Department of Biochemistry & Cell Biology, Rice University, Houston, TX 77005-1892, USA.
Curr Biol. 2012 Apr 24;22(8):701-6. doi: 10.1016/j.cub.2012.02.061. Epub 2012 Apr 5.
Plants cannot change location to escape stressful environments. Therefore, plants evolved to respond and acclimate to diverse stimuli, including the seemingly innocuous touch stimulus [1-4]. Although some species, such as Venus flytrap, have fast touch responses, most plants display more gradual touch-induced morphological alterations, called thigmomorphogenesis [2, 3, 5, 6]. Thigmomorphogenesis may be adaptive; trees subjected to winds develop less elongated and thicker trunks and thus are less likely damaged by powerful wind gusts [7]. Despite the widespread relevance of thigmomorphogenesis, the regulation that underlies plant mechanostimulus-induced morphological responses remains largely unknown. Furthermore, whether thigmomorphogenesis confers additional advantage is not fully understood. Although aspects of thigmomorphogenesis resemble ethylene effects [8], and touch can induce ethylene synthesis [9, 10], Arabidopsis ethylene response mutants show touch-induced thigmomorphogenesis [11]; thus, ethylene response is nonessential for thigmomorphogenesis. Here we show that jasmonate (JA) phytohormone both is required for and promotes the salient characteristics of thigmomorphogenesis in Arabidopsis, including a touch-induced delay in flowering and rosette diameter reduction. Furthermore, we find that repetitive mechanostimulation enhances Arabidopsis pest resistance in a JA-dependent manner. These results highlight an important role for JA in mediating mechanostimulus-induced plant developmental responses and resultant cross-protection against biotic stress.
植物无法移动位置以逃避压力环境。因此，植物进化出了对各种刺激做出反应和适应的能力，包括看似无害的触摸刺激[1-4]。虽然一些物种，如维纳斯捕蝇草，具有快速的触摸反应，但大多数植物表现出更渐进的触摸诱导形态改变，称为向触性[2,3,5,6]。向触性可能是适应性的；树木受到风的影响会形成较少细长和较厚的树干，因此不太可能被强阵风损坏[7]。尽管向触性具有广泛的相关性，但植物机械刺激诱导形态反应的调节机制在很大程度上仍不清楚。此外，向触性是否赋予植物额外的优势也不完全清楚。尽管向触性的某些方面类似于乙烯的作用[8]，而且触摸可以诱导乙烯合成[9,10]，但拟南芥乙烯反应突变体表现出触摸诱导的向触性[11]；因此，乙烯反应对于向触性不是必需的。在这里，我们表明茉莉酸（JA）植物激素既是向触性的必要条件，也是其促进因素，包括触摸诱导的开花延迟和莲座叶直径减小。此外，我们发现重复的机械刺激以 JA 依赖的方式增强了拟南芥对害虫的抗性。这些结果突出了 JA 在介导机械刺激诱导的植物发育反应以及由此产生的对生物胁迫的交叉保护中的重要作用。
