Heavy metals (HMs) contamination is one of the main abiotic factors affecting crop productivity and also threatens human health via consuming metal-contaminated crops as a food source. Over the past few years, HMs have drawn a lot of attention due to their increased use for commercial purposes and their harmful effects on plants and other life forms, thus threatening human survival. However, several methods have been adopted in recent years to combat the harsh effects of HMs. After phytohormones, the use of mineral nutrients such as selenium (Se) in the prevention of HM stress has been explored by researchers more recently. Selenium is an important micronutrient widely known for its antioxidant properties in plants and animals. Exogenous Se inhibits metal uptake and translocation and improves the antioxidant system, thus imparting resistance to HM toxicity in plants. Moreover, Se also regulates the production of various osmolytes in cells, which helps develop cell osmolarity. Selenium also produces different secondary metabolites in plants’ defense mechanisms against different stresses. The uptake of mineral nutrients is a vital process for plant growth and development, which is also positively correlated with Se under metalloid toxicity. However, to understand the exact mechanism of Se in HM tolerance, different metabolic processes stimulated by Se and their pathways need to be explored. Hence, this review focuses on the role of Se on nutritional status, antioxidant metabolism, interaction with phytohormones and its role in the regulation of various genes involved in Se-induced HM tolerance. Thus, this study will help researchers in the future for the improvement of HM tolerance via Se application in plants.

Heavy metals (HMs) contamination is one of the main among abiotic factors affecting crop productivity and also threatens human health via consuming metal contaminated crops as a food source. Over the past few years, HMs have drawn a lot of attention due to their increased use for commercial purposes and their harmful effects on plants and other life forms, thus threatening human survival. However, in recent years, several methods have been adopted to combat the harsh effects of HMs. After phytohormones, use of mineral nutrients such as selenium (Se) in the prevention of HM stress has been explored by the researchers more recently. Selenium is an important micronutrient widely known for its antioxidant properties in both plants and animals. Exogenous Se inhibits metal uptake and its translocation and also improves the antioxidant system, thus imparts resistance to HM toxicity in plants. Moreover, Se also regulates the production of various osmolytes in cells that helps in developing cell osmolarity. Selenium also induces the production of different types of secondary metabolites (SMs) that are also involved in plant's secondary defense mechanisms to different stresses. Uptake of mineral nutrients is a vital process for plant growth and development, which is also positively correlated with Se under metalloid toxicity. However, in order to understand the exact mechanism of Se in HM tolerance, different metabolic processes stimulated by Se and their pathways need to be explored. Hence, this review focuses on the role of Se on nutritional status, antioxidants metabolism, interaction with phytohormones and its role in the regulation of various genes involved in Se induced HM tolerance. Thus, this study will help researchers in the future for the improvement of HM tolerance via Se application in plants.

The common bean (Phaseolus vulgaris L.cv. BR-104) is the most widely cultivated legume crop and serves as a major dietary protein source worldwide. However, climate change-induced drought poses a severe threat to its productivity by disrupting key physiological and biochemical processes. Therefore, identifying effective strategies to enhance drought resilience in the common bean is of considerable importance. The present study investigates the regulatory role of hydrogen sulfide (H₂S) in improving drought tolerance. Polyethylene glycol (15% PEG) induced drought stress markedly reduced phenotypic changes (leaf area (LA), plant dry weight (PDW), root length (RL), and shoot length (SL) by 18.6, 20.5, 30.3 and 17.5% respectively), photosynthetic efficiency (Fv/Fm by 28.4%), and photosynthetic pigment concentrations (chlorophyll and carotenoids by 25.6 and 36%, respectively), while significantly elevating oxidative stress markers (H₂O₂ and TBARS by 137.1% and 169.8%, respectively), leading to impaired stomatal movement and damaged chloroplast structure. Exogenous H₂S application as sodium hydrogen sulfide (200 µM NaHS; H₂S donor) effectively alleviated drought-induced oxidative damage by boosting endogenous H₂S and GSH levels, upregulating activity of antioxidative enzymes, SOD, APX, and GR, thereby promoting reactive oxygen species (ROS) scavenging, and minimizing lipid peroxidation. Moreover, H₂S maintained photosynthetic efficiency via improved stomatal openings and chloroplast structure, thus sustaining chlorophyll levels and stabilizing photosystem-II functionality. Enhanced proline accumulation following NaHS application led to improved osmotic adjustment, thereby contributing to overall stress tolerance. The use of a H₂S scavenger at 100 µM HT (Hypotaurine) suppressed the mitigating effects of H₂S, confirming the role of H₂S in enhancing drought tolerance in the common bean. Collectively, these findings highlight the potential effect of H₂S as a regulatory signaling molecule to enhance drought resilience in the common bean under drought stress conditions. Further research should explore integrating H₂S-based treatments with breeding programs and agronomic practices to develop sustainable strategies to improve drought resilience in legumes and other staple crops under changing climatic conditions.