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degQsfp提高芽孢杆菌泛革素产量及其机理研究

李响, 伍辉军, 张阳, 鲁晴辉, 高学文   

  1. 南京农业大学植物保护学院/农作物生物灾害综合治理教育部重点实验室, 南京 210095
  • 收稿日期:2014-08-30 修回日期:1900-01-01 出版日期:2015-04-08 发布日期:2015-04-08
  • 通讯作者: 高学文,博士,教授,E-mail:gaoxw@njau.edu.cn

Function of degQ and sfp and Their Effects on Fengycin Productivity of Bacillus subtilis

LI Xiang, WU Huijun, ZHANG Yang, LU Qinghui, GAO Xuewen   

  1. Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education/College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
  • Received:2014-08-30 Revised:1900-01-01 Online:2015-04-08 Published:2015-04-08

摘要: 非核糖体合成途径产生的脂肽化合物泛革素(fengycin)在芽孢杆菌防治真菌病害中起着重要作用.本研究克隆了来自解淀粉芽孢杆菌模式菌株FZB42的sfp和来自枯草芽孢杆菌模式菌株168的多效调控因子degQ,构建了pP43-degQ、pMK3-sfp和pP43-degQ-sfp 3个表达载体,分别转入不能产生泛革素的168菌株中,得到3株工程菌株.抑菌试验表明,168-degQ-sfp活菌及其脂肽化合物提取物均能显著抑制油菜菌核病菌的生长,而168、168-degQ和168-sfp不具备该活性.质谱检测表明,只有168-degQ-sfp能产生泛革素.进一步的荧光定量反转录PCR检测结果表明,菌株168-degQ-sfp的泛革素合成酶基因簇ppsABCDE的表达量是其他菌株的6~16倍,而菌株168-degQ和168-sfp与菌株168无明显差异.该研究表明degQsfp 2个功能基因共同存在时能提高泛革素合成酶基因簇的表达量,进而提高泛革素的产量.

Abstract: Fengycin, a lipopeptide synthesized non-ribosomally by Bacillus spp., plays an important role in controlling plant fungus diseases. The sfp gene, which encodes 4'-phosphopantetheine transferase, is required for all cells of Bacillus subtilis to become producers of the lipopeptide. The degQ is a pleiotropic gene affecting the expression of a number of secreted gene products. For studying the effect and function of degQ and sfp activation on fengycin productivity of Bacillus subtilis 168, we cloned the sfp gene from Bacillus amyloliquefaciens FZB42 and the degQ gene from Bacillus subtilis 168, constructed expression vectors pP43-degQ, pMK3-sfp andpP43-degQ-sfp, and gained three genetically engineered bacterial strains by transformation of the strain 168 which was a nonfengycin-producer. Antimicrobial activities experiment showed that both the living cell and its lipopeptide extract from 168-degQ-sfp inhibited the growth of Sclerotinia sclerotiorum on plates, whereas 168, 168-degQ and 168-sfp did not. MALDI-TOF-MS analysis demonstrated that only 168-degQ-sfp could produce fengycin. Real-time PCR result showed that fengycin synthase gene cluster ppsABCDE in 168-degQ-sfp were expressed 6—16 folds higher than that in wild-type, while not in 168-degQ and 168-sfp were. This study indicated that the two functional genes degQ and sfp could jointly enhance the expression of fengycin synthase gene cluster, and increase fengycin production.

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