Which bacteria are involved in biological nitrogen fixation?

Biological nitrogen fixation is a crucial process that involves the conversion of atmospheric nitrogen (N2) into ammonia (NH3), which can then be utilized by plants for growth. This process is primarily facilitated by certain types of bacteria that have the necessary enzymes to perform nitrogen fixation.

Rhizobia are a group of bacteria known for their symbiotic relationship with legumes. When legumes are grown, Rhizobia infect their root hairs and form nodules, where the nitrogen fixation process occurs. These bacteria take atmospheric nitrogen and convert it into a form that plants can absorb and use, ultimately enhancing soil fertility and supporting plant growth. This is especially significant for sustainable agriculture, as it reduces the need for synthetic nitrogen fertilizers.

While other bacteria and fungi play essential roles in soil health and nutrient cycling, they do not specialize in nitrogen fixation in the way that Rhizobia do. For example, Pseudomonas are more involved in degrading organic substances and pathogens, Mycorrhizae are fungi that form beneficial relationships with plant roots to improve nutrient and water uptake, and Actinomycetes are known for their role in decomposing organic matter and soil structure improvement. However, none have the specific capability for nitrogen fixation exhibited by Rhizobia.