INRA/University Paris-Sud/CNRS/AgroParisTech, UMR 0320/UMR 8120 Génétique Végétale, Gif-sur-Yvette, 91190, France.
Mol Cell Proteomics. 2012 Oct;11(10):957-72. doi: 10.1074/mcp.M111.015867. Epub 2012 Jul 10.
Plant growth adjustment during water deficit is a crucial adaptive response. The rapid fine-tuned control achieved at the post-translational level is believed to be of considerable importance for regulating early changes in plant growth reprogramming. Aiming at a better understanding of early responses to contrasting plant water statuses, we carried out a survey of the protein phosphorylation events in the growing zone of maize leaves upon a range of water regimes. In this study, the impact of mild and severe water deficits were evaluated in comparison with constant optimal watering and with recovery periods lasting 5, 10, 20, 30, 45, and 60 min. Using four biological replicates per treatment and a robust quantitative phosphoproteomic methodology based on stable-isotope labeling, we identified 3664 unique phosphorylation sites on 2496 proteins. The abundance of nearly 1250 phosphorylated peptides was reproducibly quantified and profiled with high confidence among treatments. A total of 138 phosphopeptides displayed highly significant changes according to water regimes and enabled to identify specific patterns of response to changing plant water statuses. Further quantification of protein amounts emphasized that most phosphorylation changes did not reflect protein abundance variation. During water deficit and recovery, extensive changes in phosphorylation status occurred in critical regulators directly or indirectly involved in plant growth and development. These included proteins influencing epigenetic control, gene expression, cell cycle-dependent processes and phytohormone-mediated responses. Some of the changes depended on stress intensity whereas others depended on rehydration duration, including rapid recoveries that occurred as early as 5 or 10 mins after rewatering. By combining a physiological approach and a quantitative phosphoproteomic analysis, this work provides new insights into the in vivo early phosphorylation events triggered by rapid changes in plant water status, and their possible involvement in plant growth-related processes.
在水分亏缺下，植物生长的调节是一种至关重要的适应反应。在翻译后水平上实现的快速微调控制，被认为对于调节植物生长重编程的早期变化具有重要意义。为了更好地理解植物水分状态的早期响应，我们对一系列水分条件下玉米叶片生长区的蛋白质磷酸化事件进行了调查。在这项研究中，我们评估了轻度和重度水分亏缺与持续最佳浇水以及持续 5、10、20、30、45 和 60 分钟的恢复期的影响。每个处理使用四个生物学重复，并采用基于稳定同位素标记的稳健定量磷酸蛋白质组学方法，我们在 2496 种蛋白质上鉴定了 3664 个独特的磷酸化位点。近 1250 个磷酸化肽的丰度在处理之间具有可重复性，并以高置信度进行了定量分析。根据水分条件，共有 138 个磷酸肽显示出高度显著的变化，能够识别出对植物水分状态变化的特定响应模式。对蛋白质丰度的进一步定量强调了大多数磷酸化变化并不反映蛋白质丰度的变化。在水分亏缺和恢复过程中，直接或间接地参与植物生长和发育的关键调节剂的磷酸化状态发生了广泛变化。这些包括影响表观遗传控制、基因表达、细胞周期依赖性过程和植物激素介导反应的蛋白质。一些变化取决于胁迫强度，而另一些变化则取决于再水合的持续时间，包括再水合后 5 或 10 分钟即可快速恢复的变化。通过结合生理方法和定量磷酸蛋白质组学分析，这项工作提供了对植物水分状态快速变化触发的体内早期磷酸化事件的新见解，以及它们可能参与与植物生长相关的过程。
