摘要
在温室盆栽条件下,研究了分离自小麦全蚀病自然衰退土壤、可防治多种土传病害的荧光假单胞杆菌2P24菌株的2,4-二乙酰基间苯三酚合成基因突变体、GacS/GacA双因子调控系统突变体,以及PcoR-PcoI群体感应系统的突变体菌株在植物根围定殖能力和防病效果。结果表明,2,4-二乙酰基间苯三酚生物合成突变体不影响菌株在植物根部的定殖;GacS/GacA双因子调控系统中任一因子的突变菌株和pcoI-突变菌株显著降低了菌株在植物根部的定殖能力。温室病害防治试验结果表明,与野生菌2P24相比,phlD-,gacS-,gacA-,pcoI-突变体对小麦全蚀病和番茄青枯病生防效果均显著降低;而相应的互补菌株生防效果恢复到野生型的水平。结合前期工作结果,我们推测GacS/GacA双因子调控系统和QS系统在2P24菌株定殖和防病过程的信号传递上形成级联途径。
Pseudomonas fluorescens 2P24, a biocontrol agent isolated from suppressive soil of wheat take-all, protects plants against soil-borne diseases. This strain produces several anti-microbal secdndary metabolites, such as 2,4-diacetylphloroglucinol （2,4-DAPG）, hydrogen cyanide （ HCN）, siderophore and proteases. In this study, the regulatory system mutants of 2P24 on GacS/GacA two-component regulatory system and quorum-sensing （QS） system and a mutant on 2,4-DAPG biosynthesis gene locus were investigated for their capacities on rhizosphere colonization and plant protection ability against tomato bacterial wilt caused by Ralstonia solanacearum and wheat take-all caused by C, aeumannomyces graminis var. tritici. The results showed the mutant defective in 2,4-DAPG production did not affect the colonization of strain 2P24 in plant rhizosphere under greenhouse conditions, but significantly reduced its biocontrol activity. The mutations on GacS/GacA regulatory system and Qs system remarkably affected both colonization and biocontrol ability of strain 2P24. Complementation strains containing plasmid-borne wild- type genes restored all the lost phenotypes to the level of wild type 2P24. These data suggested that the 2,4-DAPG production, GacS/GacA regulatory system and QS system are genetically required in the biocontrol activity in P. fluorescens 2P24. Combined with our previous findings, we also speculate that the GacS/GacA and QS systems consist of a signal transduction cascade in the regulation of biocontrol activity of P. fluorescens 2P24.
出处
《中国生物防治》
CSCD
北大核心
2008年第1期40-46,共7页
Chinese Journal of Biological Control
基金
国家自然科学基金(30671403)
国家863计划(2006AA10A211)
关键词
荧光假单胞菌
生物防治
双因子调控系统
群体感应系统
Pseudomonas fluorescens
biological control
two-component regulatory system
quorumsensing system
