaliphilic isolates (HA1 and HA6) were allocated to Virgibacillus marismortui and Alkalibacillus haloalkaliphilus species, respectively. All three extremophilic native groups of bacteria had the ability to aid the wheat plant to deal with high stresses, but plants inoculated with haloalkaliphilic strains had higher yield compared to the other groups due to better root growth and development.

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