【摘要】 【背景】许多革兰氏阴性细菌通常以N-酰基高丝氨酸内酯(N-acylhomoserine lactones,AHLs)作为群体感应主要的信号分子。【目的】从土壤中筛选和鉴定新型群体感应淬灭细菌。【方法】通过"垫圈法"从土壤中原位培养分离细菌,采用琼脂条法、报告菌平板法及β-半乳糖苷酶活性测定筛选群体感应淬灭细菌,根据16S rRNA基因序列同源性分析确定菌株系统发育地位。【结果】从不同地区土样中原位培养共分离获得细菌502株。以根癌土壤杆菌Agrobacterium tumefaciens NTL4 (pZLR4)作为报告菌,最终得到11株具有较强降解AHLs能力的细菌,包括假单胞菌5株、不动杆菌4株、变形杆菌和莱茵海默氏菌各1株。大部分细菌可完全降解N-3-羰基十二酰基高丝氨酸内酯(3OC12-HSL),部分细菌对N-(3-氧代己酰)高丝氨酸内酯(3OC6-HSL)和N-3-氧代辛酰高丝氨酸内酯(3OC8-HSL)具有一定降解活性。【结论】Proteus和Rheinheimera可降解AHLs,为今后防治依赖群体感应的植物细菌病害提供新型生防资源。更多还原

【Abstract】 [Background] N-acylhomoserine lactones(AHLs) are used as the main quorum-sensing signaling molecules in many Gram-negative bacteria. [Objective] To screen and identify new quorum quenching(QQ) bacteria from soil organisms. [Methods] We used "washer method" to grow organisms by cultivation in situ. QQ bacteria were screened through "agar slice", "reporter plate" and the assay ofβ-galactosidase activity. The phylogenetic status was determined based on 16 S rRNA gene homology analysis. [Results] Here, 502 organisms were obtained from the soil samples in situ and screened for AHL-degrading bacteria using A. tumefaciens NTL4(pZLR4) as a reporter strain. Eleven isolates degraded AHLs within 24 h. Based on their 16 S rRNA gene sequences similarities, five isolates(3-49,3-58, 61, 66, 120) and four isolates(3-59, 151, 3-41, 2-34) were assigned to the genera Pseudomonas and Acinetobacter. Strain 2-63 and 129 were identified as Proteus sp. and Rheinheimera sp., respectively. Most of these strains degraded strongly 3 OC12-HSL and were active against 3 OC6-HSL and 3 OC8-HSL.[Conclusion] This study showed that Proteus sp. and Rheinheimera sp. may degrade AHLs, which might provide new biocontrol resources to control of the quorum sensing-dependent bacterial diseases.更多还原