Nitrate transporter NPF7.9 is a regulator nitrogen use efficiency and stress-induced nitrate allocation to roots in rice (Plant Physiol)

In addition to its role as a nutrient and a developmental signal, nitrate regulates stress responses in plants. By homology to nitrate transporters previously identified in Arabidopsis as contributing to stress induced-nitrate allocation to roots (SINAR) and nitrogen use efficiency (NUE), Guan et al. identified OsNPF7.9 as having a similar role in rice.  Osnpf7.9 mutants are defective in shoot nitrate allocation and display lower shoot biomass allocation and grain yield. Furthermore, downregulated expression of OsNPF7.9 under cadmium and sodium toxicities correlates with the higher root nitrate retention feature of SINAR. This gene shows a single nucleotide polymorphism between indica and japonica rice. The nitrate transport efficient OsNPF7.9 SNP G allele was found predominantly in high NUE indica rice genotypes, while the SNP A allele was associated with japonica rice. These findings are an important addition to the accumulating evidence on nitrate use divergence of rice subspecies and could be a potent molecular marker for high NUE. (Summary by Lekshmy Sathee @lekshmysnair) Plant Physiol. 10.1093/plphys/kiac044