Department of Plant Systems Biology, VIB, Ghent University, Gent, Belgium.
Mol Syst Biol. 2010 Dec 21;6:447. doi: 10.1038/msb.2010.103.
Plant development is exceptionally flexible as manifested by its potential for organogenesis and regeneration, which are processes involving rearrangements of tissue polarities. Fundamental questions concern how individual cells can polarize in a coordinated manner to integrate into the multicellular context. In canalization models, the signaling molecule auxin acts as a polarizing cue, and feedback on the intercellular auxin flow is key for synchronized polarity rearrangements. We provide a novel mechanistic framework for canalization, based on up-to-date experimental data and minimal, biologically plausible assumptions. Our model combines the intracellular auxin signaling for expression of PINFORMED (PIN) auxin transporters and the theoretical postulation of extracellular auxin signaling for modulation of PIN subcellular dynamics. Computer simulations faithfully and robustly recapitulated the experimentally observed patterns of tissue polarity and asymmetric auxin distribution during formation and regeneration of vascular systems and during the competitive regulation of shoot branching by apical dominance. Additionally, our model generated new predictions that could be experimentally validated, highlighting a mechanistically conceivable explanation for the PIN polarization and canalization of the auxin flow in plants.
植物发育具有极高的灵活性，表现为其器官发生和再生的潜力，这些过程涉及组织极性的重新排列。基本问题涉及单个细胞如何协调极化，以整合到多细胞环境中。在管化模型中，信号分子生长素作为一个极化线索，细胞间生长素流动的反馈对于同步极性重排至关重要。我们基于最新的实验数据和最小的、合理的生物学假设，提供了一个新的管化机制框架。我们的模型结合了细胞内生长素信号转导，用于表达 PINFORMED (PIN) 生长素转运蛋白，以及细胞外生长素信号转导的理论假设，用于调节 PIN 亚细胞动力学。计算机模拟忠实地、稳健地再现了实验观察到的组织极性模式和不对称生长素分布，这些模式发生在血管系统的形成和再生过程中，以及顶端优势对芽分枝的竞争调节过程中。此外，我们的模型产生了新的预测，可以通过实验验证，突出了植物中生长素流的 PIN 极化和管化的一种在机制上可以想象的解释。
