Rice WRKY45 plays important roles in fungal and bacterial disease resistance
Rice WRKY45 plays important roles in fungal and bacterial disease resistance
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DOI：
10.1111/j.1364-3703.2011.00732.x
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发表时间：
2012-01-01
影响因子：
4.9
通讯作者：
Takatsuji, Hiroshi
中科院分区：
文献类型：
--
作者：
Shimono, Masaki;Koga, Hironori;Takatsuji, Hiroshi
植物活化剂，如苯并噻二唑（BTH），通过启动植物水杨酸（SA）信号传导途径保护植物免受各种疾病。我们以前曾报道，在水稻中鉴定的转录因子，WRKY 45（OsWRKY 45），通过介导SA信号在BTH诱导的抗病性中起着关键作用。在这里，我们报告WRKY 45的进一步功能表征。不同的植物活化剂在其作用点上不同，在SA的下游（BTH和噻啶虫胺）或上游（烯丙苯咪唑）。两种植物激活剂诱导的水稻对稻瘟病菌的抗性在WRKY 45-kd水稻中均显著降低，表明WRKY 45在化学诱导的抗性中具有普遍作用。在WRKY 45-ox水稻中，真菌入侵水稻细胞的大多数尝试入侵位点（入侵前防御）被阻断。过氧化氢积累在入侵真菌附着胞下方或细胞壁和细胞质之间的细胞壁内，这意味着H2 O2在入侵前防御中可能发挥作用。此外，在水稻细胞中观察到一种过敏反应样反应，其中真菌的生长在入侵后被抑制（入侵后防御）。这两个级别的防御机制似乎对应于I型和II型非宿主抗性。WRKY 45-ox水稻植株的叶瘟抗性远高于其他已知抗稻瘟病品种。WRKY 45-ox植株也表现出较强的穗瘟抗性。BTH诱导的对黄单胞菌的抗性WRKY 45-kd水稻的抗病性受到损害，而WRKY 45-ox水稻对该病原菌高度抗性。然而，WRKY 45-ox植株对立枯丝核菌敏感。这些结果表明了该基因应用的多功能性和局限性。
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.