%0 Journal Article %T 恒定pH对Xenorhabdus nematophila YL001抑菌活性及抑菌物质合成相关基因表达的影响<br>Effect of Constant pH on Antimicrobial Activity and Related Gene Expression of Antimicrobial Bioactivities Synthesis of Xenorhabdus nematophila YL001 %A 郭蔷薇 %A 张淑静 %A 李忝珍 %A 王 %A 茜 %A 王永宏 %A 张 %A 兴 %J 西北农业学报 %D 2016 %R 10.7606/j.issn.1004-1389.2016.09.020 %X 为明确恒定pH对Xenorhabdus nematophila YL001抑菌物质产生及相关抑菌物质合成的影响，对pH 5.5、pH 7.0及pH 8.5培养条件下X.nematophila YL001的抑菌活性、主要抑菌物质［Xenocoumacin1(XCN1)和Nematophin］的代谢差异及主要抑菌物质的生物合成基因与相关转录调节子基因的表达量进行分析。结果表明，X.nematophila YL001发酵液对枯草芽孢杆菌和番茄灰霉病菌的抑菌作用在pH 7.0时最佳，而其胞外产物乙酸乙酯与甲醇提取物对枯草芽孢杆菌和番茄灰霉病菌的抑菌作用在pH 8.5时最佳；LC-MS分析表明，随pH的升高，活性物质xcn1的相对含量逐渐升高，而Nematophin的相对含量则先升高后下降；qRT-PCR分析表明，不同恒定pH下，X.nematophila YL001主要抑菌物质生物合成基因及相关转录调节子基因的表达量存在显著差异。pH可显著影响X.nematophila YL001菌株的抑菌活性及代谢，且碱性条件更利于活性物质的产生并保持稳定性。<br>This study aimed to define antimicrobial activity and the expression of main biosynthesis gene and related transcription regulate genes of Xenorhabdus nematophila YL001 strain. We analyzed the antimicrobial activities, main metabolites (xcn1 and Nematophin), the expression of main antimicrobial bioactivities genes and related transcriptional regulation genes of X.nematophila YL001 under different constant pH culture conditions. Results showed that fermented liquid of X.nematophila YL001 exhibited the highest inhibitory effect on Bacillus subtilis and Botrytis cinerea at pH 7.0, the inhibitory effect of extracellular extracts were improved with the increase of constant pH values of the medium. LC-MS revealed that the production of metabolites was regulated by pH. In addition, qRT-PCR analysis results showed that the expression of the main biosynthesis gene and related transcription regulate gene was significant different under the condition of different constant pH. The constant pH can significantly affect the antimicrobial activity and the generation of metabolites of X.nematophila YL001, and alkaline condition was more conducive to generate active substance and maintain stability. %K 嗜线虫致病杆菌 恒定pH 胞外产物提取物 基因表达< %K br> %K Xenorhabdus nematophila Constant pH Extracellular extracts Gene expression %U http://xbnyxb.alljournals.cn/ch/reader/view_abstract.aspx?file_no=20160920&flag=1