QTL Mapping and Candidate Gene Analysis of Low-temperature Tolerance at the Germination Stage of Soybean

Abstract

Abstract When soybean seeds encounter low temperature during germination, the vigor and germination of soybean seeds are affected, which leads to a lack of seedlings and weak seedlings, resulting in yield reduction. In-depth analysis of the genetic mechanism of soybean seed germination tolerance to low-temperature stress and the cultivation ofsoybean-tolerant varieties is the key to resisting low-temperature stress at the germination stage. In the present study, a chromosome segment substitution line (CSSL) population constructed by wild soybean ZYD00006 and cultivated soybean SN14 was used to map three QTLs. Five candidate genes were obtained by gene annotation, GO enrichment analysis and protein function prediction. The candidate genes were subjected to bioinformatics analysis, qRT-PCR analysis, trypsin activity analysis and soluble protein content analysis. The results showed that the secondary and tertiary structures of the Glyma.09G162700proteins were mutated. Within 0to 72 h, the expression of Glyma.09G162700 in the two materials with different toleranceswas consistent, and the change intrypsin activity was consistent with the change in protein expression. Through haplotype analysis, Glyma.09G162700 produced two haplotypes at -2420 bp. The germination rate (GR) and relative germination rate (RGR) of the two haplotypes were significantly different, indicating that the two haplotypes have wide applicability in soybean resources. In summary, Glyma.09G162700 may be a candidate gene for low-temperature tolerance at the germination stage of soybean. These results provide an important theoretical basis and marker information for analyzing the mechanism of low-temperature tolerance in soybean germination stage and cultivating low-temperature tolerant varieties.