Proteomics Analysis Reveals Post-Translational Mechanisms for Cold-Induced Metabolic Changes in Arabidopsis
Proteomics Analysis Reveals Post-Translational Mechanisms for Cold-Induced Metabolic Changes in Arabidopsis
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DOI：
10.1093/mp/ssq078
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发表时间：
2011-03-01
期刊：
影响因子：
27.5
通讯作者：
Wang, Zhi-Yong
中科院分区：
文献类型：
--
作者：
Li, Tian;Xu, Shou-Ling;Wang, Zhi-Yong
低温诱导的基因表达和代谢变化是植物在低温环境下生存的关键。最后，通过改变基因表达，暴露在一段时间的非冻结低温下可以增加植物对冻结的耐受性，这种现象被称为冷驯化。寒冷也会引起快速的新陈代谢变化，在温度降至冰点以下之前提供即时保护。这种对寒冷的快速代谢反应的分子机制在很大程度上仍然未知。在这里，我们使用二维差异凝胶电泳（2-D DIGE）分析的亚细胞组分的拟南芥蛋白质组加上现场鉴定串联质谱法，以确定早期的冷响应蛋白在拟南芥。这些蛋白质包括参与淀粉降解的四种酶、三种HSP 100蛋白、三羧酸循环中的几种蛋白质和蔗糖代谢。在冷处理后，歧化酶2（DPE 2），一种将麦芽糖代谢为葡萄糖的胞质转葡糖苷酶，在离心沉淀级分中迅速增加，而在可溶级分中减少。与冷诱导的DPE 2酶活性失活一致，DPE 2突变体表现出增加的耐冷冻性，而不影响C-重复序列结合转录因子（CBF）转录途径。这些结果支持了一个模型，即冷诱导的DPE 2失活导致麦芽糖的快速积累，麦芽糖是一种冷诱导的相容性溶质，可保护细胞免受冷冻损伤。本研究为碳水化合物代谢酶的快速翻译后调节在植物抵御突然降温中的关键作用提供了证据。
Cold-induced changes of gene expression and metabolism are critical for plants to survive freezing. Largely by changing gene expression, exposure to a period of non-freezing low temperatures increases plant tolerance to freezing-a phenomenon known as cold acclimation. Cold also induces rapid metabolic changes, which provide instant protection before temperature drops below freezing point. The molecular mechanisms for such rapid metabolic responses to cold remain largely unknown. Here, we use two-dimensional difference gel electrophoresis (2-D DIGE) analysis of sub-cellular fractions of Arabidopsis thaliana proteome coupled with spot identification by tandem mass spectrometry to identify early cold-responsive proteins in Arabidopsis. These proteins include four enzymes involved in starch degradation, three HSP100 proteins, several proteins in the tricarboxylic acid cycle, and sucrose metabolism. Upon cold treatment, the Disproportionating Enzyme 2 (DPE2), a cytosolic transglucosidase metabolizing maltose to glucose, increased rapidly in the centrifugation pellet fraction and decreased in the soluble fraction. Consistent with cold-induced inactivation of DPE2 enzymatic activity, the dpe2 mutant showed increased freezing tolerance without affecting the C-repeat binding transcription factor (CBF) transcriptional pathway. These results support a model that cold-induced inactivation of DPE2 leads to rapid accumulation of maltose, which is a cold-induced compatible solute that protects cells from freezing damage. This study provides evidence for a key role of rapid post-translational regulation of carbohydrate metabolic enzymes in plant protection against sudden temperature drop.