Zhang Yun, Gu Min, Xia Xiaojian, Shi Kai, Zhou Yanhong, Yu Jingquan
Department of Horticulture, Huajiachi Campus, Zhejiang University, Kaixuan Road 268, Hangzhou, 310029, People's Republic of China.
J Chem Ecol. 2009 Jun;35(6):679-88. doi: 10.1007/s10886-009-9642-4. Epub 2009 May 21.
Several benzoic and cinnamic acid derivatives were identified from cucumber root exudates. The effects of these phenylcarboxylic acids on root growth and cell cycle progression were examined in germinated seeds of cucumber. All 12 phenylcarboxylic acids (0.25 mM) tested significantly inhibited cucumber radicle growth, and cinnamic acid exerted a dose-dependent inhibitory effect. At 6 h after exposure to the acids, transcript levels of the cell cycle-related genes, including two cyclin-dependent kinases (CDKs) and four cyclins were reduced. Among them, transcript of CycB, a marker gene for mitosis showed a remarkable reduction. The temporal analysis showed that expression of mitotic genes (CDKB, CycA, and CycB) were reduced throughout the experiment, while the reduction of the other genes (CDKA, CycD3;1, and CycD3;2) were observed only at earlier time points. At 48 h after treatment with benzoic and cinnamic acids, an enhancement of endoreduplication was observed. Further time course analysis indicated that endoreduplication started as early as 6 h after exposure to cinnamic acid. These results provide evidence that exposure to benzoic and cinnamic acids can induce rapid and dramatic down-regulation of cell cycle-related genes, thus leading to root growth inhibition. Meanwhile, the block of mitosis caused by phenylcarboxylic acids also induced an increased level of endoreduplication.
从黄瓜根分泌物中鉴定出了几种苯甲酸和肉桂酸衍生物。在黄瓜发芽种子中检测了这些苯羧酸对根生长和细胞周期进程的影响。所有测试的12种苯羧酸（0.25 mM）均显著抑制黄瓜胚根生长，肉桂酸表现出剂量依赖性抑制作用。在接触这些酸6小时后，细胞周期相关基因的转录水平降低，包括两种细胞周期蛋白依赖性激酶（CDK）和四种细胞周期蛋白。其中，有丝分裂标记基因CycB的转录本显著减少。时间分析表明，在整个实验过程中，有丝分裂基因（CDKB、CycA和CycB）的表达均降低，而其他基因（CDKA、CycD3;1和CycD3;2）的降低仅在较早时间点观察到。在用苯甲酸和肉桂酸处理48小时后，观察到核内复制增强。进一步的时间进程分析表明，核内复制早在接触肉桂酸6小时后就开始了。这些结果证明，接触苯甲酸和肉桂酸可诱导细胞周期相关基因迅速且显著地下调，从而导致根生长受到抑制。同时，苯羧酸引起的有丝分裂阻滞也诱导了核内复制水平的增加。
