Duan Qiao-Hong, Wang Dong-Hui, Xu Zhi-Hong, Bai Shu-Nong
PKU-Yale Joint Research Center of Agricultural and Plant Molecular Biology, National Key Laboratory of Protein Engineering and Plant Gene Engineering, College of Life Sciences, Peking University, Beijing, People's Republic of China.
Planta. 2008 Sep;228(4):537-43. doi: 10.1007/s00425-008-0756-7. Epub 2008 May 28.
Cucumber (Cucumis sativus L.) has served as a model to understand hormone regulation in unisexual flower development since the 1950s and the role of ethylene in promoting female flower development has been well documented. Recent studies cloned the F-locus in gynoecious lines as an additional copy of the ACC synthase (ACS) gene, which further confirmed the role of ethylene in the promotion of female cucumber flowers. However, no direct evidence was generated to demonstrate that increases in endogenous ethylene production could induce female flowers by arresting stamen development. To clarify the relationship between ethylene production and stamen development, we overexpressed the ethylene synthesis cucumber gene CsACO2 to generate transgenic Arabidopsis, driven by the organ-specific promoter P ( AP3 ). We found that organ-specific overexpression of CsACO2 significantly affected stamen but not carpel development, similar to that in the female flowers of cucumber. Our results suggested that increases in ethylene production directly disturb stamen development. Additionally, our study revealed that among all floral organs, stamens respond most sensitively to exogenous ethylene.
自20世纪50年代以来，黄瓜（Cucumis sativus L.）一直是理解单性花发育中激素调控的模型，乙烯在促进雌花发育中的作用已有充分记录。最近的研究克隆了雌性系中的F位点，它是1-氨基环丙烷-1-羧酸合成酶（ACS）基因的一个额外拷贝，这进一步证实了乙烯在促进黄瓜雌花发育中的作用。然而，没有直接证据表明内源性乙烯产量的增加可通过阻止雄蕊发育来诱导雌花。为阐明乙烯产生与雄蕊发育之间的关系，我们通过器官特异性启动子P（AP3）驱动，过表达乙烯合成黄瓜基因CsACO2来生成转基因拟南芥。我们发现，CsACO2的器官特异性过表达显著影响雄蕊而非心皮发育，这与黄瓜雌花中的情况相似。我们的结果表明，乙烯产量的增加直接干扰雄蕊发育。此外，我们的研究表明，在所有花器官中，雄蕊对外源乙烯的反应最为敏感。
