Exploring rhizobacteria from Brazilian Pampa via multicriteria analysis to boost soybean and maize productivity

Abstract

Meeting the global food demand of a growing population requires sustainable agricultural practices. Plant growth-promoting rhizobacteria (PGPR) offer an eco-friendly alternative to reduce dependency on agrochemicals. This study aimed to identify Pampa biome soil bacteria with potential for biostimulant products development. Soil samples were collected from pasturelands, native forest, and the rhizospheres of rice and soybean crops. A total of 181 isolates were evaluated for their ability to fix nitrogen, solubilize phosphate and potassium, and produce siderophores. A multicriteria decision analysis (MCDA) was applied to integrate these four traits and identify a subset of 19 non-dominated strains based on Pareto optimality. To refine the selection for in planta evaluation, these 19 isolates were further assessed for their production of indole-3-acetic acid (IAA). The seven top IAA-producing strains, whose 16S rRNA sequences showed identity to Pseudomonas frederiksbergensis, Pseudomonas vancouverensis, Pseudomonas rhodesiae, Enterobacter ludwigii, and Burkholderia puraquae, were then selected for greenhouse trials in soybean and maize. All strains significantly enhanced soybean growth, with P. frederiksbergensis increasing aerial dry weight by up to 142 %. Additionally, P. frederiksbergensis and P. rhodesiae promoted maize growth, demonstrating their potential as biofertilizers. By integrating MCDA into the screening process, this study provides a robust approach for identifying high-performing PGPR strains to support sustainable agriculture.