Pseudomonas plecoglossicida fliP gene affects the immune response of Epinephelus fuscoguttatus ♀×Epinephelus lanceolatus ♂ to infection

Li He; Lingmin Zhao; Qi Li; Lixing Huang; Yingxue Qin; Zhixia Zhuang; Xiaoru Wang; Huabin Huang; Jiaonan Zhang; Jiaolin Zhang; Qingpi Yan

doi:10.1016/j.fsi.2023.108971

Pseudomonas plecoglossicida fliP gene affects the immune response of Epinephelus fuscoguttatus ♀×Epinephelus lanceolatus ♂ to infection

Fish Shellfish Immunol. 2023 Sep:140:108971. doi: 10.1016/j.fsi.2023.108971. Epub 2023 Jul 20.

Authors

Li He¹, Lingmin Zhao¹, Qi Li¹, Lixing Huang¹, Yingxue Qin¹, Zhixia Zhuang², Xiaoru Wang², Huabin Huang², Jiaonan Zhang³, Jiaolin Zhang³, Qingpi Yan⁴

Affiliations

¹ Fisheries College, Jimei University, Xiamen, Fujian, 361021, China.
² College of Environment and Public Health, Xiamen Huaxia University, Xiamen, Fujian, 361024, China.
³ Key Laboratory of Special Aquatic Feed for Fujian, Fujian Tianma Technology Company Limited, Fuzhou, Fujian, 350308, China.
⁴ Fisheries College, Jimei University, Xiamen, Fujian, 361021, China. Electronic address: yanqp@jmu.edu.cn.

PMID: 37481102
DOI: 10.1016/j.fsi.2023.108971

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.

Keywords: Hybrid grouper; Immune response; Inflammation; Pathogenicity; Pseudomonas plecoglossicida; fliP.

MeSH terms

Animals
Bass* / genetics
Immunity, Innate / genetics
Inflammation
Pseudomonas / genetics

Supplementary concepts

Pseudomonas plecoglossicida