Isolation and Evaluation of Qatari Rhizobacteria: Antagonistic Potential Against Phytopathogens and Growth Promotion in Tomato Plants

In this research, numerous plant growth promoting rhizobacteria were examined, aiming to enhance plant growth. The study involved the collection of native rhizobacterial isolates from the rhizosphere of various wild plant species in Qatar. These isolates underwent in-vitro evaluation to assess their antagonistic potential against Fusarium oxysporum and Botrytis cinerea using the dual culture technique. The results indicated significant growth inhibition, reaching up to 50%. Subsequent in-vivo evaluations were conducted under greenhouse conditions, revealing that local strains exhibited significant growth-promoting effects. Further in-vivo tests were carried out using the Hoagland medium to assess the rhizobacteria's efficacy in the presence of phytopathogens. The strains not only aided tomato seedlings in overcoming diseases but also increased both above and belowground biomasses compared to the control, demonstrating significant results (p ≤ 0.05). Moreover, the selected strains were subjected to various characterization tests, revealing their ability to directly and indirectly promote plant growth. It was found that the isolates were capable of the producing Indole-3-acetic acid (IAA), hydrogen cyanide (HCN), hydrolytic enzymes, ACC deaminase, ammonia (NH3), some strains displayed phosphate solubilization capabilities and most were capable of growing under saline conditions (5-10% NaCl). In summary, this study highlighted the valuable traits possessed by indigenous rhizobacterial isolates from arid regions. These traits position them as promising candidates for bio-control agents and bio-fertilizers in agricultural applications, showcasing their potential for sustainable and enhanced crop cultivation.