When soybean seeds encounter low temperature during germination, the vigour 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 of soybean-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 quantitative trait loci (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.09G162700 proteins were mutated. Within 0–72 h, the expression of Glyma.09G162700 in the two materials with different tolerances was consistent, and the change in trypsin 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 analysing the mechanism of low-temperature tolerance in soybean germination stage and cultivating low-temperature-tolerant varieties.

中文翻译：

---

大豆萌发期耐低温QTL定位及候选基因分析

大豆种子在发芽时遇到低温，会影响大豆种子的活力和发芽，导致缺苗、弱苗，导致产量降低。深入分析大豆种子萌发耐低温胁迫的遗传机制并培育耐大豆品种是萌发阶段抵抗低温胁迫的关键。在本研究中，利用野生大豆ZYD00006和栽培大豆SN14构建的染色体片段替代系（CSSL）群体来定位三个数量性状基因座（QTL）。通过基因注释、GO富集分析和蛋白功能预测，获得5个候选基因。对候选基因进行生物信息学分析、qRT-PCR分析、胰蛋白酶活性分析和可溶性蛋白含量分析。结果显示Glyma.09G162700蛋白的二级和三级结构发生突变。0~72 h内，不同耐受性的两种材料中Glyma.09G162700的表达量一致，且胰蛋白酶活性的变化与蛋白表达的变化一致。通过单倍型分析，Glyma.09G162700在-2420 bp处产生了两个单倍型。两种单倍型的发芽率（GR）和相对发芽率（RGR）差异显着，表明两种单倍型在大豆资源中具有广泛的适用性。综上所述，Glyma.09G162700可能是大豆萌发期耐低温的候选基因。该研究结果为分析大豆发芽期耐低温机制、培育耐低温品种提供了重要的理论依据和标记信息。