Soil salinity is a major threat to modern agriculture, as it affects crop growth and development. The present study focuses on the integration of eco-friendly biostimulants in salinity stress as a strategy to achieve the alleviation of abiotic stress. Field experiments were conducted at two locations, consisting of saline and non-saline soil, to investigate the utilization of exopolysaccharide (EPS)-producing bacteria (Azotobacter chroococcum) and melatonin at different concentrations (0, 25, 50, and 100 µM) for alleviating the adverse effects of salinity on the growth and production of faba bean plants. Salinity stress caused a reduction in all measured parameters of the faba bean plants grown in the saline soil relative to the plants grown in the non-saline soil. The addition of bacteria and/or melatonin significantly increased the growth parameters and yield components under both soils compared to the respective control plants. Both bacteria inoculation and melatonin application enhanced N, P, and K concentrations; the proline content; RWC%; and the K⁺/Na⁺ ratio; however, Na⁺ and Cl⁻ concentrations were decreased significantly in salt-stressed faba beans. The combined use of bacteria and melatonin exhibited the highest stimulating effects. The present study recommends the combined use of EPS-producing bacteria and melatonin for the salinity stress management strategy of faba bean.

The biological activities of two species of bacteria isolated from soil of cotton fields identified as Bacillus subtilis strain NRC313 (BS NRC313) and Bacillus thuringiensis strain NRC335 (BT NRC335) were evaluated against the third larval instar of the cotton leafworm, Spodoptera littoralis (Boisd.). The different entomopathogenic bacteria of BS NRC313and BT NRC335 contained 10 × 10⁸ cell/ml, and caused mortality of 100 and 97.3% for the above mentioned strains, respectively. Concentrations of 2.5 × 10⁸ to 10 × 10⁸ cell/ml of strains BS NRC313 and BT NRC335 were applied to the larvae: LC₅₀ were 3.3 × 10⁸ and 3.9 × 10⁸ cell/ml respectively. The influence of exposure to toxin concentrations manifested in terms of decreasing the adult emergence and prolongation of the generation period. The percentage of larvae that survived and succeeded to pupate increased by decreasing the concentration. The longevity of adult emergence that resulted from larvae treated with Bacillus subtilis were 6.0 ± 0.51 and 9.0 ± 0.63 days at 5 × 10⁸ and 2.5 × 10⁸ cell/ml, respectively compared with 9.8 ± 0.47 in control. The results indicated that Bacillus subtilis was more potent than Bacillus thuringiensis. Field applications of B. thuringiensis, B. subtilis and Reldan achieved 55.6, 67.4 and 89.4% reduction of the cotton leafworm larvae Spodoptera littoralis in clover plants under field conditions.

The present study investigated the biosynthesis of silver (AgNPs), zinc oxide (ZnONPs) and titanium dioxide (TiO₂NPs) nanoparticles using Aspergillusoryzae, Aspergillusterreus and Fusariumoxysporum. Nanocomposites (NCs) were successfully synthesized by mixing nanoparticles using a Sonic Vibra-Cell VC/VCX processor. A number of analytical techniques were used to characterize the synthesized biological metal nanoparticles. Several experiments tested biologically synthesized metal nanoparticles and nanocomposites against two types of human pathogenic bacteria, including Gram-positive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA), and Gram-negative Escherichia coli and Pseudomonasaeruginosa. Additionally, the antitumor activity in HCT-116 cells (colonic carcinoma) was also evaluated. Significant antimicrobial effects of various synthesized forms of nanoparticles and nanocomposites against E. coli and P. aeruginosa bacteria were detected. Various synthesized biogenic forms of nanoparticles and nanocomposite (9.0 to 29 mm in diameter) had high antibacterial activity and high antitumor activity against HCT-116 cells (colonic carcinoma) with IC₅₀ values of 0.7–100 µg/mL. Biosynthesized NPs are considered an alternative to large-scale biosynthesized metallic nanoparticles and nanocomposites, are simple and cost effective, and provide stable nanomaterials.

Foliar diseases, like powdery mildew, septoria leaf blotch (SLB) and stem rust, affect wheat plants causing severe yield losses. Biofertilizers Pseudomonas fluorescens Migula (NRC2041) and Bacillus subtilis Ehrenberg (NRC313) or the arbuscular mycorrhizal fungi Glomus mosseae Tul. & C. Tul. (NRC212A) and G. fasciculatum Tul. & C. Tul. (NRC212B) were used for soil treatment followed by foliar spray with Trichoderma harzianum or P. fluorescens to manage severity of wheat foliar diseases under field conditions for two successive growing seasons. Under field conditions, at all soil drench and foliar application treatments, Sids 14 was the most sensitive cultivar for high disease severity followed by Misr 2 and Giza 168. Also, the obtained results showed that the most effective treatments were soil drench with mycorrhizae followed by foliar spray with either T. harzianum or P. fluorescens. Meanwhile, the fungicide Amistar showed a superior reduction in disease severity compared to other applied treatments. In addition, the increased yield was correlated to the decreased severity of the recorded diseases. The present study suggests using bioagents for reducing the severity of wheat leaf diseases and increasing the grain yield under field conditions.

Aims: The interest in magnetic nanoparticles (MNP) is rising in the recent years. Pseudomonas aeruginosa Kb1 isolated from Egyptian habitat found to synthesis intracellular magnetosomes. This work aimed at characterization of produces magnetosomes and prospective application of the magnetotactic P. aeruginosa. Methodology: The Kb1 isolate was grow in a batch experiment for three days. The synthesis of magnetosomes was confirmed by TEM microscope. The produced MNP were extracted, purified and characterized. The ability of P. aeruginosa Kb1 to remove heavy metals from its solutions was examined as well. Results: The biosynthesis of mature magnetosomes, quasi-spherical or cubical in shape and 30- 70 nm in size, was affirmed after 72 h. The produced particles were crystals and displayed a super paramagnetic behaviour. Elemental analysis of the extracted MNP produced by P. aeruginosa revealed the presence of carbon, oxygen, iron and chloride. This result indicates that the composition of the produced magnetosomes is Fe₃O₄ mainly while the finding of high carbon level could be refer the protein coat surrounding the magnetosomes. The FTIR spectrum analysis reveled the detection of Fe-O group which point to magnetite as the main MNP. The existence of H-O group, N-H group, C-H, C=C and C-C groups prove presence of the protein coat. Furthermore, magnetotactic P. aeruginosa was able to remove 99.4% and 70% of Cd² and Pb² at initial concentration of 4 ppm although it survived at high concentrations (up to 8 ppm) of each. Conclusion: Pseudomonas aeruginosa Kb1 is a promising candidate for magnetic nanoparticles production and heavy metal removal.