The State Key Laboratory of Freshwater Ecology and Biotechnology, The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
Plant Physiol. 2022 Oct 27;190(3):1777-1791. doi: 10.1093/plphys/kiac382.
In heterophyllous plants, leaf shape shows remarkable plasticity in response to environmental conditions. However, transgenic studies of heterophylly are lacking and the molecular mechanism remains unclear. Here, we cloned the KNOTTED1-LIKE HOMEOBOX family gene SHOOT MERISTEMLESS (STM) from the heterophyllous plant Hygrophila difformis (Acanthaceae). We used molecular, morphogenetic, and biochemical tools to explore its functions in heterophylly. HdSTM was detected in different organs of H. difformis, and its expression changed with environmental conditions. Heterologous, ectopic expression of HdSTM in Arabidopsis (Arabidopsis thaliana) increased leaf complexity and CUP-SHAPED COTYLEDON (CUC) transcript levels. However, overexpression of HdSTM in H. difformis did not induce the drastic leaf change in the terrestrial condition. Overexpression of HdSTM in H. difformis induced quick leaf variations in submergence, while knockdown of HdSTM led to disturbed leaf development and weakened heterophylly in H. difformis. HdCUC3 had the same spatiotemporal expression pattern as HdSTM. Biochemical analysis revealed a physical interaction between HdSTM and HdCUC3. Our results provide genetic evidence that HdSTM is involved in regulating heterophylly in H. difformis.
在异形叶性植物中，叶片形状对环境条件表现出显著的可塑性。然而，异形叶性的转基因研究尚缺乏，其分子机制尚不清楚。在这里，我们从异形叶性植物水蓑衣（爵床科）中克隆了 KNOTTED1-LIKE HOMEOBOX 家族基因 SHOOT MERISTEMLESS（STM）。我们使用分子、形态发生和生化工具来探索其在异形叶性中的功能。HdSTM 在水蓑衣的不同器官中被检测到，其表达随环境条件而变化。HdSTM 在拟南芥（Arabidopsis thaliana）中的异位表达增加了叶片的复杂性和 CUP-SHAPED COTYLEDON（CUC）转录水平。然而，HdSTM 在水蓑衣中的过表达并没有在陆生条件下引起叶片的剧烈变化。HdSTM 在水蓑衣中的过表达诱导了淹水时叶片的快速变化，而 HdSTM 的敲低导致叶片发育紊乱，减弱了水蓑衣的异形叶性。HdCUC3 与 HdSTM 具有相同的时空表达模式。生化分析显示 HdSTM 和 HdCUC3 之间存在物理相互作用。我们的研究结果提供了遗传证据，表明 HdSTM 参与了水蓑衣异形叶性的调节。
