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標題: | 阿拉伯芥轉錄因子HY5參與茉莉酸訊息傳遞途徑之功能性研究 Functional Studies of Transcription Factor ELONGATED HYPOCOTYL5 Involved in Jasmonate Signaling Pathway in Arabidopsis |
作者: | Yen-Ho Chen 陳彥合 |
指導教授: | 謝旭亮(Hsu-Liang Hsieh) |
關鍵字: | 光形態發生,茉莉酸,遠紅光,HY5,JAZ1,FIN219, Photomorphogenesis,JA,Far-red light,HY5,JAZ1,FIN219, |
出版年 : | 2016 |
學位: | 碩士 |
摘要: | 光是影響植物生長發育之重要訊息,而茉莉酸則是調控植物逆境反應以及生長與發育之重要荷爾蒙。目前已有研究證據顯示光與茉莉酸間的交互作用機制:受光敏素A所調控的FAR-RED INSENSITIVE219 (FIN219/JAR1)不僅是遠紅光作用下的光型態發生的正調控者,同時也是茉莉酸訊息源—茉莉酸甲酯(JA-Ile)—之生合成催化者。此外,甲基茉莉酸(MeJA)可促進光型態發生的主要促進者ELONGATED HYPOCOTYL5(HY5)轉錄因子於不同光源下的累積,而該現象僅在FIN219存在時發生,且在遠紅光照射下則更為顯著。進一步分析顯示,包含JAZ基因家族成員的受茉莉酸誘導之基因的表現在hy5-1突變株中相較野生型更高。儘管如此,HY5蛋白質受茉莉酸誘導累積現象的功能調控及其分子機制仍未知。本研究中試圖剖析阿拉伯芥HY5在茉莉酸訊息傳遞中的調控功能。分子證據顯示HY5會藉由結合在JAZ1啟動子上之G-box區段,進而抑制JAZ1基因的表現,而JAZ1蛋白質也可能藉與HY5的交互作用,進而調控自身基因表現。另外,藉由雙重突變株(即hy5fin219-2 與hy5pGR219)與親本突變株之光型態性狀比較,得知FIN219與HY5位於平行途徑,共同調控阿拉伯芥幼苗的下胚軸生長。綜上所述,我們認為HY5可能藉由與JAZ1進行交互作用,進而調控茉莉酸訊息傳遞。 Light is one of the most essential environmental factors that dramatically affect plant growth and development. Jasmonate (JA) is a phytohormone that regulates biotic and abiotic stress responses as well as growth and development. Some evidences gradually unveil the regulatory mechanisms between JA and light. The phyA-mediated FAR-RED INSENSITIVE219 (FIN219/JAR1), an enzyme that catalyzed the final step of bioactive JA-isoleucine (JA-Ile) production, functions as a positive regulator of photomorphogenesis in plants under far-red (FR) light. Moreover, the major positive regulator of photomorphogenesis, ELONGATED HYPOCOTYL 5 (HY5), is inducible by MeJA under various light conditions in which the FR is the most significant. JA-responsive genes, including JAZ genes, are elevated in MeJA-treated hy5 null mutant compared to wild type under the same condition. However, the function of the JA-responsive HY5 and the underlying molecular mechanisms are still beyond our knowledge. In this study, we used several approaches to dissect the regulatory functions of HY5 involved in JA signaling. Molecular evidence indicates that HY5 binds with the G-boxes of JAZ1 promoter, leading to a suppression of JAZ1 expression. Besides, JAZ1 may auto-regulate expression of its own by interacting with HY5. Furthermore, the double mutants, hy5fin219-2 and hy5pGR219 as compared with their parental single mutants, suggest that FIN219 and HY5 may synergistically regulate the hypocotyl growth in response to light and JA. Thus, we proposed that HY5 together with JAZ1 fine-tunes the JA signaling. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/49353 |
DOI: | 10.6342/NTU201602832 |
全文授權: | 有償授權 |
顯示於系所單位: | 植物科學研究所 |
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