Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA.
Plant Signal Behav. 2009 Oct;4(10):933-41. doi: 10.4161/psb.4.10.9470. Epub 2009 Oct 30.
In flowering plants, gravity perception appears to involve the sedimentation of starch-filled plastids, called amyloplasts, within specialized cells (the statocytes) of shoots (endodermal cells) and roots (columella cells). Unfortunately, how the physical information derived from amyloplast sedimentation is converted into a biochemical signal that promotes organ gravitropic curvature remains largely unknown. Recent results suggest an involvement of the Translocon of the Outer Envelope of (Chloro)plastids (TOC) in early phases of gravity signal transduction within the statocytes. This review summarizes our current knowledge of the molecular mechanisms that govern gravity signal transduction in flowering plants and summarizes models that attempt to explain the contribution of TOC proteins in this important behavioral plant growth response to its mechanical environment.
在开花植物中，重力感知似乎涉及到充满淀粉的质体（称为淀粉体）在芽（内胚层细胞）和根（中柱细胞）的专门细胞（平衡细胞）中的沉降。不幸的是，淀粉体沉降所产生的物理信息如何转化为促进器官向重性弯曲的生化信号，在很大程度上仍然未知。最近的结果表明，质体（类囊体）外被的转运蛋白（TOC）在平衡细胞中的重力信号转导的早期阶段发挥作用。这篇综述总结了我们目前对调控开花植物重力信号转导的分子机制的认识，并总结了试图解释 TOC 蛋白在植物对其机械环境的这一重要生长反应中的作用的模型。
