Comparative Transcriptomic Analysis Reveals the Regulated Expression Profiles in in Response to Coinfection of and .

Tilapia ( sp.) is one of the important economical fishes in the world. Streptococcosis is commonly found in tilapia, causing severe and devastating effects in tilapia cultures. and are the predominant pathogens causing tilapia streptococcosis. To understand the molecular mechanisms underlying differential streptococcal infection patterns, Nile tilapias () were infected by 1 × 10 CFU/mL , 1 × 10 CFU/mL , and 1 × 10 CFU/mL and (1:1), respectively, and transcriptome analysis was conducted to the intestine samples of Nile tilapia () at 6, 12, 24 h, and 7 days post-infection. A total of 6,185 genes that differentially expressed among groups were identified. Eight differentially expressed genes (DEGs) including , , , , , , , (), and , that involved in the immune system were selected, and their expression levels in the coinfection group were significantly higher than those in either of the single infection groups. These genes were associated with four different KEGG pathways. Additionally, the differential expression of eight DEGs was validated by using the RT-qPCR approach, and their immunological importance was discussed. The results provided insights into the responses of tilapia against and at the transcriptome level, promoting our better understanding of immune responses for aquatic animal against .