Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 16 6 2024 12 08 812 826 EN Ebrahim Eshaghi Department of Plant Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran Sara Mousae Department of Biology, Nourdanesh Institute of Higher Education, Meymeh, Iran Ali Hendiyani Department of Textile Engineering, Islamic Azad University, Science and Research Branch, Tehran, Iran Alireza Habibi Khave Department of Organic Chemistry, Payame Noor University, Tehran, Iran Rahim Nosrati Cellular and Molecular Research Center, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran 2024 02 23 2024 11 06 Background and Objectives: Plant growth-promoting rhizobacteria (PGPR) with a diverse set of traits can improve crop yield in agriculture. The current study aimed to evaluate the potential of multi-trait PGPR isolates as inoculants for maize (Zea mays L.) growth. Materials and Methods: In this study, 23 bacterial isolates were initially screened from maize plant rhizosphere. Ten isolates (A1–A10) were selected based on N fixation, P and K solubilization and their in vitro specific PGPR traits, such as solubilization of Zn, and Mn, the production of IAA, siderophore, ammonia, and HCN were assayed. Finally, the potential of selected isolates in enhancing the germination, height, shoot collar diameter, shoot fresh and dry weight biomass, and root dry weight of maize were evaluated. Results: Among the positive-PGPR colonies, the selected isolates demonstrated the better performance of PGPR traits such as highest nitrogen fixation, P, K, Mn, and Zn solubilization, and production of siderophore, HCN, NH3, and IAA. In addition, the maize seed germination and improvement of maize yield in a pot experiment were observed after their treatment by bacterial inoculants. Biochemical characteristics, 16S rDNA amplification, and sequencing demonstrated a high similarity of PGPR isolates to the strains of Enterobacter, Pantoea, Kluyvera, Lelliottia, Klebsiella, Pectobacterium, and Stenotrophomonas. Conclusion: The findings demonstrated that these strains could prove effective PGPR inoculants for the improvement of maize crops as multiple bio-fertilizers. https://ijm.tums.ac.ir/index.php/ijm/article/view/4614 https://ijm.tums.ac.ir/index.php/ijm/article/download/4614/1733