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Shi Y, Cheng T, Cheang QW, Zhao X, Xu Z, Liang Z, Xu L, Wang J. A cyclic di-GMP-binding adaptor protein interacts with a N5-glutamine methyltransferase to regulate the pathogenesis in Xanthomonas citri subsp. citri. MOLECULAR PLANT PATHOLOGY 2024; 25:e13496. [PMID: 39011828 PMCID: PMC11250160 DOI: 10.1111/mpp.13496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 06/04/2024] [Accepted: 07/03/2024] [Indexed: 07/17/2024]
Abstract
The second messenger cyclic diguanylate monophosphate (c-di-GMP) regulates a wide range of bacterial behaviours through diverse mechanisms and binding receptors. Single-domain PilZ proteins, the most widespread and abundant known c-di-GMP receptors in bacteria, act as trans-acting adaptor proteins that enable c-di-GMP to control signalling pathways with high specificity. This study identifies a single-domain PilZ protein, XAC3402 (renamed N5MapZ), from the phytopathogen Xanthomonas citri subsp. citri (Xcc), which modulates Xcc virulence by directly interacting with the methyltransferase HemK. Through yeast two-hybrid, co-immunoprecipitation and immunofluorescent staining, we demonstrated that N5MapZ and HemK interact directly under both in vitro and in vivo conditions, with the strength of the protein-protein interaction decreasing at high c-di-GMP concentrations. This finding distinguishes N5MapZ from other characterized single-domain PilZ proteins, as it was previously known that c-di-GMP enhances the interaction between those single-domain PilZs and their protein partners. This observation is further supported by the fact that the c-di-GMP binding-defective mutant N5MapZR10A can interact with HemK to inhibit the methylation of the class 1 translation termination release factor PrfA. Additionally, we found that HemK plays an important role in Xcc pathogenesis, as the deletion of hemK leads to extensive phenotypic changes, including reduced virulence in citrus plants, decreased motility, production of extracellular enzymes and stress tolerance. Gene expression analysis has revealed that c-di-GMP and the HemK-mediated pathway regulate the expression of multiple virulence effector proteins, uncovering a novel regulatory mechanism through which c-di-GMP regulates Xcc virulence by mediating PrfA methylation via the single-domain PilZ adaptor protein N5MapZ.
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Affiliation(s)
- Yu Shi
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease ControlSouth China Agricultural UniversityGuangzhouChina
- Guangdong Provincial Key Laboratory of Utilization and Conservation of Food and Medicinal Resources in Northern RegionShaoguan UniversityShaoguanChina
| | - Tianfang Cheng
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease ControlSouth China Agricultural UniversityGuangzhouChina
| | - Qing Wei Cheang
- School of Biological SciencesNanyang Technological UniversitySingaporeSingapore
| | - Xiaoyan Zhao
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease ControlSouth China Agricultural UniversityGuangzhouChina
| | - Zeling Xu
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease ControlSouth China Agricultural UniversityGuangzhouChina
| | - Zhao‐Xun Liang
- School of Biological SciencesNanyang Technological UniversitySingaporeSingapore
| | - Linghui Xu
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease ControlSouth China Agricultural UniversityGuangzhouChina
| | - Junxia Wang
- Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease ControlSouth China Agricultural UniversityGuangzhouChina
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Tang X, Yang Q, Hu S, Guo K, Li Y, Wu Z. Comparative transcriptome reveals importance of export apparatus subunit (ascR) in type III secretion system and its roles on biological properties, gene expression profiles, virulence and colonization of Aeromonas veronii. Int J Biol Macromol 2024; 274:133270. [PMID: 38906357 DOI: 10.1016/j.ijbiomac.2024.133270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/14/2024] [Accepted: 06/18/2024] [Indexed: 06/23/2024]
Abstract
Aeromonas veronii, an opportunistic pathogen, is known to cause serious infections across various species. In our previous study, we discovered that A. veronii GL2 exhibited a virulence up to ten times greater than that of FO1. To ascertain the factors contributing to the disparity in virulence between the two strains, we conducted a comparative transcriptome analysis. This analysis reveals a significant upregulation (P < 0.05) of the ascR gene in GL2 compared with FO1. Additionally, six differentially expressed genes (DEGs) were identified within the "Bacterial secretion system" pathway (map03070), with ascR being an essential component of type III secretion system (T3SS). AscR, considered as SctR family export apparatus subunit within the T3SS, has ambiguous roles in the biological properties, gene expression profiles, virulence and colonization of A. veronii. Therefore, we constructed a mutant strain (ΔascR) by homologous recombination. Comparative analysis with the wide-type GL2 reveals no significant differences in terms of colony morphology, growth curve, hemolytic activity and protease activity. However, significant reductions (P < 0.01) were observed in the abilities of biofilm formation and swimming mobility. No remarkable difference was noted in the lengths of flagella. The LD50 value of ΔascR was to be 5.15 times higher than that of GL2. Interestingly, the mRNA expression of ascC, ascD, ascJ and ascI genes in the T3SS, and mshB, mshE, mshK and mshP genes in the MSHA type pili were significantly upregulated (P < 0.05) in ΔascR, potentially due to transcriptional compensation. Further analysis of enzymatic biomarkers revealed that ΔascR might not destruct the recognition of innate immune response in host remarkably, but the colonization levels of A.veronii were significantly suppressed (P < 0.01) in ΔascR group. In conclusion, the ascR gene may be a key determinant in regulating the virulence of A. veronii, and the destruction of the T3SS caused by ascR deficiency results in these notable changes.
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Affiliation(s)
- Xiaoqi Tang
- College of Fisheries, Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Research Center for Aquatic Biodiversity Conservation in the Upper Reaches of Yangtze River, Southwest University, Chongqing 400715, China
| | - Qinglin Yang
- College of Fisheries, Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Research Center for Aquatic Biodiversity Conservation in the Upper Reaches of Yangtze River, Southwest University, Chongqing 400715, China
| | - Shaoyu Hu
- College of Fisheries, Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Research Center for Aquatic Biodiversity Conservation in the Upper Reaches of Yangtze River, Southwest University, Chongqing 400715, China
| | - Kefan Guo
- College of Fisheries, Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Research Center for Aquatic Biodiversity Conservation in the Upper Reaches of Yangtze River, Southwest University, Chongqing 400715, China
| | - Yanhong Li
- College of Fisheries, Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Research Center for Aquatic Biodiversity Conservation in the Upper Reaches of Yangtze River, Southwest University, Chongqing 400715, China
| | - Zhengli Wu
- College of Fisheries, Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Research Center for Aquatic Biodiversity Conservation in the Upper Reaches of Yangtze River, Southwest University, Chongqing 400715, China.
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Belhart K, Sisti F, Gestal MC, Fernández J. Bordetella bronchiseptica diguanylate cyclase BdcB inhibits the type three secretion system and impacts the immune response. Sci Rep 2023; 13:7157. [PMID: 37130958 PMCID: PMC10154355 DOI: 10.1038/s41598-023-34106-x] [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] [Received: 12/17/2022] [Accepted: 04/24/2023] [Indexed: 05/04/2023] Open
Abstract
Bordetella bronchiseptica is a gram-negative bacterium that causes respiratory diseases in different animals, including mice, making B. bronchiseptica the gold-standard model to investigate host-pathogen interaction at the molecular level. B. bronchiseptica utilizes many different mechanisms to precisely regulate the expression of virulence factors. Cyclic di-GMP is a second messenger synthesized by diguanylate cyclases and degraded by phosphodiesterases that regulates the expression of multiple virulence factors including biofilm formation. As in other bacteria, we have previously shown that c-di-GMP regulates motility and biofilm formation in B. bronchiseptica. This work describes the diguanylate cyclase BdcB (Bordetella diguanylate cyclase B) as an active diguanylate cyclase that promotes biofilm formation and inhibits motility in B. bronchiseptica. The absence of BdcB increased macrophage cytotoxicity in vitro and induced a greater production of TNF-α, IL-6, and IL-10 by macrophages. Our study reveals that BdcB regulates the expression of components of T3SS, an important virulence factor of B. bronchiseptica. The Bb∆bdcB mutant presented increased expression of T3SS-mediated toxins such as bteA, responsible for cytotoxicity. Our in vivo results revealed that albeit the absence of bdcB did not affect the ability of B. bronchiseptica to infect and colonize the respiratory tract of mice, mice infected with Bb∆bdcB presented a significantly higher pro-inflammatory response than those infected with wild type B. bronchiseptica.
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Affiliation(s)
- Keila Belhart
- Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Instituto de Biotecnología y Biología Molecular (IBBM)-CCT-CONICET-La Plata, Universidad Nacional de La Plata, La Plata, Argentina
| | - Federico Sisti
- Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Instituto de Biotecnología y Biología Molecular (IBBM)-CCT-CONICET-La Plata, Universidad Nacional de La Plata, La Plata, Argentina
| | - Mónica C Gestal
- Department of Microbiology and Immunology, Louisiana State University (LSU) Health Sciences Center at Shreveport, Shreveport, LA, USA.
| | - Julieta Fernández
- Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Instituto de Biotecnología y Biología Molecular (IBBM)-CCT-CONICET-La Plata, Universidad Nacional de La Plata, La Plata, Argentina.
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