2008-01-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/684612摘要：環境逆境為影響作物產量及品質之重要因素。此計畫以T-DNA 插入水稻突變庫為基礎材料，篩選出與非生物性環境逆境反應相關之基因，並分析其基因表現調控機制及功能。本實驗室已篩選出數個鹽害逆境反應相關T-DNA插入突變株，並進行目標基因之序列及表現分析。其中一篩選出的salt-responsive gene，其預測之氨基酸序列與鉬輔因子硫化脢(molybdenum cofactor sulfurase; MCSU)之C端的序列保留性區域(Mo-cofactor sulfurase C-terminal conserved domain; MOSC domain)具極高之相似性，因此暫命名其為鉬輔因子硫化脢相似基因(OsMCSUL)。MCSU為將與aldehyde oxidase (AO)結合之鉬輔因子硫化，以促AO活化之酵素，並進而促進離層酸(ABA)生合成之重要因子。經基因組序列比對，發現水稻具有三個OsMCSUL基因(OsMCSUL1,2,3)。其中OsMCSUL1,2為單獨之MOSC domain蛋白，而OsMCSUL3在其蛋白質之N端(即MOSC domain前)尚具有一NifS domain。OsMCSUL3基因與阿拉伯芥與蕃茄之MCSU基因具高同源性。目前已知OsMCSUL1,2,3分別在水稻不同發育階段及不同組織中之表現會受NaCl及ABA調控，且初步已知OsMCSUL2基因無論在正常或是高鹽逆境下均會影響植物之生長、發育。在此延伸研究計畫中，將繼續藉由對OsMCSUL2 homozygous mutant 之分析，及以水稻基因轉殖方式分別大量表現OsMCSUL1,2,3基因或抑制其基因表現，以探討OsMCSUL1,2,3基因對水稻生長、發育及對鹽害逆境反應之影響。再者，將藉由啟動子-報導基因系統，探討OsMCSUL基因表現之組織特異性及其調控機制。此外，亦將藉由microarray 分析受OsMCSUL 影響之相關基因及生理作用。<br> Abstract: Unflavoritable environments negatively impact crop productivity and quality. The goal of this project is to reveal the molecular mechanisms of abiotic-stress tolerance of rice plants. To achieve this, we tried to identify the genes that contribute to the abiotic stress hypertolerance/ hypersensitivity phenotype. First, the abiotic stress-responsive mutants were screened from the T-DNA inserted rice mutant pool generated by Dr. Su-May Yu. Following, the T-DNA target genes or promoters of the T-DNA inserted stress-responsive mutants were isolated and characterized. Among the selected genes that we identified, one salt stress-responsive gene shared the high amino acid homology with the C-terminal conserved domain of molybdenum cofactor sulfurase (MOSC domain), and it was named molybdenum cofactor sulfurase-like gene (OsMCSUL). MCSU is the the key enzyme to process the sulfuration of molybdenum cofactor (Moco) which is bound with the aldehyde oxidase (AO). The sulfurylated Moco-AO is in charged to active the last step of ABA biosynthesis. Therefore, the MCSU plays an important role to regulate ABA biosynthesis. Based on the results of sequence search and aligment, there are at least three OsMCSUL genes on rice genome, OsMCSUL1, 2, and 3. Both OsMCSUL1 and 2 are belonged to the MOSC domain only proteins. On the other hand, the OsMCSUL3 is a two-domain protein, which contains a NifS domain on the N-terminus and a MOSC domain on the C-terminus. The deduced OsMCSUL3 amino acid sequence has high homology with MCSU protein of Arabidopsis and tomato. So far, according to our studies, it was known that the OsMCSUL1, 2, 3 gene expressions were differentially regulated in seeds, leaf and root tissues under NaCl and ABA treatment. In addition, preliminary data also showed that the OsMCSUL2 gene may function on the mechanism of plant growth and development in both normal and salt-stressed conditions. Following, the research will be focused on the study of the functions of OsMCSUL family genes. The approach will mediate the morphology, physiology and biochemical analyses on the OsMCSUL gene overexpressed and antisense transgenic rice and OsMCSUL T-DNA inserted mutant. Moreover, the tissue-specific expression and regulatory mechanism of OsMCSUL genes also are planning to be studied by promoter analysis with promoter-reporter gene system. Besides, to get more information about the effect of OsMCSUL function under salt stress, the microarray analysis will be used to find out the genes that would be differentially expressed between wild type and OsMCSUL mutant or overexpressed rice plants.鹽害逆境鉬輔因子硫化脢離層酸salt-stressmolybdenum cofactor sulfuraseABA