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Shi L, Zhao L, Li Q, Huang L, Qin Y, Zhuang Z, Wang X, Huang H, Zhang J, Zhang J, Yan Q. Role of the Pseudomonas plecoglossicida fliL gene in immune response of infected hybrid groupers (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂). Front Immunol 2024; 15:1415744. [PMID: 39026675 PMCID: PMC11254626 DOI: 10.3389/fimmu.2024.1415744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Accepted: 06/19/2024] [Indexed: 07/20/2024] Open
Abstract
Pseudomonas plecoglossicida, a gram-negative bacterium, is the main pathogen of visceral white-point disease in marine fish, responsible for substantial economic losses in the aquaculture industry. The FliL protein, involved in torque production of the bacterial flagella motor, is essential for the pathogenicity of a variety of bacteria. In the current study, the fliL gene deletion strain (ΔfliL), fliL gene complement strain (C-ΔfliL), and wild-type strain (NZBD9) were compared to explore the influence of the fliL gene on P. plecoglossicida pathogenicity and its role in host immune response. Results showed that fliL gene deletion increased the survival rate (50%) and reduced white spot disease progression in the hybrid groupers. Moreover, compared to the NZBD9 strain, the ΔfliL strain was consistently associated with lower bacterial loads in the grouper spleen, head kidney, liver, and intestine, coupled with reduced tissue damage. Transcriptomic analysis identified 2 238 differentially expressed genes (DEGs) in the spleens of fish infected with the ΔfliL strain compared to the NZBD9 strain. Based on Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, the DEGs were significantly enriched in seven immune system-associated pathways and three signaling molecule and interaction pathways. Upon infection with the ΔfliL strain, the toll-like receptor (TLR) signaling pathway was activated in the hybrid groupers, leading to the activation of transcription factors (NF-κB and AP1) and cytokines. The expression levels of proinflammatory cytokine-related genes IL-1β, IL-12B, and IL-6 and chemokine-related genes CXCL9, CXCL10, and CCL4 were significantly up-regulated. In conclusion, the fliL gene markedly influenced the pathogenicity of P. plecoglossicida infection in the hybrid groupers. Notably, deletion of fliL gene in P. plecoglossicida induced a robust immune response in the groupers, promoting defense against and elimination of pathogens via an inflammatory response involving multiple cytokines.
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Affiliation(s)
- Lian Shi
- Fisheries College, Jimei University, Xiamen, China
| | - Lingmin Zhao
- Fisheries College, Jimei University, Xiamen, China
| | - Qi Li
- Fisheries College, Jimei University, Xiamen, China
| | - Lixing Huang
- Fisheries College, Jimei University, Xiamen, China
| | - Yingxue Qin
- Fisheries College, Jimei University, Xiamen, China
| | - Zhixia Zhuang
- College of Environment and Public Health, Xiamen Huaxia University, Xiamen, China
| | - Xiaoru Wang
- College of Environment and Public Health, Xiamen Huaxia University, Xiamen, China
| | - Huabin Huang
- College of Environment and Public Health, Xiamen Huaxia University, Xiamen, China
| | - Jiaonan Zhang
- Key Laboratory of Special Aquatic Feed for Fujian, Fujian Tianma Technology Company Limited, Fuzhou, China
| | - Jiaolin Zhang
- Key Laboratory of Special Aquatic Feed for Fujian, Fujian Tianma Technology Company Limited, Fuzhou, China
| | - Qingpi Yan
- Fisheries College, Jimei University, Xiamen, China
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Cai J, Yin B, Wang Y, Pan K, Xiao Y, Wang X. Gut microbiome play a crucial role in geographical and interspecies variations in mercury accumulation by fish. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169381. [PMID: 38101636 DOI: 10.1016/j.scitotenv.2023.169381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 11/24/2023] [Accepted: 12/12/2023] [Indexed: 12/17/2023]
Abstract
Mercury (Hg) contamination in fish has raised global concerns for decades. The Hg biotransformation can be manipulated by gut microbiome and it is found to have a substantial impact on the speciation and final fate of Hg in fish. However, the contribution of intestinal microbiota in geographical and interspecies variations in fish Hg levels has not been thoroughly understood. The present study compared the Hg levels in wild marine fish captured from two distinct regions in South China sea. We observed a quite "ironic" phenomenon that MeHg levels in carnivorous fish from a region with minimal human impacts (Xisha Islands, 92 ± 7.2 ng g-1 FW) were much higher than those from a region with severe human impacts (Daya Bay, 19 ± 0.41 ng g-1 FW). Furthermore, the results showed that gut microbiome determined Hg biotransformation and played a crucial role in the variances in fish Hg levels across different geographical locations and species. The intestinal methylators, rather than demethylators, were more significant in affecting Hg biotransformation in fish. The carnivorous species in Xisha Islands exhibited a higher abundance of intestinal methylators, leading to higher MeHg accumulation. Besides, the gut microbiome could be shaped in response to the elevated Hg levels in these fish, which may benefit their adaptation to Hg toxicity and overall health preservation. However, anthropogenic activities (particularly overfishing) in Daya Bay have severely affected the fish population, disrupting the reciprocal relationships between fish and intestinal microbiota and rendering them more susceptible to pathogenic microbes. Overall, this study provided a comprehensive understanding of the role of gut microbiome in Hg bioaccumulation in fish and offered valuable insights into the co-evolutionary dynamics between fish and gut microbiome in the presence of Hg exposure.
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Affiliation(s)
- Jieyi Cai
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Bingxin Yin
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Yunhui Wang
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Ke Pan
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
| | - Yayuan Xiao
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Science, Guangzhou 510300, China; Guangdong Provincial Key Laboratory of Fishery Ecology Environment, Guangzhou 510300, China
| | - Xun Wang
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China.
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Yang D, Zhao L, Li Q, Huang L, Qin Y, Wang P, Zhu C, Yan Q. The involvement of the T6SS vgrG gene in the pathogenicity of Pseudomonas plecoglossicida. JOURNAL OF FISH DISEASES 2023; 46:1097-1108. [PMID: 37401135 DOI: 10.1111/jfd.13829] [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: 04/27/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 07/05/2023]
Abstract
Pseudomonas plecoglossicida, the causative agent of white spot disease of large yellow croaker, has caused serious economic losses to the aquaculture industry. The type VI secretion system (T6SS) is a significant virulence system widely distributed among Gram-negative bacteria. VgrG, a structural and core component of T6SS, is crucial to the function of T6SS. To explore the biological profiles mediated by vgrG gene and its effects on the pathogenicity of P. plecoglossicida, the vgrG gene deletion (ΔvgrG) strain and complementary (C-ΔvgrG) strain were constructed and the differences in pathogenicity and virulence-related characteristics between different strains were analysed. The results showed that vgrG gene deletion significantly affected the virulence-related characteristics of P. plecoglossicida, including chemotaxis, adhesion, and biofilm formation. In addition, the LD50 of ΔvgrG strain was nearly 50-fold higher than that of the NZBD9 strain. Transcriptome data analysis suggested that the vgrG gene may affect the virulence of P. plecoglossicida by regulating the quorum sensing pathway to inhibit the secretion of virulence factors and affect biofilm formation. Besides, deletion of the vgrG gene may reduce bacterial pathogenicity by affecting bacterial signal transduction processes and the ability to adapt to chemotactic substances.
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Affiliation(s)
- Dou Yang
- Fisheries College, Jimei University, Xiamen, China
| | - Lingmin Zhao
- Fisheries College, Jimei University, Xiamen, China
| | - Qi Li
- Fisheries College, Jimei University, Xiamen, China
| | - Lixing Huang
- Fisheries College, Jimei University, Xiamen, China
| | - Yingxue Qin
- Fisheries College, Jimei University, Xiamen, China
| | - Pan Wang
- Key Laboratory of Aquatic Functional Feed and Environmental Regulation of Fujian Province, Fujian Dabeinong Aquatic Sci. & Tech. Co., Ltd, Zhangzhou, China
| | - Chuanzhong Zhu
- Key Laboratory of Aquatic Functional Feed and Environmental Regulation of Fujian Province, Fujian Dabeinong Aquatic Sci. & Tech. Co., Ltd, Zhangzhou, China
| | - Qingpi Yan
- Fisheries College, Jimei University, Xiamen, China
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He L, Zhao L, Li Q, Huang L, Qin Y, Zhuang Z, Wang X, Huang H, Zhang J, Zhang J, Yan Q. Pseudomonas plecoglossicida fliP gene affects the immune response of Epinephelus fuscoguttatus ♀×Epinephelus lanceolatus ♂ to infection. FISH & SHELLFISH IMMUNOLOGY 2023; 140:108971. [PMID: 37481102 DOI: 10.1016/j.fsi.2023.108971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 07/15/2023] [Accepted: 07/20/2023] [Indexed: 07/24/2023]
Abstract
Pseudomonas plecoglossicida is a pathogen that causes visceral white spot disease in a variety of teleosts. The protein encoded by fliP gene is involved in the assembly of bacterial flagella, which plays a vital role in bacterial pathogenicity. However, the roles of the fliP gene on the host immune response remain unclear. Here, we compared the pathogenicity of fliP gene-deleted (ΔfliP) strain, fliP gene-complemented (C-ΔfliP) strain and wild-type (NZBD9) strain of P. plecoglossicida to hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂), and explored the impacts of fliP gene on the immune response of hybrid grouper to P. plecoglossicida infection by using RNA-seq. In this study, the grouper in the ΔfliP strain-infected group had a 30% higher survival rate than those in the NZBD9 strain-infected group. In addition, the deletion of fliP gene decreased bacterial load in the spleen, intestine, liver as well as head kidney of hybrid grouper and the tissues damage were weakened. Moreover, the infection of hybrid grouper spleen by the ΔfliP strain induced 1,189 differential expression genes compared with the counterpart infected by NZBD9 strain. KEGG enrichment analysis showed that 9 immune-related pathways, 5 signal transduction pathways, and 3 signaling molecules and interaction pathways were significantly enriched. qRT-PCR analysis revealed that the ΔfliP strain mainly up-regulated the expression of inflammation related genes (IL-6, IL-12, IL-1β, IL-10, CXCL8, CXCL10) and immune regulation related genes (TLR2, P65, MyD88, P85, AKT), but down-regulated the expression of cell death related genes (FoxO1, Bim, PLK2 and LDHA) during infection. Based on the above results, fliP gene contributed to the pathogenicity of P. plecoglossicida to hybrid grouper (E. fuscoguttatus ♀ × E. lanceolatus ♂), deletion of fliP gene promoted the inflammation and immune response of hybrid grouper to P. plecoglossicida infection, which accelerating host clearance of pathogen and reducing tissue damages.
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Affiliation(s)
- Li He
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China
| | - Lingmin Zhao
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China
| | - Qi Li
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China
| | - Lixing Huang
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China
| | - Yingxue Qin
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China
| | - Zhixia Zhuang
- College of Environment and Public Health, Xiamen Huaxia University, Xiamen, Fujian, 361024, China
| | - Xiaoru Wang
- College of Environment and Public Health, Xiamen Huaxia University, Xiamen, Fujian, 361024, China
| | - Huabin Huang
- College of Environment and Public Health, Xiamen Huaxia University, Xiamen, Fujian, 361024, China
| | - Jiaonan Zhang
- Key Laboratory of Special Aquatic Feed for Fujian, Fujian Tianma Technology Company Limited, Fuzhou, Fujian, 350308, China
| | - Jiaolin Zhang
- Key Laboratory of Special Aquatic Feed for Fujian, Fujian Tianma Technology Company Limited, Fuzhou, Fujian, 350308, China
| | - Qingpi Yan
- Fisheries College, Jimei University, Xiamen, Fujian, 361021, China.
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