Rhizobia to Cyanobacteria: Advances in Nitrogen Fixation Research

Nitrogen fixation is crucial for ecological health, converting atmospheric nitrogen (N₂) into ammonia (NH₃) that supports life on Earth. Rhizobia bacteria form symbiosis via specialized nodules in legume roots, directly supplying nitrogen to their host plants, while associative fixers like Azospirillum inhabit roots to boost nutrient absorption. Free-living cyanobacteria are highly versatile, which enrich ecosystems by fixing nitrogen, improving soil fertility, fertilizing rice, and revitalizing infertile lands through legume symbiosis and supportingnon-leguminous crops and natural plant growth. Modern biotechnologies, including genetic engineering and synthetic biology, have strengthened nitrogen fixation efficacy in rhizobia and cyanobacteria, which promotes sustainable farming by reducing dependence on harmful synthetic fertilizers. Biofertilizers not only sustain crop yields but also benefit medicinal and aromatic plants such as basil, mint, and patchouli while enhancing secondary metabolites in tulsi and lavender. Derivatives with antimicrobial properties help protect turmeric and ginger from fungal infections by increasing stress resistance. Integrating genomics and microbiome research with field applications empowers farmers to meet rising costs and climate challenges. Strong policies and interdisciplinary collaboration are crucial for translating these scientific advances into practical solutions. From rhizobia to cyanobacteria, nitrogen fixation remains nature’s model for sustainable and resilient agriculture.