Abstract: The disclosure provides nucleic acid constructs encoding novel chimeric peptides that are useful for nuclear and chloroplast expression of active nitrogenase components including dinitrogenase reductase and dinitrogenase, in plant cells. The disclosure thus provides nucleic acid constructs encoding the chimeric proteins, as well as plant expression constructs comprising the same for expression and/or targeting to the nucleus, plastids, or mitochondria of plant cells. The disclosure also provides methods of use for the novel chimeric peptides that function to provide active dinitrogenase reductase, dinitrogenase, and thus nitrogenase, expressed in plant cells, and plants comprising such nucleic acid constructs.