摘要双效菌素(Zwittermicin A, ZwA)是一种广谱、新型的抗生素，对很多植物病原菌具有抑制作用；酰基高丝氨酸内酯酶(AHL内酯酶)通过降解植物病原菌群体感应（Quorum-Sensing）系统的信号分子，减弱致病基因的表达从而达到抗病的效果。结合这两种物质的不同抗病机理，本研究将来自苏云金芽胞杆菌中的AHL内酯酶基因导入到ZwA产量不同的蜡状芽胞杆菌中，得到相应的重组菌株。实验表明，AHL内酯酶基因在重组菌中可正常表达，并且不影响受体菌ZwA的表达和产量；感病实验证明，同时表达ZwA和AHL内酯酶的重组菌对于胡萝卜软腐欧文氏菌感染马铃薯所引起的病害的抗病效果比单独含产ZwA或AHL内酯酶的蜡状芽胞杆菌的抗病效果有明显增强。说明结合ZwA和AHL内酯酶的不同抗病机理来提高抗病效果是可行的。
Abstract：Zwittermicin A (ZwA) is a broad spectrum, novel antibiotic which shows diverse inhibitory activity against a broad target of plant pathogens; and Acyl-homoserine Lactonase (AHL lactonase) can attenuate expression of virulence genes in bacterial pathogens and then to suppress certain plant diseases by degrading N-acyl-homoserine lactones (AHLs) which are involved in the inducement of the expression of many virulence genes in bacterial pathogens. In order to increase disease suppression by combining the two different disease suppression mechanisms of ZwA and AHL lactonase, AHL lactonase gene was introduced into ZwA+ Bacillus cereus strains, and the recombinant stains were attained and showed higher expression level of AHL lactonase compared to their parental strains, without affecting the expression level of ZwA. Furthermore, the recombinant stains exhibited stronger ability of AHLs inactivation and higher restraint to the potato rot disease caused by Erwinia carotovora than their parental stains. Thus, it was indicated it was feasible to increase disease suppression by combining the biological functions of ZwA and AHL lactonase.
