Quantitative predictions on auxin-induced polar distribution of PIN proteins during vein formation in leaves
Quantitative predictions on auxin-induced polar distribution of PIN proteins during vein formation in leaves
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DOI：
10.1140/epje/i2010-10604-5
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发表时间：
2010-10-01
影响因子：
1.8
通讯作者：
Frey, E.
中科院分区：
文献类型：
--
作者：
Alim, K.;Frey, E.
植物激素生长素及其外排促进剂 PIN 蛋白的动态模式是植物发育的空间和时间组织的关键调节因子。特别是生长素诱导其自身的外排促进剂的极性定位。由于这种正反馈，生长素流被定向，并且出现了生长素和 PIN 的模式。在叶子静脉起始的最早阶段，生长素积累在表皮细胞边缘的单个细胞中，从该细胞流入叶片的地面分生组织。局部生长素供应导致 PIN 沿细胞链分布连续极化。我们使用最小的管道化模型对细胞内的生长素和 PIN 动力学进行建模。通过分析求解模型，我们发现了一个可兴奋的极化前沿，该极化前沿触发细胞中 PIN 蛋白的极性分布。由于极化前沿可能从其起始位点延伸到相反的方向，我们提出了解决双极细胞令人费解的现象的可能解决方案，从而为闭合、环状静脉的发展提供了解释。采用非线性分析，我们确定了极化过程中微观过程的作用。此外，我们推论了极化前沿的定量预测，建立了一条确定迄今为止很大程度上未知的生长素和 PIN 动力学动力学速率的路线。
The dynamic patterning of the plant hormone auxin and its efflux facilitator the PIN protein are the key regulators for the spatial and temporal organization of plant development. In particular auxin induces the polar localization of its own efflux facilitator. Due to this positive feedback, auxin flow is directed and patterns of auxin and PIN arise. During the earliest stage of vein initiation in leaves auxin accumulates in a single cell in a rim of epidermal cells from which it flows into the ground meristem tissue of the leaf blade. There the localized auxin supply yields the successive polarization of PIN distribution along a strand of cells. We model the auxin and PIN dynamics within cells with a minimal canalization model. Solving the model analytically we uncover an excitable polarization front that triggers a polar distribution of PIN proteins in cells. As polarization fronts may extend to opposing directions from their initiation site, we suggest a possible resolution to the puzzling occurrence of bipolar cells, thus we offer an explanation for the development of closed, looped veins. Employing non-linear analysis, we identify the role of the contributing microscopic processes during polarization. Furthermore, we deduce quantitative predictions on polarization fronts establishing a route to determine the up to now largely unknown kinetic rates of auxin and PIN dynamics.