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.

植物体细胞胚发生是指在没有受精的情况下从体细胞发育出胚的现象。先前的研究表明，植物激素生长素通过诱导细胞全能状态在体细胞胚发生中起着至关重要的作用，尽管其基本机制尚不清楚。在这里，我们显示出生长素通过改变染色质的可及性迅速重新连接细胞全能网络。对染色质可及性动力学的分析进一步揭示了体细胞胚发生基础的分层基因调控网络。特别地，我们发现外植体的胚胎性质是体细胞重编程的先决条件。重新编程细胞后，B3型全能转录因子LEC2通过直接激活早期胚胎模式基因来促进体细胞胚的形成WOX2和WOX3。因此，我们的结果阐明了生长素促进植物细胞全能的获得并建立细胞全能基因与胚胎发育途径之间直接联系的分子机制。