Rice WRKY45 plays important roles in fungal and bacterial disease resistance

Authors

  • MASAKI SHIMONO,

    1. Disease Resistant Crops Research Unit, GMO Research Center, National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602, Japan
    Search for more papers by this author
    • Present address: Michigan State University, Department of Plant Pathology, 104 Center for Integrated Plant Systems, East Lansing, MI 48824, USA.

    • These authors contributed equally to this work.

  • HIRONORI KOGA,

    1. Department of Bioproduction Science, Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa 921-8836, Japan
    Search for more papers by this author
    • These authors contributed equally to this work.

  • AYA AKAGI,

    1. Disease Resistant Crops Research Unit, GMO Research Center, National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602, Japan
    Search for more papers by this author
  • NAGAO HAYASHI,

    1. Disease Resistant Crops Research Unit, GMO Research Center, National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602, Japan
    Search for more papers by this author
  • SHINGO GOTO,

    1. Disease Resistant Crops Research Unit, GMO Research Center, National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602, Japan
    Search for more papers by this author
  • MIYUKI SAWADA,

    1. Department of Bioproduction Science, Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa 921-8836, Japan
    Search for more papers by this author
  • TAKAYUKI KURIHARA,

    1. Department of Bioproduction Science, Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa 921-8836, Japan
    Search for more papers by this author
  • AKANE MATSUSHITA,

    1. Disease Resistant Crops Research Unit, GMO Research Center, National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602, Japan
    Search for more papers by this author
  • SHOJI SUGANO,

    1. Disease Resistant Crops Research Unit, GMO Research Center, National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602, Japan
    Search for more papers by this author
  • CHANG-JIE JIANG,

    1. Disease Resistant Crops Research Unit, GMO Research Center, National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602, Japan
    Search for more papers by this author
  • HISATOSHI KAKU,

    1. Disease Resistant Crops Research Unit, GMO Research Center, National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602, Japan
    Search for more papers by this author
    • Present address: Sakata Seed Corporation, Kimitsu Research Station, 358 Uchikoshi, Sodegaura, Chiba 299-00217, Japan.

  • HARUHIKO INOUE,

    1. Disease Resistant Crops Research Unit, GMO Research Center, National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602, Japan
    Search for more papers by this author
  • HIROSHI TAKATSUJI

    Corresponding author
    1. Disease Resistant Crops Research Unit, GMO Research Center, National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602, Japan
    Search for more papers by this author

Email: takatsuh@affrc.go.jp

SUMMARY

Plant ‘activators’, such as benzothiadiazole (BTH), protect plants from various diseases by priming the plant salicylic acid (SA) signalling pathway. We have reported previously that a transcription factor identified in rice, WRKY45 (OsWRKY45), plays a pivotal role in BTH-induced disease resistance by mediating SA signalling. Here, we report further functional characterization of WRKY45. Different plant activators vary in their action points, either downstream (BTH and tiadinil) or upstream (probenazole) of SA. Rice resistance to Magnaporthe grisea, induced by both types of plant activator, was markedly reduced in WRKY45-knockdown (WRKY45-kd) rice, indicating a universal role for WRKY45 in chemical-induced resistance. Fungal invasion into rice cells was blocked at most attempted invasion sites (pre-invasive defence) in WRKY45-overexpressing (WRKY45-ox) rice. Hydrogen peroxide accumulated within the cell wall underneath invading fungus appressoria or between the cell wall and the cytoplasm, implying a possible role for H2O2 in pre-invasive defence. Moreover, a hypersensitive reaction-like reaction was observed in rice cells, in which fungal growth was inhibited after invasion (post-invasive defence). The two levels of defence mechanism appear to correspond to Type I and II nonhost resistances. The leaf blast resistance of WRKY45-ox rice plants was much higher than that of other known blast-resistant varieties. WRKY45-ox plants also showed strong panicle blast resistance. BTH-induced resistance to Xanthomonas oryzae pv. oryzae was compromised in WRKY45-kd rice, whereas WRKY45-ox plants were highly resistant to this pathogen. However, WRKY45-ox plants were susceptible to Rhizoctonia solani. These results indicate the versatility and limitations of the application of this gene.

Ancillary