title: Rice OsNAR2.1 interacts with OsNRT2.1, OsNRT2.2 and OsNRT2.3a nitrate transporters to provide uptake over high and low concentration ranges.
abstract: Plants take up both nitrate and ammonium as main nitrogen (N) sources. Although ammonium is the predominant form in anaerobic-flooded paddy soil, it has been proposed that rice and other wetland plants may take up significant amounts of nitrate formed by nitrification of ammonium in the rhizosphere. A two-component system for nitrate transport including NRT2s with a partner protein (NAR2 or NRT3.1) has been identified in Arabidopsis. We report the physiological function of another member of the NAR2 family, OsNAR2.1 in rice (Oryza sativa, ssp. Japonica, cv. Nipponbare). OsNAR2.1 was mainly expressed in roots and induced by nitrate and suppressed by ammonium and some amino acids. Knockdown of OsNAR2.1 by RNA interference synchronously suppressed expression of OsNRT2.1, OsNRT2.2 and OsNRT2.3a in the osnar2.1mutants. Both high- and low-affinity nitrate transports were greatly impaired by OsNAR2.1 knockdown. Yeast two hybridization showed that OsNAR2.1 not only interacted with OsNRT2.1/OsNRT2.2, but also with OsNRT2.3a. Taken together, the data demonstrate that OsNAR2.1 plays a key role in enabling the plant to cope with variable nitrate supply.
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Yan
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Fan
authors.forename: Huiming
authors.initials: H
authors.lastname: Feng
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Miller
authors.forename: Qirong
authors.initials: Q
authors.lastname: Shen
authors.forename: Guohua
authors.initials: G
authors.lastname: Xu
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000818:Animals; D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D018506:Gene Expression Regulation, Plant; D055785:Gene Knockdown Techniques; D008564:Membrane Potentials; D009154:Mutation; D000091285:Nitrate Transporters; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D012275:Oryza / Q000254:growth & development / Q000378:metabolism*; D018517:Plant Roots / Q000166:cytology / Q000378:metabolism; D060066:Protein Interaction Maps; D034622:RNA Interference; D020798:Two-Hybrid System Techniques
chemical_list: D027321:Anion Transport Proteins; D000091285:Nitrate Transporters; D009566:Nitrates; D000641:Ammonia; D009584:Nitrogen