Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany.
Plant Signal Behav. 2011 Jun;6(6):873-7. doi: 10.4161/psb.6.6.15243. Epub 2011 Jun 1.
The juvenile-to-adult phase transition is an important and critical step during plant development to ensure maximum reproductivity. This transition is regulated by different pathways, in some of which microRNAs are considered to be essential key components. In seed plants, miR156 and miR172 act sequentially in well characterized pathways to induce the vegetative phase change and floral formation by the establishment of spatiotemporal gradients of their cognate target transcripts that encode master regulators of development. Recently, we reported on an unrelated, moss-specific miRNA that acts similarly in the control of the juvenile-to-adult phase transition in Physcomitrella patens. Physcomitrella miR534a defines the spatial expression of two transcripts encoding BLADE-ON-PETIOLE (BOP) transcriptional coactivators in a cytokinin-dependent manner. We propose that this miRNA-mediated control is a major mechanism underlying the cytokinin-induced formation of the gametophore meristem in Physcomitrella. Furthermore, it suggests a convergent evolution of miRNA-controlled pathways regulating phase transitions in seed and non-seed plants.
从幼年到成年的阶段过渡是植物发育过程中的一个重要且关键的步骤，以确保最大的繁殖能力。这个过渡受不同途径的调控，其中一些途径被认为是microRNAs 是必不可少的关键组成部分。在种子植物中，miR156 和 miR172 按照顺序在特征明确的途径中起作用，通过建立其同源靶转录本的时空梯度来诱导营养阶段的变化和花的形成，这些靶转录本编码发育的主要调节剂。最近，我们报道了一种与苔藓植物Physcomitrella patens 中控制幼年到成年的阶段过渡有关的、不相关的、苔藓植物特异性的 miRNA，其作用方式相似。Physcomitrella miR534a 以细胞分裂素依赖的方式定义了两个编码 BLADE-ON-PETIOLE (BOP) 转录共激活因子的转录物在空间表达。我们提出，这种 miRNA 介导的控制是 Physcomitrella 中细胞分裂素诱导的配子体原基形成的主要机制。此外，它表明了调控种子植物和非种子植物阶段过渡的 miRNA 调控途径的趋同进化。
