Korean Soybean Research Articles

Anti-Inflammatory Effect of Korean Soybean Sauce (Ganjang) on Mice with Induced Colitis.

Inflammatory bowel disease (IBD), characterized by chronic inflammation of the gut, is caused by several factors. Among these factors, microbial factors are correlated with the gut microbiota, which produces short-chain fatty acids (SCFAs) via anaerobic fermentation. Fermented foods are known to regulate the gut microbiota composition. Ganjang (GJ), a traditional fermented Korean soy sauce consumed worldwide, has been shown to exhibit antioxidant, anticancer, anti-colitis, and antihypertensive activities. However, its effects on the gut microbiota remain unknown. In the present study, we aimed to compare the anti-inflammatory effects of GJ manufactured using different methods and investigate its effect on SCFA production in the gut. To evaluate the anti-inflammatory effects of GJ in the gut, we performed animal experiments using a mouse model of dextran sulfate sodium (DSS)-induced colitis. All GJ samples attenuated DSS-induced colitis symptoms, including reduced colonic length, by suppressing the expression of inflammatory cytokines. In addition, GJ administration modulated SCFA production in the DSS-induced colitis model. Overall, GJ exerted anti-inflammatory effects by reducing DSS-induced symptoms via regulation of inflammation and modulation of SCFA levels in a DSS-induced colitis model. Thus, GJ is a promising fermented food with the potential to prevent IBD.

SUnSeT: spectral unmixing of hyperspectral images for phenotyping soybean seed traits

Key messageHyperspectral features enable accurate classification of soybean seeds using linear discriminant analysis and GWAS for novel seed trait genes.Evaluating crop seed traits such as size, shape, and color is crucial for assessing seed quality and improving agricultural productivity. The introduction of the SUnSet toolbox, which employs hyperspectral sensor-derived image analysis, addresses this necessity. In a validation test involving 420 seed accessions from the Korean Soybean Core Collections, the pixel purity index algorithm identified seed- specific hyperspectral endmembers to facilitate segmentation. Various metrics extracted from ventral and lateral side images facilitated the categorization of seeds into three size groups and four shape groups. Additionally, quantitative RGB triplets representing seven seed coat colors, averaged reflectance spectra, and pigment indices were acquired. Machine learning models, trained on a dataset comprising 420 accession seeds and 199 predictors encompassing seed size, shape, and reflectance spectra, achieved accuracy rates of 95.8% for linear discriminant analysis model. Furthermore, a genome-wide association study utilizing hyperspectral features uncovered associations between seed traits and genes governing seed pigmentation and shapes. This comprehensive approach underscores the effectiveness of SUnSet in advancing precision agriculture through meticulous seed trait analysis.

Whole-genome sequencing analysis of soybean diversity across different countries and selection signature of Korean soybean accession.

Soybean is an important agricultural crop known for its high protein and oil content, contributing to essential nutritional and health benefits for humans. Domesticated in China over 5,000 years ago, soybean has since adapted to diverse environments and spread worldwide. This study aimed to investigate the genomic characteristics and population structures of 2,317 publicly available soybean whole-genome sequences from diverse geographical regions, including China, Korea, Japan, Europe, North America, and South America. We used large-scale whole-genome sequencing data to perform high-resolution analyses to reveal the genetic characteristics of soybean accessions. Soybean accessions from China and Korea exhibited landrace characteristics, indicating higher genetic diversity and adaptation to local environments. On the other hand, soybean accessions from Japan, the European Union, and South America were found to have low genetic diversity due to artificial selection and breeding for agronomic traits. We also identified key variants and genes associated with the ability to adapt to different environments. In Korean soybean accessions, we observed strong selection signals for isoflavone synthesis, an adaptive trait critical for improving soybean adaptability, survival, and reproductive success by mitigating environmental stress. Identifying specific genomic regions showing unique patterns of selective sweeps for genes such as HIDH, CYP73A11, IFS1, and CYP81E11 associated with isoflavone synthesis provided valuable insights into potential adaptation mechanisms. Our research has significantly improved our understanding of soybean diversity at the genetic level. We have identified key genetic variants and genes influencing adaptability, laying the foundation for future advances in genomics-based breeding programs and crop improvement efforts.

Natural variation in tocopherols, B vitamins, and isoflavones in seeds of 13 Korean conventional soybean varieties

Soybean seeds are excellent sources of tocopherols, B vitamins, and isoflavones, which are well known for their health benefits. This study investigated the influence of environment and genotype on these constituents across 13 Korean soybean varieties cultivated in three locations during the 2017–2019 growing seasons. Statistical analyses, employing both univariate and multivariate methods, revealed significant impacts of genetic and environmental factors on the composition of tocopherols, B vitamins, and isoflavones. Through permutational univariate analysis of variance, the primary contributors to each measured component were identified. Genotype strongly influenced the levels of β- and δ-tocopherols, whereas the interaction between location and year predominantly affected α- and γ-tocopherols. Vitamin B1 content was predominantly determined by genotype, whereas B3 and B6 were influenced by annual variations. Vitamin B2 level was primarily affected by the interplay between environmental and genotypic effects. Genotype had a significant effect on isoflavone components, with the exception of daidzein. Furthermore, early maturing varieties and those with black seed coats exhibited low levels of isoflavone components and total isoflavones, suggesting a relationship between maturity group and seed coat color in isoflavone variation. These findings can be used as reference values for compositional equivalence assessment of genetically modified soybeans.

Media Optimization for Bacteriocin Production by Enterococcus faecium Strains Isolated from Traditional Korean Soybean Paste

Media Optimization for Bacteriocin Production by Enterococcus faecium Strains Isolated from Traditional Korean Soybean Paste

Unveiling synergistic QTLs associated with slow wilting in soybean (Glycine max [L.] Merr.)

Key messageA stable QTL qSW_Gm10 works with a novel locus, qSW_Gm01, in a synergistic manner for controlling slow-wilting traits at the early vegetative stage under drought stress in soybean.Drought is one of the major environmental factors which limits soybean yield. Slow wilting is a promising trait that can enhance drought resilience in soybean without additional production costs. Recently, a Korean soybean cultivar SS2-2 was reported to exhibit slow wilting at the early vegetative stages. To find genetic loci responsible for slow wilting, in this study, quantitative trait loci (QTL) analysis was conducted using a recombinant inbred line (RIL) population derived from crossing between Taekwangkong (fast-wilting) and SS2-2 (slow-wilting). Wilting score and leaf moisture content were evaluated at the early vegetative stages for three years. Using the ICIM-MET module, a novel QTL on Chr01, qSW_Gm01 was identified, together with a previously known QTL, qSW_Gm10. These two QTLs were found to work synergistically for slow wilting of the RILs under the water-restricted condition. Furthermore, the SNP markers from the SoySNP50K dataset, located within these QTLs, were associated with the wilting phenotype in 30 diverse soybean accessions. Two genes encoding protein kinase 1b and multidrug resistance-associated protein 4 were proposed as candidate genes for qSW_Gm01 and qSW_Gm10, respectively, based on a comprehensive examination of sequence variation and gene expression differences in the parental lines under drought conditions. These genes may play a role in slow wilting by optimally regulating stomatal aperture. Our findings provide promising genetic resources for improving drought resilience in soybean and give valuable insights into the genetic mechanisms governing slow wilting.

Microbial communities in the fermentation of Meju, a Korean traditional soybean brick.

Meju is a traditional Korean soybean brick characterized by diverse microbial communities. The microbial communities in Meju were identified at the phylum and genus levels using high-throughput sequencing. During Meju fermentation, diverse factors such as total bacterial cell numbers, moisture content, salinity, pH, enzyme activities, and free amino acids were monitored. After 30days of fermentation, microbial adaptation and increased protease activity resulted in significant changes, including an increase in pH and alterations in free amino acid content by day 70. Bacterial community analysis revealed significant changes in Bacillus, Lactococcus, and Enterococcus levels as fermentation progressed. The decrease in pH during fermentation was influenced by lactic acid bacteria, which affected bacterial dynamics. At the end of fermentation, the fungal community was dominated by Monascus, Aspergillus, and Scopulariopsis, which affected the free amino acid levels. These results indicate that pH and moisture content may be significant factors in determining microbial communities.

Overexpression of R2R3-MYB IbMYB1a induces anthocyanin pigmentation in soybean cotyledon.

This is the first report showing anthocyanin accumulation in the soybean cotyledon via genetic transformation of a single gene. Soybean [Glycine max (L.) Merrill] contains valuable components, including anthocyanins. To enhance anthocyanin production in Korean soybean Kwangankong, we utilized the R2R3-type MYB gene (IbMYB1a), known for inducing anthocyanin pigmentation in Arabidopsis. This gene was incorporated into constructs using two promoters: the CaMV 35S promoter (P35S) and the β-conglycinin promoter (Pβ-con). Kwangankong was transformed using Agrobacterium, and the presence of IbMYB1a and Bar transgenes in T0 plants was confirmed through polymerase chain reaction (PCR), followed by gene expression validation. Visual inspection revealed that one P35S:IbMYB1a and three Pβ-con:IbMYB1a lines displayed seed color change. Pβ-con:IbMYB1a T1 seeds accumulated anthocyanins in cotyledon outer layers, whereas P35S:IbMYB1a and non-transgenic black soybean (Cheongja 5 and Seum) accumulated anthocyanins in the seed coat. During the germination and growth phase, T1 seedlings from Pβ-con:IbMYB1a lines exhibited anthocyanin pigmentation in cotyledons for up to 1month without growth aberrations. High-performance liquid chromatography confirmed cyanidin-3-O-glucoside as the major anthocyanin in the Pβ-con:IbMYB1a line (#3). We analyzed the expression patterns of anthocyanin biosynthesis genes, chalcone synthase 7,8, chalcone isomerase 1A, flavanone 3-hydroxylase, flavanone 3'-hydroxylase, dihydroflavanol reductase 1, dihydroflavanol reductase 2, anthocyanidin synthase 2, anthocyanidin synthase 3, and UDP glucose flavonoid 3-O-glucosyltransferase in transgenic and control Kwangankong and black soybean (Cheongja 5 and Seum) seeds using quantitative real-time PCR. We conclude that the induction of gene expression in transgenic plants in comparison with Kwangankong was attributable to IbMYB1a transformation. Notably, flavanone 3-hydroxylase, flavanone 3'-hydroxylase, and dihydroflavanol reductase 1 were abundantly expressed in black soybean seed coat, distinguishing them from transgenic cotyledons.

Complete genome sequence of Arthrobacter sp. KFRI-F3372, a strain isolated from Korean soybean paste Doenjang.

Arthrobacter sp. KFRI-F3372 is a Gram-positive bacterium with a high G + C content of 65.7%, which was isolated from Doenjang, a traditional Korean fermented soybean paste. In this report, we introduce the complete genome sequence of Arthrobacter sp. KFRI-F3372.

Identification of a Novel KTi-1 Allele Associated with Reduced Trypsin Inhibitor Activity in Soybean Accessions

Trypsin inhibitors (TIs) in soybean seeds reduce the availability of processed soybean foods and animal feed. This study aimed to evaluate the trypsin inhibitor activity (TIA) in 999 Korean soybean accessions and conduct molecular characterization of soybean accessions with low TIA. TIA was evaluated using colorimetric analysis through a substrate–enzyme reaction. The average TIA of the 999 soybean accessions was 90.31%, ranging from 43.70% to 99.51%. Kunitz trypsin inhibitor 3 (KTi-3) gene target sequencing analysis was performed on seven soybean germplasm accessions (IT105782, IT170889, IT273590, IT274513, IT274515, IT276197, and IT022891) showing less than 60% TIA. Four soybean accessions (IT274513, IT274515, IT276197, and IT022891) exhibited the same mutations (a G-to-T transversion and an AG deletion) in the KTi-3 gene (Glyma.08g341500) in PI542044. In addition, whole-genome re-sequencing was performed on three soybean accessions with no mutations in the KTi-3 gene. Compared with the reference soybean genome, an in-frame insertion and five missense mutations were identified in the coding sequencing of the KTi-1 gene (Glyma.01g09500) in IT105782. A RT-qPCR analysis showed that the mRNA expression level of KTi-1 was reduced by approximately 17% in IT105782 during seed development. In this study, we identified a previously unreported mutation in the KTi-1 gene and developed a KASP marker using this new KTi-1 variant.

Isolation and Characterization of Enterococcus faecium from Fermented Korean Soybean Paste with Antibacterial Effects

In the present study, a total of eight Enterococcus faecium (OQ940301, OQ940302, OQ940303, OQ940304, OQ940305, OQ940308, OQ940309, and OQ940310) were isolated from soybean paste, a traditional Korean fermented food, and evaluated for their probiotic properties. The results showed that all the E. faecium strains survived in simulated human gastrointestinal conditions (4.1–5.59 log10 CFU/mL). In addition, the range of auto-aggregation was 5–25%, the hydrophobicity was around 94%, and it exhibited significant co-aggregation ability with Salmonella enterica and Staphylococcus aureus. However, all the isolates were shown to be resistant to Gentamycin. The bacterial cell-free supernatant showed antibacterial activity against S. enterica, Escherichia coli, Bacillus cereus, Listeria monocytogenes, and S. aureus. Furthermore, E. faecium exhibited potent anti-oxidant activity by scavenging 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) free radicals. In addition, safety was confirmed by evaluating the hemolytic activity in blood agar; none of the bacterial isolates showed hemolysis. These results demonstrated that E. faecium (OQ940301 and OQ940309) isolated from soybean paste showed a higher probiotic potential.

Complete Genome Sequence of Bacillus sp. Strain KICET-1, Isolated from Soybean Paste (Doenjang).

Bacillus sp. strain KICET-1, a bacterium isolated from traditional Korean soybean paste (Doenjang) at Osong, has one 4,099,652-bp DNA chromosome. The G+C content is 46.1%, and KICET-1 shares 99.64% similarity with Bacillus velezensis CR-502T (AY603658), according to phylogenetic classification based on 16S rRNA gene sequences.

Effect of the Types of Starter on Microbiological and Physicochemical Properties of Dry-Cured Ham.

This study analyzed the microbiological (Lactobacillus spp., Staphylococcus spp., mold, yeast, aerobic bacteria) and physicochemical properties [pH, salinity, water activity, volatile basic nitrogen (VBN), and thiobarbituric acid reactive substances]. The starters were used by mixing Debaryomyces hansenii separated from Korean Doenjang (D) and fermented sausage (S). The starter was inoculated with dry-cured ham and aged for 6 weeks at 20°C and 25°C, respectively. The aerobic bacteria, Lactobacillus spp., and Staphylococcus spp. of D, S, and DS treatment showed significantly higher values at 25°C than at 20°C. Among them, S25 treatment showed a high tendency. At week 6, the mold of the S25 treatment was significantly higher than the S20 treatment, and the yeast was higher in 25°C than 20°C (p<0.05). The pH of all treatment groups increased with the aging period. Compared with that at 25°C, the pH was significantly higher at 20°C (p<0.05). The water activity showed a significant decrease as the aging period increased, and the treatment of D25, S20, and DS20 showed a significantly higher value at week 6 (p<0.05). Compared with that at 20°C, the VBN content was higher at 25°C. At week 6, the VBN contents of the C20, S25, and DS25 groups were higher than those of the other treatment groups. Therefore, inoculation of D. hansenii separated from fermented sausage produced in Korean starter at 25°C is expected to improve the safety of harmful microorganisms and physiochemical properties in dry-cured ham.

감태 분말 첨가 된장의 품질 특성

Doenjang (Korean soybean paste) was prepared by adding of Ecklonia cava powder (w/w 0.3.6,9%) to Meju fermented for 30℃ for 40 days. The pH level of all samples did not show any significant decrease or increase by days 20 and 30, but the pH level increased near the end of the fermentation process by day 40 compared to the early days of fermentation, with the highest pH for the control group with no added powder and the lowest for the 9% group. The titratable acidity in the 9% group was measured to be the highest, as all the samples increased from the initial fermentation on the 40th day of fermentation. At the start of fermentation, the control group showed the lowest levels of total nitrogen and amino acid content and the 9% group showed the highest. However, by day 40 of fermentation, the control group showed the highest levels and the 9% group showed the lowest levels. The nitrogen degradation rate (NDR) was increased as the fermentation process continued, the control group showed the highest levels by day 40, but the 9% group showed the lowest levels of NDR, showing a decreasing trend as more powder is added. As the fermentation process continued, the levels of reducing sugar decreased, with the control group showing the lowest level and the 9% group with the highest level. The total number of bacteria was significantly reduced from 7.12 to 8.28 log CFU/g at the beginning of fermentation to 6.00 to 6.15 log CFU/g by day 40 of fermentation. The total polyphenol content and % DPPH radical scavenging activity increased significantly with the addition of Ecklonia cava powder in both the early fermentation and the last day of fermentation, showing a higher polyphenol content on the last day of fermentation compared to the first day. In a survey of consumer preferences was showed that the control group with no addition of Ecklonia cava powder showed the highest values in appearance and aroma. However, although there were no significant differences in taste-related assessments (salty taste, umami, after taste) and overall acceptability, the preference for the group with 6% Ecklonia cava powder was the highest. Based on these findings, it was confirmed that soybean paste with 6% of Ecklonia cava powder had the best effect on the preference and functionality of soybean paste, and the possibility of manufacturing soybean paste using Ecklonia cava powder has potential in food development.

Sugar and Isoflavone Contents of Traditional Korean Soybean Fermented Foods

Sugar and Isoflavone Contents of Traditional Korean Soybean Fermented Foods

Comparative untargeted metabolomic analysis of Korean soybean four varieties (Glycine max (L.) Merr.) based on liquid chromatography mass spectrometry

Comparative untargeted metabolomic analysis of Korean soybean four varieties (<i>Glycine max</i> (L.) Merr.) based on liquid chromatography mass spectrometry

RNA-seq Gene Profiling Reveals Transcriptional Changes in the Late Phase during Compatible Interaction between a Korean Soybean Cultivar (Glycine max cv. Kwangan) and Pseudomonas syringae pv. syringae B728a

Soybean (Glycine max (L) Merr.) provides plant-derived proteins, soy vegetable oils, and various beneficial metabolites to humans and livestock. The importance of soybean is highly underlined, especially when carbon-negative sustainable agriculture is noticeable. However, many diseases by pests and pathogens threaten sustainable soybean production. Therefore, understanding molecular interaction between diverse cultivated varieties and pathogens is essential to developing disease-resistant soybean plants. Here, we established a pathosystem of the Korean domestic cultivar Kwangan against Pseudomonas syringae pv. syringae B728a. This bacterial strain caused apparent disease symptoms and grew well in trifoliate leaves of soybean plants. To examine the disease susceptibility of the cultivar, we analyzed transcriptional changes in soybean leaves on day 5 after P. syringae pv. syringae B728a infection. About 8,900 and 7,780 differentially expressed genes (DEGs) were identified in this study, and significant proportions of DEGs were engaged in various primary and secondary metabolisms. On the other hand, soybean orthologs to well-known plant immune-related genes, especially in plant hormone signal transduction, mitogen-activated protein kinase signaling, and plant-pathogen interaction, were mainly reduced in transcript levels at 5 days post inoculation. These findings present the feature of the compatible interaction between cultivar Kwangan and P. syringae pv. syringae B728a, as a hemibiotroph, at the late infection phase. Collectively, we propose that P. syringae pv. syringae B728a successfully inhibits plant immune response in susceptible plants and deregulates host metabolic processes for their colonization and proliferation, whereas host plants employ diverse metabolites to protect themselves against infection with the hemibiotrophic pathogen at the late infection phase.

Contents of Isoflavone in a Prime Core Set of Korean Soybean Germplasms

Contents of Isoflavone in a Prime Core Set of Korean Soybean Germplasms

Comparison of Hyperspectral Imagery and Physiological Characteristics of Bentazone-Tolerant and -Susceptible Soybean Cultivars

Bentazone is a broadleaf post-emergence herbicide widely used for crop production that inhibits photosynthetic activity, resulting in phytotoxicity and injury in plants. Evaluating and identifying herbicide-tolerant genotypes is a critical step in plant breeding programs. In this study, we determined the reaction of 138 Korean soybean cultivars to bentazone using visual evaluation, and selected cultivars were further evaluated to determine the effects of bentazone on physiological parameters. For physiological parameters, we measured the normalized difference vegetation index (NDVI) from hyperspectral reflectance images. From 2 to 4 DAT, the NDVI for two sensitive cultivars was between 0.60 and 0.69, while the NDVI for tolerant cultivars was between 0.70 and 0.86. Photosynthesis rate (A), transpiration (E), stomatal conductance (gsw), and total conductance of CO2 (gtc) were measured using chlorophyll fluorescence. Visual score evaluation showed that moderate bentazone-tolerant cultivars were predominant among the Korean cultivars. For physiological measurements, differences in NDVI were detected between bentazone-tolerant and -sensitive cultivars 2 days after treatment (DAT). However, the A, E, gsw, and gtc levels dramatically decreased 1 DAT in the sensitive cultivars. This study provides insights into the tolerance and sensitivity of soybeans to bentazone.

Erratum to: Identification of resistance loci toward Phytophthora sojae in South Korean soybean plant introductions 407974B and 424487B

The published version of Figure 2 was incorrect; the distance of the markers is not evident. The correct version of Figure 2 is below.