Over-expression of a single Ca2+-dependent protein kinase confers both cold and salt/drought tolerance on rice plants

Authors

  • Yusuke Saijo,

    1. Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan,
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  • Shingo Hata,

    1. Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan,
    2. Laboratory of Plant Physiology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan, and
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  • Junko Kyozuka,

    1. Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Takayama, Ikoma 630-0101, Japan
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  • Ko Shimamoto,

    1. Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Takayama, Ikoma 630-0101, Japan
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  • Katsura Izui

    Corresponding author
    1. Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan,
    2. Laboratory of Plant Physiology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan, and
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For correspondence (fax +81 75 7536470; e-mail izui@kais.kyoto-u.ac.jp).

Summary

A rice gene encoding a calcium-dependent protein kinase (CDPK), OsCDPK7, was induced by cold and salt stresses. To elucidate the physiological function of OsCDPK7, we generated transgenic rice plants with altered levels of the protein. The extent of tolerance to cold and salt/drought stresses of these plants correlated well with the level of OsCDPK7 expression. Therefore, OsCDPK7 was shown to be a positive regulator commonly involved in the tolerance to both stresses in rice. Over-expression of OsCDPK7 enhanced induction of some stress-responsive genes in response to salinity/drought, but not to cold. Thus, it was suggested that the downstream pathways leading to the cold and salt/drought tolerance are different from each other. It seems likely that at least two distinct pathways commonly use a single CDPK, maintaining the signalling specificity through unknown post-translational regulation mechanisms. These results demonstrate that simple manipulation of CDPK activity has great potential with regard to plant improvement.

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