Liu Yuan, Li Xinbo, Zhao Jing, Tang Xingchun, Tian Shujuan, Chen Junyi, Shi Ce, Wang Wei, Zhang Liyao, Feng Xianzhong, Sun Meng-Xiang
Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China; College of Life Sciences, Hubei University, Wuhan, 430062, China;
Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China;
Proc Natl Acad Sci U S A. 2015 Oct 6;112(40):12432-7. doi: 10.1073/pnas.1508651112. Epub 2015 Sep 22.
The suspensor is a temporary supporting structure of proembryos. It has been proposed that suspensor cells also possess embryogenic potential, which is suppressed by the embryo as an effect of the embryo-suspensor interaction. However, data to support this hypothesis are not yet available. In this report, using an in vivo living cell laser ablation technique, we show that Arabidopsis suspensor cells can develop into embryos after removing the embryo proper. The embryo proper plays a critical role in maintaining suspensor cell identity. However, this depends on the developmental stage; after the globular embryo stage, the suspensors no longer possess the potential to develop into embryos. We also reveal that hypophysis formation may be essential for embryo differentiation. Furthermore, we show that, after removing the embryo, auxin gradually accumulates in the top suspensor cell where cell division occurs to produce an embryo. Auxin redistribution likely reprograms the fate of the suspensor cell and triggers embryogenesis in suspensor cells. Thus, we provide direct evidence that the embryo suppresses the embryogenic potential of suspensor cells.
胚柄是原胚的一个临时支撑结构。有人提出，胚柄细胞也具有胚胎发生潜能，但由于胚与胚柄之间的相互作用，这种潜能受到胚的抑制。然而，目前尚无支持这一假说的数据。在本报告中，我们使用体内活细胞激光消融技术表明，去除胚体后，拟南芥胚柄细胞能够发育成胚。胚体在维持胚柄细胞特性方面起着关键作用。然而，这取决于发育阶段；在球形胚阶段之后，胚柄不再具有发育成胚的潜能。我们还发现，垂体细胞的形成可能对胚的分化至关重要。此外，我们表明，去除胚后，生长素逐渐在顶端胚柄细胞中积累，在该细胞中发生细胞分裂以产生胚。生长素重新分布可能会重新编程胚柄细胞的命运，并触发胚柄细胞中的胚胎发生。因此，我们提供了直接证据，证明胚抑制了胚柄细胞的胚胎发生潜能。
