Soil salinisation has become one of the major abiotic stresses limiting crop growth in the world. To enhance soybean productivity on saline lands, understanding its salt-stress response and underlying mechanisms is necessary. In this study, the salt-tolerant soybean Kefeng 1 and the salt-sensitive soybean Qihuang 1 were used to elucidate the synergistic regulatory networks underlying soybean salt tolerance. After 12 days of 150 mM NaCl treatment, both varieties were subjected to phenotypic evaluation, physiological measurements, and integrated transcriptomic and metabolomic analysis. The results showed that the salt tolerance in Kefeng 1 primarily originated from its root. Under salt stress, Kefeng 1 maintained Na⁺/K⁺ ion homeostasis by up-regulating Cation/H⁺ Exchanger 15 (CHX15) and Cation Exchanger 3 (CAX3), and down-regulating Cyclic Nucleotide-Gated Channel 13 (CNGC13). Furthermore, Kefeng 1 stabilised auxin (IAA) homeostasis by inhibiting IAA biosynthesis and regulating concentrations through PIN-FORMED 3 (PIN3)-mediated efflux. It also scavenged reactive oxygen species (ROS) by employing enhanced enzymatic antioxidant systems, specifically aldo-keto reductase 1 (AKR1), glutathione S-transferase (GST), and catalase (CAT), alongside non-enzymatic antioxidants like the isoflavone genistein. Gene–metabolite correlation network analysis identified Glyma.09G117900 (PIN3) and Glyma.19G244200 (AKR1) as two hub genes. These two genes were specifically up-regulated in Kefeng 1 root under NaCl stress, and the proteins they encoded played important roles in salt tolerance in Kefeng 1 root as described above. Accordingly, these two genes were identified as candidate genes for salt tolerance in Kefeng 1. This study offered a theoretical framework and genetic resources for developing salt-tolerant soybean cultivars.

Background: The colour of tea beverages during processing and storage significantly influences their visual quality. However, natural pink tea products are rare. This study investigated the mechanism behind the pink colouration in the mixed infusion of Biluochun (a green tea) and rosemary. Methods: Infusions of Biluochun (B), rosemary (R), and their mixture (BR), brewed with boiling water for 10 min, were analysed using liquid chromatography-mass spectrometry (LC-MS). Additionally, the pH value and tea pigment content were measured. Results: A total of 134 differential metabolites (DEMs) were detected. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that phenylalanine metabolism and tyrosine metabolism pathways were enriched with abundant DEMs. Some amino acids in BR showed degradation. The content of pelargonin, a compound in the anthocyanin biosynthetic pathway, was significantly elevated in BR compared to that in B and R. DEMs related to fatty acid metabolism were at low levels in BR. Other compounds, such as quercetin, caffeate, rosmarinic acid, and isoferulic acid, were also more abundant in BR. No significant differences in pH value and tea pigment content were found among the three infusions. Conclusions: A model of pink colouration formation in BR was proposed based on the results of this study. Some substances in Biluochun and rosemary were released during the brewing process. Tyrosine was converted into p-coumaric acid, which further reacted to form pelargonin. Pelargonin, an orange-red (pH ≈ 5.0) anthocyanin, was the primary contributor to the pink colouration in BR. Additionally, p-coumaric acid formed co-pigments such as quercetin, caffeic acid, rosmarinic acid, and isovaleric acid. These co-pigments stabilised or enhanced the colour of pelargonin through co-pigmentation. The findings provide a theoretical basis for optimising tea processing techniques and improving quality control in beverage production.

Shanghai-native vegetable soybean (Glycine max [L.] Merril) landraces are valuable germplasms, but their systematic evaluation for agronomic and nutritional traits remains insufficient. This study aimed to assess their phenotypic and nutritional diversity to explore their potential for breeding and meeting dietary needs. Twenty-nine local landraces and one control cultivar (‘Qingsu 7’) were evaluated for key agronomic traits, yield components, nutritional traits, and isoflavone profiles, using hierarchical clustering, principal component analysis (PCA), and correlation analysis. Substantial phenotypic diversity was found, with the germplasm classified into four groups. First pod height and effective pods per plant were highly variable. Nutritional traits showed low variability for crude protein but high diversity for crude fat, soluble sugars (dominated by sucrose), vitamin C, and free amino acids. Total isoflavone content in dry seeds varied widely, with genistin, daidzin, and daidzein as the main forms. ‘Xiangshui Maodou’ had high free amino acids and vitamin C, ‘Heiyan Susudou’ showed superior soluble sugar content, and two landraces exceeded 1500 μg/g DW total isoflavones. The landraces possess rich phenotypic diversity and nutritional diversity. This germplasm represents a valuable resource for breeding programs to enhance crop quality and address global nutritional demands.