Correlation between SNPs in Toll-like receptor5 membrane form (TLR5m) gene and immune respond in Rainbow trout (Oncorhynchus mykiss) exposed to Aeromonas hydrophila

Toll-like receptors (TLRs) generally are involved in host immune responses against microbial invasions. Mono meric felagellin, the structure component of bacterial felagella is the agonist of TLR5m. After binding to felagellin, TLR5m initiates specific signal transduction pathways and triggers immune responses. Single nucleotide polymorphisms (SNPs) in this gene regulate inflammatory pathways and are associated with susceptibility/resistance to infection. In this study using polymerase chain reaction, sequencing and aligning the sequences, we investigated TLR5m gene of Rainbow Trout (Oncorhynchus mykiss) and identified 6 polymorphisms consist in 3 SNPs: (2412, T/A), (2415,T/A) and (2385, G/A) and 3 insert/deletion: (inser/dele. C, C/T, 2091), (inser/dele. T, 2566) and (inser/dele. C, 2102). A bacterial challenge was performed to explore their association with humoral immune responses such as lysozym content and complement activity levels in serum. The results show that polymorphisms (inser/dele. C, C/T, 2091) and (inserldele. T, 2566) were significantly correlated with higher complement activity levels (p<0.05).These results suggested that these 2 polymorphisms could be potential markers applied in future selection of Rainbow Trout with enhanced resistance to Aeromonas hydrophila.