不定根发生问题,既是植物无性繁殖和工厂化育苗实践的核心问题,又是植物发育和形态建成等方面的重要理论问题.由于不定根发生过程的复杂性,到目前为止对其调控机制的了解还十分有限.大量研究证实,不定根发生与植物生长素类物质密切相关,因此现有的研究不仅围绕生长素及其信号传导途径展开,而且还涉及到基因表观遗传学调控水平.目前已经鉴定出一些与不定根发生相关的生长素信号传导因子,如NO、cGMP、microRNAs等.同时,还克隆到一些与不定根发生相关的基因,如OsPIN1、OsCKI1、NPK1、ARL1等.此外,发现DNA甲基化可以抑制DNA与蛋白(MeCP2)的结合,从而抑制基因转录;microRNA可以使基因沉默来调控不定根的发生状况.本文围绕不定根发生的激素调控、不定根发生的基因调控、不定根发生的生长素信号传导机制、表观遗传调控等几个方面综述了近年来的研究进展.
Adventitious root is an important issue both on the theoretical aspect of plant development and organogenesis and on the practical side of plant propagation and excised issue or organ regeneration. The way of molecular regulation underlying adventitious root is complex and far beyond understanding now. As crucial elements, plant hormone, particular auxin, play an important role on adventitious rooting. In addition, adventitious rooting is also regulated by epigenetics. By now, some signal molecules, such as NO, cGMP, microRNA, have been identified and adventitious root related genes such as OsPIN1, OsCKI1, NPK1, ARL1 have been cloned. It was confirmed that DNA methylation involved in the adventitious rooting regulation through a way of preventing MeCP2 binding to DNA and restarting gene transcription. Moreover, microRNAs play an important role in the process of adventitious rooting through gene silencing. In this paper, we summarize the researches on the auxin regulation, the gene regulation, the signal molecules and the epigenetic regulation related to plant adventitious rooting and propose some important points needed to be concerned in future research.