N-Acylhomoserine lactone (AHL) and diffusible signal factor (DSF) molecules are two families of widely conserved quorum sensing (QS) signals. Quorum quenching (QQ) via enzymatic inactivation of QS signals is a promising strategy of biocontrol. In the search for biocontrol agent quenching both AHL and DSF signals, it has been recently identified that DSF-quenching biocontrol agent Pseudomonas sp. HS-18 contains at least three genes (aigA, aigB, and aigC) encoding AHL-acylases displaying strong AHL-acylase activities on various AHLs. Among them, AigA and AigC presented broad-spectrum enzyme activity against AHLs, while AigB preferred longer AHLs. Interestingly, transcriptional expression of aigC could be significantly induced by AHL signals. Heterologous expression of aigA–C in Burkholderia cenocepacia and Pseudomonas aeruginosa resulted in drastically decreased AHL accumulation, virulence factor production, biofilm formation, motility, and virulence on plants. Significantly, the two types of QQ mechanisms in HS-18 showed a strong and much desired synergistic effect for enhanced biocontrol potency against AHL- and DSF-dependent pathogens.

中文翻译：

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能够淬灭扩散信号因子和 N-酰基高丝氨酸内酯家族群体感应信号的细菌分离物显示出显着增强的生物防治效力

N-酰基高丝氨酸内酯 (AHL) 和扩散信号因子 (DSF) 分子是两个广泛保守的群体感应 (QS) 信号家族。通过 QS 信号的酶失活实现群体猝灭 (QQ) 是一种很有前景的生物防治策略。在寻找能够同时淬灭 AHL 和 DSF 信号的生物防治剂时，最近发现能够淬灭 DSF 的生物防治剂Pseudomonas sp。HS-18 包含至少三个编码 AHL 酰化酶的基因（aigA、aigB和aigC），这些基因在各种 AHL 上显示出强 AHL 酰化酶活性。其中，AigA 和 AigC 对 AHLs 具有广谱酶活性，而 AigB 则更喜欢较长的 AHLs。有趣的是， aigC的转录表达可以被 AHL 信号显着诱导。aigA- C 在新洋葱伯克霍尔德菌和铜绿假单胞菌中的异源表达导致 AHL 积累、毒力因子产生、生物膜形成、运动性和对植物的毒力急剧下降。值得注意的是，HS-18 中的两种 QQ 机制显示出强烈且非常理想的协同效应，可增强针对 AHL 和 DSF 依赖性病原体的生物防治效力。