Desert plants are able to survive under harsh environmental stresses inherent to arid and semiarid regions due to their association with bacterial endophytes. However, the identity, functions, and the factors that influence the association of bacterial endophytes with desert plants are poorly known. These bacterial endophytes can be used as an untapped resource to favor plant growth and development in agro-ecosystems of arid regions. The present study is therefore focused on the isolation and identification of bacterial endophytes from two native medicinal plants (Fagonia mollis Delile and Achillea fragrantissima (Forssk) Sch. Bip.) growing spontaneously in the arid region of the South Sinai (Egypt), and characterization of their plant growth promoting (PGP) traits. Thirteen putative bacterial endophytes were isolated from the leaves of both plant species and characterized for their plant growth promoting abilities using molecular and biochemical approaches, as well as greenhouse trials. Selected endophytic bacterial strains were applied to maize plants (Zea mays L. var. Single cross Pioneer 30K08) to further evaluate their PGP abilities under greenhouse conditions. Isolated bacterial strains have variable plant growth promoting activities. Among these activities, isolated bacterial endophytes have the efficacy of phosphate solubilizing with clear zones ranging from 7.6 ± 0.3 to 9.6 ± 0.3 mm. Additionally, the obtained bacterial endophytes increased the productivity of indole acetic acid (IAA) in broth media from 10 to 60 µg·mL⁻¹ with increasing tryptophan concentration from 1 to 5 mg·mL⁻¹. Bacillus and Brevibacillus strains were frequently isolated from the leaves of both plant species, and had significant positive effects on plant growth and shoot phosphorus (P) and nitrogen (N) contents. Results suggest that these endophytes are good candidates as plant growth promoting inoculants to help reduce chemical input in conventional agricultural practices and increase nutrient uptake and stress resilience in plant species.

Recently, the green synthesis of nanomaterials has grown in popularity and has become one of the most used approaches. Plant extracts are safe for the environment and could be cost-effective for nanoparticle preparation. Silver nanoparticles (AgNPs) have been synthesized using aqueous extracts of Nigella sativa (N. sativa) seeds. The formation of AgNPs was confirmed by using an X-ray diffractometer, a UV-visible spectrometer, and a transmission electron microscope. The phytotoxicity and genotoxicity of different AgNP concentrations (12.5, 25, 50, 75, and 100μg·L⁻¹) were evaluated by wheat (Triticum aestivum L.) seed germination. The results showed that AgNPs did not significantly affect germination, while root and coleoptile lengths decreased considerably. On the contrary, the biomass of seedlings markedly increased in response to AgNP treatments. Moreover, genotoxicity was detected, especially at high concentrations of AgNPs. DNA, RNA, and total soluble proteins of wheat seedlings significantly decreased. In addition, antimicrobial activities of biosynthesized AgNPs were detected.

Lycium schweinfurthii is a Mediterranean wild shrub rich in plant secondary metabolites. In vitro propagation of this plant may support the production of valuable dietary supplements for humanity, introduction of it to the world market, and opportunities for further studies. The presented study aimed to introduce an efficient and reproducible protocol for in vitro micropropagation of L. schweinfurthii and assess the genetic stability of micropropagated plants (MiPs) as well as to estimate phenolic, flavonoid, ferulic acid contents, and the antioxidant activity in leaves of micropropagated plants. Two DNA-based techniques, random amplified polymorphic DNA (RAPD) and inter-simple sequence repeats (ISSR), and one biochemical technique, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), were used to assess the genetic stability in MiPs. Spectrophotometric analysis was performed to estimate total phenolic and flavonoid contents and antioxidant activity of MiPs leaves, while ferulic acid content was estimated using high-performance thin-layer chromatography (HPTLC). Sufficient shoot proliferation was achieved at MS (Murashige and Skoog) medium supplemented with 0.4 mg L⁻¹ kinetin and rooted successfully on half-strength MS medium fortified with 0.4 mg L⁻¹ Indole-3-butyric acid (IBA). The Jaccard’s similarity coefficients detected in MiPs reached 52%, 55%, and 82% in the RAPD, ISSR, and SDS-PAGE analyses, respectively. In the dried leaves of MiPs, the phenolic, flavonoid, and ferulic acid contents of 11.53 mg gallic acid equivalent, 12.99 mg catechin equivalent, and 45.52 mg were estimated per gram, respectively. However, an IC₅₀ of 0.43, and 1.99 mg mL⁻¹ of MiP dried leaves’ methanolic extract was required to scavenge half of the DPPH, and ABTS free radicals, respectively. The study presented a successful protocol for in vitro propagation of a valued promising plant source of phenolic compounds.

The Hypocholesterolemic is an effective and friendly process for the removal of cholesterol and an important aspect of human health. Removal of cholesterol by probiotic bacteria was investigated in this study. The potential probiotic bacterium was preliminarily identified as Lactobacillus casei. In addition, the various operating parameters like cholesterol concentration, incubation time, bile salts concentration, probiotic dose and initial pH was studied. The optimum parameters for most probiotics studied are cholesterol concentration is 100 μg /ml, incubation time is 48 h, bile salts concentration is 0.5%, probiotic dose is 200μl and initial pH is 6. The maximum percentage removal of cholesterol using Lactobacillus casei is 93.6. The probiotics bacteria are favorable for Hypocholesterolemic.

Sewage water is causing a potential threat to agriculture sector due to industrial effluents having heavy metals. Present investigation was carried to study the role of ethylenediaminetetraacetic acid (EDTA) or aqueous extracts of Hyacinth and Hedychium on soil quality and growth of spinach and turnip plants irrigated with sewage water (SW). Treatment of plants with SW resulted in an increment of catalase (CAT), peroxidase (POD) and polyphenol oxidase (PPO) activities. However, EDTA or plant extracts further enhanced their activities. At both stages of development of the tested crops, a substantial increase was found in the content of proline and total phenols, indicating the strengthening of the antioxidant protection mechanism to boost the oxidative effects of SW stress. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) studies revealed considerable variation in the protein profile among the different treatments, with an expression of some unique proteins obvious with other treatments. SW treatments increased heavy metals (HM) content in soil and plants; however, EDTA or plant extracts greatly decreased the levels of HMs in both shoots and roots and soils. The present study results suggest that the application of EDTA or aqueous plant extracts can be a useful strategy for phytoextraction in areas irrigated with sewage water.