Figure 5.

A simplified model represents the microbial beneficial effects and the signal pathways involved in modulating the effects on N availability. This overview of plant–microbe interactions in the rhizosphere represents the bacterial colonization of the roots to enhance nutrient uptake, resulting in plant growth promotion. N source limitation also increases NH₄⁺ and NO₃⁻ uptake activity as a promising strategy to achieve the sustainability of agriculture. In response to the nutrient deficiency, plant roots release some exudates that may recruit beneficial microbes to improve nutrient uptake. In return, they make nutrients available to plants that influence plant development. The availability of N is one of the critical elements in the process of BNF that converts atmospheric N₂ to NH₃. Accordingly, this model confirms that microbes might replace synthetic fertilizers in the future.