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Chinese Journal of Biological Control ›› 2022, Vol. 38 ›› Issue (3): 602-612.DOI: 10.16409/j.cnki.2095-039x.2022.02.024

• RESEARCH REPORTS • Previous Articles    

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

SHEN Jiahui1,2, ZUO Yang2, QIAO Junqing2, LIU Yongfeng2, LIU Youzhou1,2   

  1. 1. College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China;
    2. Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
  • Received:2022-02-17 Published:2022-06-20

Abstract: 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.

Key words: Bacillus velezensis, siderophore, dhbC, antibacterial activity

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