Mitsuya Yoshiko, Takahashi Yoshihiro, Berberich Thomas, Miyazaki Atsushi, Matsumura Hideo, Takahashi Hideki, Terauchi Ryohei, Kusano Tomonobu
Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan.
J Plant Physiol. 2009 Apr 1;166(6):626-43. doi: 10.1016/j.jplph.2008.08.006. Epub 2008 Oct 14.
We have proposed that the polyamine spermine (Spm) functions as a signaling molecule to evoke defense reactions/cell death in avirulent pathogen-attacked tobacco plants. To understand its molecular basis in depth, Spm-responsive genes in Arabidopsis thaliana were identified by SuperSAGE analysis. Close to 90% of the Spm-responsive genes also responded during cucumber mosaic virus (CMV)-elicited hypersensitive response. Spm modulated the expression of genes of redox components, and genes involved in protein folding and secretion, protein degradation and defense. Two other prominent changes, the coordinately enhanced expression of members of the photorespiration pathway and a diversion in electron flow from the primary electron transfer chain of respiration to an alternative oxidase pathway, occurred in response to Spm. Spm activated the expression of 6 transcription factor genes including ZAT7, ZAT12, AtWRKY40 and AtbZIP60, of which the former three genes' products are currently assigned as components of H(2)O(2) signaling pathway, suggesting the involvement of H(2)O(2) in Spm-triggered responses. Since AtbZIP60 plays a proven master role in the unfolded protein response in Arabidopsis thaliana, it may function to control the expression of genes participating in protein folding and secretion, which were mentioned above. Spm induction and CMV-triggered up-regulation of the genes described mainly coincided and their induction was suppressed by inhibitors of Spm oxidation. Furthermore, treatment with those inhibitors prior to CMV inoculation allowed higher viral multiplication in Arabidopsis thaliana plants. These results support the existence of a Spm-signaling pathway in Arabidopsis thaliana and its significant role in defense against CMV.
我们提出多胺精胺（Spm）作为一种信号分子，可在无毒病原体侵袭的烟草植株中引发防御反应/细胞死亡。为深入了解其分子基础，通过SuperSAGE分析鉴定了拟南芥中对Spm有响应的基因。近90%对Spm有响应的基因在黄瓜花叶病毒（CMV）引发的过敏反应中也有响应。Spm调节氧化还原成分相关基因以及参与蛋白质折叠与分泌、蛋白质降解和防御的基因的表达。另外两个显著变化是，光呼吸途径成员的表达协同增强，以及电子流从呼吸作用的初级电子传递链转向交替氧化酶途径，这是对Spm的响应。Spm激活了包括ZAT7、ZAT12、AtWRKY40和AtbZIP60在内的6个转录因子基因的表达，其中前三个基因的产物目前被认为是H(2)O(2)信号通路的组成部分，这表明H(2)O(2)参与了Spm引发的反应。由于AtbZIP60在拟南芥的未折叠蛋白反应中起已证实的主导作用，它可能起到控制上述参与蛋白质折叠和分泌的基因表达的作用。Spm诱导以及CMV引发的上述基因上调主要是一致的，并且它们的诱导受到Spm氧化抑制剂的抑制。此外，在接种CMV之前用这些抑制剂处理，会使拟南芥植株中的病毒增殖更高。这些结果支持了拟南芥中存在Spm信号通路及其在防御CMV中的重要作用。
