Background: In plants, GABA plays a critical role in regulating salinity stress tolerance. However, the response of soybean seedlings (Glycine max L.) to exogenous gamma-aminobutyric acid (GABA) under saline stress conditions has not been fully elucidated. Results: This study investigated the effects of exogenous GABA (2 mM) on plant biomass and the physiological mechanism through which soybean plants are affected by saline stress conditions (0, 40, and 80 mM of NaCl and Na₂SO₄ at a 1:1 molar ratio). We noticed that increased salinity stress negatively impacted the growth and metabolism of soybean seedlings, compared to control. The root-stem-leaf biomass (27- and 33%, 20- and 58%, and 25- and 59% under 40- and 80 mM stress, respectively]) and the concentration of chlorophyll a and chlorophyll b significantly decreased. Moreover, the carotenoid content increased significantly (by 35%) following treatment with 40 mM stress. The results exhibited significant increase in the concentration of hydrogen peroxide (H₂O₂), malondialdehyde (MDA), dehydroascorbic acid (DHA) oxidized glutathione (GSSG), Na⁺, and Cl⁻ under 40- and 80 mM stress levels, respectively. However, the concentration of mineral nutrients, soluble proteins, and soluble sugars reduced significantly under both salinity stress levels. In contrast, the proline and glycine betaine concentrations increased compared with those in the control group. Moreover, the enzymatic activities of ascorbate peroxidase, monodehydroascorbate reductase, glutathione reductase, and glutathione peroxidase decreased significantly, while those of superoxide dismutase, catalase, peroxidase, and dehydroascorbate reductase increased following saline stress, indicating the overall sensitivity of the ascorbate-glutathione cycle (AsA-GSH). However, exogenous GABA decreased Na⁺, Cl⁻, H₂O₂, and MDA concentration but enhanced photosynthetic pigments, mineral nutrients (K⁺, K⁺/Na⁺ ratio, Zn²⁺, Fe²⁺, Mg²⁺, and Ca²⁺); osmolytes (proline, glycine betaine, soluble sugar, and soluble protein); enzymatic antioxidant activities; and AsA-GSH pools, thus reducing salinity-associated stress damage and resulting in improved growth and biomass. The positive impact of exogenously applied GABA on soybean plants could be attributed to its ability to improve their physiological stress response mechanisms and reduce harmful substances. Conclusion: Applying GABA to soybean plants could be an effective strategy for mitigating salinity stress. In the future, molecular studies may contribute to a better understanding of the mechanisms by which GABA regulates salt tolerance in soybeans.

Plants have evolved a circadian clock to adapt to ever-changing diel and seasonal environmental conditions. The circadian clock is generally considered an internal system that has evolved to adapt to cyclic environmental cues, especially diel light and temperature changes, which is essential for higher plants as they are sessile organisms. This system receives environmental signals as input pathways which are integrated by circadian core oscillators to synchronize numerous output pathways, such as photosynthesis, the abiotic stress response, metabolism, and development. Extreme temperatures, salinity, and drought stresses cause huge crop losses worldwide, imposing severe pressure on areas of agricultural land. In crop production, the circadian system plays a significant role in determining flowering time and responding to external abiotic stresses. Extensive studies over the last two decades have revealed that the circadian clock can help balance the tradeoff between crop yield-related agronomic traits and adaptation to stress. Herein, we focus on summarizing how the circadian clock coordinates abiotic stress responses and crop yield. We also propose that there might be an urgent need to better utilize circadian biology in the future design of crop breeding to achieve high yields under stress conditions.

Salinized soil can significantly hinder soybean growth, leading to a reduction in overall yield. To address this issue, identifying key genes related to salt tolerance in soybeans is essential for improving their resistance to salinity and ensuring sustainable development of soybean production. While current research predominantly focuses on salt tolerance during the seedling stage, there is still a lack of comprehensive studies on the genes involved in salt tolerance during the germination stage. This study established the optimal screening criteria by phenotyping the salt-tolerant variety R063 and the salt-sensitive variety W82 during the germination stage under salt stress. RNA-seq analysis was performed on 24 samples from both varieties at 36 and 48 hours under two different salt concentrations (0 and 150 mM/L NaCl). Differential expression analysis revealed that the salt-tolerant variety R063 exhibited the fewest differentially expressed genes (DEGs) compared to its control after 48 hours of salt stress. A total of 305 DEGs were commonly identified between the salt-tolerant variety R063 and the salt-sensitive variety W82 under salt stress at both time points. Additionally, 187 DEGs were commonly identified between R063 under salt stress and its corresponding control group across the two time points. Gene ontology (GO) enrichment analysis revealed that the differentially expressed genes were significantly enriched in ADP binding, monooxygenase activity, oxidoreductase activity, defense response, and protein phosphorylation signaling pathways. The weighted gene co-expression network analysis (WGCNA) method was employed to identify modules strongly correlated with salt tolerance during soybean germination. Candidate genes associated with soybean sprouting salt tolerance were identified by evaluating the connectivity and expression profiles of genes within these modules. These findings provide a theoretical foundation for further elucidating the molecular mechanisms underlying salt tolerance during soybean germination and present new genetic resources for studying this trait.

Soil salinity threatens agriculture worldwide. Nano-fertilizers offer a promising strategy to enhance tolerance to salinity and other stresses in crops, but their field performance is sometimes unpredictable, potentially due to complex interactions within the plant–microbe holobiont. Here, we designed chitosan-stabilized selenium nanoparticles (SeNPs@CS) as a novel nano-fertilizer. SeNPs@CS exhibited a uniform size (∼109.8 nm) and a positively charged surface (+14.7 mV), which confers good adhesion to plant tissues. Due to their good biocompatibility and small size, SeNPs@CS can be readily absorbed and utilized by plant leaves. When SeNPs@CS were combined with glutathione (GSH) to form a nanocomposite (SeG), they significantly promoted plant growth and enhanced salt tolerance in soybean (Glycine max). Multi-omics analyses revealed that SeG activates jasmonic acid (JA) pathways in the plant and remodels the root metabolic profile, leading to the enrichment of arbutin, a key signaling molecule, in the rhizosphere. This metabolic shift recruits and enriches beneficial salt-tolerant microbes, including Bacillus and Streptomyces, thereby establishing a protective microbiome. Treatment of plants with a synthetic microbial community (SynCom) composed of these elite strains, in combination with arbutin, reproduced the salt tolerance phenotype conferred by SeG treatment. Therefore, SeG improves salt tolerance in soybean via activation of the JA defense pathway and arbutin-driven recruitment of salt-tolerant rhizosphere microorganisms. Together, these two mechanisms enhance plant resilience under salt stress. This multi-kingdom synergistic mechanism for alleviating stress provides a new paradigm for developing smart agricultural inputs that target the plant holobiont to improve crop resilience.

Soil salinity is rapidly spreading across agricultural regions and has become one of the most critical constraints on soybean growth, yield, and sustainable production. Despite the central role of transcription factors (TFs) in coordinating plant responses to abiotic stresses, the molecular mechanisms by which RWP-RK domain-containing TFs regulate salt-tolerant responses in soybean remain poorly understood. Our previous genome-wide characterization identified 28 RWP-RK TFs in soybean exhibiting abiotic stress-responsive expression, yet their biological functions under salt stress have not been experimentally validated. Here, we investigated a 981-bp GmRWP-RK1 encoding region and demonstrated its regulatory role in enhancing salt tolerance by activating antioxidant defence, Na⁺/K⁺ homeostasis, and transcriptional control of salt-responsive genes using a cross-species overexpression approach. The two Arabidopsis lines (OE1 & OE4) overexpressing GmRWP-RK1 demonstrated significantly improved salt tolerance, as evidenced by ~18% greater survival and enhanced germination compared to non-transgenic plants under salinity stress. This phenotype was supported by stronger antioxidant protection, as indicated by elevated proline levels, reduced MDA accumulation, and increased SOD and POD activities. At the molecular level, the transgenic lines also showed up-regulated expression of key stress-responsive genes (AtACS10, AtSUMO1, AtGBF1), confirming the regulatory influence of GmRWP-RK1 on salt-adaptation pathways. Consistent with the Arabidopsis results, GmRWP-RK1 overexpression in soybean hairy roots also led to improved salt-stress tolerance by accumulating significantly reduced ROS contents (27.38% lower H₂O₂ and 33.98% lower O₂⁻), and maintained a balanced Na⁺/K⁺ ratio compared to that of non-transgenic hairy roots under salinity. Furthermore, GmRWP-RK1-overexpressing transgenic soybean hairy roots showed increased expression of stress-responsive genes, especially GmATG-5, GmOLP-1, and GmOLP-2. Overall, our results support a possible role of GmRWP-RK1 in soybean salt tolerance and provide a foundation for future functional and breeding-oriented studies.

Cadmium (Cd) toxicity is an alarming issue for our agricultural soils and serious threat to crop productivity. The concentration of Cd in our soils is continuously increasing which is posing serious threat to plants, animals and humans. Mung bean is a conventional pulse crop cultivated all over...