FNR (ferredoxin-NADP+-oxidoreductase) catalyzes reduction of NADP+ using Fd that has accepted electrons from photosystem II in the final step of linear photosynthetic electron transport. In higher plants FNRs are encoded by a small multiple gene family (two chloroplast-targeted FNR in Arabidopsis and rice and three isoenzymes in maize). All forms are evenly distributed between the thylakoids and stroma.