阿拉伯芥果膠甲基酯化酶在非生物性逆境下的功能性研究

Functional Study of Pectin Methylesterases in Response to Abiotic Stress in Arabidopsis

王胤達(Yin-Da, Wang)

指導教授 ： 靳宗洛

國立臺灣大學/生命科學院/植物科學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201702447

摘要

果膠甲基酯化酶 (PME)是一種改變細胞壁構造的酵素，可以去除果膠中的甲基酯基團。果膠甲基酯化酶已被指出參與植物的生長、發育及與病原體之間的交互作用。近年來，有許多文獻顯示果膠甲基酯化酶的活性會被生物性與非生物性逆境所誘導，但是在熱逆境的研究卻顯得相當稀少。實驗室先前研究發現PME34會藉由調控氣孔的開闔來影響阿拉伯芥對熱逆境的反應。本研究發現PME34會受到離層酸(ABA)的調控來影響植物對熱的反應。另一方面，PME12，PME53，及PME68在經過ABA的處理後會專一性地表現在氣孔。這三個PME會被鹽逆境、滲透壓逆境及熱逆境等非生物性逆境所調控，且會表現在細胞壁或細胞膜上。PME12，PME53，及PME68的活性在乾旱處理後上升。在失水率方面突變株與野生型並無差異，但在氣孔的寬度、長寬比及密度，突變株及大量表現PME的轉殖株卻著有顯著性的差異。因此，PME12，PME53，及PME68這三個基因在植物適應乾旱逆境中扮演重要的角色。

關鍵字

阿拉伯芥 ； 果膠甲基酯化酶 ； 耐熱性 ； 失水 ； 氣孔大小

並列摘要

Pectin methylesterase (PME) is considered a cell wall remodeling enzyme that catalyzes the demethylesterification of polygalacturonans, the major component in pectin. It has been demonstrated that PME involves in plant growth, development, and plant-pathogen interaction. In recent years, many literatures showed that PME can be induced by abiotic and biotic stress, although there are limited reports about heat stress (HS). In our previous studies, PME34, contributing to regulation of stomatal movement, was required for HS response in Arabidopsis. We showed that the function of PME34 could be regulated by ABA signaling pathway in acquired thermotolerance. In addition, PME12, PME53 and PME68 genes were specifically expressed in guard cells after ABA treatment and abiotic stresses by microarray database. Histochemical GUS staining showed exogenous ABA treatment could upregulate these PMEs expression in guard cells. PME12, PME53, and PME68 were regulated by salt, mannitol, and heat treatment. PME12, PME53, and PME68 were located to the apoplast and/or cell membrane. The activities of PME12, PME53, and PME68 increased after drought treatment. These pme mutants had no major difference in respiration rate, but the stomatal aperture of the pore width, width/length ratio, and density of the mutants and overexpression lines showed significant difference compared to the WT. Hence, PME12, PME53, and PME68 had important roles in making plants to adapt the drought stress.

並列關鍵字

Arabidopsis thaliana ； Pectin methylesterase ； Thermotolerance ； Heat Shock ； Water loss ； Stomatal aperture

參考文獻

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