Identification of olive flounder (Paralichthys olivaceus) toll-like receptor genes: Involvement in immune response to temperature stress and Edwardsiella tarda infection

Toll-like receptor (TLR) genes are best known for their roles in the innate immune defense. However, studies focusing on the reaction mechanisms of TLR genes in olive flounder (Paralichthys olivaceus) immune responses are still limited. In this study, 11 TLR family members (PoTLRs) were identified and classified from P. olivaceus genome. Phylogenetic analysis showed that PoTLRs were highly conserved in olive flounder. The analysis of motif prediction and gene structure indicated that TLRs had high sequence similarity. The expression patterns in developmental stages and different tissues showed that TLR members were spatially and temporally specific. RNA-Seq analysis of temperature stress and Edwardsiella tarda infection suggested that TLR members were involved in inflammatory responses, PoTLR5b and PoTLR22 showed significant differences in response to both temperature stress and E. tarda stress, indicating their potential immune functions. The results of this study suggested that TLR genes played important roles in the innate immune response of olive flounder, and would provide a solid basis for further study of their functions.

Automated summary

In this study, 11 Toll-like receptor (TLR) genes were identified and classified from the olive flounder genome. Phylogenetic analysis showed high conservation of these genes in the species. Gene structure and motif prediction analysis indicated high sequence similarity among TLRs. Expression patterns in different tissues and developmental stages were spatially and temporally specific. RNA-Seq analysis revealed the involvement of TLR members in inflammatory responses, with two specific genes showing significant differences in response to temperature stress and bacterial infection. This study highlights the important roles of TLR genes in the innate immune response of olive flounder and provides a basis for further functional studies.