Gibberellin Signaling Controls Cell Proliferation Rate in Arabidopsis
Gibberellin Signaling Controls Cell Proliferation Rate in Arabidopsis
复制标题
DOI：
10.1016/j.cub.2009.05.059
复制
发表时间：
2009-07-28
期刊：
影响因子：
9.2
通讯作者：
Genschik, Pascal
中科院分区：
文献类型：
--
作者：
Achard, Patrick;Gusti, Andi;Genschik, Pascal
植物生长涉及许多环境和内源信号的整合，这些信号与内在遗传程序一起决定植物大小。在细胞水平上，生长速率受两个过程的组合活性调节：细胞增殖和扩增。赤霉素（GA）是植物特异性激素，其在相对于环境变化的生长和发育的调节中发挥核心作用[1-3]。已经确定GA通过刺激生长抑制DELLA蛋白（DELLA）的破坏而通过细胞扩增促进生长[1，4-6];然而，它们对细胞增殖的影响仍然未知。叶和根分生组织生长的运动学分析揭示了一个新的功能，在抑制细胞生产的DELLA。此外，通过可视化的细胞周期标志物cyclinB 1：：β-葡萄糖醛酸苷酶在GA信号突变体，我们表明，GA调节细胞周期的活动在根分生组织通过DELLA依赖的机制。因此，仅在根分生组织中表达gai（一种不可降解的DELLA蛋白[4]）实质上减少了分裂细胞的数量。我们还表明，DELLAs通过提高细胞周期抑制剂Kip相关蛋白2（KRP 2）和SIAMESE（SIM）的水平来抑制细胞生产。因此，DELLA通过降低细胞增殖和扩增速率来发挥一般的植物生长抑制活性，从而实现表型可塑性。
Plant growth involves the integration of many environmental and endogenous signals that together with the intrinsic genetic program determine plant size. At the cellular level, growth rate is regulated by the combined activity of two processes: cell proliferation and expansion. Gibberellins (GA) are plant-specific hormones that play a central role in the regulation of growth and development with respect to environmental variability [1-3]. It is well established that GA promote growth through cell expansion by stimulating the destruction of growth-repressing DELLA proteins (DELLAs) [1, 4-6]; however, their effects on cell proliferation remain unknown. Kinematic analysis of leaf and root meristem growth revealed a novel function of DELLAs in restraining cell production. Moreover, by visualizing the cell cycle marker cyclinB1::beta-glucuronidase in GA-signaling mutants, we show that GA modulate cell cycle activity in the root meristem via a DELLA-dependent mechanism. Accordingly, expressing gai (a nondegradable DELLA protein [4]) solely in root meristem reduced substantially the number of dividing cells. We also show that DELLAs restrain cell production by enhancing the levels of the cell cycle inhibitors Kip-related protein 2(KRP2) and SIAMESE (SIM). Therefore, DELLAs exert a general plant growth inhibitory activity by reducing both cell proliferation and expansion rates, enabling phenotypic plasticity.