FIN219在藍光與乙烯訊息傳遞交感作用之研究

Investigation of the involvement of Arabidopsis FIN219 in the integration of blue light and ethylene signaling pathways

杜信杰(Xin-Jie Du)

指導教授 ： 謝旭亮

國立臺灣大學/生命科學院/植物科學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.00751

摘要

FIN219位於phyA下游，為遠紅光訊息傳遞因子，在遠紅光下能抑制阿拉伯芥下胚軸之延長。由先前的實驗得知，大量表現FIN219，造成轉殖株對遠紅光、藍光及白光過度敏感，因此推測FIN219可能參與了藍光的訊息傳訊。以酵母菌雙雜交法測試，發現FIN219的C-端能與隱花色素cryptochrome1 (cry1) 及cryptochrome2 (cry2) 有交互作用；然而分別大量表現FIN219在cry1、cry2、或cry1cry2突變體中，轉殖株與遺傳背景植株都沒有顯著的外表型差異，推斷必須有CRY1及CRY2同時作用，才得以將藍光訊息傳遞給FIN219。此外，大量表現FIN219，可以使GUS-CCT1 (overexpression of GUS-CRY1 C-terminus) 轉殖株原本在黑暗中持續光型態發生外表型回復成具較長下胚軸，較接近暗型態發生的外表型，推測是由FIN219與GUS-CCT1的交互作用，而削弱了GUS-CCT1對COP1抑制能力，造成外表型的改變。
由microarray的資料顯示，在fin219突變體中有四個與乙烯相關的基因表現量上升，暗示FIN219可能可以調控乙烯的訊息傳遞。另外，cry1cry2雙突變株在黑暗中生長在含1 μM ACC (1-aminocyclopropane-1-carboxylic acid，乙烯合成的前驅物)的培養基中，會有對ACC較不敏感的外表型；大量表現FIN219在cry1cry2雙突變體中能回復其對ACC敏感的外表型；FIN219啟動子驅動的GUS活性測試，FIN219會受到ACC誘導而表現在擴大的頂點鉤區域中；此外，FIN219-GUS融合蛋白可能受ACC的誘導而自子葉、頂點鉤由維管束向下運送。在遠紅光下，甲基茉莉酸 (methyl jasmonic acid) 及生長素皆會影響FIN219的表現，顯示遠紅光造成的光型態發生可能還共同受到多種荷爾蒙的調控，而FIN219可能扮演居中調節的功能。

關鍵字

FIN219 ； 遠紅光 ； 藍光 ； 乙烯 ； 荷爾蒙 ； 阿拉伯芥 ； 頂點鉤

並列摘要

FIN219 has been demonstrated to be involved in phytochromes A-mediated inhibition of hypocotyl elongation in far-red light (FR) and its overexpressed transgenic Arabidopsis seedlings display a hypersensitive phenotype under FR, blue and white light conditions, which suggests that FIN219 may play a role in blue light signaling. To explore this possibility, a yeast two-hybrid interaction approach was utilized to examine whether FIN219 can interact with blue light photoreceptors, cryptochrome 1 (cry1) and 2 (cry2). The result indicated that the C-terminus of FIN219 can interact with CRY1 and CRY2. As well, FIN219 overexpression in cry1, cry2, or cry1cry2 mutant backgrounds did not show obvious phenotype, which implies that FIN219 may function only in the presence of CRYs proteins. Overexpression of FIN219 in GUS-CCT1 transgenic plants can rescue the constitutive photomorphogenic phenotype of GUS-CCT1 in darkness, which indicates that the interaction between FIN219 and GUS-CCT1 may exclude the binding of GUS-CCT1 to COP1
Microarray data revealed that fin219 mutation resulted in the upregulation of 4 different ethylene signaling components. This findings lead us to test whether FIN219 regulates ethylene response or signaling. The FIN219 overexpression in the cry1cry2 mutant background can rescue the defect of cry1cry2 mutants in response to 1-aminocyclopropane-1-carboxylic acid (ACC, a precursor of ethylene). Histochemical GUS staining indicated that ACC induced FIN219 expression in the exaggerated apical hook. ACC might promotes the downward transport of FIN219-GUS fusion proteins. In addition, FIN219 promoter activity was regulated by the addition of methyl jasmonate and auxin under FR light, which indicates that the photomorphogenic phenotype triggered by FR may be the result of combinatory interactions among multiple hormones and FR, where FIN219 may play a vital function to fine tune the process.

並列關鍵字

FIN219 ； far-red light ； blue ligth ； ethylene ； hormones ； Arabidopsis ； apical hook

參考文獻

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