Salinity stress is a barrier to crop production, quality yield, and sustainable agriculture. The current study investigated the plant growth promotion, biochemical and molecular characterization of bacterial strain Enterobacter cloacae PM23 under salinity stress (i.e., 0, 300, 600, and 900 mM). E. cloacae PM23 showed tolerance of up to 3 M NaCl when subjected to salinity stress. Antibiotic-resistant Iturin C (ItuC) and bio-surfactant-producing genes (sfp and srfAA) were amplified in E. cloacae PM23, indicating its multi-stress resistance potential under biotic and abiotic stresses. Moreover, the upregulation of stress-related genes (APX and SOD) helped to mitigate salinity stress and improved plant growth. Inoculation of E. cloacae PM23 enhanced plant growth, biomass, and photosynthetic pigments under salinity stress. Bacterial strain E. cloacae PM23 showed distinctive salinity tolerance and plant growth-promoting traits such as indole-3-acetic acid (IAA), siderophore, ACC deaminase, and exopolysaccharides production under salinity stress. To alleviate salinity stress, E. cloacae PM23 inoculation enhanced radical scavenging capacity, relative water content, soluble sugars, proteins, total phenolic, and flavonoid content in maize compared to uninoculated (control) plants. Moreover, elevated levels of antioxidant enzymes and osmoprotectants (Free amino acids, glycine betaine, and proline) were noticed in E. cloacae PM23 inoculated plants compared to control plants. The inoculation of E. cloacae PM23 significantly reduced oxidative stress markers under salinity stress. These findings suggest that multi-stress tolerant E. cloacae PM23 could enhance plant growth by mitigating salt stress and provide a baseline and ecofriendly approach to address salinity stress for sustainable agriculture.

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Soil salinity is one of the abiotic constraints that imbalance nutrient acquisition, hampers plant growth, and leads to potential loss in agricultural productivity. Salt-tolerant plant growth-promoting rhizobacteria (PGPR) can alleviate the adverse impacts of salt stress by mediating molecular, biochemical, and physiological status. In the present study, the bacterium Bacillus mycoides PM35 showed resistance up to 3 M NaCl stress and exhibited plant growth-promoting features. Under salinity stress, the halo-tolerant bacterium B. mycoides PM35 showed significant plant growth-promoting traits, such as the production of indole acetic acid, siderophore, ACC deaminase, and exopolysaccharides. Inoculation of B. mycoides PM35 alleviated salt stress in plants and enhanced shoot and root length under salinity stress (0, 300, 600, and 900 mM). The B. mycoides PM35 alleviated salinity stress by enhancing the photosynthetic pigments, carotenoids, radical scavenging capacity, soluble sugars, and protein content in inoculated maize plants compared to non-inoculated plants. In addition, B. mycoides PM35 significantly boosted antioxidant activities, relative water content, flavonoid, phenolic content, and osmolytes while reducing electrolyte leakage, H2O2, and MDA in maize compared to control plants. Genes conferring abiotic stress tolerance (CzcD, sfp, and srfAA genes) were amplified in B. mycoides PM35. Moreover, all reactions are accompanied by the upregulation of stress-related genes (APX and SOD). Our study reveals that B. mycoides PM35 is capable of promoting plant growth and increasing agricultural productivity.

Soil salinity is the major abiotic stress that disrupts nutrient uptake, hinders plant growth, and threatens agricultural production. Plant growth-promoting rhizobacteria (PGPR) are the most promising eco-friendly beneficial microorganisms that can be used to improve plant responses against biotic and abiotic stresses. In this study, a previously identified B. thuringiensis PM25 showed tolerance to salinity stress up to 3 M NaCl. The Halo-tolerant Bacillus thuringiensis PM25 demonstrated distinct salinity tolerance and enhance plant growth-promoting activities under salinity stress. Antibiotic-resistant Iturin C (ItuC) and bio-surfactant-producing (sfp and srfAA) genes that confer biotic and abiotic stresses were also amplified in B. thuringiensis PM25. Under salinity stress, the physiological and molecular processes were followed by the over-expression of stress-related genes (APX and SOD) in B. thuringiensis PM25. The results detected that B. thuringiensis PM25 inoculation substantially improved phenotypic traits, chlorophyll content, radical scavenging capability, and relative water content under salinity stress. Under salinity stress, the inoculation of B. thuringiensis PM25 significantly increased antioxidant enzyme levels in inoculated maize as compared to uninoculated plants. In addition, B. thuringiensis PM25-inoculation dramatically increased soluble sugars, proteins, total phenols, and flavonoids in maize as compared to uninoculated plants. The inoculation of B. thuringiensis PM25 significantly reduced oxidative burst in inoculated maize under salinity stress, compared to uninoculated plants. Furthermore, B. thuringiensis PM25-inoculated plants had higher levels of compatible solutes than uninoculated controls. The current results demonstrated that B. thuringiensis PM25 plays an important role in reducing salinity stress by influencing antioxidant defense systems and abiotic stress-related genes. These findings also suggest that multi-stress tolerant B. thuringiensis PM25 could enhance plant growth by mitigating salt stress, which might be used as an innovative tool for enhancing plant yield and productivity.

Adiantum capillus veneris is a medicinally essential plant used for the treatment of diverse infectious diseases. The study of phytochemical and antimicrobial activities of the plant extracts against multidrug-resistant (MDR) bacteria and medically important fungi is of immense significance. Extracts from the leaves, stems, and roots of Adiantum capillus veneris were extracted with water, methanol, ethanol, ethyl acetate, and hexane and screened for their antimicrobial activity against ten MDR bacterial strains and five fungal strains isolated from clinical and water samples. Ash, moisture, and extractive values were determined according to standard protocols. FTIR (Fourier transform infrared Spectroscopy) studies were performed on different phytochemicals isolated from the extracts of Adiantum capillus Veneris. Phytochemical analysis showed the presence of flavonoids, alkaloids, tannins, saponins, cardiac glycosides, terpenoids, steroids, and reducing sugars. Water, methanol, and ethanol extracts of leaves, stems, and roots showed significant antibacterial and antifungal activities against most of the MDR bacterial and fungal strains. This study concluded that extracts of Adiantum capillus veneris have valuable phytochemicals and significant activities against most of the MDR bacterial strains and medically important fungal strains.