The application of liquid bacterial consortia to soil under natural conditions may fail due to various environmental constraints. In this study, the suitability and efficiency of compost, biogas slurry, crushed corn cob, and zeolite as carriers to support the survival of plant growth-promoting rhizobacteria (PGPR) and improve the performance of multi-strain bacterial consortia to mitigate the effects of salinity stress on wheat under pot conditions were evaluated. The survival of strains of Pseudomonas putida, Serratia ficaria, and Pseudomonas fluorescens labelled with gusA was evaluated for up to 90 days. Seeds coated with different carrier-based formulations of multi-strain consortia were sown in pots at three different salinity levels (1.53, 10, and 15 dS m-1). Results showed that salinity stress significantly reduced wheat growth, yield, gas exchange, and ionic and biochemical parameter values, but the 1-aminocyclopropane-1-carboxylate (ACC) deaminase-containing multi-strain consortium used mitigated the inhibitory effects of salinity on plant growth and yield parameters. However, carrier-based inoculation further improved the efficacy of multi-strain consortium inoculation and significantly (P < 0.05) increased the growth, yield, and physiological parameters value of wheat at all salinity levels. On the basis of the observed trends in survival and the outcomes of the pot trials, the inoculation of multi-strain consortia in compost and biogas slurry carriers resulted in more successful wheat growth under salinity stress compared to that in the rest of the treatments tested.

Owing to inconsistent results of a single bacterial strain, co-inoculation of more than one strain under salinity stress could be a more effective strategy to induce salt tolerance. Co-inoculation of more than one bacterial strain could be more effective due to the presence of several growths promoting traits. This study was conducted to evaluate the effectiveness of multi-strains bacterial consortium to promote wheat growth under salinity stress. Several plant growth promoting rhizobacteria (PGPR) had been isolated and tested for their ability to grow in increasing concentrations of sodium chloride (NaCl). Those rhizobacterial strains having tolerance against salinity were screened to evaluate their ability to promote wheat growth in the presence of salinity by conducting jar trials under axenic conditions. The rhizobacteria with promising results were tested for their compatibility with each other before developing multi-strain inoculum of PGPR. The compatible PGPR strains were characterized, and multi-strain inoculum was then evaluated for promoting wheat growth under axenic conditions at different salinity levels, i.e., 2.1 (normal soil), 6, 12, and 18 dS m^–1. The most promising combination was further evaluated by conducting a pot trial in the greenhouse. The results showed that compared to a single rhizobacterial strain, better growth-promoting effect was observed when rhizobacterial strains were co-inoculated. The multi-strain consortium of PGPR caused a significant positive impact on shoot length, root length, shoot fresh weight, and root fresh weight of wheat at the highest salinity level in the jar as well as in the pot trial. Results showed that the multi-strain consortium of PGPR caused significant positive effects on the biochemical traits of wheat by decreasing electrolyte leakage and increasing chlorophyll contents, relative water contents (RWC), and K/Na ratio. It can be concluded that a multi-strain consortium of PGPR (Ensifer adhaerens strain BK-30, Pseudomonas fluorescens strain SN5, and Bacillus megaterium strain SN15) could be more effective to combat the salinity stress owing to the presence of a variety of growth-promoting traits. However, further work is going on to evaluate the efficacy of multi-strain inoculum of PGPR under salt-affected field conditions.

This work was conducted to study the chemical composition, antioxidant, antibacterial, and antifungal activities of essential oil and hydrolat from Withania frutescens. The essential oil was extracted by hydrodistillation. The chemical characterization was performed using gas chromatography-mass spectrometry (GC/MS). The antioxidant activity was studied using four different assays (DPPH, TAC, FRAP, and β-carotene bleaching). The antibacterial activity test was carried out on multidrug-resistant bacteria including Gram-negative and Gram-positive strains. Antifungal activity was tested on Candida albicans and Saccharomyces cerevisiae. The yield of essential oil (EO) obtained by hydrodistillation of W. frutescens was 0.31% majorly composed of camphor, α-thujone, carvacrol, and thymol. Regarding the antioxidant activities, the concentration of the sample required to inhibit 50% of radicals (IC₅₀) of EO and hydrolat were 14.031 ± 0.012 and 232.081 ± 3.047 µg/mL (DPPH), 4.618 ± 0.045 and 8.997 ± 0.147 µg/mL (FRAP), 0.091 ± 0.007 and 0.131 ± 0.004 mg AAE/mg (TAC), 74.141 ± 1.040% and 40.850 ± 0.083% (β-carotene), respectively. Concerning the antibacterial activity of essential oil and hydrolat, the minimum inhibitory concentration (MIC) values found were 0.006 ± 0.001 and 6.125 ± 0.541 µg/mL (Escherichia coli 57), 0.003 ± 0.001 and 6.125 ± 0.068 µg/mL (Klebsiella pneumoniae), 0.001 ± 0.0 and 6.125 ± 0.046 µg/mL (Pseudomonas aeruginosa) and 0.012 ± 0.003 and 6.125 ± 0.571 µg/mL (Staphylococcus aureus), respectively. MIC values of essential oil and hydrolat vs. both C. albicans and S. cerevisiae were lower than 1/20,480 µg/mL. Based on the findings obtained, essential oils of Withania frutescens can be used as promising natural agents to fight free radical damage and nosocomial antibiotic-resistant microbes.

Microbial resistance and other emerging health risk problems related to the side effects of synthetic drugs are the major factors that result in the research regarding natural products. Fruits, leaves, seeds, and oils-based phyto-constituents are the most important source of pharmaceutical products. Plant extract chemistry depends largely on species, plant components, solvent utilized, and extraction technique. This study was aimed to compare the ethanolic extracts of a mangrove plant, i.e., Avicennia marina (1E: Lower half of A. marina‘s pneumatophores, 2E: A. marina‘s leaves, 3E: Upper half of A. marina‘s pneumatophores, and 4E: A. marina‘s shoots), with non-mangrove plants, i.e., Phragmites australis (5E: P. australis‘s shoot), and Moringa oleifera (6E: M. oleifera‘s leaves) for their antimicrobial activities, total phenolic contents, antioxidant activity, and cytotoxicity potential. The antimicrobial activity assays were performed on gram-positive bacteria (i.e., Bacillus subtilis and Staphylococcus aureus), gram-negative bacteria (i.e., Escherichia coli, and Pseudomonas aeruginosa), and fungi (i.e., Aspergillus niger, Candida albicans, and Rhizopus spp.). We estimated antioxidant activity by TAC, DPPH, and FRAP assays, and the cytotoxicity was evaluated by MTT assay. The results of antimicrobial activities revealed that B. subtilis was the most sensitive to the tested plant extracts compared to S. aureus, while it only showed sensitivity to 6E and Imipenem. 5E and 6E showed statistically similar results against P. aeruginosa as compared to Ceftazidime. E. coli was the most resistant bacteria against tested plant extracts. Among the tested plant extracts, maximum inhibition activity was observed by 6E against A. niger (22 ± 0.57 mm), which was statistically similar to the response of 6E against C. albicans and 3E against Rhizopus spp. 2E did not show any activity against tested fungi. We found that 6E (208.54 ± 1.92 mg g⁻¹) contains maximum phenolic contents followed by 1E (159.42 ± 3.22 mg g⁻¹), 5E (131.08 ± 3.10 mg g⁻¹), 4E (i.e., 72.41 ± 2.96 mg g⁻¹), 3E (67.41 ± 1.68 mg g⁻¹), and 2E (48.72 ± 1.71 mg g⁻¹). The results depict a significant positive correlation between the phenolic contents and the antioxidant activities. As a result, phenolic content may be a natural antioxidant source.

Streptococcus gallolysticus (Sg) is an opportunistic Gram-positive, non-motile bacterium, which causes infective endocarditis, an inflammation of the inner lining of the heart. As Sg has acquired resistance with the available antibiotics, therefore, there is a dire need to find new therapeutic targets and potent drugs to prevent and treat this disease. In the current study, an in silico approach is utilized to link genomic data of Sg species with its proteome to identify putative therapeutic targets. A total of 1,138 core proteins have been identified using pan genomic approach. Further, using subtractive proteomic analysis, a set of 18 proteins, essential for bacteria and non-homologous to host (human), is identified. Out of these 18 proteins, 12 cytoplasmic proteins were selected as potential drug targets. These selected proteins were subjected to molecular docking against drug-like compounds retrieved from ZINC database. Furthermore, the top docked compounds with lower binding energy were identified. In this work, we have identified novel drug and vaccine targets against Sg, of which some have already been reported and validated in other species. Owing to the experimental validation, we believe our methodology and result are significant contribution for drug/vaccine target identification against Sg-caused infective endocarditis.