Modular electron-transport chains from eukaryotic organelles function to support nitrogenase activity

Significance Engineering nitrogenase into cereal crops requires detailed understanding of the components required for efficient nitrogen fixation. We have used a synthetic biology modular approach to evaluate components from chloroplast, root plastids, and mitochondria that function as electron donors to both conventional Mo nitrogenase and the alternative Fe nitrogenase systems. The knowledge obtained in this study not only identifies electron-transfer components from plant organelles that can be used to support nitrogenase activity, but also is likely to enable reduction of the number of target genes required to engineer nitrogen fixation in plants.