Transcriptome profiling and digital gene expression analysis of Nile tilapia (Oreochromis niloticus) infected by Streptococcus agalactiae.
Tilapia is an important freshwater aquaculture species worldwide. In recent years, streptococcal diseases have severely threatened development of tilapia aquaculture, while effective prevention and control methods have not yet been established. In order to understand the immunological response of tilapia to infection by Streptococcus agalactiae (S. agalactiae), this study employed Solexa/Illumina RNA-seq and digital gene expression (DGE) technology to investigate changes in the tilapia transcriptome before and after S. agalactiae infection. We obtained 82,799 unigenes (mean size: 618 bp) using de novo assembly. Unigenes were annotated by comparing against databases including Nr, Swissprot, cluster of orthologous groups of proteins, Kyoto encyclopedia of genes and genomes, and gene ontology. Combined with DGE technology, transcriptomic changes in tilapia before and after bacteria challenging were examined. A total of 774 significantly up-regulated and 625 significantly down-regulated unigenes were identified, among which 293 were mapped to 181 signaling pathways including 17 immune-related pathways involving 65 differentially expressed genes. We observed a change in the expression of six genes in the Toll-like receptor signaling pathway, and this was subsequently confirmed via quantitative real-time PCR. This comparative study of the tilapia transcriptome before and after S. agalactiae infection identified important differentially-expressed immune-related genes and signaling pathways that will provide useful insights for further analysis of the mechanisms of tilapia defense against S. agalactiae infection.
Key Laboratory of Tropical & Subtropical Fisheries Resource Application & Cultivation, China Ministry of Agriculture, Pearl River Fisheries Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510380, China.
Rui
R
Zhang
Li-li
LL
Zhang
Xing
X
Ye
Yuan-yuan
YY
Tian
Cheng-fei
CF
Sun
Mai-xin
MX
Lu
Jun-jie
JJ
Bai
D000818:Animals; D023681:Cichlids / Q000235:genetics* / Q000382:microbiology*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D015723:Gene Library; D063990:Gene Ontology; D007109:Immunity / Q000235:genetics; D058977:Molecular Sequence Annotation; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics; D013290:Streptococcal Infections / Q000235:genetics* / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000502:physiology*; D051193:Toll-Like Receptors / Q000378:metabolism; D059467:Transcriptome; D015854:Up-Regulation / Q000235:genetics
D051193:Toll-Like Receptors