Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA.
Development. 2010 Feb;137(4):541-9. doi: 10.1242/dev.041426.
The establishment of the primary meristems through proliferation after germination is essential for plant post-embryonic development. Cytokinins have long been considered a key regulator of plant cell division. Here we show that cytokinins are essential for early seedling development of Arabidopsis. Loss of cytokinin perception leads to a complete failure of meristem establishment and growth arrest after germination. We also present evidence that cytokinin signaling is involved in activation of the homeobox gene STIMPY (STIP or WOX9) expression in meristematic tissues, which is essential for maintaining the meristematic fate. Cytokinin-independent STIP expression is able to partially compensate for the shoot apical meristem growth defects in mutants that cannot sense cytokinin. These findings identify a new branch of the cytokinin signaling network, linking cytokinin to the process of meristem and seedling establishment.
通过发芽后的增殖来建立初生分生组织，对于植物的胚胎后发育是至关重要的。细胞分裂素一直被认为是植物细胞分裂的关键调节因子。在这里，我们证明了细胞分裂素对于拟南芥早期幼苗发育是必需的。细胞分裂素感知的丧失导致分生组织建立的完全失败，并在发芽后生长停滞。我们还提供了证据表明，细胞分裂素信号转导参与了同源盒基因 STIMPY（STIP 或 WOX9）在分生组织中的表达的激活，这对于维持分生组织状态是必需的。在不能感知细胞分裂素的突变体中，细胞分裂素非依赖性 STIP 表达能够部分补偿其顶端分生组织生长缺陷。这些发现确定了细胞分裂素信号网络的一个新分支，将细胞分裂素与分生组织和幼苗建立过程联系起来。
