GWAS identified candidate variants and genes associated with acute heat tolerance of large yellow croaker

Abstract

Abstract Heat tolerance is an important ability for fish to cope with increased temperature. Large yellow croaker (Larimichthys crocea) is one of the most economically important mariculture fish in China. However, the sustainable development of large yellow croaker aquaculture has long been hampered by extremely high temperature in summer, which is further intensified by the ever-increased global warming. To relieve mass death caused by extreme heat events, it is essential to improve the heat tolerance of this species, which will benefit from a comprehensive understanding of the genetic basis underlying heat tolerance. Here, using a 650\xa0K high density SNP array, we conducted a genome-wide association study (GWAS) on acute heat tolerance (AHT) of large yellow croaker. As a result, 5 significant single nucleotide polymorphisms (SNPs) on 4 chromosomes were identified, indicating the polygenic control characteristics of this trait. A clear peak on Chr19 was found and most of the nearby genes showed differential expression during heat stress, indicating the potential relevance of this region with AHT. Based on the 5 identified SNPs, we predicted 30 candidate genes including heat shock factor protein 1, DnaJ homolog subfamily B member 4, protein Hikeshi, protein disulfide-isomerase A3 etc. Further comparative and validation analysis suggested the importance of blood vessel regulation, heat shock response and endoplasmic reticulum stress response in mediating the interindividual AHT variation of large yellow croaker. These results provide insights into the genetic basis of AHT in fish and will be helpful for heat-tolerance improvement of large yellow croaker by marker-assisted selection.