The Arabidopsis MAP kinase kinase MKK1 participates in defence responses to the bacterial elicitor flagellin
The Arabidopsis MAP kinase kinase MKK1 participates in defence responses to the bacterial elicitor flagellin
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DOI：
10.1111/j.1365-313x.2006.02888.x
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发表时间：
2006-11-01
期刊：
影响因子：
7.2
通讯作者：
Bogre, L.
中科院分区：
文献类型：
--
作者：
Meszaros, T.;Helfer, A.;Bogre, L.
植物通过病原体相关的分子模式和种族特异性毒力因子的识别来感知病原体，这分别诱导基础防御或加速防御（通常表现为局部细胞死亡的形式）。拟南芥中的丝裂原活化蛋白激酶（MAPK）模块先前被提出从细菌诱导子鞭毛蛋白的感知到基础防御相关基因的激活的信号。在这里，我们提出了一个平行的MAPK信号通路参与flg22，一个肽对应于最保守的结构域的鞭毛蛋白的反应的证据。内源性拟南芥MAP激酶激酶MKK 1在用flg22处理的细胞中被激活，在体外磷酸化MAPK MPK 4，并在体内在原生质体中激活它。在mkk1突变体植物中，MPK4和另外两个flg22诱导的MAPK（MPK3和MPK6）的flg22激活受损。在mkk1突变体中，一组flg22诱导和flg22抑制的基因表现出改变的表达，表明MKK1负调控鞭毛蛋白反应基因的活性。有趣的是，与mpk4突变体相反，mkk1没有显示出形态异常，并且在对有毒和无毒假单胞菌菌株的抗性方面受到损害。因此，MKK1信号通路调节响应于激发子的基因的表达，并且在病原体防御中起重要作用。
Plants sense pathogens through both pathogen-associated molecular patterns and recognition of race-specific virulence factors, which induce basal defence or an accelerated defence (often manifest in the form of local cell death), respectively. A mitogen-activated protein kinase (MAPK) module in Arabidopsis was previously proposed to signal from perception of the bacterial elicitor flagellin to the activation of basal defence-related genes. Here, we present evidence for a parallel MAPK-signalling pathway involved in the response to flg22, a peptide corresponding to the most conserved domain of flagellin. The endogenous Arabidopsis MAP kinase kinase MKK1 is activated in cells treated with flg22, phosphorylates the MAPK MPK4 in vitro, and activates it in vivo in protoplasts. In mkk1 mutant plants, the activation by flg22 of MPK4 and two other flg22-induced MAPKs (MPK3 and MPK6) is impaired. In the mkk1 mutant, a battery of both flg22-induced and flg22-repressed genes show altered expression, indicating that MKK1 negatively regulates the activity of flagellin-responsive genes. Intriguingly, in contrast to the mpk4 mutant, mkk1 shows no morphological anomalies and is compromised in resistance to both virulent and avirulent Pseudomonas syringae strains. Thus, the MKK1 signalling pathway modulates the expression of genes responding to elicitors and plays an important role in pathogen defence.