Identification of Soybean Asparagine Synthetase Superfamily and Haplotype Module Stacking Analysis

Asparagine synthase (ASN) is a key enzyme in nitrogen metabolism. It is responsible for the synthesis of asparagine, but the function and molecular mechanism of its superfamily in the seed storage protein of soybean is not yet clear. In this study, a total of 34 members of the ASN superfamily were identified in soybean by in silico analysis (GmASNs). Phylogenetic and structural analyses show that most proteins in the GmASN superfamily contain conserved functional domains, which are predicted to be hydrophilic proteins, and are mainly located in the cytoplasm and chloroplasts, and a few are located in mitochondria. The chromosome distribution shows that they are randomly scattered on 13 chromosomes, and gene replication drives the expansion of the family. In addition, the haplotype analysis of four key GmASN superfamily genes (GmASN11, GmASN16, GmASN20, GmASN29) shows that they are significantly associated with the content of seed storage protein (SSP). Importantly, the aggregation of favorable haplotypes at these loci can significantly improve the SSP level. These results elucidate the evolutionary history of the GmASN gene superfamily and identify valuable haplotypes. These haplotypes are promising targets for the development of high-protein soybean varieties through marker-assisted breeding.