糖溶液處理造成氣孔發育異常機制之研究

Abstract

植物的氣孔發育受到複雜的訊息整合所調控，使植物能適應外界環境的變化。糖在植物中不僅是代謝物，其濃度亦會隨著環境變化而改變，近期研究顯示，高濃度的糖會造成氣孔發育異常。ICE1/SCRM 在植物冷逆境之反應過程扮演重要的調控因子，同時也被發現具有促進氣孔前驅細胞分化的功能，顯示 ICE1 可能扮演整合環境訊息及氣孔發育的角色。透過氣孔指標之計算，我們發現ICE1的突變株 ice1-2 對於糖溶液浸泡處理不敏感，並無出現如同野生型植株一樣受糖促進氣孔細胞發育之性狀，顯示在糖調控氣孔發育過程中 ICE1 可能是重要的。本研究使用數種氣孔發育相關的突變株，以找出可能參與糖調控氣孔發育的基因及植物荷爾蒙訊息。結果顯示，離層酸生合成及訊息傳遞及MAPK訊息傳遞缺失之突變株，對於糖溶液浸泡處理也是不敏感的，而胜肽及油菜素類固醇訊息缺失之突變株，則如同野生型植株一樣受糖影響促使氣孔細胞發育。根據實驗結果，ICE1可能在糖調控氣孔發育中扮演重要的角色，並且可能是受到離層酸及MAPK訊息所調控。

Stomatal development is regulated to cope with external changing environment by a complex signaling network. Sugar, as an integrator of environmental signals and metabolites, has been known to perturb stomatal patterning. ICE1/SCRM, a transcriptional activator of freezing tolerance, has been found to promote the cell fate transition during stomatal development. This implicates ICE1 might be a link between environmental adaptation and stomatal development. We found that an ICE1 mutant, ice1-2, was less sensitive to sugar solution immersion treatment, which enhanced cell transition of stomatal development, than WT as shown by stomata index. This finding indicates the crucial role of ICE in sugar-mediated stomatal development. In this study, several mutants related to stomatal development were used to find components that participate in sugar-mediated stomatal development. Mutants of ABA biosynthesis and signaling and MAPK signaling pathway were shown to be less sensitive to sugar solution immersion treatment, while mutants of small peptide ligands and BR-mediated signaling were not. Our results suggested that ICE1 may be a key component to sugar induced promotion of the cell fate transition of stomatal development, and this process is likely regulated by ABA and MAPK signaling.