Native rhizobia from arid and semi-arid regions of Algeria exhibit drought tolerance

Abstract The purpose of this study was to assess the potential of the native rhizobia that were isolated in the root nodules of goat-thorn, broom, and narrowest ononis in the arid and semi-arid arid regions of Algeria. Seventeen Rhizobium isolates were attained and morphologically and biochemically characterized. They were tested for biostimulant potential and tolerance to salinity, drought, extreme pH, and temperature, as well as for hydrogen cyanide (HCN) production and antagonistic activity against Fusarium species. GSB16, GSB9, GSB3, and OS2 were four stress-tolerant strains selected from these screening results for further testing. These were their effects on seed germination and the early development of durum wheat and pea seedlings under water stress. Strains GSB16, GSB9, GSB3, and OS2 had the most promising profiles. In vitro experiments showed that bacterial inoculation significantly affected wheat seed germination parameters under drought conditions, compared with the uninoculated control (up to + 80% of OS2). The same had been recorded in the pea experiment (maximum of + 175% in GSB16 and GSB3). Molecular identification revealed that the four selected strains belonged to the genus Rhizobium . The results suggest that native stress-tolerant Rhizobium isolates identified in this study can enhance seed germination and plant vitality under drought stress, providing a sustainable approach to supporting the early establishment of cereals and legumes.