The focus of our research is beneficial soil microbes. They influence plant growth, soil health, and resource use efficiency. When selected microbes are applied as bioinoculants, they improve plant nutritional status and protect against biotic and abiotic stresses. Focusing on nitrogen-fixing bacteria, we aim to understand how bacterial regulatory networks control different aspects of the cell physiology through a signalling cross-talk, allowing the cell to act at different times relative to their metabolic requirements, environmental signals and stress conditions. Unravelling the net result of tightly regulated microbial activities is key to understanding microbe-microbe and plant-microbe interactions to ensure an optimal cell function in bacterial bioinoculants for sustainable agriculture, soil health and food production. This includes complex interactions among bacterial communities, involving both cooperation and competition.