Unlocking the diversity and plant‐growth promoting potential of the bulk soil bacteria associated with the Saharan tree Vachellia tortilissubsp. raddiana

In this study, we investigated the bacterial diversity and plant growth‐promoting (PGP) properties of bulk soil bacteria of Vachellia tortilissubsp. raddianacollected from the Taidalt and Amazloug nature preserves area in southern Morocco. Using repetitive extragenic palindromic polymerase chain reaction fingerprinting and 16S rDNA sequencing, 93 strains were identified. They belonged mainly to the genera Bacillusand Peribacillus. In vitro tests for PGP traits showed high levels of activity for strains belonging to the genera Bacillusand Pseudomonas. It was relevant that several Bacillusstrains produced auxin (maximum amount 262.61 µg mL−1for Bacillussp. LMR1097), solubilized phosphate (maximum amount 22.10 µg mL−1), or produced siderophores, while three strains were able to fix atmospheric nitrogen (LMR1145, LMR1013, and LMR1015). Inoculation of V. tortilissubsp. raddianaplants with selected bacterial strains (LMR881 and LMR1097) increased shoot and root growth parameters. The strain Pantoeasp. LMR881 had the highest mean values for shoot and root length (24.60–14.80 cm) and shoot dry weight (1.31 g), whereas Bacillussp. LMR1097 showed the lowest mean shoot dry weight. Overall, these results highlight the potential of using selected native bacterial inoculants for improving growth of candidate tree plants to be used in restoration programs of arid degraded areas. The study investigated the diversity of bacteria in the semiarid‐adapted legume.The study identified 93 strains of bacteria, mainly belonging to the genera Bacillusand Peribacillus.Inoculation of V. tortilis raddianawith certain bacterial strains significantly improved plant growth parameter.