Rice (Oryza sativa) is sensitive to salt stresses and cannot survive under low salt conditions, such as 50 mM NaCl. In an attempt to improve salt tolerance of rice, we introduced katE, a catalase gene of Escherichia coli, into japonica rice cultivar, Nipponbare. The resultant transgenic rice plants constitutively expressing katE were able to grow for more than 14 days in the presence of 250 mM NaCl, and were able to form flower and produce seeds in the presence of 100 mM NaCl. Catalase activity in the transgenic rice plants was 1.5-to 2.5-fold higher than non-transgenic rice plants. Our results clearly indicate that simple genetic modification of rice to express E. coli-derived catalase can efficiently increase its tolerance against salt stresses. The transformant presented here is one of the most salt-tolerant rice plants created by molecular breeding so far.

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