Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom.
School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom.
Proc Natl Acad Sci U S A. 2022 Aug 2;119(31):e2121288119. doi: 10.1073/pnas.2121288119. Epub 2022 Jul 25.
The hormone gibberellin (GA) controls plant growth and regulates growth responses to environmental stress. In monocotyledonous leaves, GA controls growth by regulating division-zone size. We used a systems approach to investigate the establishment of the GA distribution in the maize leaf growth zone to understand how drought and cold alter leaf growth. By developing and parameterizing a multiscale computational model that includes cell movement, growth-induced dilution, and metabolic activities, we revealed that the GA distribution is predominantly determined by variations in GA metabolism. Considering wild-type and UBI::GA20-OX-1 leaves, the model predicted the peak in GA concentration, which has been shown to determine division-zone size. Drought and cold modified enzyme transcript levels, although the model revealed that this did not explain the observed GA distributions. Instead, the model predicted that GA distributions are also mediated by posttranscriptional modifications increasing the activity of GA 20-oxidase in drought and of GA 2-oxidase in cold, which we confirmed by enzyme activity measurements. This work provides a mechanistic understanding of the role of GA metabolism in plant growth regulation.
激素赤霉素（GA）控制植物生长并调节对环境胁迫的生长反应。在单子叶植物叶片中，GA 通过调节分裂区大小来控制生长。我们使用系统方法研究了玉米叶片生长区 GA 分布的建立，以了解干旱和寒冷如何改变叶片生长。通过开发和参数化一个包括细胞运动、生长诱导稀释和代谢活动的多尺度计算模型，我们揭示了 GA 分布主要由 GA 代谢的变化决定。考虑到野生型和 UBI::GA20-OX-1 叶片，该模型预测了 GA 浓度的峰值，该峰值已被证明决定了分裂区的大小。干旱和寒冷改变了酶转录本水平，但模型表明这并不能解释观察到的 GA 分布。相反，该模型预测 GA 分布也受到转录后修饰的调节，这些修饰增加了干旱中 GA20-氧化酶和寒冷中 GA2-氧化酶的活性，我们通过酶活性测量证实了这一点。这项工作提供了对 GA 代谢在植物生长调节中的作用的机制理解。
