He Z H, He D, Kohorn B D
Developmental, Cell and Molecular Biology Group, Duke University, Durham, NC 27708, USA.
Plant J. 1998 Apr;14(1):55-63. doi: 10.1046/j.1365-313x.1998.00092.x.
Pathogen infection of angiosperms must rely on some interaction between the extracellular matrix (ECM) and the invading agent, and may be accompanied by signaling between the ECM and cytoplasm. An Arabidopsis cell wall associated receptor kinase (Wak1) has an amino-terminal domain that is tightly associated with the ECM, spans the plasma membrane and has a cytoplasmic protein kinase domain. Wak1 expression is induced when Arabidopsis plants are infected with pathogen, or when the pathogen response is stimulated either by exogenous salicylate (SA) or its analog 2,2-dichloroisonicotinic acid (INA). This Wak1 induction requires the positive regulator NPR1/NIM1. Thus Wak1 is a pathogen-related (PR) protein. Expression of an antisense and a dominant negative allele of Wak1 shows that induced expression of Wak1 is needed for a plant to survive if stimulated by INA. Ectopic expression of the entire Wak1, or the kinase domain alone, can provide resistance to otherwise lethal SA levels. These experiments suggest that Wak1 expression and other PR proteins are protecting plants from detrimental effects incurred during the pathogen response. These results provide a direct link between a protein kinase that could mediate signals from the ECM, to the events that are precipitated by a pathogen infection.
被子植物的病原体感染必须依赖细胞外基质（ECM）与入侵病原体之间的某种相互作用，并且可能伴随着ECM与细胞质之间的信号传导。拟南芥细胞壁相关受体激酶（Wak1）有一个与ECM紧密相连的氨基末端结构域，跨越质膜并具有一个细胞质蛋白激酶结构域。当拟南芥植物被病原体感染时，或者当病原体反应被外源水杨酸（SA）或其类似物2,2 - 二氯异烟酸（INA）刺激时，Wak1的表达会被诱导。这种Wak1的诱导需要正向调节因子NPR1 / NIM1。因此，Wak1是一种病程相关（PR）蛋白。Wak1的反义等位基因和显性负等位基因的表达表明，如果受到INA刺激，植物存活需要诱导表达Wak1。完整的Wak1或单独的激酶结构域的异位表达可以对原本致死的SA水平提供抗性。这些实验表明，Wak1的表达和其他PR蛋白可保护植物免受病原体反应期间产生的有害影响。这些结果在一个可能介导来自ECM信号的蛋白激酶与病原体感染引发的事件之间建立了直接联系。
