Scripting a new dialogue between diazotrophs and crops

The availability of nutrients such as nitrogen (N) affects crop productivity. Unfortunately, the intensive use of synthetic N fertilizers has detrimental economic and environmental consequences. Engineered associative diazotrophs hold immense potential to help many crops acquire N from the air via biological N fixation. The mechanistic understanding of plant–diazotroph interactions forms the basis of engineering these associations to increase the transfer of fixed N to the plants. Biorthogonal signaling is a promising approach to engineering specific, efficient, ecofriendly plant–diazotroph interactions. The composition of root exudates, the physical proximity of diazotrophs to the plants, their nontoxic nature, their efficiency in fixing N, and their amenability to genetic manipulations are essential for engineering associations between diazotrophs and crops for sustainable agriculture. Diazotrophs are bacteria and archaea that can reduce atmospheric dinitrogen (N2) into ammonium. Plant–diazotroph interactions have been explored for over a century as a nitrogen (N) source for crops to improve agricultural productivity and sustainability. This scientific quest has generated much information about the molecular mechanisms underlying the function, assembly, and regulation of nitrogenase, ammonium assimilation, and plant–diazotroph interactions. This review presents various approaches to manipulating N fixation activity, ammonium release by diazotrophs, and plant–diazotroph interactions. We discuss the research avenues explored in this area, propose potential future routes, emphasizing engineering at the metabolic level via biorthogonal signaling, and conclude by highlighting the importance of biocontrol measures and public acceptance. Diazotrophs are bacteria and archaea that can reduce atmospheric dinitrogen (N2) into ammonium. Plant–diazotroph interactions have been explored for over a century as a nitrogen (N) source for crops to improve agricultural productivity and sustainability. This scientific quest has generated much information about the molecular mechanisms underlying the function, assembly, and regulation of nitrogenase, ammonium assimilation, and plant–diazotroph interactions. This review presents various approaches to manipulating N fixation activity, ammonium release by diazotrophs, and plant–diazotroph interactions. We discuss the research avenues explored in this area, propose potential future routes, emphasizing engineering at the metabolic level via biorthogonal signaling, and conclude by highlighting the importance of biocontrol measures and public acceptance.