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Rice with reduced radiocesium uptake

Updated:May 31, 2017 (Wednesday)

New potential in rice as countermeasure against cesium contamination

The Institute for Agro-Environmental Sciences, NARO has succeeded in developing a mutant line of cultivar Koshihikari which hardly absorbs radioactive cesium by mutation using ion beam irradiation. The low-cesium rice mutant 1 (lcs1) line showed mutation in the protein kinase gene (OsSOS2) which is responsible for the salt tolerance of rice, and suppresses the cesium absorption. As a result, the radiocesium concentration in grain is about half that in the wild-type cultivar. This mutant line could be used directly in agriculture particularly in radiocesium-contaminated paddy fields for reducing radiocesium in rice grains.

Summary

1. Increased application of potassium (K+) fertilizer has been found to be very effective measure to reduce the absorption of radioactive cesium by crops from agricultural soil. However, agricultural production sites demand new reduction measures which can be labor and cost-saving.
2. In order to address this issue, the Institute for Agro-Environmental Sciences, NARO (NIAES) in collaboration with the Iwate Biotechnology Research Center (IBRC) has developed a low cesium mutant line of Koshihikari by mutation using ion beam irradiation. Upon cultivation, the low-cesium rice mutant 1 (lcs1) line hardly absorbed radioactive cesium and the concentration of cesium in the grains was decreased by half.
3. Genetic analysis of the low-cesium Koshihikari revealed a mutation in the protein kinase gene (OsSOS2) which is involved in salt tolerance. As a result of this mutation, absorption of cesium in the low-cesium Koshihikari is suppressed.
4. The low-cesium Koshihikari shows almost the same growth characteristics and yield, and can be cultivated in the same way as the normal Koshihikari cultivar. The taste is also the same as Koshihikari.
5. This mutant line could be used directly in agriculture particularly in contaminated rice fields due to the nuclear power plant disaster.
6. The research article is now available in the online edition of the British journal Scientific Reports published on May 25, 2017.

Citation

Satoru Ishikawa, Shimpei Hayashi, Tadashi Abe, Masato Igura, Masato Kuramata, Hachidai Tanikawa, Manaka Iino, Takashi Saito, Yuji Ono, Tetsuya Ishikawa, Shigeto Fujimura, Akitoshi Goto & Hiroki Takagi (2017) Low-cesium rice: mutation in OsSOS2 reduces radiocesium in rice grains. Scientific Reports 7, 2432. doi:10.1038/s41598-017-02243-9

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