Cell Cycle Modulation in the Response of the Primary Root of Arabidopsis to Salt Stress1
Cell Cycle Modulation in the Response of the Primary Root of Arabidopsis to Salt Stress1
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DOI：
10.1104/pp.104.040022
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发表时间：
2004-06
期刊：
影响因子：
7.4
通讯作者：
Gerrit West;D. Inzé;G. Beemster
中科院分区：
文献类型：
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作者：
Gerrit West;D. Inzé;G. Beemster
盐胁迫抑制植物生长发育。我们研究了细胞周期调控在介导拟南芥盐胁迫下主根生长反应中的重要性。当幼苗转移到培养基中的NaCl浓度增加，根的生长速率进行性降低。在幼苗转移到含有0.5%NaCl的生长培养基后第3天，初生根以远低于转移前的恒定速率生长，而转移到对照培养基的初生根保持加速生长。运动学分析表明，胁迫根的生长减少是由于细胞产量减少和成熟细胞长度变小。令人惊讶的是，平均细胞周期持续时间不受影响。因此，减少的细胞产量是由于分裂细胞的数量较少，即分生组织尺寸减小。为了分析分生组织大小适应的机制之前，3天，我们调查了短期细胞周期事件转移到盐水培养基。直接转移后，细胞周期蛋白依赖性激酶（CDK）的活性和CYCB 1;2启动子活性瞬时降低。由于CDKA;1和CDKB 1;1的蛋白质水平不受影响，因此允许适应应激条件的有丝分裂活性的暂时抑制最有可能由CDK活性的翻译后控制介导。因此，对盐胁迫的适应包括两个阶段：第一，细胞周期的快速瞬时抑制，导致更少的细胞保留在分生组织中。当分生组织达到给定条件下的适当大小时，细胞周期持续时间恢复到其默认值。
Salt stress inhibits plant growth and development. We investigated the importance of cell cycle regulation in mediating the primary root growth response of Arabidopsis to salt stress. When seedlings were transferred to media with increasing concentrations of NaCl, root growth rate was progressively reduced. At day 3 after transfer of seedlings to growth medium containing 0.5% NaCl the primary roots grew at a constant rate well below that prior to the transfer, whereas those transferred to control medium kept accelerating. Kinematic analysis revealed that the growth reduction of the stressed roots was due to a decrease in cell production and a smaller mature cell length. Surprisingly, average cell cycle duration was not affected. Hence, the reduced cell production was due to a smaller number of dividing cells, i.e. a meristem size reduction. To analyze the mechanism of meristem size adaptation prior to day 3, we investigated the short-term cell cycle events following transfer to saline medium. Directly after transfer cyclin-dependent kinase (CDK) activity and CYCB1;2 promoter activity were transiently reduced. Because protein levels of both CDKA;1 and CDKB1;1 were not affected, the temporary inhibition of mitotic activity that allows adaptation to the stress condition is most likely mediated by posttranslational control of CDK activity. Thus, the adaptation to salt stress involves two phases: first, a rapid transient inhibition of the cell cycle that results in fewer cells remaining in the meristem. When the meristem reaches the appropriate size for the given conditions, cell cycle duration returns to its default.