Potential of PGPR to Enhance Soybean Productivity in Europe

Soybean cultivation in Europe remains limited compared to major global producing regions, resulting in dependence on imported sources of plant protein. Although soybean cultivation has expanded in several European countries in recent years, production is still constrained by climatic variability, soil conditions, restricted availability of locally adapted varieties, and yield instability. To improve the stimulation of plant defense mechanisms against biotic and abiotic stress, and above all, to achieve yield stability, there is an increasing search for environmentally friendly products, such as biofertilizers, that can be used to rebuild and maintain a sustainable ecosystem. However, environmental intervention requires extensive research on plant species and bacteria. Therefore, increasing attention is being focused on plant growth-promoting rhizobacteria (PGPR), among other factors. These microorganisms stimulate the growth of their host through various pathways, enabling biomass growth, and improving vitality. In the near future, this may explain the various detailed mechanisms of their interactions with plants. This article reviews the current state of soybean production in Europe and synthesizes recent advances in the understanding of PGPR–soybean interactions, with particular emphasis on both direct and indirect mechanisms of action. The roles of PGPR in nutrient acquisition, phytohormone modulation, biological nitrogen fixation efficiency, and stress tolerance are discussed alongside their capacity to suppress soil-borne pathogens and induce systemic resistance. Furthermore, recent European field and greenhouse studies evaluating seed and soil inoculation strategies are summarized to highlight region-specific responses under diverse agroecological conditions. Collectively, the available evidence indicates that PGPR application can contribute to improved soybean performance in Europe, although its effectiveness remains strongly dependent on environmental factors, strain selection, and crop management practices.