阿拉伯芥ice1-2突變株之代謝物分析與研究

Abstract

本實驗室先前的研究中，透過基因層次的分析了解到轉錄因子ICE1在糖訊息及離層酸(ABA)的訊息傳導中扮演著重要的角色。除了基因層次的分析，代謝層次的分析也在近年來受到重視，而代謝體學的研究亦為植物之基因功能及生理現象帶來更深入的了解。因此，本研究希望從代謝體學的角度，藉由分析不同處理下特定代謝物的含量變化，如糖類及植物荷爾蒙，進一步了解ICE1是否會透過影響糖類及荷爾蒙含量，而參與在糖訊息及離層酸訊息傳導，繼而影響植株之生長發育。 實驗結果顯示，七天大之ice1-2突變株幼苗相較於野生型幼苗，植株內之葡萄糖 (glucose)、果糖 (fructose)、離層酸及水楊酸 (SA)含量較低，而海藻糖(trehalose)及茉莉酸(JA)之含量較高，表示ice1-2突變株在幼苗長成階段 (establishment stage) 中發生能量及荷爾蒙受到干擾的現象。而在外加離層酸處理下，七天大之ice1-2植株內之葡萄糖、果糖、海藻糖、水楊酸及茉莉酸的含量皆有明顯上升，然而在野生型植株體內卻沒有上升且維持一樣的含量。另一方面，前述所提到之野生型植株及ice1-2突變株之間的差異，卻在到了不同生長階段後便差異減少。綜上所述，我們藉由糖類及荷爾蒙含量的分析，推測ICE1可能會在幼苗長成階段作為一個多重調控者，參與在糖類代謝及荷爾蒙訊息傳導途徑中，而影響植株之生長發育。

Our previous study has revealed the multifaceted role of ICE1 in sugar and ABA signaling at transcription level. Considering metabolomic analysis is a powerful tool to study plant responses to different conditions in addition to transcriptome or proteome analysis, we try to further investigate the role of ICE1 in sugar metabolism and phytohormone status in this study by analyzing soluble sugar (glucose, fructose, trehalose) levels and phytohormone (ABA, JA, SA) levels under different treatments. The results showed that, in comparison to the WT, 7 day-old ice1-2 seedlings possessed lower levels of endogenous glucose, fructose, ABA and SA, while higher levels of trehalose and JA. This implied that a perturbation in energy homeostasis and hormone status occurred in ice1-2 during plant establishment stage. Exogenous ABA application induced elevation in the levels of glucose, fructose, trehalose, JA, and SA in ice1-2, while these metabolites remained in consistent levels in the WT. Furthermore, differences between the WT and ice1-2 in sugar and phytohormone analysis diminished at different growth stages. Taking together, soluble sugar and phytohormone analysis suggested ICE1 as a multiple regulator in sugar metabolism and phytohormone signaling pathways, especially in the stage of plant establishment.