Sena Giovanni, Wang Xiaoning, Liu Hsiao-Yun, Hofhuis Hugo, Birnbaum Kenneth D
New York University, Department of Biology, Center for Genomics and Systems Biology, Silver Building, 100 Washington Square East, New York, New York 10003, USA.
Nature. 2009 Feb 26;457(7233):1150-3. doi: 10.1038/nature07597. Epub 2009 Jan 28.
Plants rely on the maintenance of stem cell niches at their apices for the continuous growth of roots and shoots. However, although the developmental plasticity of plant cells has been demonstrated, it is not known whether the stem cell niche is required for organogenesis. Here we explore the capacity of a broad range of differentiating cells to regenerate an organ without the activity of a stem cell niche. Using a root-tip regeneration system in Arabidopsis thaliana to track the molecular and functional recovery of cell fates, we show that re-specification of lost cell identities begins within hours of excision and that the function of specialized cells is restored within one day. Critically, regeneration proceeds in plants with mutations that fail to maintain the stem cell niche. These results show that stem-cell-like properties that mediate complete organ regeneration are dispersed in plant meristems and are not restricted to niches, which nonetheless seem to be necessary for indeterminate growth. This regenerative reprogramming of an entire organ without transition to a stereotypical stem cell environment has intriguing parallels to recent reports of induced transdifferentiation of specific cell types in the adult organs of animals.
植物依靠其顶端干细胞微环境的维持来实现根和茎的持续生长。然而，尽管植物细胞的发育可塑性已得到证实，但尚不清楚器官发生是否需要干细胞微环境。在此，我们探索了广泛的分化细胞在没有干细胞微环境活性的情况下再生器官的能力。利用拟南芥根尖再生系统来追踪细胞命运的分子和功能恢复，我们发现丢失细胞身份的重新指定在切除后数小时内就开始了，并且特化细胞的功能在一天内得以恢复。至关重要的是，在无法维持干细胞微环境的突变植物中再生仍能进行。这些结果表明，介导完整器官再生的干细胞样特性分散在植物分生组织中，并不局限于微环境，尽管微环境对于无限生长似乎是必要的。这种在不转变为定型干细胞环境的情况下对整个器官进行的再生重编程，与动物成体器官中特定细胞类型诱导转分化的近期报道有着有趣的相似之处。
