The Function of a Maize-Derived Phosphoenol pyruvate Carboxylase (PEPC) in Phosphorus-Deficient Transgenic Rice |
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Authors: | Hasna Hena Begum Mitsuru Osaki Takuro Shinano Hiroaki Miyatake Jun Wasaki Takuya Yamamura Toshihiro Watanabe |
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Affiliation: | Graduate School of Agriculture, Hokkaido University, Kitaku, Sapporo, 060–8589 Japan;Creative Research Institute "Sousei" (CRIS), Hokkaido University, Kitaku, Sapporo, 001–0021 Japan |
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Abstract: | Transgenic rice ( Oryza sativa L., a C3 plant) lines carrying a complete phospho enol pyruvate carboxylase (PEPC) gene from maize (a C4 plant) were tested for their performance in terms of organic acid synthesis and organic acid exudation into the rhizosphere under phosphorus (P)-deficient conditions. High PEPC activity increased the fraction of photosynthetically fixed carbon allocated to the organic acid pool, and P deficiency enhanced oxalate exudation from the roots of the transgenic plants. There was no evidence that the transformed PEPC was involved in internal P recycling in the plant. However, the root PEPC activity was positively correlated with the oxalate exudation and negatively correlated with the root P concentration, and a higher root PEPC activity led to a higher oxalate exudation. Thus, it is suggested that C4-PEPC transgenic rice plants had acquired the ability to exude oxalate, which enhanced their capacity to adapt to low P soil conditions. |
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Keywords: | C4-PEPC transgenic rice organic acid exudation Oryza sativa phosphorus deficiency phosphorus use efficiency |
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