Pseudomonas sp. G31 and Azotobacter sp. PBC2 Changed Structure of Bacterial Community and Modestly Promoted Growth of Oilseed Rape

Oilseed rape is one of the most important oilseed crops, requiring high levels of nitrogen fertilization. Excessive nitrogen use, however, leads to numerous negative environmental impacts, spurring the search for sustainable, environmentally friendly alternatives to reduce reliance on mineral nitrogen fertilizers. One promising approach involves plant-growth-promoting bacteria (PGPB), which can support oilseed rape growth and lessen the need for traditional nitrogen fertilizers. This study evaluates a selected microbial consortium comprising bacterial isolates obtained from soil: <i>Pseudomonas</i> sp. G31 and <i>Azotobacter</i> sp. PBC2 (P1A). The applied PGPB significantly increased seed yield (a 27.12% increase) and, in the initial phase of the study, reduced the ammonium nitrogen content in the soil (a 20.18% decrease). Metataxonomic analyses were performed using Next-Generation Sequencing (NGS) technology by Illumina. Although P1A did not significantly affect alpha diversity, it altered the relative abundance of some dominant soil microorganisms. In the BBCH 75 phase, the P1A consortium increased the abundance of bacteria of <i>Firmicutes phylum</i>, including the genera <i>Bacillus</i> and <i>Paenibacillus</i>, which was considered a beneficial change. In summary, the <i>Pseudomonas</i> sp. G31 and <i>Azotobacter</i> sp. PBC2 consortium increased seed yield and was found to be part of the native rhizosphere community of oilseed rape, making it a promising candidate for commercialization.