Seo S, Sano H, Ohashi Y
Department of Molecular Genetics, National Institute of Agrobiological Resources, Tsukuba, Ibaraki 305-8602, Japan.
Plant Cell. 1999 Feb;11(2):289-98. doi: 10.1105/tpc.11.2.289.
A gene encoding a tobacco mitogen-activated protein kinase (WIPK) is transcriptionally activated in response to wounding. Transgenic tobacco plants, in which expression of endogenous wipk was suppressed, did not accumulate jasmonic acid or its methyl ester when wounded, suggesting that WIPK is involved in jasmonate-mediated wound signal transduction. Here, we demonstrate that activation of WIPK is required for triggering the jasmonate-mediated signal transduction cascade that occurs when wild-type tobacco plants are wounded. We also show that when plants are wounded, WIPK is rapidly and transiently activated, whereas the quantity of WIPK protein is maintained at a constant level. A transgenic tobacco plant in which the wipk gene was constitutively expressed at a high level showed constitutive enzymatic activation of WIPK and exhibited three- to fourfold higher levels of jasmonate than did its wild-type counterpart. This plant also showed constitutive accumulation of jasmonate-inducible proteinase inhibitor II transcripts. These results show that WIPK is activated in response to wounding, which subsequently causes an increase in jasmonate synthesis.
一个编码烟草促分裂原活化蛋白激酶（WIPK）的基因在受到创伤时会被转录激活。在内源wipk表达受到抑制的转基因烟草植株中，受伤时不会积累茉莉酸或其甲酯，这表明WIPK参与了茉莉酸介导的创伤信号转导。在此，我们证明，激活WIPK是触发野生型烟草植株受伤时发生的茉莉酸介导的信号转导级联反应所必需的。我们还表明，当植株受伤时，WIPK会迅速且短暂地被激活，而WIPK蛋白的量则维持在恒定水平。一个wipk基因持续高水平表达的转基因烟草植株表现出WIPK的组成型酶活性，其茉莉酸水平比野生型植株高3至4倍。该植株还表现出茉莉酸诱导的蛋白酶抑制剂II转录本的组成型积累。这些结果表明，WIPK在受到创伤时被激活，随后导致茉莉酸合成增加。
