Modern agriculture is primarily focused on the massive production of cereals and other food-based crops in a sustainable manner in order to fulfill the food demands of an ever-increasing global population. However, intensive agricultural practices, rampant use of agrochemicals, and other environmental factors result in soil fertility degradation, environmental pollution, disruption of soil biodiversity, pest resistance, and a decline in crop yields. Thus, experts are shifting their focus to other eco-friendly and safer methods of fertilization in order to ensure agricultural sustainability. Indeed, the importance of plant growth-promoting microorganisms, also determined as “plant probiotics (PPs),” has gained widespread recognition, and their usage as biofertilizers is being actively promoted as a means of mitigating the harmful effects of agrochemicals. As bio-elicitors, PPs promote plant growth and colonize soil or plant tissues when administered in soil, seeds, or plant surface and are used as an alternative means to avoid heavy use of agrochemicals. In the past few years, the use of nanotechnology has also brought a revolution in agriculture due to the application of various nanomaterials (NMs) or nano-based fertilizers to increase crop productivity. Given the beneficial properties of PPs and NMs, these two can be used in tandem to maximize benefits. However, the use of combinations of NMs and PPs, or their synergistic use, is in its infancy but has exhibited better crop-modulating effects in terms of improvement in crop productivity, mitigation of environmental stress (drought, salinity, etc.), restoration of soil fertility, and strengthening of the bioeconomy. In addition, a proper assessment of nanomaterials is necessary before their application, and a safer dose of NMs should be applicable without showing any toxic impact on the environment and soil microbial communities. The combo of NMs and PPs can also be encapsulated within a suitable carrier, and this method aids in the controlled and targeted delivery of entrapped components and also increases the shelf life of PPs. However, this review highlights the functional annotation of the combined impact of NMs and PPs on sustainable agricultural production in an eco-friendly manner.

Modern agriculture pays attention to improving agricultural production by producing zinc-enriched crops through zinc-solubilizing bacteria to strengthen the bioeconomy. Zinc deficiency in the soil reduces plant growth and also leads to less uptake of zinc in the edible portion of plants. Therefore, the zinc content in the edible parts of plants can be increased through the biofortification approach. However, most of the biofortification approaches are laborious and need expensive input in routine practices. Therefore, the microbiological biofortification approach may be beneficial in increasing the zinc concentration in plants and improving crop quality with the ultimate benefit of a greener path. The use of microbes may thus be favorable for elevating zinc content in plants and enhancing crop quality, ultimately providing a summation of the role of microorganisms for a greener strategy. In addition, the application of zinc-solubilizing bacteria as a potential biosource represents a cost-effective and alternate biofortification strategy. Zinc-solubilizing bacteria act as natural bio-fortifiers that can solubilize the unavailable form of zinc by secreting organic acids, siderophores, and other chelating compounds. This review thus focuses on zinc-solubilizing bacteria for plant biofortification and their contribution to enhance crop yield and the bioeconomy in a more sustainable manner.

The novel coronavirus severe acute respiratory syndrome-CoV-2 (SARS-CoV-2) is responsible for COVID-19 infection. The COVID-19 pandemic represents one of the worst global threats in the 21st century since World War II. This pandemic has led to a worldwide economic recession and crisis due to lockdown. Biomedical researchers, pharmaceutical companies, and premier institutes throughout the world are claiming that new clinical trials are in progress. During the severe phase of this disease, mechanical ventilators are used to assist in the management of outcomes; however, their use can lead to the development of pneumonia. In this context, mesenchymal stem cell (MSC)-derived exosomes can serve as an immunomodulation treatment for COVID-19 patients. Exosomes possess anti-inflammatory, pro-angiogenic, and immunomodulatory properties that can be explored in an effort to improve the outcomes of SARS-CoV-2-infected patients. Currently, only one ongoing clinical trial (NCT04276987) is specifically exploring the use of MSC-derived exosomes as a therapy to treat SARS-CoV-2-associated pneumonia. The purpose of this review is to provide insights of using exosomes derived from mesenchymal stem cells in management of the co-morbidities associated with SARS-CoV-2-infected persons in direction of improving their health outcome. There is limited knowledge of using exosomes in SARS-CoV-2; the clinicians and researchers should exploit exosomes as therapeutic regime.

The extreme conditions linked with abiotic stresses have greatly affected soil and plant health. The diverse biochemical activities occurring in the soil environment have been attributed to shaping the dynamics of plant–soil microbiomes by contributing to microbial lifestyles and enhancing microbial functional properties to boost plant tolerance to abiotic-induced stresses. Soil microbiomes play crucial roles in enhancing plant nutrition and abiotic stress management through diverse mechanisms. With the current insights into the use of engineered soil microbes as single or combined inoculants, their use has contributed to plant fitness and stability under different environmental stress conditions by activating plant defense mechanisms, enzyme production (lowering free radicals resulting in plant oxidative stress), protein regulation, and the production of growth factors. The detection of certain genes involved in the growth factors can underline microbial functions in mitigating plant stress. Hence, the projections for sustainable eco-friendly agriculture with the possible exploration of beneficial rhizosphere microbes to manage the effect of abiotic stress on plant nutrition remain critical points of discussion recently, with prospects for ensuring food security. Therefore, this review focuses on the impacts of soil microbiomes in abiotic stress mitigation for enhancing plant nutrition.

The term “zinc-solubilizing bacteria” (ZSB) refers to a specific group of soil bacteria that are associated with zinc-solubilizing activity in the soil through a variety of mechanisms. The functional use of ZSB has been proposed for the zinc (Zn) biofortification of crops to address Zn malnutrition. The application of zinc-solubilizing bacterial inoculants that harbor significant plant probiotic traits offers an eco-friendly approach to producing crops with improved Zn content in various edible parts of plants. In soil, ZSB solubilize complex forms of Zn compounds by producing organic acids and employing other mechanisms (such as the secretion of “siderophore,” extrusion of “proton,” expression of “oxidoreductive systems” on cell membranes, and secretion of “chelated ligands”), making the resulting soluble form of zinc readily accessible to plants. ZSB also act as plant growth stimulators, demonstrating both direct and indirect mechanisms that promote robust plant growth. In recent years, the application of two or more ZSB strains in a consortium has gained attention as a cost-effective alternative for Zn biofortification. This approach may serve as a promising strategy for promoting plant growth and optimizing yield performance. This review discusses various methods of Zn biofortification, highlighting ZSB and their consortia in increasing Zn content in grains and other edible crop parts, as well as the mechanisms involved in Zn solubilization by these bacteria. This insight paves the way for developing eco-friendly strategies that integrate microbial-based solutions to improve crop nutrient bioavailability.

The use of bacterial inoculants as biofertilisers has gained considerable attention in agriculture due to their ability to enhance crop productivity and improve soil fertility. However, the limited shelf life of liquid-based bacterial formulations remains a major constraint to their commercialisation and widespread adoption. To address this challenge, the present study evaluated the effect of different additives on the shelf life of newly developed liquid bacterial formulations and assessed their impact on lentil growth, microbial activity and soil health. In vitro experiments were conducted to determine the influence of various additives on the survival of two bacterial strains, Rhizobium leguminosarum bv. viciae DPR2 and Bacillus tequilensis DPB4. Among the tested combinations, the formulation containing 1.5–2 % polyvinyl pyrrolidone (PVP) supplemented with 1.5 % cassava starch proved to be optimal, significantly enhancing bacterial viability during storage. A field experiment was subsequently carried out to evaluate the agronomic performance of co-inoculation using both bacterial strains in the optimised liquid formulation and to assess its influence on soil microbial activity. The application of liquid biofertiliser treatment (T6), comprising both bacterial strains in the optimised formulation (1.5–2 % PVP + 1.5 % cassava starch), significantly improved plant height, nodule number and other growth attributes of lentil. Furthermore, key soil health parameters including available nitrogen (N), phosphorus (P) and potassium (K), soil microbial biomass carbon (SMBC), CO₂ evolution and dehydrogenase activity were significantly enhanced compared to charcoal-based inoculation and the uninoculated control, indicating increased soil microbial activity. Overall, the findings demonstrate that the optimised liquid formulation (1.5–2 % PVP + 1.5 % cassava starch) effectively extends shelf life and improves the performance of co-inoculated bacterial strains, leading to enhanced lentil growth, soil nutrient availability and microbial activity. These results highlight the potential of this formulation for sustainable agricultural applications.