Meroz Yasmine, Bastien Renaud
Applied Mathematics, School of Engineering and Applied Science, Harvard University Cambridge, MA, USA.
Front Plant Sci. 2014 Nov 26;5:674. doi: 10.3389/fpls.2014.00674. eCollection 2014.
In this short review we focus on the role of noise in gravitropism of plants - the reorientation of plants according to the direction of gravity. We briefly introduce the conventional picture of static gravisensing in cells specialized in sensing. This model hinges on the sedimentation of statoliths (high in density and mass relative to other organelles) to the lowest part of the sensing cell. We then present experimental observations that cannot currently be understood within this framework. Lastly we introduce some current alternative models and directions that attempt to incorporate and interpret these experimental observations, including: (i) dynamic sensing, where gravisensing is suggested to be enhanced by stochastic events due to thermal and mechanical noise. These events both effectively lower the threshold of response, and lead to small-distance sedimentation, allowing amplification, and integration of the signal. (ii) The role of the cytoskeleton in signal-to-noise modulation and (iii) in signal transduction. In closing, we discuss directions that seem to either not have been explored, or that are still poorly understood.
在这篇简短的综述中，我们聚焦于噪声在植物向重力性中的作用——植物根据重力方向重新定向。我们简要介绍了专门负责感知的细胞中静态重力感知的传统图景。该模型基于平衡石（相对于其他细胞器，密度和质量都很高）沉降到感知细胞的最底部。然后我们展示了目前在此框架内无法理解的实验观察结果。最后，我们介绍了一些当前的替代模型和方向，这些模型和方向试图纳入并解释这些实验观察结果，包括：（i）动态感知，即有人认为由于热噪声和机械噪声引发的随机事件会增强重力感知。这些事件既有效地降低了响应阈值，又导致小距离沉降，从而实现信号的放大和整合。（ii）细胞骨架在信噪调制中的作用以及（iii）在信号转导中的作用。最后，我们讨论了似乎尚未被探索或仍未被充分理解的方向。
