Abstract: The present disclosure belongs to the technical field of biological control and prevention, and it was found that Pseudomonasnitroreducens strain HS-18 has good degradation activity on AHLs with C4-C14 chain length, with an efficient and notable degradation effect, providing a new biocontrol agent for prevention and treatment of AHLs-mediated pathogens provides and broadening the quorum quenching species of AHL signaling molecules. By using molecular biology technologies, AHL-quenching genes for HS-18, i.e., the encoding genes aigA and aigC of N-acyl homoserine lactone acyl transferase are cloned. The genes aigA and aigC have broad-spectrum and efficient quenching activities on AHLs with different side chain lengths and different side chain substituents. The expression of aigA and aicC can significantly weaken the motility of AHL-mediated pathogens, the formation of biofilm and the production of virulence factors and significantly weaken the pathogenicity of pathogens to the host plant.