植物中逆境相關蛋白質與基因的特性分析

Characterization of Stress-Related Proteins and Genes in Plants

陳怡君(Yi-Jiun Chen)

指導教授 ： 林彩雲

國立清華大學/生命科學院/生命科學系/博士(2007年)

摘要

植物的生長和新陳代謝會受各種生物性和非生物性刺激的影響，包括微生物和昆蟲的攻擊以及溫度和生長素的影響。不同於動物，無法移動的植物需要更複雜和有效率的防禦系統來對抗不同的刺激。本論文著重於三個綠豆熱休克蛋白質的鑑定和高氏柴胡組培根中受甲基茉莉酸誘導基因的分析。
生物常合成分子保護子來應對高溫、低溫、傷害、重金屬以及缺水等逆境。分子量是70 kDa的熱休克蛋白Hsp70以及同源的Hsc70在各種生物之間的相似度很高。此外，Hsp/Hsc70也可以在非逆境狀態下表現於特定的發育時期。本研究之第一部分，分離三個綠豆熱休克蛋白基因並鑑定其在發育期的基因和蛋白質層次的表現。我們的結果顯示這三個綠豆熱休克蛋白質可能是參與正常的生長與發育，在種子成熟或耐受乾燥較不重要。
茉莉酸和甲基茉莉酸是廣泛存在的植物訊號分子，在調控新陳代謝的過程、繁殖、和防禦病蟲害與昆蟲中，扮演關鍵性的角色。本研究之第二部分，將甲基茉莉酸添加到高氏柴胡組培根，並研究受誘導基因間表現的資訊。我們的結果顯示茉莉酸有一種複雜的訊號網路，會牽涉大規模的轉錄重整。有些受甲基茉莉酸誘導的基因，具有農業、醫藥和食品工程應用的潛力。

關鍵字

熱休克蛋白 ； 綠豆 ； 發育期 ； 甲基茉莉酸 ； 高氏柴胡組培根 ； 基因微矩陣

並列摘要

Plant growth and metabolism are affected by various biotic and abiotic stimuli including microorganisms and insects attack as well as temperatural and hormonal effects. Unlike animals, plants cannot move independently and need a more complicated and efficient defense system against different stimuli. This thesis focused on the identification of three VrHsc70 proteins in Vigna radiata and the analyses of methyl jasmonate (MeJA)-induced genes in Bupleurum kaoi adventitious roots.
Organisms often synthesize molecular chaperons to cope with stress such as heat, cold, wounding, heavy metals, and water deficit. The 70 kDa heat shock protein (Hsp70) and the constitutively expressed heat shock cognate (Hsc70) are conserved among all organisms. In addition, Hsp/Hsc70s have been found to be upregulated at specific developmental stages in the absence of stress. In the first part of this study, three mungbean Hsc70 cDNAs were isolated and their developmental expressions were characterized at both transcriptional and protein levels. Our results indicate that these three VrHsc70s may not be important in seed maturation or desiccation tolerance, but probably involved in normal growth and development.
Jasmonic acid (JA) and MeJA are ubiquitous plant signaling compounds that play a key role in the regulation of metabolic processes, reproduction, and defense against pathogens and insects. In the second part of this study, MeJA was applied to adventitious root culture of B. kaoi and the expression profiles of induced genes were investigated. Our results indicate that MeJA has a complex signaling network involving a large-scale transcriptional reprogramming. Some of the MeJA-induced genes may have applications in agricultural, medicinal and food industries.