Direct evidence that suspensor cells have embryogenic potential that is suppressed by the embryo proper during normal embryogenesis
Direct evidence that suspensor cells have embryogenic potential that is suppressed by the embryo proper during normal embryogenesis
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直接证据表明，悬索细胞具有胚胎发生潜力，但在正常胚胎发生过程中，该潜力受到胚胎本身的抑制
DOI：
10.1073/pnas.1508651112
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发表时间：
2015-10-06
影响因子：
11.1
通讯作者：
Sun, Meng-Xiang
中科院分区：
文献类型：
--
作者：
Liu, Yuan;Li, Xinbo;Sun, Meng-Xiang
意义胚柄是种子成熟过程中经历细胞程序性死亡的一种临时结构。已有研究表明，胚柄细胞具有胚胎发生潜能，但这种潜能受到胚胎的抑制。利用已建立的活体细胞激光消融系统，我们证实了拟南芥胚柄的胚胎发生潜力以及胚胎本身在施加胚柄细胞特性方面的作用。我们还表明，胚胎激光消融后，胚柄细胞中生长素的重新分布可能在胚柄胚胎的启动过程中起着重要作用。胚柄是原胚的临时支撑结构。有人提出，胚柄细胞也具有胚性发生能力，但由于胚胎-胚柄相互作用的影响，胚性细胞的胚性受到抑制。然而，目前还没有支持这一假设的数据。在这份报告中，我们利用活体细胞激光消融技术，证明了拟南芥胚柄细胞在去除胚胎本身后可以发育成胚胎。胚胎本身在维持胚柄细胞特性方面起着至关重要的作用。然而，这取决于发育阶段；在球形胚胎阶段之后，悬钩子不再具有发育成胚胎的潜力。我们还揭示了脑垂体的形成可能是胚胎分化所必需的。此外，我们发现，在移除胚胎后，生长素逐渐积累在顶端的胚柄细胞中，在那里发生细胞分裂，产生胚胎。生长素的重新分配可能重新编程胚柄细胞的命运，并触发胚柄细胞的胚胎发生。因此，我们提供了胚胎抑制胚柄细胞胚胎发生潜力的直接证据。
Significance The suspensor is a temporary structure that undergoes programmed cell death during seed maturation. It has been suggested that suspensor cells have embryogenic potential that is suppressed by the embryo. Using an established in vivo living cell laser ablation system, we confirmed the embryogenic potential of the Arabidopsis suspensor and the role of the embryo proper in imposing suspensor cell identity. We also showed that auxin redistribution in suspensor cells after laser ablation of embryos may play an essential role in the initiation of suspensor embryos. 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.