Cadmium is a widespread toxic pollutant of occupational and environmental concern because of its diverse toxic effects: extremely protracted biological half-life (approximately 20–30 years in humans), low rate of excretion from the body and storage predominantly in soft tissues (primarily, liver and kidneys). It is an extremely toxic element of continuing concern because environmental levels have risen steadily due to continued worldwide anthropogenic mobilization. Cadmium is absorbed in significant quantities from cigarette smoke, food, water and air contamination and is known to have numerous undesirable effects in both humans and animals. Cadmium has a diversity of toxic effects including nephrotoxicity, carcinogenicity, teratogenicity and endocrine and reproductive toxicities. At the cellular level, cadmium affects cell proliferation, differentiation, apoptosis and other cellular activities. Current evidence suggests that exposure to cadmium induces genomic instability through complex and multifactorial mechanisms. Most important seems to be cadmium interaction with DNA repair mechanism, generation of reactive oxygen species and induction of apoptosis. In this article, we have reviewed recent developments and findings on cadmium toxicology.

The biotic and abiotic stresses are key constraints for food quality, crop yield and global food security. It is necessary to take action to cope with global threats caused by abiotic and biotic stresses such as a reduction in precipitation, increasing drought, salinity, improper temperature, heavy metals, nutrient deficiency and invasion of plants pathogenic microbes, which lead to the reduction of agricultural crops productivity. Plants are severely affected by these stresses and have impaired functioning. One of the strategies to cope with abiotic and biotic stresses is taking advantage of the potential of soil microbes, including plant growth-promoting rhizobacteria (PGPR). The solution is completely environmentally compatible and has no negative effects on the environment. Effective PGPR have a substantial role in biotic and abiotic stresses management, reduce chemical fertilizers and increase the yield of plant cultivars by affecting elemental cycling and nutrient management. These beneficial bacteria can stimulate plant growth under abiotic and biotic stress conditions via mechanisms such as the production of phytohormones, ACC (1-aminocyclopropane-1-carboxylate) deaminase, exopolysaccharides, siderophore, organic acids, nitrogen fixation, phosphate solubilization, various osmolytes, systemic resistance induction, etc. In this review, the role of the PGPR as a new strategy was investigated that may be responsible for the increase in crop productivity and eventually by effectively answering biotic and abiotic stresses leads to food security.

• Constructed wetlands (CWs) emulate natural wetland processes for wastewater treatment. • Efficiency of CW relies on the synergy of plant species, substrate characteristics, microbial consortia, wastewater dosing strategies, and operational parameters. • Microbial degradation is a pivotal force in pollutant removal within constructed wetlands. • Suggests that insights from further research can contribute to optimizing the functional attributes of microbial communities.

Methanotrophy is a biological process that effectively reduces global methane emissions by utilizing microorganisms that can utilize methane as a source of energy under both oxic and anoxic conditions, using a variety of different electron acceptors. Methanotrophic microbes, which utilize methane as their primary source of carbon and energy, are microorganisms found in various environments, such as soil, sediments, freshwater, and marine ecosystems. These microbes play a significant role in the global carbon cycle by consuming methane, a potent greenhouse gas, and converting it into carbon dioxide, which is less harmful. However, methane is known to be the primary contributor to ozone formation and is considered a major greenhouse gas. Methane alone contributes to 30% of global warming; its emissions increased by over 32% over the last three decades and thus affect humans, animals, and vegetation adversely. There are different sources of methane emissions, like agricultural activities, wastewater management, landfills, coal mining, wetlands, and certain industrial processes. In view of the adverse effects of methane, urgent measures are required to reduce emissions. Methanotrophs have attracted attention as multifunctional bacteria with potential applications in biological methane mitigation and environmental bioremediation. Methanotrophs utilize methane as a carbon and energy source and play significant roles in biogeochemical cycles by oxidizing methane, which is coupled to the reduction of various electron acceptors. Methanotrophy, a natural process that converts methane into carbon dioxide, presents a promising solution to mitigate global methane emissions and reduce their impact on climate change. Nonetheless, additional research is necessary to enhance and expand these approaches for extensive use. In this review, we summarize the key sources of methane, mitigation strategies, microbial aspects, and the application of methanotrophs in global methane sinks with increasing anthropogenic methane emissions.