The increasingly serious trend of soil salinization inhibits the normal growth and development of soybeans, leading to reduced yields and a serious threat to global crop production. Microsomal ω-3 fatty acid desaturase encoded by the FAD3 gene is a plant enzyme that plays a significant role in α-linolenic acid synthesis via regulating the membrane fluidity to better accommodate various abiotic stresses. In this study, PfFAD3a was isolated from perilla and overexpressed in soybeans driven by CaMV P35S, and the salt tolerance of transgenic plants was then evaluated. The results showed that overexpression of PfFAD3a increased the expression of PfFAD3a in both the leaves and seeds of transgenic soybean plants, and α-linolenic acid content also significantly increased; hence, it was shown to significantly enhance the salt tolerance of transgenic plants. Physiological and biochemical analysis showed that overexpression of PfFAD3a increased the relative chlorophyll content and PSII maximum photochemical efficiency of transgenic soybean plants under salt stress; meanwhile, a decreased accumulation of MDA, H₂O₂, and ${\mathrm{O}}_2^{•-}$, increased the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbic acid peroxidase (APX), as well as the production of proline and soluble sugar. In summary, the overexpression of PfFAD3a may enhance the salt tolerance in transgenic soybean plants through enhanced membrane fluidity and through the antioxidant capacity induced by C18:3.

The content of protein and oil in soybeans is an important trait for evaluating quality and is regulated by genetic and environmental factors, lacking comprehensive identification under a variety of ecological conditions. Therefore, evaluating the stability of soybean quality traits under different environmental conditions has great significance for various applications. In this study, we compare 150 soybean varieties from Northeast China (Group A and Group B) and the Huang-Huai-Hai region (Group C). As the release time progressed, the oil content in the soybean varieties showed an upward trend in both Northeast China and the Huang-Huai-Hai region, while the protein content showed a downward trend. Additionally, the oil contents were negatively correlated with the protein contents and the sum of protein and oil contents, while the protein contents were positively correlated with the sum of protein and oil contents, with the correlation becoming stronger as the latitude decreased. Moreover, there were obvious variations in quality stability among different varieties. Hefeng 45, Jilinxiaolidou 4, and Zhonghuang 19 had relatively high protein contents and exhibited good stability across different environments, while Kenjiandou 25, Changnong 17, Dongnong 46, Kennong 17, Liaodou 14, and GR8836 had relatively high oil contents with good stability performance in varying environments.

Tocopherol plays an important role as a powerful antioxidant in human beings and in plants. This study investigated the genetic basis of tocopherol content in soybean. A RIL population of 192 lines derived from 2 cultivars, ZH13 and ZH35, was evaluated for tocopherol content across 3 environments. QTL mapping identified 38 QTL for tocopherol, with stable QTL identified on Chromosomes 5 and 12. Ninety polymorphic genes were identified from these regions. Further SNP variation of a natural population identified 47 SNPs, with missense variants in 19 genes, including the heat shock transcription factor gene (GmHSFA8) and gamma-tocopherol methyltransferase (GmVTE4), potentially related to tocopherol accumulation in soybean. Haplotype analysis revealed significant variations in these missense variants in the natural population. This study provides insights into the genetic mechanisms underlying tocopherol content in soybean, which is important for breeding high tocopherol soybean cultivars.

Soybean is an important food crop and economic crop, and its grain protein is about 40%, which is one of the main sources of high-quality vegetable protein. Mining the quantitative trait loci (QTL) that control soybean high protein and molecular marker breeding are of great significance for the breeding of high protein soybean. In this study, a recombinant inbred line population consisting of 192 lines constructed by crossing Zhonghuang 35 (ZH35) and Zhonghuang 13 (ZH13) with significant differences in protein content was used as the experimental materials. A high-density genetic map containing 4879 bin markers was constructed with the total genetic distance of 3760.71 cM and the genetic distance between adjacent markers of 0.77 cM by resequencing the two parents and the RIL population. The RIL population and its parents were grown in Shunyi, Beijing and Puyang, Henan, respectively. A total of 15 protein content-related QTL loci were detected in the two environments, which were distributed on chromosomes 5, 12, 15, 17, 18, 19, and 20, respectively. The contribution rate was 4.36%-11.39%, among which, qPro-20-1 and qPro-20-3 were detected in Shunyi, Beijing and Puyang, Henan, respectively. The contribution rates of the two QTLs were 7.65% and 7.58%, respectively, and the overlapping regions included 33 genes. This study is helpful for fine mapping and map-based cloning of soybean protein content-related genes, and provides genetic resources for further breeding of high-protein soybean varieties.

Soybeans (Glycine max L.), originating in China, were introduced to South America in the late 19th century after passing through North America. South America is now a major soybean-producing region, accounting for approximately 40% of the global soybean production. Crops like soybeans gradually adapt to the local climate and human-selected conditions, resulting in beneficial variations during cultivation in different regions. Comparing the phenotypic and genetic variations in soybeans across different regions is crucial to determining the variations that may enhance soybean productivity. This study identified seed-related traits and conducted a genetic diversity analysis using 46 breeding soybean varieties from China and Uruguay. Compared to the Chinese soybean germplasm, the Uruguayan equivalent had a lower 100-grain weight, higher oil content, lower protein content, and higher soluble sugar content. Using ZDX1 gene chips, genetic typing was performed on the 46 breeding varieties. Cluster analysis based on SNP sites revealed significant differences in the genetic basis of Sino-Uruguayan soybean germplasm. Selection analysis, including nucleotide polymorphism (π) and fixation indexes (Fst), identified several genomic regions under selection between Sino-Uruguayan soybean germplasm. The selected intervals significantly enriched gene ontology (GO) terms related to protein metabolism. Additionally, differentiation occurred in genes associated with the oil content, seed weight, and cyst nematodes between Sino-Uruguayan soybean germplasm, such as GmbZIP123 and GmSSS1. These findings highlight the differences in seed-related phenotypes between Sino-Uruguay soybean germplasm and provide genomic-level insights into the mechanisms behind phenotypic differences, offering valuable references for understanding soybean evolution and molecular breeding.