National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences (CAS), Shanghai 200032, China; University of Chinese Academy of Sciences (UCAS), Shanghai 200032, China.
National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences (CAS), Shanghai 200032, China; ShanghaiTech University, Shanghai 200031, China.
Dev Cell. 2020 Sep 28;54(6):742-757.e8. doi: 10.1016/j.devcel.2020.07.003. Epub 2020 Aug 4.
Plant somatic embryogenesis refers to a phenomenon where embryos develop from somatic cells in the absence of fertilization. Previous studies have revealed that the phytohormone auxin plays a crucial role in somatic embryogenesis by inducing a cell totipotent state, although its underlying mechanism is poorly understood. Here, we show that auxin rapidly rewires the cell totipotency network by altering chromatin accessibility. The analysis of chromatin accessibility dynamics further reveals a hierarchical gene regulatory network underlying somatic embryogenesis. Particularly, we find that the embryonic nature of explants is a prerequisite for somatic cell reprogramming. Upon cell reprogramming, the B3-type totipotent transcription factor LEC2 promotes somatic embryo formation by direct activation of the early embryonic patterning genes WOX2 and WOX3. Our results thus shed light on the molecular mechanism by which auxin promotes the acquisition of plant cell totipotency and establish a direct link between cell totipotent genes and the embryonic development pathway.
植物体细胞胚胎发生是指在没有受精的情况下，胚胎从体细胞中发育而来的现象。先前的研究表明，植物激素生长素通过诱导细胞全能性状态，在体细胞胚胎发生中起着至关重要的作用，尽管其潜在的机制还不清楚。在这里，我们表明生长素通过改变染色质可及性来快速重编细胞全能性网络。对染色质可及性动力学的分析进一步揭示了体细胞胚胎发生的层次基因调控网络。特别是，我们发现外植体的胚胎性质是体细胞重编程的前提。在细胞重编程后，B3 型全能转录因子 LEC2 通过直接激活早期胚胎模式形成基因 WOX2 和 WOX3 促进体细胞胚胎形成。因此，我们的研究结果揭示了生长素促进植物细胞全能性获得的分子机制，并在细胞全能性基因和胚胎发育途径之间建立了直接联系。
