Menke Frank L H, Kang Hong-Gu, Chen Zhixiang, Park Jeong Mee, Kumar Dhirendra, Klessig Daniel F
Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA.
Mol Plant Microbe Interact. 2005 Oct;18(10):1027-34. doi: 10.1094/MPMI-18-1027.
The salicylic acid-induced protein kinase (SIPK) of tobacco, which is a mitogen-activated protein kinase (MAPK), is activated by various biotic and abiotic treatments. Overexpression of SIPK has been shown to trigger cell death. In this study, a targeted yeast two-hybrid approach identified the tobacco transcription factor WRKY1 as a potential substrate. SIPK phosphorylated WRKY1, which resulted in enhanced DNA-binding activity of WRKY1 to its cognate binding site, a W box sequence from the tobacco chitinase gene CHN50. SIPK-mediated enhancement of WRKY1 DNA-binding activity was inhibited by staurosporine, a general kinase inhibitor. Co-expression of SIPK and WRKY1 in Nicotiana benthamiana led to more rapid cell death than expression of SIPK alone, suggesting that WRKY1 is involved in the formation of hypersensitive response-like cell death and may be a component of the signaling cascade downstream of SIPK.
烟草中的水杨酸诱导蛋白激酶（SIPK）属于丝裂原活化蛋白激酶（MAPK），可被多种生物和非生物处理激活。已证明SIPK的过表达会引发细胞死亡。在本研究中，一种靶向酵母双杂交方法鉴定出烟草转录因子WRKY1为潜在底物。SIPK使WRKY1磷酸化，导致WRKY1对其同源结合位点（烟草几丁质酶基因CHN50的W盒序列）的DNA结合活性增强。星形孢菌素（一种通用激酶抑制剂）可抑制SIPK介导的WRKY1 DNA结合活性增强。在本氏烟草中共同表达SIPK和WRKY1比单独表达SIPK导致更快的细胞死亡，这表明WRKY1参与了过敏反应样细胞死亡的形成，并且可能是SIPK下游信号级联反应的一个组成部分。
