NMR metabolite profiling analysis reveals changes in phospholipid metabolism associated with the re-establishment of desiccation tolerance upon osmotic stress in germinated radicles of cucumber
NMR metabolite profiling analysis reveals changes in phospholipid metabolism associated with the re-establishment of desiccation tolerance upon osmotic stress in germinated radicles of cucumber
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DOI：
10.1111/j.1365-3040.2005.01424.x
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发表时间：
2006-04-01
影响因子：
7.3
通讯作者：
Leprince, O
中科院分区：
文献类型：
--
作者：
Avelange-Macherel, MH;Ly-Vu, B;Leprince, O
新陈代谢的适应被认为在获得脱水耐受性(DT)中起作用。然而，这种作用的重要性以及是否存在具体的监管途径仍有待评估。利用体外(31)P和C-13核磁共振波谱和生化分析方法，分析了黄瓜发芽胚根高氯酸提取物的代谢产物谱，以确定与DT相关的碳和磷代谢的变化。通过在水势为-1.5兆帕的聚乙二醇水溶液中孵育，长达2毫米的新出现的胚根可以耐受干燥。然而，在4毫米长的牙根中，这种治疗是无效的。这种可操纵的系统能够区分与DT相关的代谢物的变化和与渗透胁迫反应相关的代谢物的变化。与胚根长度无关，聚乙二醇组分的蔗糖(Suc)含量增加，而葡萄糖(GLC)、果糖(Fu)、己糖磷酸库和磷酸烯醇式丙酮酸含量下降3-4倍。此外，三种在磷脂分解代谢早期产生的衍生物(甘油基磷胆碱、甘油基磷酰乙醇胺和甘油基磷脂酰肌醇)出现在聚乙二醇处理的胚根中。有趣的是，磷脂的降解在渗透压挑战的胚根中更加明显，这些胚根对干燥仍然敏感。仅在4 mM聚乙二醇处理的胚根中出现分解代谢物，如磷胆碱和磷乙醇胺，就证明了这一点。此外，3-磷酸甘油及其衍生物3-磷酸甘油酸酯显著增加。我们的数据表明，导致DT重建的代谢反应与渗透反应并不完全相同。推测膜重塑和/或磷脂分解代谢增加是渗透调节和DT共同的适应性反应，但在耐受根和敏感根中受到不同的控制。
The adaptation of metabolism is thought to play a role in the acquisition of desiccation tolerance (DT). However, the importance of such a role and whether specific regulatory pathways exist remain to be assessed. Using in vitro(31)P and C-13 nuclear magnetic resonance (NMR) spectroscopy and biochemical assays, we analysed metabolite profiles of perchloric extracts from germinating radicles of cucumber to identify changes in carbon and phosphate metabolism associated with DT. Emerged radicles measuring 2 mm long can be rendered tolerant to desiccation by incubation in a polyethylene glycol (PEG) solution with a water potential of -1.5 MPa. However, in 4-mm-long emerged radicles, this treatment was ineffective. This manipulable system enabled the discrimination of changes in metabolites associated with DT from those associated with the response to osmotic stress. Independent of radicle length, the PEG treatment resulted in an increase in sucrose (Suc) content, whereas glucose (Glc), fructose (Fru) and the hexose phosphate pool, as well as phosphoenolpyruvate decreased three- to fourfold. In addition, three derivatives arising early during phospholipid catabolism (glycerylphosphorylcholine, glycerylphosphorylethanolamine and glycerylphosphorylinositol) appeared in the PEG-treated radicles. Interestingly, phospholipid degradation was much more pronounced in osmotically challenged radicles that remain sensitive to drying. This was proved by the appearance of catabolites, such as phosphocholine and phosphoethanolamine, solely in 4 mm PEG-treated radicles. Furthermore, glycerol-3-phosphate and its derivative 3-phosphoglycerate increased significantly. Our data suggest that the metabolic response leading to the re-establishment of DT is not entirely identical to that of an osmotic response. It is inferred that membrane remodelling and/or increased phospholipid catabolism is an adaptive response common to osmotic adjustment and DT but is controlled differently in tolerant and sensitive radicles.