臺灣大學: 植物科學研究所靳宗洛羅丹利Luo, Dan-LiDan-LiLuo2013-03-212018-07-062013-03-212018-07-062011http://ntur.lib.ntu.edu.tw//handle/246246/248270在乾旱或缺水等等的逆境環境下，植物會誘導細胞壁蛋白及具分解細胞壁功能的酵素，在細胞壁中扮演重要的角色。細胞壁果膠甲基酯酶(Pectin Methylesterase, PME)為一種普遍存在於細菌、真菌及植物的酵素，對植物細胞壁果膠進行去甲基酯化作用(demethylesterification)，會改變果膠構造影響植物細胞壁之堅固程度。目前研究顯示，單子葉植物水稻及雙子葉植物黃豆，在熱休克(HS)誘導下能藉由調節PME之活性，參與細胞壁之重建並增強細胞間之黏結作用，恢復植物抵抗高溫之能力。分析阿拉伯芥基因組，顯示至少具有66個編譯PME的基因，本研究以正向遺傳(forward genetics)的方式，針對阿拉伯芥53個T-DNA插入造成PME基因缺失之突變株，進行熱逆境處理之篩選。結果顯示，PME34 (At3g49220)基因的缺失，明顯地減少其誘導耐熱性(acquired thermotolerance)，存活率下降50%。以阿拉伯芥原生質體及洋蔥表皮細胞短暫表現PME34，證實其位於原生質膜上；另外，切除N端跨膜區域後PME34呈現點狀分散於細胞質。HS處理後，pme34突變株之PME及聚半乳醣醛酸酵素(PG)酵素活性均較野生型高，推測會加速細胞壁結構之分解而降低突變株之耐熱性。在pme34中研究與HS相關基因的表現，顯示PME34可能會受到AtHas32和AtHsfA3的調控。本研究以遺傳的層次，證實這個特殊的PME34對於植物誘導耐熱性之獲得扮演重要的角色，因此植物可藉由PME活性之調節來反應外在環境之變化。Pectin modification is catalyzed by a large enzyme family of pectin methylesterase (PME) residing in the cell wall. PME might modify the structure of pectin in order to adjust the characteristics of cell wall by pectin demethylesterification. In our previous study, we found that the activity of PME is induced by heat shock (HS), we further established the role of PME by retained plasma membrane integrity and coordinated with heat shock response (HSP) to confer acquired thermotolerance in planta. At least potential 66 members of PME genes are annotated in the Arabidopsis genome by a phylogenetic analysis. We tested 53 AtPME T-DNA insertion lines by thermotolerance assays, two mutants allele of AtPME34 (At3g49220) were characterized and revealed a consistent reduction in the acquired thermotolerance. The plasma membrane-localized of AtPME34 was transiently expressed in Arabidopsis protoplasts and onion cells. However, AtPME34 lacking the transmembrane domain showed the punctuated shape structures in the cytoplasm. We confirm again that the action of PME and PG during HSR might have a pronounced effect on the development of acquired thermotolerance. Furthermore, we demonstrated that the transcript of AtPME34 is probably regulated by HS–related genes such as AtHsa32 and AtHSFA3 involved in the HS response (HSR). In this study, we provide a genetic evidence, address that the unique AtPME34 plays a role during HSR to confer the acquisition of thermotolerance.6522868 bytesapplication/pdfen-US耐熱性果膠甲基酯化?熱休克ThermotolerancePectin MethylesteraseHeat Shockthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/248270/1/ntu-100-R97b42018-1.pdf