Identification of a Novel Salt Tolerance-Related Locus in Wild Soybean (Glycine soja Sieb. & Zucc.)

Abstract

Salinity is an important abiotic stress factor that affects growth and yield of soybean. NY36-87 is a wild soybean germplasm with high salt tolerance. In this study, two F_2:3 mapping populations derived from NY36-87 and two salt-sensitive soybean cultivars, Zhonghuang39 and Peking, were used to map salt tolerance-related genes. The two populations segregated as 1 (tolerant):2 (heterozygous):1 (sensitive), indicating a Mendelian segregation model. Using simple sequence repeat (SSR) markers together with the bulked segregant analysis (BSA) mapping strategy, we mapped a salt tolerance locus on chromosome 03 in F_2:3 population Zhonghuang39×NY36-87 to a 98-kb interval, in which the known gene <i>GmSALT3</i> co-segregated with the salt tolerance locus. In the F_2:3 population of Peking×NY36-87, the dominant salt tolerance-associated gene was detected and mapped on chromosome 18. We named this gene <i>GmSALT18</i> and fine mapped it to a 241-kb region. Time course analysis and a grafting experiment confirmed that Peking accumulated more Na⁺ in the shoot <i>via</i> a root-based mechanism. These findings reveal that the tolerant wild soybean line NY36-87 contains salt tolerance-related genes <i>GmSALT3</i> and <i>GmSALT18</i>, providing genetic material and a novel locus for breeding salt-tolerant soybean.