关键词: 三角鲂, 团头鲂, 嗜水气单胞菌, 转录组, 基因表达

Abstract: To investigate the differences in resistance to Aeromonas hydrophila infection between Megalobrama terminalis and M. amblycephala, the transcriptome of the infected M. terminalis and M. amblycephala was sequenced by the Illumina HiSeq sequencing platform. The results showed that 62 780 Unigenes were obtained from the samples of M. terminalis and M. amblycephala after sequencing and filtering, with an average length of 531.883 bp, and the N50 of Unigenes was 652 bp. The NR and COG database identified 35 443 and 8 632 Unigenes, respectively, accounting for 56.46 and 13.75 percent of all annotated genes. Among the 62 780 Unigenes, 33 693 Unigenes were expressed in M. terminalis and 32 936 Unigenes were expressed in M. amblycephala, of which 24 834 Unigenes were co-expressed in M. terminalis and M. amblycephala. Cluster analysis of differential gene expression trends revealed that the gene expression trends of M. terminalis and M. amblycephala at 3 h and 24 h could be divided into 6 categories, with cluster mode 4 containing the most differentially expressed genes (16), cluster mode 1 containing the second-most (15), and cluster mode 5 containing the fewest (4). GO enrichment analysis showed that the differentially expressed genes of M. terminalis and M. amblycephala after infection mainly were concentrated on GO items such as immune response (GO:0006955), antigen processing and presentation (GO:0019882), and membrane (GO:0016020). Enrichment analysis of the KEGG pathway showed that Autoimmune thyroid disease (ko05320), Type I diabetes mellitus (ko04940), Viral myocarditis (ko05416), Cell adhesion molecules (ko04514), and Antigen processing and presentation (ko04612) pathways were highly enriched. The GO and KEGG enrichment analysis showed that the gene expression difference between M. terminalis and M. amblycephala after infection was closely related to antigen presentation genes. This study provided a basis for analyzing the differences between M. terminalis and M. amblycephala immune response during the A. hydrophila infection.

Key words: Megalobrama terminalis, Megalobrama amblycephala, Aeromonas hydrophila, transcriptome, gene expression