Melatonin-rich transgenic rice plants exhibit resistance to herbicide-induced oxidative stress

Authors

  • Sangkyu Park,

    1. Department of Biotechnology, Bioenergy Research Center, Interdisciplinary Program of Bioenergy and Biomaterials, Chonnam National University, Gwangju, South Korea
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    • These authors equally contributed to this article.

  • Da-Eun Lee,

    1. Department of Biotechnology, Bioenergy Research Center, Interdisciplinary Program of Bioenergy and Biomaterials, Chonnam National University, Gwangju, South Korea
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    • These authors equally contributed to this article.

  • Hyunki Jang,

    1. Department of Biotechnology, Bioenergy Research Center, Interdisciplinary Program of Bioenergy and Biomaterials, Chonnam National University, Gwangju, South Korea
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  • Yeong Byeon,

    1. Department of Biotechnology, Bioenergy Research Center, Interdisciplinary Program of Bioenergy and Biomaterials, Chonnam National University, Gwangju, South Korea
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  • Young-Soon Kim,

    1. Department of Biotechnology, Bioenergy Research Center, Interdisciplinary Program of Bioenergy and Biomaterials, Chonnam National University, Gwangju, South Korea
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  • Kyoungwhan Back

    Corresponding author
    • Department of Biotechnology, Bioenergy Research Center, Interdisciplinary Program of Bioenergy and Biomaterials, Chonnam National University, Gwangju, South Korea
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Address reprint requests to Kyoungwhan Back, Department of Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, South Korea.

E-mail: kback@chonnam.ac.kr

Abstract

To examine whether melatonin-rich plants can defend against oxidative stress, we subjected melatonin-rich transgenic (MRT) rice plants to the singlet-oxygen-generating herbicide butafenacil. Both MRT and transgenic control (TC; expressing the vector only) rice seeds germinated and grew equally well in continuous dark on half-strength Murashige and Skoog (MS) medium containing 0.1 μm butafenacil. However, after transferring the seedlings to light, the TCs rapidly necrotized, whereas the MRT seedlings showed resistant phenotypes. Seven-day-old MRT seedlings treated with 0.1 μm butafenacil were resistant to the herbicide and contained high chlorophyll levels and low malondialdehyde and hydrogen peroxide contents compared with the TCs. As they did before the herbicide treatment, the MRT plants also produced much more melatonin after the herbicide treatment than the TCs. In addition, the MRT plants exhibited higher superoxide dismutase and catalase activities before and after the herbicide treatment compared with the TCs. This is the first report showing that MRT plants exhibit resistance against a peroxidizing herbicide that acts by generating reactive oxygen species (ROS) that kill plants. This result indicates that melatonin scavenges ROS efficiently in vivo in the transgenic plants, leading to oxidative stress resistance.

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