2017-07-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/681935摘要：Abiotic stress of extreme temperatures, water availability, and salinity are serious threats that result in major crop yield loss worldwide. Heat stress response (HSR) is a conserved mechanism developed to increase the expression of heat shock proteins (HSPs) via a heat shock factor (HSF)-dependent mechanism. Signaling by the stress phytohormone abscisic acid (ABA) is involved in acquired thermotolerance as well. The Arabidopsis HSFA6b, a class-A HSF, extensively increased with salinity, osmotic, and cold stresses, but not heat. Our previous study revealed a network in which HSFA6b operates as a downstream regulator of the ABA-mediated stress response and is required for HS resistance (Huang et. al., 2016). The microarray data collected from the HSFA6 overexpression and dominant-negative mutants in response to heat and NaCl stress revealed that a gene cluster plays a vital role, and are required for HSFA6b to connect ABA signaling and ABA-mediated thermotolerance. Our preliminary data confirmed that several mutants of the gene cluster showed the increased thermotolerance phenotype or more sensitive to high temperature. Our data highlighted that a transcription factor (TF) serves as a negative regulator (harbor a typical EAR motif) of HSFA6b function. Therefore, microarray or RNAseq analysis in TF-null, -overexpression, dominant-positive (EAR replaced with VP16) and dominant-negative (EAR replaced with SRDX) mutants in response to HS should be conducted to further elucidate the specific nature of TF. Thus, this study would broaden our knowledge in understanding the complexity of this new ABA-signaling pathway integrated into the complex HS response network, and bring possible clues for improvement of HS tolerance. <br> Abstract: 極端的氣候變化與環境逆境導致全球作物產量大幅度減損。已知熱逆境反應(Heat stress response; HSR)是植物藉由熱休克轉錄因子調控表現增加熱休克蛋白的保護性機制。雖然逆境荷爾蒙離層酸(ABA)的訊息傳遞也涉及植物的耐熱性，但其中的調控過程卻無法提出深入的證據說明。我們先前研究證實熱休克轉錄因子HSFA6b受高鹽、滲透壓與冷逆境所誘導表現，但不受熱逆境誘導，是連接ABA訊息傳遞與植物熱休克反應的重要連接點(Huang et. al., 2016)。目前研究的進展已完成HSFA6b過量表現與顯性負向表現之突變株，於高溫與鹽分逆境下的微陣列數據分析與篩選其中特定基因之突變株對於高溫耐受性的測試，此重要的資料有助於後續研究植物於高溫逆境中藉由HSFA6b的調控，啟動何種重要的調控機制使植物度過高溫逆境並促使植物具備逆境的保護能力以獲得存活。這個新穎的ABA訊息傳遞途徑擴充了現今我們對於植物面對高溫逆境時重要的分子生理調控機制豐富度。熱逆境反應離層酸訊息傳遞熱休克轉錄因子高溫耐受性heat stress responseABA signalingheat shock factorthermotolerance