Seasonal variation in two culture systems and genome-wide association analysis of taurine content in the foot muscles of the Pacific abalone (Haliotis discus hannai)

Abstract

Abalone is one of the most economically valuable shellfish in the world's aquaculture industry, and as production has increased, it has led to a diversification of market quality needs. Taurine, an essential amino acid component, has yet to be well investigated for its seasonal variation and genetically associated genes or loci in Pacific abalone (Haliotis discus hannai). In this study, we investigated the variation of taurine content in different seasons under two typical culturing systems in southern China. In addition, we conducted a genome-wide association study (GWAS) with 274 abalone array sequencing and phenotypic data of taurine content. The results revealed that the taurine content showed a trend of significantly decreasing and then increasing with seasonal changes. Individuals farmed in land-based industrial culture system had a greater taurine content than those farmed in sea-based floating raft culture system, with notable differences observed between May and September. A total of 69,530 high-quality SNPs and 274 individuals were identified by quality control. And 32 significantly related SNP loci of taurine content were identified by GWAS, with chromosome 9 hosting the lowest P value. A total of 33 candidate genes, including SLC6A7, EGF1, B3gnt6, and Ptpra, were annotated. These genes may be connected to amino acid synthesis, transmembrane transport, energy production, protein phosphorylation, and other processes. Among them, genes belonging to the SLC6A family may be the key gene taurine content. This study helped us better understand the genetics of the taurine content of Pacific abalone.