Unraveling the associations of the tilapia DNA polymerase delta subunit 3 (POLD3) gene with saline tolerance traits

DNA polymerases play important roles in repairing synthesis of DNA damage in cells induced by environmental stress. However, little information about function of DNA polymerase delta for DNA damage that induced by salinity stress was available. In our study, we identified 7 SNPs in a subunit of DNA polymerase delta, POLD3, and found that these SNPs were significantly associated with saline tolerance traits in a full-sib family of Nile tilapia (N = 192). The expression of the POLD3 gene was also dramatically regulated at brain, gill and intestine in response to the acute salinity challenges as indicated by qRT-PCR. Our data indicated that the POLD3 gene itself or close-linked genes played important roles in saline tolerance in tilapia and provided a basis for developing molecular marker resources from POLD3 gene for breeding of salt-tolerant tilapia in future.