Characterization of grass carp spleen transcriptome during GCRV infection

Abstract

ABSTRACT. The aim of the study was to investigate the grass carp hemorrhagic infection pathway and its key-related genes. Grass carp reovirus (GCRV) might cause hemorrhagic disease in grass carps. Healthy grass carp fingerlings (N = 60) were divided into control and infected groups. Fish in the control group were intraperitoneally (ip) injected with 0.6% fish physiological saline; the infected group received 5,000,000 50% tissue culture infective doses of GCRV 873 standard strain, a double-stranded RNA (dsRNA) virus strain, ip, in 0.5 mL. Illumina HiSeq TM 2000 was used for transcriptome sequencing, and real-time polymerase chain reaction (PCR) used to detect complement factors II (C2), III (C3), and V (C5); profibrinolysin (PLG); and coagulation factor II (F2) expression. A total of 2,722,223 reads were detected in the control group, and 2,751,111 in the infected group. Among 11,023 unigenes obtained after transcriptome assembly, 10,021 unigenes were significantly differentially expressed. Gene ontology and KEGG analysis, a collection of databases dealing with genomes and biological pathways, were performed to classify unigenes into functional categories, to understand gene function and identify regulatory pathways. Real-time PCR analysis showed that C2, C3, C5, PLG, and F2 expression levels were down-regulated, confirming results of pathway-enrichment analysis. This is the first application of highthroughput sequencing technology to investigate the in vivo effects of GCRV, on genes and pathways involved in the immune response to infection in grass carp.

Transcriptomics Sequencing Provides Insights into Understanding the Mechanism of Grass Carp Reovirus Infection

“…At present, previous studies on grass carp transcriptome profiles in response to grass carp reovirus infection have been carried out [ 10 , 11 , 12 , 13 , 14 ]. Most of them involved in the discovery of immune-related genes or uncovered the antiviral immunity mechanism of grass carp.…”

“…Grass carp haemorrhage disease outbreaks are frequent and result in huge economic losses in the aquaculture industry, hence the GCRV is of particular interest to geneticists aiming to develop strategies for breeding disease-resistant fish. Recent studies on GCRV have mainly focused on identification of genes involved in immune responses to GCRV infection [ 4 , 5 ], cloning and characterization of GCRV-encoded proteins [ 6 , 7 ], the development of vaccines against GCRV [ 8 , 9 ], and transcriptomic sequencing of discovered immune-related genes or uncovered the antiviral immunity mechanism of grass carp infected with GCRV [ 10 , 11 , 12 , 13 , 14 ]. However, the mechanisms of grass carp reovirus invasion and infection remain poorly explored.…”

Host–microbiota interactions and responses to grass carp reovirus infection in Ctenopharyngodon idellus

“…All the fish were reared under identical conditions, and fed with the same commercial diet after intraperitoneal injections. To test responses of gut microbiota to GCRV infection, grass carp from the GCRV infection group (abbreviated as G) and control group (abbreviated as C) were collected at infection stage (1 dpi), incubation stage (4 dpi), outbreak stage (7 dpi), and recovering stage (21 dpi) respectively (Xu et al ., 2016). An additional GCRV infection group with serious haemorrhagic symptoms (i.e., hyperemia in the operculum and fin ray) at 7 dpi (hereinafter referred to as G7s) was also analyzed (Fig.…”

Transcriptome Analysis Based on RNA-Seq in Understanding Pathogenic Mechanisms of Diseases and the Immune System of Fish: A Comprehensive Review

“…However, the immune response of the spleen was more intense than that of the head kidney, which provides evidence that alternative splicing plays a pivotal regulatory role in the immune response [ 71 ]. Also, a transcriptome analysis combined with RT-PCR validation identified the complement and coagulation cascade pathways as relevant pathways in the defense against GCRV infection [ 73 ].…”