AGRICULTURAL BIOTECHNOLOGY STRATEGIES FOR ENHANCING NITROGEN FIXATION IN CEREAL CROPS

Abstract

Background: Nitrogen deficiency is a major limiting factor for cereal crop production worldwide. Excessive application of synthetic nitrogen fertilizers is a major reason for environmental pollution, greenhouse gas emissions, soil degradation and decreasing sustainable farming. Improving biological nitrogen fixation in cereal crops is a promising approach for increasing crop productivity with little reliance on fertilizers.

Objective: Here, we review state-of-the-art approaches in agricultural biotechnology to improve nitrogen fixation effectiveness in cereal crops via genome engineering, optimization of microbial symbiosis, synthetic biology and rhizosphere engineering.

Method: Comparative analysis was made of CRISPR-mediated genome editing, nitrogen-fixing microbial inoculation, synthetic nitrogen fixation pathways, root microbiome engineering, and biofertilizer technologies based on recent studies in agricultural biotechnology.

Findings:  Reduced fertilizer conditions substantially enhanced nitrogen uptake, biomass accumulation and grain productivity of engineered cereal crops. We showed that CRISPR-mediated editing of nitrogen assimilation pathways improved nitrogen-use efficiency by ~30–45% in both rice and maize models. Synthetic microbial consortia while engineered rhizosphere systems have been further used to improve root-associated nitrogen fixation, microbial colonization and sustainable crop productivity in greenhouse and field conditions.

Conclusion:  Agricultural biotechnology: approaches to sustainable production of cereal crops and enhancing biological nitrogen fixation. Yet, critical challenges remain for potential large-scale agricultural implementation, i.e., ecological stability, biosafety oversight, field scalability, as well as long-term environmental sustainability.