In the context of climate change, abiotic stresses are recognized as significant environmental challenges that limit agricultural productivity globally. These conditions disrupt normal plant growth and development processes. The ability of plants to tolerate these stressors is linked to their resilience mechanisms. Glycine betaine (GB), also known as betaine, is a derivative of methylated glycine identified in numerous plant species as a substance that mitigates the detrimental effects of stressful environments. GB is synthesized in the cytosol as an initial response to abiotic stress, and signaling molecules, such as jasmonic acid and methyl jasmonate, primarily initiate its production. Recent studies have highlighted their role in stimulating GB synthesis and its subsequent accumulation. The concentration of GB within a plant system can effectively indicate tolerance levels, ultimately contributing to the understanding of resilience mechanisms. GB plays a crucial role in reducing the accumulation and detoxification of reactive oxygen species (ROS), which aids in restoring photosynthesis and alleviating oxidative stress. It contributes to the stabilization of membranes and macromolecules and is essential for the protection and stabilization of photosynthetic components, such as ribulose-1,5-bisphosphate carboxylase/oxygenase, photosystem II, and quaternary enzyme and protein complex structures, under environmental stress conditions. Furthermore, GB can enhance stress tolerance even at minimal concentrations by activating the genes associated with stress defense mechanisms. Recent studies have demonstrated that the application of GB can protect against environmental challenges, thereby improving both crop yield and quality. This review concentrates on the role of GB in promoting abiotic stress tolerance and explores potential strategies for engineering GB biosynthesis in plants.

The Na+/H+ antiporter (NHX) gene subfamily is essential for plant adaptation to salt stress, contributing significantly to ion homeostasis. These antiporters play crucial function in various biological processes by regulating Na+ and H+ balance within plant cells. Yet their genomic features and roles of salicylic acid (SA) in regulating them, activating antioxidant defense mechanisms as well as nutrients acquisition under salt stress conditions remain largely unknown in many crop species. In this study, we identified the NHX gene family members of three Brassicaceae species including Brassica napus, Brassica rapa and Brassica oleracea and analyzed the expression patterns of NHX genes in response to salt stress and phytohormonal application (SA). Comprehensive computational analyses, encompassing domain and motif prediction, cellular localization, cis-regulatory elements (CREs), and post-translational modification (PTM) sites revealed distinct group-specific characteristics within the NHX gene family. These characteristics included chromosomal distribution, motif composition, exon count and protein length (amino acids). qRT-PCR analysis depicted significantly induced expression of NHXs, specifically, BnNHX7, BraNHX6 and BoNHX6 (4 ~ 6 folds) using different concentrations of NaCl (100 mM and 200 mM) and SA (10 mg/L and 20 mg/L) at different periods of time. SA induced antioxidant enzymatic activity (SOD 3 ~ 4 folds, POD 2 ~ 3 folds, CAT 1 ~ 2 folds and APX 11 ~ 12 folds), upregulated antioxidant genes (SOD, POD, APX, CAT) by 3 ~ 5 folds under salt stress, and improved nutrient acquisition in all respective Brassicaceae species. We have conducted the first molecular characterization of NHX genes in three Brassica species, revealing their dual role in salt stress adaptation through ion homeostasis and salicylic acid induced antioxidant regulation, thus identifying promising targets for crop improvement. Not applicable.

Utilizing phytohormones—brassinosteroids (BRs), jasmonic acid (JA), and strigolactones (SLs) presents a novel approach to overcome toxicity of arsenic (As) in agricultural settings. The present study investigates the role of three phytohormones BRs, JA, and SLs in ameliorating As-induced stressed in Oryza sativa L. (rice) seedlings. s In the present study, we have used different levels of BRs (0.1 µM), JA (1 µM), and SLs (0.05 µM) every 7 days to O. sativa seedlings when exposed to different levels of As levels of 100 mg⁻¹ kg and 200 mg kg⁻¹ (as sodium arsenate) to examine various growth and biochemical parameters in O. sativa. The results showed that the As toxicity in the soil showed a significantly (P < 0.05) declined in the growth, gas exchange attributes, sugars, AsA-GSH cycle, cellular fractionation, proline metabolism in O. sativa. However, As toxicity significantly (P < 0.05) increased oxidative stress biomarkers, enzymatic and nonenzymatic antioxidants including their gene expression in O. sativa. Although, the application of phytohormones including BRs, JA, and SLs showed a significant (P < 0.05) increase in the plant growth and biomass, gas exchange characteristics, enzymatic and non-enzymatic compounds and their gene expression and also decreased the oxidative stress, and As uptake. In addition, individual or combined application of phytohormones including BRs, JA, and SLs enhanced the cellular fractionation and decreases the proline metabolism and AsA − GSH cycle in O. sativa. These results open new insights for sustainable agriculture practices and hold immense promise in addressing the pressing challenges of heavy metal contamination in agricultural soils.

Gadolinium (Gd) is an increasingly found lanthanide element in soil; thus, understanding its impact on plant physiology, biochemistry, and molecular responses is crucial. Here, we aimed to provide a comprehensive understanding of Gd (150 mg kg− 1) impacts on guar (Cyamopsis tetragonoloba L.) plant yield and metabolism and whether the symbiotic relationship with arbuscular mycorrhizal fungi (AMF) can mitigate Gd toxicity of soil contamination. AMF treatment improved mineral nutrient uptake and seed yield by 38–41% under Gd stress compared to non-inoculated stressed plants. Metabolic analysis unveiled the defense mechanisms adopted by AMF-treated plants, revealing carbon and nitrogen metabolism adaptations to withstand Gd contamination. This included an increase in the synthesis of primary metabolites, such as total sugar (+ 39% compared to control), soluble sugars (+ 29%), starch (+ 30%), and some main amino acids like proline (+ 57%) and phenylalanine (+ 87%) in the seeds of AMF-treated plants grown under Gd contamination. Furthermore, fatty acid and organic acid profile changes were accompanied by the production of secondary metabolites, including tocopherols, polyamines, phenolic acids, flavones, and anthocyanins. Overall, the coordinated synthesis of these compounds underscores the intricate regulatory mechanisms underlying plant-AMF interactions and highlights the potential of AMF to modulate plant secondary metabolism for enhanced Gd stress tolerance.

The need for improving plant production, nutritional value, and medicinal applications has become increasingly important due to the growing global population. The caraway (Carum carvi L) plant has been recognized for its broad range of nutritional and therapeutic uses. Consequently, this study aimed to increase caraway seeds’ nutritional and biological value. To achieve this, the Actinopolyspora sp. JTT-0 strain, isolated from the medicinal plant Tephrosia purpurea, was investigated for its potential biofortification role to enhance caraway yield and quality. Our results revealed significant improvements (p < 0.05) in various physical parameters, such as seed yield, pod length, and bulk density, in the treated seeds compared to the controls. Along with the yield increase, there were notable elevations in primary metabolites such as total sugars, proteins, and amino acids. Furthermore, secondary metabolites, including essential oils (EOs), alkaloids, steroids, phenols, and vitamins (e.g., tocopherol and ascorbic acid), also showed significant increases. Notably, the EO constituents showed varying levels of enhancements, with the highest increases in β-pinene (186.2%) and carvacrol (49.2%). Moreover, the treated seeds exhibited improved biological activity, as evidenced by their anti-oxidant (anti-lipid peroxidation and DPPH assays) and anti-microbial properties compared to the controls. The study reported a positive biofortification effect of the Actinopolyspora sp. JTT-01 strain on enhancing caraway seed’s quality and yield. However, additional field trials are needed to evaluate the commercial biofertilization capacity of this strain for caraway and other plants.