贝莱斯芽胞杆菌Bacillus velezensis YL2021嗜铁素合成基因dhbC的功能研究  

Functional Analysis of dhb C Gene from the Siderophore Producing Bacterium Bacillus velezensis YL2021

作　　者：沈佳慧 左杨 乔俊卿[2] 刘永锋[2] 刘邮洲[1,2] SHEN Jiahui;ZUO Yang;QIAO Junqing;LIU Yongfeng;LIU Youzhou(College of Plant Protection,Nanjing Agricultural University,Nanjing 210095,China;Institute of Plant Protection,Jiangsu Academy of Agricultural Sciences,Nanjing 210014,China)

机构地区：[1]南京农业大学植物保护学院,南京210095 [2]江苏省农业科学院植物保护研究所,南京210014

出　　处：《中国生物防治学报》2022年第3期602-612,共11页Chinese Journal of Biological Control

基　　金：江苏省农业科技自主创新资金项目(CX(21)3096)。

摘　　要：贝莱斯芽胞杆菌Bacillus velezensis YL2021是一株对多种病原细菌均有良好防治效果的生防菌,基因组中含有完整的儿茶酚型(2,3-Dihydroxybenzoate,DHB)嗜铁素合成基因簇。为了探明贝莱斯芽胞杆菌YL2021嗜铁素的功能,本研究以嗜铁素合成基因dhbC为对象,构建重组质粒pMD19-dhbc(cm),利用同源重组技术获得突变株ΔdhbC。生防相关性状研究结果表明,与野生型菌株YL2021相比,突变株ΔdhbC泳动能力和生物膜形成能力明显下降,但是群集运动能力未发生改变。在营养丰富的LB培养基中,野生型菌株YL2021和突变株ΔdhbC均不产生嗜铁素,生长能力未发生改变,室内抑菌能力相当;但在缺铁M9培养基中,野生型菌株YL2021能产生儿茶酚型嗜铁素,生长缓慢,对供试细菌有较强的抑菌作用,突变株ΔdhbC不能产生嗜铁素,生长能力明显下降,完全丧失抑菌能力。本文结果表明,缺铁条件下,dhbC基因是贝莱斯芽胞杆菌YL2021嗜铁素生物合成的关键基因,嗜铁素是菌株YL2021发挥生防作用的重要抑菌物质。Bacillus velezensis YL2021 was isolated from rice field and showed broad-spectrum antibacterial activities against plant phytopathogens that are economically important in agriculture. In order to explore the function of siderophore produced by strain YL2021, we selected a siderophore biosynthesis gene dhbC as a representative example to generate a mutant ΔdhbC. First, we amplified dhbC gene from strain YL2021 by PCR.Using the pMD19-T vector, chloramphenicol resistance marker gene was inserted into dhbC gene. The recombinant plasmid was transformed into wild type strain YL2021 via homologous recombinant approach, and mutant ΔdhbC was generated and validated. Compared to the wild type, the mutant ΔdhbC exhibited equal swarming motility, but a significant decrease in swimming motility and biofilm forming ability. Both strain YL2021 and mutant ΔdhbC can’t produce siderophore in LB medium. No difference was observed on growth capacity or antibacterial activity between B. velezensis YL2021 and mutant ΔdhbC when cultured in nutrient-rich LB broth. However, on low-iron M9 medium, wild-type strain YL2021 produced siderophore and demonstrated a wide range of inhibitory effects against Gram-negative and Gram-positive bacteria in vitro,while mutant ΔdhbC can’t produce siderophore, nearly lost growth capacity and antibacterial activity.Together, our results implied that under low-iron condition, dhbc gene plays an important role in growth capacity and siderophore biosynthesis of B. velezensis YL2021, and siderophore is essential for the antibacterial activity of strain YL2021.

关 键 词：贝莱斯芽胞杆菌 嗜铁素 dhbC基因 抑菌作用 

分 类 号：S476[农业科学—农业昆虫与害虫防治]