PNAS：通过建模揭示GA代谢酶响应干旱和寒冷的转录后调控

今天介绍的是由英国、比利时和埃及科学家在PNAS上发表的研究论文《Modeling reveals posttranscriptional regulation of GA metabolism enzymes in response to drought and cold》。

了解为何植物在干旱和寒冷中生长减缓对于确定这些条件如何影响作物产量至关重要。激素赤霉素(GA)控制植物生长并调节受环境条件胁迫的生长反应。在单子叶植物的叶子中，GA通过调节分裂区的大小来控制生长。了解分子和细胞过程是如何相互作用以建立、维持和调节控制器官生长的激素分布是具有挑战性的，而理论模型已被证明在理解这些机制方面极具价值。

在本研究中，作者团队通过将玉米叶片每个细胞内的GA代谢的详细模型与细胞生长动力学相结合从而开发了玉米叶片在生长过程中GA动力学的多尺度模型。研究人员通过研究玉米叶能够将模型预测与空间代谢物和酶数据进行比较，揭示了生物活性GA分布主要由代谢的空间变化决定。通过进一步开发和参数化包括细胞运动、生长诱导的稀释和代谢活动在内的多尺度计算模型，作者同样揭示了GA分布主要由GA代谢的变化决定。关于野生型和UBI：：GA20-OX-1叶片，该模型预测了GA浓度的峰值，该峰值已被证明可确定分区大小。干旱和寒冷修饰了酶转录水平，该模型预测GA分布在增强干旱时GA -20氧化酶的活性和寒冷时GA -2氧化酶的活性也由转录后修饰介导，作者通过酶活性测量证实了这一点。这项工作为GA代谢在植物生长调节中的作用提供了一个机制的理解。

综上，作者通过建立计算模型并将预测与配子测量进行比较，发现GA分布主要由气体合成和降解的空间变化造成。虽然合成和降解酶转录物受到干旱和寒冷的影响，但这并不能完全解释GA的分布。由特定的酶活性增加以产生GA分布，这是生长反应的基础，从而进一步了解了干旱和寒冷对植物生长的抑制作用。

Understanding why plant growth decreases in drought and cold is essential to ascertaining how these conditions affect crop yields.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.Understanding how molecular and cellular processes interact to establish, maintain, and adjust the hormone distributions that control organ growth can be challenging, and theoretical models have proven invaluable in providing a mechanistic understanding.In this study, the authors developed a multiscale model of GA dynamics within the maize leaf growth.Focusing on the maize leaf enabled us to compare model predictions to spatial metabolite and enzyme data，revealing that bioactive GA distribution is predominantly determined by spatial variations in 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 modifified 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 modififications increasing the activity of GA 20-oxidase in drought and of GA 2-oxidase in cold, which we confifirmed by enzyme activity measurements. This work provides a mechanistic understanding of the role of GA metabolism in plant growth regulation.In a word, by developing a computational model and comparing predictions with GA measurements, we show that the GA distribution is mainly created by spatial variations in GA synthesis and degradation. We reveal that although the synthesis and degradation enzyme transcripts are affected by drought and cold, this does not explain the GA distributions. Instead, we fifind that specifific enzyme activities are increased to create the GA distributions that underlie the growth responses. Thus, we gain an understanding of plant growth inhibition by drought and cold.

原文链接：http://dx.doi.org/10.3389/fpls.2022.967352

转自：植物科学SCI

如有侵权，请联系本站删除！