Systems Biology Approach Pinpoints Minimum Requirements for Auxin Distribution during Fruit Opening.
Systems Biology Approach Pinpoints Minimum Requirements for Auxin Distribution during Fruit Opening.
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系统生物学方法确定了果实开放期间生长素分布的最低要求。
DOI：
10.1016/j.molp.2019.05.003
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发表时间：
2019
期刊：
影响因子：
27.5
通讯作者：
Li XR
中科院分区：
文献类型：
--
作者：
Li XR
植物激素生长素以浓度依赖的方式在植物形态发生过程中指导各种发育决定。生长素最大值已被证明保持分生组织的活性，例如，在根尖分生组织中，并定位新的生长部位，例如在侧根起始和叶序期间。最近，有研究表明，生长素最小的部位也提供了更多的位置信息。在拟南芥果实的发育中，生长素最小是正确分化瓣缘所必需的。然而，目前还不清楚这一生长素最低值是如何产生和维持的。在这里，我们使用系统生物学方法在实验观察的基础上模拟生长素的运输。这使我们能够确定建立它的最低要求。我们的模拟显示，两个可供选择的过程--我们称之为“通量屏障”和“通量通道”--都能够产生最小生长素，但在不同的参数设置下。这两个模型原则上能够产生相似的生长素图谱，但呈现出不同的生长素流量模式。这些模型通过组织特异性诱导消融进行了测试，揭示了水果中生长素的最低水平很可能是由通量通道过程产生的。通过3D PIN定位成像和实施实验观察的转运体定位，进一步支持了模型预测。通过这样一个实验建模周期，我们预测生长素在果实发育过程中如何逐渐成熟，以确保及时的果实开放和种子传播。
The phytohormone auxin is implied in steering various developmental decisions during plant morphogenesis in a concentration-dependent manner. Auxin maxima have been shown to maintain meristematic activity, for example, of the root apical meristem, and position new sites of outgrowth, such as during lateral root initiation and phyllotaxis. More recently, it has been demonstrated that sites of auxin minima also provide positional information. In the developingArabidopsisfruit, auxin minima are required for correct differentiation of the valve margin. It remains unclear, however, how this auxin minimum is generated and maintained. Here, we employ a systems biology approach to model auxin transport based on experimental observations. This allows us to determine the minimal requirements for its establishment. Our simulations reveal that two alternative processes—which we coin "flux-barrier" and "flux-passage"—are both able to generate an auxin minimum, but under different parameter settings. Both models are in principle able to yield similar auxin profiles but present qualitatively distinct patterns of auxin flux. The models were tested by tissue-specific inducible ablation, revealing that the auxin minimum in the fruit is most likely generated by a flux-passage process. Model predictions were further supported through 3D PIN localization imaging and implementing experimentally observed transporter localization. Through such an experimental–modeling cycle, we predict how the auxin minimum gradually matures during fruit development to ensure timely fruit opening and seed dispersal.