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.

In this study, the anti-stress capabilities of the foliar application of chitosan, dissolved in four different organic acids (acetic acid, ascorbic acid, citric acid and malic acid) have been investigated on tomato (Solanum lycopersicum L.) plants under salinity stress (100 mM NaCl). Morphological traits, photosynthetic pigments, osmolytes, secondary metabolites, oxidative stress, minerals, antioxidant enzymes activity, isozymes and protein patterns were tested for potential tolerance of tomato plants growing under salinity stress. Salinity stress was caused a reduction in growth parameters, photosynthetic pigments, soluble sugars, soluble proteins and potassium (K⁺) content. However, the contents of proline, ascorbic acid, total phenol, malondialdehyde (MDA), hydrogen peroxide (H₂O₂), sodium (Na⁺) and antioxidant enzyme activity were increased in tomato plants grown under saline conditions. Chitosan treatments in any of the non-stressed plants showed improvements in morphological traits, photosynthetic pigments, osmolytes, total phenol and antioxidant enzymes activity. Besides, the harmful impacts of salinity on tomato plants have also been reduced by lowering MDA, H₂O₂ and Na⁺ levels. Chitosan treatments in either non-stressed or stressed plants showed different responses in number and density of peroxidase (POD), polyphenol oxidase (PPO) and superoxide dismutase (SOD) isozymes. NaCl stress led to the diminishing of protein bands with different molecular weights, while they were produced again in response to chitosan foliar application. These responses were varied according to the type of solvent acid. It could be suggested that foliar application of chitosan, especially that dissolved in ascorbic or citric acid, could be commercially used for the stimulation of tomato plants grown under salinity stress.

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.

One of the leading global causes of environmental contamination, heavy metals hurt agriculture and human health through the food chain. Through the use of mitotic index (MI), chromosomal aberrations (CAs), and DNA damage, the cytotoxic and genotoxic effects of Cr (VI) on the root tips of Allium cepa and Nigella sativa were assessed. Six Cr(VI) concentrations of 50,100,400,700,1000,and 2000 ppm were administered for 6,12,18,and 24 hours. The germination percentages of A. cepa and N. sativa seeds decreased at 400 ppm for both plants, with no germination detected in N. sativa L after 700 ppm application. The percentage of mitotic index in the treated group was significantly lower than that of the control cells after exposure to varying concentrations of Cr (VI) for varying amounts of time. It was determined that these decreases were statistically significant. The reduction of MI in N. sativa root tips was more pronounced than that of A. cepa. The largest abnormal percentages were identified in N. sativa after 24 hours of exposure to 100 ppm, while A. cepa showed abnormal percentages after 24 hours of exposure to 400 ppm. In all mitotic phases, distinct anomalies in the division of root tip cells were found in both plant species. A few examples of these deviations are stickiness, c-mitosis, anaphase-telophase bridges, disturbed laggards, and micronucleus. The comet test, which looks for single-strand breaks in DNA, was used to figure out how dangerous Cr (VI) is to the DNA in A. cepa root cells.

Gebel Mousa located in Saint Katherine Protectorate (SKP), South Sinai, Egypt. It harbors many endemic and endangered medicinal plants that are overexploited and facing serious threat of extinction. From these important medicinally plant species, we select Thymus decussatus (near-endemic and endangered plant) to investigate the genetic diversity level among eight populations using both of random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) molecular markers. Seven primers were chosen for RAPD and six primers for ISSR analysis. Thirteen RAPD and ISSR primers amplified 97 bands with an average of 7.46 fragments / primer and the total number of polymorphic fragments was 84, thus, representing a level of polymorphism of 86.70%. Jaccard’s similarity coefficient values ranged from 0.37 to 0.64. The highest similarly value (0.64) was scored between Farsh Shoeib and Corridor between Farsh El-Hamar & Farsh Shoeib populations as the closet. On the other hand, the lowest similarity value (0.37) was recorded between Farsh Ellya in direction of G. Mousa and Corridor between Farsh El-Loza & Farsh Ellya populations as most distant. The dendrogram separated the eight T. decussates populations into two clusters. The first cluster included Farsh El-Sefsafa, Farsh El-Hamar; Corridor between Farsh El-Loza & Farsh Ellya. The second cluster included Farsh Shoeib, Corridor between Farsh El-Hamar & Farsh Shoeib, Farsh Ellya and Farsh Ellya in direction of G. Mousa and Farsh El-Loza. Assessing of genetic polymorphisms among the Thymus populations at varying microhabitats can help in their genetic improvement and their conserving programs.