Identification of beneficial bacteria in Rosemary rhizospheres and determination of plant growth promoting (PGP) potential

Plant growth-promoting rhizobacteria (PGPR), which colonize the rhizosphere, are eco-friendly and beneficial bacteria that directly or indirectly promote plant growth. In this study, 13 isolates from the rhizosphere of Rosmarinus officinalis L. (Rosemary) were identified using MALDI-TOF-MS to assess morphology, biochemistry, and plant growth-promoting traits and to evaluate their antagonistic effects against Fusarium oxysporum. Among all isolates, 9 isolates fixed nitrogen, 8 isolates dissolved inorganic phosphate, 8 isolates produced siderophores, 7 isolates produced IAA (Indole-3-Acetic Acid), and 6 isolates produced HCN. Isolate BBR-6 showed the highest antifungal activity against Fusarium oxysporum, with an inhibition rate of 61.54 %. The isolate BBR-10 (19.40 %) showed the weakest effect against F. oxysporum. Although research on PGPRs has increased recently, research on rosemary is still limited. This study aimed to identify the local bacterial community in the rhizosphere of rosemary and assess its growth-promoting properties and antifungal activity against disease-causing F. oxysporum, potentially acting as a microbial fertilizer and biocontrol agentents.