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Nie C, Huang X, Xiang T, Wang Z, Zhang X. Discovery and characterization of the PpqI/R quorum sensing system activated by GacS/A and Hfq in Pseudomonas protegens H78. Microbiol Res 2024; 287:127868. [PMID: 39126862 DOI: 10.1016/j.micres.2024.127868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 08/01/2024] [Accepted: 08/03/2024] [Indexed: 08/12/2024]
Abstract
Pseudomonas protegens can generally produce multiple antibiotics including pyoluteorin (Plt), 2,4-diacetylphloroglucinol (DAPG), and pyrrolnitrin (Prn). In this study, we discovered and characterized a quorum sensing (QS) system, PpqI/R, in P. protegens H78. PpqI/R, encoded by two open reading frames (ORFs) (H78_01960/01961) in P. protegens H78 genome, is a LuxI/R-type QS system. Four long-chain acyl homoserine lactone (AHL) signaling molecules, 3-OH-C10-HSL, 3-OH-C12-HSL, C12-HSL, and 3-OH-C14-HSL, are produced by H78. Biosynthesis of these AHLs is catalyzed by PpqI synthase and activated by the PpqR regulator in H78 and in Escherichia coli when heterologously expressed. PpqR activates ppqI expression by targeting the lux box upstream of the ppqI promoter in cooperation with corresponding AHLs. The four aforementioned AHLs exhibited different capabilities to induce ppqI promoter expression, with 3-OH-C12-HSL showing the highest induction activity. In H78 cells, ppqI/R expression is activated by the two-component system GacS/A and the RNA chaperone Hfq. Differential regulation of the PpqI/R system in secondary metabolism has a negative effect on DAPG biosynthesis and ped operon (involved in volatile organic compound biosynthesis) expression. In contrast, Plt biosynthesis and prn operon expression were positively regulated by PpqI/R. In summary, PpqI/R, the first characterized QS system in P. protegens, is activated by GacS/A and Hfq and controls the expression of secondary metabolites, including antibiotics.
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Affiliation(s)
- Chenxi Nie
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xianqing Huang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Tao Xiang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zheng Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xuehong Zhang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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Cai Y, Zhang X. The atypical organization of the luxI/R family genes in AHL-driven quorum-sensing circuits. J Bacteriol 2024; 206:e0043023. [PMID: 38240569 PMCID: PMC10882985 DOI: 10.1128/jb.00430-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024] Open
Abstract
Quorum sensing (QS) is an elaborate regulatory mechanism associated with virulence and bacterial adaptation to the changing environment. QS is widespread in Proteobacteria and acts primarily through N-acylhomoserine lactone (AHL) signals. At the core of the AHL-driven QS systems are the AHL synthase gene (luxI family) and its cognate transcriptional regulator gene (luxR family). Several QS systems display one or more genes intervening between the luxI and luxR, in which gene arrangements are notably different due to the relative position and the transcriptional orientation between the essential luxI/R and the genes of location correlation. These adjacent genes may exert a regulatory impact on the primary QS genes or contribute toward an extension of QS regulatory control. In this review, we describe the organization of AHL-driven QS genes based on previous research and specific genome databases and provide new insights into these atypical QS gene arrangements.
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Affiliation(s)
- Yuyuan Cai
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Xuehong Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- National Experimental Teaching Center for Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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Wang Z, Huang X, Nie C, Xiang T, Zhang X. The Lon protease negatively regulates pyoluteorin biosynthesis through the Gac/Rsm-RsmE cascade and directly degrades the transcriptional activator PltR in Pseudomonas protegens H78. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:506-519. [PMID: 35297175 DOI: 10.1111/1758-2229.13057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 03/05/2022] [Indexed: 06/14/2023]
Abstract
Pyoluteorin (Plt) is a broad-spectrum antibiotic with antibacterial and antifungal activities. In Pseudomonas protegens H78, the Plt biosynthetic operon pltLABCDEFG is transcriptionally activated by the LysR-type regulator PltR and is positively regulated by the Gac/Rsm signal transduction cascade (GacS/A-RsmXYZ-RsmE-pltR/pltAB). Additionally, Plt biosynthesis has been shown to be significantly enhanced by mutation of the Lon protease-encoding gene. This study aims to understand the negative regulation pathway and molecular mechanism by which Lon functions in Plt biosynthesis. lon deletion was first found to improve the antimicrobial ability of strain H78 due to its increased Plt production, while partially inhibiting the growth of H78 strain. Lon protease decreases the abundance and stability of the two-component system response regulator GacA and thus participates in the abovementioned Gac/Rsm cascade and negatively regulates Plt biosynthesis. Similarly, Lon protease also decreases the abundance and stability of transcriptional activator PltR. PltR protein can be directly degraded by the Lon protease but not by a mutated form of Lon protease with an amino acid replacement of S674 -A. In summary, Lon protease negatively regulates Plt biosynthesis via both the Gac/Rsm-mediated global regulatory pathway and the direct degradation of the transcriptional activator PltR in P. protegens H78.
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Affiliation(s)
- Zheng Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xianqing Huang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Chenxi Nie
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Tao Xiang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xuehong Zhang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
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Liao J, Shen D, Lin L, Chen H, Jin Y, Chou SH, Yu XQ, Li T, Qian G. Bacterial quorum sensing quenching activity of Lysobacter leucyl aminopeptidase acts by interacting with autoinducer synthase. Comput Struct Biotechnol J 2021; 19:6179-6190. [PMID: 34900131 PMCID: PMC8632722 DOI: 10.1016/j.csbj.2021.11.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 11/09/2021] [Accepted: 11/13/2021] [Indexed: 01/02/2023] Open
Abstract
Acyl-homoserine lactone (AHL) is the most studied autoinducer in gram-negative bacteria controlling infections of various pathogens. Quenching of AHL signaling by inhibiting AHL synthesis or AHL-receptor binding via small molecular chemicals or enzymatically degrading AHL is commonly used to block bacterial infections. Here, we describe a new quorum-quenching strategy that directly “acquires” bacterial genes/proteins through a defined platform. We artificially expressed a typical AHL synthase gene pcoI from the biocontrol Pseudomonas fluorescens 2P24 in the antifungal bacterium Lysobacter enzymogenes OH11 lacking AHL production. This step led to the discovery of multiple PcoI interacting protein candidates from L. enzymogenes. The individual expression of these candidate genes in 2P24 led to the identification of Le0959, which encodes leucyl aminopeptidase, an effective protein that inhibits AHL synthesis in 2P24. Therefore, we define Le0959 as LqqP (Lysobacterquorum-quenching protein). The expression of pcoI in E. coli could produce AHL, and the introduction of lqqP into E. coli expressing pcoI could prevent the production of AHL. LqqP directly binds to PcoI, and this protein–protein binding reduced the abundance of free PcoI (capable of AHL synthesis) in vivo, thereby blocking PcoI-dependent AHL production. Overall, this study highlights the discovery of LqqP in quenching AHL quorum sensing by binding to AHL synthase via developing a previously-uncharacterized screening technique for bacterial quorum quenching.
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Affiliation(s)
- Jinxing Liao
- College of Plant Protection, Laboratory of Plant Immunity, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, PR China
| | - Danyu Shen
- College of Plant Protection, Laboratory of Plant Immunity, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, PR China
| | - Long Lin
- College of Plant Protection, Laboratory of Plant Immunity, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, PR China
| | - Hongjun Chen
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China
| | - Yajie Jin
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China
| | - Shan-Ho Chou
- Institute of Biochemistry, and NCHU Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Xiao-Quan Yu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Tao Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China
| | - Guoliang Qian
- College of Plant Protection, Laboratory of Plant Immunity, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, PR China
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