Transcriptome Sequencing and Analysis of Immune-related Genes of Barbel Steed (Hemibarbus labeo) After Aeromonas hydrophila Infection
CHEN Jie1,2,3, YU Jing1, ZHU Qun-Yin1, LIU Zi-Ming1, CHEN Xu-Tang3, ZHU Yang-Chun1, DING Guo-Hua1, SHU Miao-An2,*
1 College of Ecology, Lishui University, Lishui 323000, China; 2 College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; 3 Lishui Institute for Ecological Economy Research, Lishui 323000, China
Abstract：Bacterial enteritis occurs frequently in aquaculture, however, the exact mechanism of bacterial enteritis was not well understood. This study aimed to identify novel candidate genes associated with Aeromonas hydrophila infection-induced enteritis. Barbel steed (Hemibarbus labeo) were infected with A. hydrophila, transcriptome sequencing of its intestine using the BGISEQ-500 platform. The results showed that a total of 120 173 unigenes were obtained by sequencing, with an average length of 1 328 bp and an N50 of 2 647 bp, of which 72.71% were known genes. Screening of differentially expressed genes (DEGs) found that there were 33 706 genes significantly differentially expressed after A. hydrophila infection, of which 18 878 unigenes were up-regulated, and 14 828 genes were down-regulated. Through GO enrichment analysis, DEGs were mainly enriched in cellular process, metabolic process, biological regulation, cell, cell part, and binding. The KEGG enrichment analysis showed that DEGs were mainly enriched in signal pathways such as signal transduction, immune system, cancers, infectious diseases, etc. According to DEGseq analysis and qPCR verification, it was found that the antimicrobial peptide genes, antimicrobial peptide genes (hepcidin and liver-expressed antimicrobial peptide 2 (leap2)) and inflammatory cytokine genes (interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), IL6 and IL8) were significantly increased after A. hydrophila infection. Meanwhile, the antibacterial activities of chemically synthesized Hepcidin, LEAP2 and NK-lysin against A. hydrophila were detected, and it was found that Hepcidin and LEAP2 could effectively inhibit the reproduction of A. hydrophila. This study provides basic data for further understanding of the pathogenic mechanism of bacterial enteritis in barbel steed and other farmed fish.
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