Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, France.
J Exp Bot. 2017 Dec 16;68(21-22):5801-5811. doi: 10.1093/jxb/erx402.
The CUP-SHAPED COTYLEDON (CUC) transcription factors control plant boundary formation, thus allowing the emergence of novel growth axes. While the developmental roles of the CUC genes in different organs and across species are well characterized, upstream and downstream events that contribute to their function are still poorly understood. To identify new players in this network, we performed a suppressor screen of CUC2g-m4, a line overexpressing CUC2 that has highly serrated leaves. We identified a mutation that simplifies leaf shape and affects MURUS1 (MUR1), which is responsible for GDP-L-fucose production. Using detailed morphometric analysis, we show that GDP-L-fucose has an essential role in leaf shape acquisition by sustaining differential growth at the leaf margins. Accordingly, reduced CUC2 expression levels are observed in mur1 leaves. Furthermore, genetic analyses reveal a conserved role for GDP-L-fucose in different developmental contexts where it contributes to organ separation in the same pathway as CUC2. Taken together, our results reveal that GDP-L-fucose is necessary for proper establishment of boundary domains in various developmental contexts.
杯状子叶（CUC）转录因子控制植物边界的形成，从而允许新的生长轴的出现。虽然 CUC 基因在不同器官和物种中的发育作用已经得到很好的描述，但有助于其功能的上游和下游事件仍知之甚少。为了在这个网络中鉴定新的参与者，我们对 CUC2g-m4 进行了抑制筛选，CUC2g-m4 是一个过表达 CUC2 的品系，其叶片具有高度锯齿状。我们鉴定到一个突变，该突变简化了叶片形状并影响了负责 GDP-L-岩藻糖生产的 MURUS1（MUR1）。通过详细的形态计量分析，我们表明 GDP-L-岩藻糖通过维持叶缘的差异生长，对叶片形状的获得具有重要作用。因此，mur1 叶片中观察到 CUC2 表达水平降低。此外，遗传分析揭示了 GDP-L-岩藻糖在不同发育背景下的保守作用，它在与 CUC2 相同的途径中有助于器官分离。总之，我们的结果表明 GDP-L-岩藻糖是各种发育背景下正确建立边界域所必需的。
