A Genome-Wide Association Study of Heat Stress-Associated SNPs in Catfish

Heat tolerance is a complex and economically important trait for catfish genetic breeding programs. Ongoing global climate change will lead to a continuous rise in temperature, which may become a major stressor for fish living in natural or artificial systems. The hybrid catfish is expected to have a higher heat tolerance performance than that of the channel catfish (Ictalurus punctatus) because blue catfish (I. furcatus) has a more southern distribution than does channel catfish. To better understand the molecular basis of heat stress, a genome-wide association study (GWAS) was carried out using the 250K catfish SNP array with 192 interspecific backcross progenies derived from crossing female channel catfish with male F1 hybrid catfish (female channel catfish × male blue catfish). Three significant associated SNPs were detected by GWAS analysis. The SNP located on linkage group 14 explained 12.1% of phenotypic variation. The other two SNPs, located on linkage group 16, explained 11.3% and 11.5% of phenotypic variation, respectively. A total of 14 genes with heat stress related functions were detected within the significant associated regions. Among them, five genes—TRAF2, FBXW5, ANAPC2, UBR1 and KLHL29— have known functions in the protein degradation process through the ubiquitination pathway. Other genes related to heat stress included genes involved in protein biosynthesis (PRPF4 and SYNCRIP), protein folding (DNAJC25), molecule and iron transport (SLC25A46 and CLIC5), cytoskeletal reorganization (COL12A1) and energy metabolism (COX7A2, PLCB1 and PLCB4) processes. The results provided insights into potential genes and pathways involved in heat stress responses.