With the growing emphasis on sustainable agriculture, food security, and environmental protection, the use of beneficial soil microbes is imperative, as the use of chemicals such as fertilizers, pesticides, and herbicides has resulted in food contamination, disease, weed resistance, and negative environmental consequences, which ultimately impacted human health. Climate change is a major factor and is of great concern for crop production. Abiotic stresses, including salt and drought stress, restrain the crop yield. The aim of this particular study is to understand what role do plant growth-promoting rhizobacteria (PGPR) play in combating the salinity and drought stresses through modification of nutritional profile. In the current study, inoculated barley (Hordeum vulgare L.) plants were subjected to various stresses such as 200mM and 1000mM salinity stress as well as drought stress, and then their various parameters such as seed germination as well as shoot and root biomasses and photosynthetic activity were compared with non-treated stressed barley plants. Our data depicted an improvement or significant enhancement of these parameters in PGPR (Pseudomonas fluorescens SBW25 and Pseudomonas putida KT2440) applied barley plants. Furthermore, the particle-induced X-ray emission (PIXE) technique was used for the elemental analysis of PGPR-inoculated and non-inoculated plants under stress vs. no stress conditions. Our PIXE analysis of various macro- and micronutrients revealed an enhancement of Ca, Mg, K, P, S, Al, and Si uptake in PGPR-treated plants. PGPR applications depicted reduced Cl⁻ contents in 200mM salt-stressed barley roots (KT2440=7.7mg/kg and SBW25=6.3mg/kg) and stems (KT2440=406.4mg/kg and SBW25=365.5mg/kg) as compared to controls (roots=8.9 and stems=469.5), while they displayed a significant increase in the barley leaves (KT2440=405mg/kg and SBW25=416.4mg/kg) when compared to control (110.6mg/kg) under the same stress condition. In 1000mM salt stress, a significant reduction in the Cl⁻ content was observed in PGPR-applied barley roots (KT2440=7.6mg/kg), stems (KT2440=1205.8mg/kg and SBW25=1008.3mg/kg), and leaves (KT2440=967.8mg/kg and SBW25=530.8mg/kg) when compared to controls (roots=15.2mg/kg, stems=1605.2mg/kg, and leaves=1165.2mg/kg). On the other hand, a significant increase in the Cl⁻ content was noticed in PGPR-applied barley roots (KT2440=29.5mg/kg and SBW25=25.8mg/kg), stems (KT2440=1023.8mg/kg and SBW25=894.9mg/kg), and leaves (KT2440=369.2mg/kg and SBW25=409.8mg/kg) when compared to controls (roots=13.5mg/kg, stems=505.3mg/kg, and leaves=219.9mg/kg) under drought stress condition. PGPR application was also found to be effective for enhancing the uptake of micronutrients (Mn, Fe, Co, Ni, Cu, and Zn) in barley plant parts under control and also under stressed conditions. Overall, our findings revealed an improvement in the uptake of macro- and micronutrients for the enhancement of salinity and drought stress tolerance. Conclusively, these PGPR species are an effective source of plant stress tolerance and elevated growth of barley and related plants under stress conditions.

A combination of humoral and cell-mediated immune system stimulation is essential for developing an effective HIV vaccine. Traditional treatment options and the challenges posed by drug resistance necessitate the discovery of a viable vaccine candidate capable of eliciting a robust immunological response. This research aims to develop an HIV vaccine with a multi-epitope component using a unique immunoinformatics approach. A subunit vaccine comprising B-cell, helper T-cell, and cytotoxic T-cell epitopes, along with appropriate adjuvants and linkers, was employed to identify conserved regions in the Pol, Vpr, Gag, Tat, Env, Nef, and Vif proteins. The HIV subunit vaccine demonstrated the potential to activate both cell-mediated and humoral immune responses, indicating its immunogenicity. The application of homology modeling and refinement further enhanced the model’s accuracy. Subsequently, the molecular docking procedure utilized the refined model structure to bind to the immunological receptor TLR-3 in lymphocyte cells. Following this, the potential interactions of the subunit vaccine with TLR-3 were investigated using molecular dynamics modeling. The vaccine’s stability was improved through a meticulous disulfide engineering technique that involved inserting cysteine residues into highly flexible regions. Finally, in silico cloning was employed to validate the efficacy of translating and producing the vaccine in a microbiological setting. The vaccine shows promising results in terms of population coverage, reaching 82% of the global population, with extraordinary efficacy in Asia, covering up to 95% of the population. Our HIV vaccine candidate is highly stable and elicits a robust immune response against HIV-1.