Microbial endophytes organize symbiotic relationships with the host plant, and their excretions contain diverse plant beneficial matter such as phytohormones and bioactive compounds. In the present investigation, six bacterial and four fungal strains were isolated from the common bean (Phaseolus vulgaris L.) root plant, identified using molecular techniques, and their growth-promoting properties were reviewed. All microbial isolates showed varying activities to produce indole-3-acetic acid (IAA) and different hydrolytic enzymes such as amylase, cellulase, protease, pectinase, and xylanase. Six bacterial endophytic isolates displayed phosphate-solubilizing capacity and ammonia production. We conducted a field experiment to evaluate the promotion activity of the metabolites of the most potent endophytic bacterial (Bacillus thuringiensis PB2 and Brevibacillus agri PB5) and fungal (Alternaria sorghi PF2 and, Penicillium commune PF3) strains in comparison to two exogenously applied hormone, IAA, and benzyl adenine (BA), on the growth and biochemical characteristics of the P. vulgaris L. Interestingly, our investigations showed that bacterial and fungal endophytic metabolites surpassed the exogenously applied hormones in increasing the plant biomass, photosynthetic pigments, carbohydrate and protein contents, antioxidant enzyme activity, endogenous hormones and yield traits. Our findings illustrate that the endophyte Brevibacillus agri (PB5) provides high potential as a stimulator for the growth and productivity of common bean plants.

The in vitro callus induction of Solanum incanum L. was executed on MS medium supplemented with different concentrations of auxin and cytokinin utilizing petioles and explants of leaves. The highest significant fresh weights from petioles and leaf explants were 4.68 and 5.13 g/jar for the medium supplemented with1.0 mg L⁻¹ BA and 1.0 mg L⁻¹ 2,4-D. The callus extract of the leaves was used for the green synthesis of silver nanoparticles (Ag-NPs). Analytical methods used for Ag-NPs characterization were UV-vis spectroscopy, Fourier Transform Infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Transmission Electron Microscopy (TEM). Spherical, crystallographic Ag-NPs with sizes ranging from 15 to 60nm were successfully formed. The FT-IR spectra exhibited the role of the metabolites involved in callus extract in reducing and capping Ag-NPs. The biological activities of Ag-NPs were dose-dependent. The MIC value for Staphylococcus aureus, Bacillus subtilis, and Escherichia coli was 12.5 µg mL⁻¹, while it was 6.25 µg mL⁻¹ for Klebsiella pneumoniae, Pseudomonas aeruginosa, and Candida albicans. The highest inhibition of phytopathogenic fungi Alternaria alternata, Fusarium oxysporum, Aspergillus niger, and Pythium ultimum was 76.3 ± 3.7, 88.9 ± 4.1, 67.8 ± 2.1, and 76.4 ± 1.0%, respectively at 200 µg mL⁻¹. Moreover, green synthesized Ag-NPs showed cytotoxic efficacy against cancerous cell lines HepG2, MCF-7 and normal Vero cell line with IC₅₀ values of 21.76 ± 0.56, 50.19 ± 1.71, and 129.9 ± 0.94 µg mL⁻¹, respectively.

Few reports explain the mechanism of PEG action on stomatal behavior and anatomical structure and analyze the photosynthetic pigments of in vitro date palm plantlets for better tolerance to ex vitro exposure. The main challenge for in vitro micropropagation of date palm techniques remains restricted to high survival rates and vigorous growth after ex vitro transplantation. In vitro hardening is induced by Polyethylene glycol PEG (0.0, 10, 20, 30 g L⁻¹) for 4 weeks. Leaf anatomy, stomatal behavior, water loss %, photosynthetic pigments, and reducing sugars were examined in date palm plantlets (Phoenix dactylifera L.) cv. (Sewi) after 4 weeks from in vitro PEG treatment and after 4 weeks from ex vitro transplanting to the greenhouse. Leaf anatomy and the surface ultrastructure of in vitro untreated leaves showed a thin cuticle layer, wide opened malfunctioning stomata, and abnormal leaf anatomy. Furthermore, addition of PEG resulted in increasing cuticle thickness, epicuticular wax depositions, and plastids density, improving the stomatal ability to close and decreasing the stomatal aperture length while reducing the substomatal chambers and intercellular spaces in the mesophyll. As a result, a significant reduction in water loss % was observed in both in vitro and ex vitro PEG treated leaves as compared to untreated ones, which exhibited rapid wilting when exposed to low humidity for 4 h. PEG application significantly increased Chlorophylls a, b and carotenoids concentrations, especially 10, 20 g L⁻¹ treatments, which were sequentially reflected in increasing the reducing sugar concentration. However, leaves of plantlets treated with PEG at 30 g L⁻¹ became yellow and had necrosis ends with death. In vitro hardening by 20 g L⁻¹ PEG increased the survival rate of plantlets to 90% after ex vitro transfer compared to 63% recorded for the untreated plantlets. Therefore, this application provides normal date palm plantlets developed faster and enhances survival after ex vitro transfer.

In this study, we established of an application protocol for the micropropagation of Dillenia indica with an estimate of betulinic acid from callus, leaf, and regeneration plant. Moreover, the antimicrobial and cytotoxic efficacy of the crude extract and pure compound was compared. The highest number of shoots (3.667 shoots), leaf number per jar (27 leaves) and shoot length (3.667 cm) were recorded from the MS medium containing 2.0 mg L-1 of benzyl amino purine (BAP). Moreover, different physical elicitors (ultraviolet irradiation, microwave radiation, and light quality) were used on the production and increased the concentration of betulinic acid in callus of D. indica. The data revealed that the highest betulinic acid content (341.775 mg/100 g fresh weight) was recorded in callus microwaved with 200 watts for 10 s. Which was three times more than the betulinic acid content recorded in the mother plant. In addition, different crude extracts of D. indica were used to determine their biological activity against six microorganisms. The data showed that the highest diameter of inhibition zones (17.0 mm) was recorded in callus culture extractions incubated under blue light with Candida albicans. The cytotoxic efficacy of betulinic acid and extract of callus, mother plant leaf or in vitro regeneration plants of D. indica were investigated against the Vero cell line by MTT. The results revealed that The IC50 values were 115.7 ± 9.17, 114.98 ± 5.2, 59.45 ± 3.06, and 72.76 ± 6.93 μgmL-1 of betulinic acid, callus extract, leaf, and regeneration plant, respectively.