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OsARG is a key enzyme in Arg catabolism and plays a critical role during panicle development.

Annotated Information


Phenotypic characteristics of the nglf-1 mutant. (from reference [1]).

OsARG encodes an arginase in rice. Arginine is one of the main amino acids in nitrogen recycling and remobilization. In the case of rice, remobilized nitrogen from the vegetative organs accounts for 70-90% of the total panicle nitrogen. [2] [3] The Arg concentration in leaves, roots and seeds varied from 0.4% to 3.4%, and abnormally high Arg levels ranging from 7.5 to 11.6% of total free amino acids, Arg which originate from the recycling of nitrogen, have been found in phloem sap. [4][5][6][7]The difference in the Arg concentration of storage organs versus phloem sap in the reproductive stage is probably due to the activity of OsARG. Arg catabolism is well known for providing a significant portion of nitrogen during seedling development. Arginase, urease and its co-enzymes, and glutamine synthetases all play important roles in this pathway. Until now, only OsGS1;1 was found to exert an effect on panicle development in rice. [8] Under low exogenous nitrogen conditions, the panicle mainly utilized the nitrogen hydrolyzed from Arg catabolism; when exogenous nitrogen supplementation was increased, the pattern of nitrogen utilization in the panicles shifted to depend much more on exogenous nitrogen. The pathway that is used depends on the exogenous nutrition concentration, as described for nitrogen.[9]


Schematic diagram of the structure of OsARG. (from reference [1]).

The rice narrow-grain and low-fertility mutant nglf-1 was derived from an anther culture of autotetraploid indica/japonica hybrid H3774 (H2088 × H891). [10][11]Sequence comparison revealed a single nucleotide substitution resulting in a stop codon (TGA) in ORF8 of nglf-1. It has been verify that the mutation in OsARG is responsible for the nglf-1 phenotype. [1]


Expression of OsARG in various organs of WT and mutant nglf-1 analyzed by quantitative RT-PCR analysis.(from reference [1]).

OsARG is expressed ubiquitously in all organs, including the root, stem, leaf blade, leaf sheath and panicle. Compared to WT, the expression in nglf-1 is reduced. The OsARG protein was localized in the mitochondria, consistent with other arginases. [1]


Phylogenetic analysis of OsARG and related proteins. (from reference [1]).

In the rice genome, OsARG is the only gene encoding arginase. A BLAST search with translated OsARG revealed that most plant arginases are encoded by one or two genes. OsARG has high identity with proteins from other organisms, including Arabidopsis thaliana, [12] Solanum lycopersicum, [13] Pinus taeda [14] and Glycine max. [15] OsARG also has high identity with arginases from five genera of monocotyledonous plants, including the arginases in Zea mays, Sorghum bicolor, Brachypodium distachyon, Triticum aestivum and Hordeum vulgare, all of which are members of the same clade, distinguishing them from all dicotyledonous species analyzed. The shared identity may indicate a different role in monocotyledonous plants than in dicotyledonous species. The OsARG protein comprises 340 residues with a predicted molecular mass of 36.96 kDa and pI of 5.90. Sequence alignment indicated a conserved arginase domain, and all plant arginases contain two His and four Asp residues that bind the Mn2+ co-factor. [13] A predicted mitochondrial targeting peptide is located at the N-terminal end, and this region showed the greatest diversity among various plant arginases. [1]

Knowledge Extension

OsARG is a potential gene for improving rice nitrogen use efficiency.Improving nitrogen use efficiency is an important objective of breeding programs. In maize over-expressing the Gln1-3 gene, an increase in kernel number was observed under either high-nitrogen or low-nitrogen growth conditions. [16] A recent investigation of rice transformed with the cytosolic glutamine synthetase (GS1) gene indicated that, due to enhanced nitrogen use efficiency, lines over-expressing GS1 exhibited a 25–35% higher spikelet yield. [17]The possibility of increasing OsARG expression, highlighting the potential use of manipulation of OsARG expression to improve rice yield under sub-optimal nitrogen conditions. However, extensive field experiments are needed. [1]

Labs working on this gene

1.National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China

2.Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China

3.National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China

Conserved Domains

Conserved Domains of OsARG (from NCBI).


  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Xuefeng Ma, X.F., Zhijun Cheng , Z.J., Qin, R.Z., Qiu, Y., Heng, Y.Q., Yang, H., Ren Y.L., Wang, X.L., Bi, J.C., Ma, X.D., Zhang, X., Wang, J.L., Lei, C.L., Guo, X.P., Wang, L., Wu, F.Q., Jiang L., Wang, H.Y. and Wan, J.M. (2013) OsARG encodes an arginase that plays critical roles in panicle development and grain production in rice. Plant J. 73, 190-200.
  2. Mae, T. (1997) Physiological nitrogen ef?ciency in rice: nitrogen utilization, photosynthesis, and yield potential. Plant Soil, 196, 201-210.
  3. Tabuchi, M., Abiko, T. and Yamaya, T. (2007) Assimilation of ammonium ions and reutilization of nitrogen in rice (Oryza sativa L.). J. Exp. Bot. 58, 2319-2327.
  4. Cagampang, G.B., Cruz, L.J. and Juliano, B.O. (1971) Free amino acids in the bleeding sap and developing grain of the rice plant. Cereal Chem. 48, 533-539.
  5. Hayashi, H. and Chino, M. (1990) Chemical composition of phloem sap from the uppermost internode of the rice plant. Plant Cell Physiol. 31, 247-251.
  6. Sogawa, K., Hattori, M. and Liu, G. (2002) Free amino acid (FAA) analysis of phloem sap in hybrid rice Shanyou 63 and its parents. Chinese Rice Res. News. 10, 8-9.
  7. Takahashi, H., Hayashi, M., Goto, F., Sato, S., Soga, T., Nishioka, T., Tomita, M., Kawai-Yamada, M. and Uchimiya, H. (2006) Evaluation of metabolic alteration in transgenic rice overexpressing dihydro?avonol-4-reductase. Ann. Bot. 98, 819-825.
  8. Tabuchi, M., Sugiyama, K., Ishiyama, K., Inoue, E., Sato, T., Takahashi, H. and Yamaya, T. (2005) Severe reduction in growth rate and grain ?lling of rice mutants lacking OsGS1;1, a cytosolic glutamine synthetase1;1. Plant J. 42, 641-651.
  9. Howarth, J.R., Parmar, S., Jones, J., Shepherd, C.E., Corol, D.I., Galster, A.M., Hawkins, N.D., Miller, S.J., Baker, J.M. and Verrier, P.J. (2008) Co-ordinated expression of amino acid metabolism in response to N and S de?ciency during wheat grain ?lling. J. Exp. Bot. 59, 3675-3689.
  10. Cheng, Z.J., Qin, R.Z., Zhang, X., Lei, C.L., Guo, X.P. and Wan, J.M. (2005) Molecular mechanism for phenotypic mutation arisen from polyploidization in plant. Acta Agron. Sin. 31, 940 - 943.
  11. Qin, R.Z., Cheng, Z.J. and Guo, X.P. (2005) The establishment of mutant pool using anther culture of autotetrapolyploid rice. Acta Agron. Sin. 31, 392 - 394.
  12. Flores, T., Todd, C.D., Tovar-Mendez, A., Dhanoa, P.K., Correa-Aragunde,N., Hoyos, M.E., Brown?eld, D.M., Mullen, R.T., Lamattina, L. and Polac-co, J.C. (2008) Arginase-negative mutants of Arabidopsis exhibitincreased nitric oxide signaling in root development. Plant Physiol. 147,1936 - 1946.
  13. 13.0 13.1 Chen, H., McCaig, B.C., Melotto, M., He, S.Y. and Howe, G.A. (2004) Regula- tion of plant arginase by wounding, jasmonate, and the phytotoxin coronatine. J. Biol. Chem. 279, 45998 - 46007.
  14. Todd, C.D., Cooke, J.E.K., Mullen, R.T. and Gifford, D.J. (2001) Regulation of loblolly pine (Pinus taeda L.) arginase in developing seedling tissue during germination and post-germinative growth. Plant Mol. Biol. 45, 555 - 565.
  15. Goldraij, A. and Polacco, J.C. (1999) Arginase is inoperative in developing soybean embryos. Plant Physiol. 119, 297 - 304.
  16. Martin, A., Lee, J., Kichey, T. et al. (2006) Two cytosolic glutamine synthe- tase isoforms of maize are speci?cally involved in the control of grain production. Plant Cell, 18, 3252 - 3274.
  17. Brauer, E.K., Rochon, A., Bi, Y.-M., Bozzo, G.G., Rothstein, S.J. and Barry, J. S. (2011) Reappraisal of nitrogen use ef?ciency in rice overexpressing glutamine synthetase1. Physiol. Plant. 141, 361 - 372.

Structured Information