Rice DUR3 mediates high-affinity urea transport and plays an effective role in improvement of urea acquisition and utilization when expressed in Arabidopsis

• Published in: The New phytologist Vol. 193; no. 2; pp. 432 - 444
• Main Authors: Wang, Wei‐Hong, Köhler, Barbara, Cao, Feng‐Qiu, Liu, Guo‐Wei, Gong, Yuan‐Yong, Sheng, Song, Song, Qi‐Chao, Cheng, Xiao‐Yuan, Garnett, Trevor, Okamoto, Mamoru, Qin, Rui, Mueller‐Roeber, Bernd, Tester, Mark, Liu, Lai‐Hua
• Format: Journal Article
• Language: English
• Published: Oxford, UK New Phytologist Trust 01.01.2012; Blackwell Publishing Ltd
• Subjects: Animals; Arabidopsis - drug effects; Arabidopsis - genetics; Arabidopsis - growth & development; Biological Transport - drug effects; Cell Membrane - drug effects; Cell Membrane - metabolism; Gene Expression Profiling; Gene Expression Regulation, Plant - drug effects; Genetic Complementation Test; Green Fluorescent Proteins - metabolism; high‐affinity transporter; Kinetics; leaf senescence; Leaves; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Mutation - genetics; Nitrogen; Nitrogen - metabolism; nitrogen remobilization; Oocytes; Oocytes - drug effects; Oocytes - metabolism; Oryza - drug effects; Oryza - genetics; Oryza - growth & development; Oryza - metabolism; OsDUR3; overexpression; Plant growth; Plant Proteins - genetics; Plant Proteins - metabolism; Plant roots; Plant Roots - drug effects; Plant Roots - metabolism; Plants; Plants, Genetically Modified; Polymerase chain reaction; Recombinant Fusion Proteins - metabolism; Rice; rice plant; RNA, Messenger - genetics; RNA, Messenger - metabolism; Saccharomyces cerevisiae - drug effects; Saccharomyces cerevisiae - genetics; Sequence Homology, Amino Acid; Subcellular Fractions - drug effects; Subcellular Fractions - metabolism; Urea - metabolism; Urea - pharmacology; urea transport and utilization; Urea Transporters; Xenopus laevis; Yeasts
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2011.03929.x

Despite the great agricultural and ecological importance of efficient use of urea-containing nitrogen fertilizers by crops, molecular and physiological identities of urea transport in higher plants have been investigated only in Arabidopsis. We performed short-time urea-influx assays which have identified a low-affinity and high-affinity (K m of 7.55 μM) transport system for urea-uptake by rice roots (Oryza sativa). A high-affinity urea transporter OsDUR3 from rice was functionally characterized here for the first time among crops. OsDUR3 encodes an integral membrane-protein with 721 amino acid residues and 15 predicted transmembrane domains. Heterologous expression demonstrated that OsDUR3 restored yeast dur3-mutant growth on urea and facilitated urea import with a K m of c. 10 μM in Xenopus oocytes. Quantitative reverse-transcription polymerase chain reaction (qPCR) analysis revealed upregulation of OsDUR3 in rice roots under nitrogen-deficiency and urea-resupply after nitrogen-starvation. Importantly, overexpression of OsDUR3 complemented the Arabidopsis atdur3-1 mutant, improving growth on low urea and increasing root urea-uptake markedly. Together with its plasma membrane localization detected by green fluorescent protein (GFP)-tagging and with findings that disruption of OsDUR3 by T-DNA reduces rice growth on urea and urea uptake, we suggest that OsDUR3 is an active urea transporter that plays a significant role in effective urea acquisition and utilisation in rice.