The promotive effect of latrunculin B on maize root gravitropism is concentration dependent
The promotive effect of latrunculin B on maize root gravitropism is concentration dependent
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DOI：
10.1016/s0273-1177(03)00247-3
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发表时间：
2003-01-01
期刊：
影响因子：
--
通讯作者：
Mohamalawari, DR
中科院分区：
文献类型：
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作者：
Blancaflor, EB;Hou, G;Mohamalawari, DR
细胞骨架被认为是高等植物向重力反应的关键因素。确定细胞骨架在向重力性中的作用的主要方法是使用抑制剂来破坏细胞骨架，并观察这种破坏对器官弯曲的影响。一些研究者报道，肌动蛋白或微管抑制剂不能阻止根向地性，从而得出细胞骨架不参与这一过程的结论。然而，最近的报道显示，用肌动蛋白抑制剂latrunculin B破坏肌动蛋白细胞骨架，促进根和芽的向重力反应。在根，曲率是持续在长期的clinorotation，尽管短期的重力刺激。这些结果表明，早期的重力诱导的信号继续坚持，尽管撤回的恒定重力刺激。为了进一步研究肌动蛋白破坏对根向地性的促进作用的机制，我们用不同浓度的latrunculin B处理玉米根，以确定对根弯曲有影响的latrunculin B的最低浓度。在10分钟重力刺激后，将处理的根在1rpm回转器上轴向旋转，并在15小时后测量曲率。我们的研究结果表明，100 nM的latrunculin B诱导最强的促进作用的曲率上生长的回转器的玉米根。此外，用100 nM latrunculin B处理的连续重力刺激的根表现出更强的弯曲反应，而用该浓度的latrunculin B处理的去帽根在连续重力刺激期间不发生弯曲。低浓度的latrunculin B的曲率上的clinorated和连续gravistimated根的较强的促进作用表明，破坏的更精细，更动态的组件的肌动蛋白细胞骨架可能是增强热带反应的根重力的原因。(C)2003年空间研委会。由爱思唯尔有限公司出版。保留所有权利。
The cytoskeleton has been proposed to be a key player in the gravitropic response of higher plants. A major approach to determine the role of the cytoskeleton in gravitropism has been to use inhibitors to disrupt the cytoskeleton and their to observe the effect that such disruption has on organ bending. Several investigators have reported that actin or microtubule inhibitors do not prevent root gravitropism, leading to the conclusion that the cytoskeleton is not involved in this process. However, there are recent reports showing that disruption of the actin cytoskeleton with the actin inhibitor, latrunculin B, promotes the gravitropic response of both roots and shoots. In roots, curvature is sustained during prolonged periods of clinorotation despite short periods of gravistimulation. These results indicate that an early gravity-induced signal continues to persist despite withdrawal of the constant gravity stimulus. To investigate further the mechanisms underlying the promotive effect of actin disruption on root gravitropism, we treated maize roots with varying concentrations of latrunculin B in order to determine the lowest concentration of latrunculin B that has an effect on root bending. After a 10-minute gravistimulus, treated roots were axially rotated on a one rpm clinostat and curvature was measured after 15 hours. Our results show that 100 nM latrunculin B induced the strongest promotive effect on the curvature of maize roots grown on a clinostat. Moreover, continuously gravistimulated roots treated with 100 nM latrunculin B exhibited stronger curvature responses while decapped roots treated with this concentration of latrunculin B did not bend during continuous gravistimulation. The stronger promotive effect of low concentrations of latrunculin B on the curvature of both clinorotated and continuously gravistimulated roots suggests that disruption of the finer, more dynamic component of the actin cytoskeleton could be the cause of the enhanced tropic responses of roots to gravity. (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.