OsARG encodes an arginase that plays critical roles in panicle development and grain production in rice

Authors

  • Xuefeng Ma,

    1. National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
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    • These authors contributed equally to this work.
  • Zhijun Cheng,

    1. National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
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    • These authors contributed equally to this work.
  • Ruizhen Qin,

    1. National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
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    • These authors contributed equally to this work.
  • Yang Qiu,

    1. Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
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  • Yueqin Heng,

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

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

    1. National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
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  • Xiaole Wang,

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

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

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

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

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

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

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

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

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

    1. National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
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  • Haiyang Wang,

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

    Corresponding author
    1. National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
    • National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
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(e-mail wanjm@caas.net.cn).

Summary

Nitrogen is a crucial nutrient for plant growth and development. Arginine is considered to be an important amino acid for nitrogen transport and storage, playing a crucial role during plant seedling development. However, little is known about the role of arginine in nitrogen remobilization at the reproductive stage. We isolated a rice mutant nglf-1 with reduced plant height, small panicle and grain size, and low seed-setting rate (10% in nglf-1 compared to 93% in wild-type). Map-based cloning revealed that the mutant phenotype was caused by loss of function of a gene (OsARG) encoding an arginine hydrolysis enzyme, which is consistent with arginine accumulation in the mutant. The phenotype was partially corrected supplying exogenous nitrogen, and fully corrected by expression of a wild-type OsARG transgene. Over-expression of OsARG in rice (cv. Kitaake) increased grain number per plant under nitrogen-limited conditions. OsARG was ubiquitously expressed in various organs, but most strongly in developing panicles. The OsARG protein was localized in the mitochondria, consistent with other arginases. Our results suggest that the arginase encoded by OsARG, a key enzyme in Arg catabolism, plays a critical role during panicle development, especially under conditions of insufficient exogenous nitrogen. OsARG is a potential target for crop improvement.

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