Efficacy of endophytic bacteria as promising inducers for enhancing the immune responses in tomato plants and managing Rhizoctonia root-rot disease

Around the world, a variety of crops, including tomatoes, suffer serious economic losses due to the Rhizoctonia root-rot disease. Herein, Bacillus velezensis, Bacillus megaterium, and Herpaspirillum huttiense isolated from strawberry (Fragaria chiloensis var. ananassa) plants were pragmatic as plant growth promotors for battling the Rhizoctonia root rot disease and bringing about defense mechanisms as well as growth promotional strategies in tomato plants. These endophytic bacteria demonstrated potent antifungal activity against R. solani in vitro along in vivo. Data explained that the isolated endophytic bacteria could produce Indole acetic acid, Gibberellic acid GA, and siderophore as well as solubilize phosphate in the soil. The consortium of (Bacillus velezensis, Bacillus megaterium, and Herpaspirillum huttiense) increased the protection % against Rhizoctonia infection by (79.4%), followed by B. velezensis by (73.52%), H. huttiense by (70.5%), and B. megaterium by (67.64%), respectively. There was an increase in soluble proteins and carbohydrates in infected plants treated with a consortium of endophytic bacteria by 30.7% and 100.2% over untreated infected plants, respectively. Applying endophytic bacteria either alone or in combination lowered the level of malondialdehyde MDA and hydrogen peroxide H2O2 and improved the activities of antioxidant enzymes in both infected and uninfected plants. Also, bacterial endophytes have distinctive reactions regarding the number and concentrations of isozymes in both infected and uninfected plants. It could be recommended the commercial usage of a mixture of targeted bacterial endophyte strains as therapeutic nutrients against Rhizoctonia root-rot disease as well as plant growth inducer.

Management of potato brown rot disease using chemically synthesized CuO-NPs and MgO-NPs

BACKGROUND

Potatoes are a crucial vegetable crop in Egypt in terms of production and consumption. However, the potato industry suffers significant annual losses due to brown rot disease. This study aimed to suppress Ralstonia solanacearum (R. solanacearum), the causative agent of brown rot disease in potatoes, using efficient and economical medications such as CuO and MgO metal oxide nanoparticles, both in vitro and in vivo, to reduce the risk of pesticide residues.

RESULTS

CuO and MgO metal oxide nanoparticles were synthesized via a simple chemical process. The average particle size, morphology, and structure of the nanoparticles were characterized using UV-visible spectroscopy, transmission electron microscopy (TEM), zeta potential analysis, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The growth of R. solanacearum was strongly inhibited by CuO and MgO NPs at a concentration of 3 mg/mL, resulting in zones of inhibition (ZOI) of 19.3 mm and 17 mm, respectively. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CuO-NPs and MgO-NPs were 0.5, 0.6, and 0.6, 0.75 mg/mL, respectively. When applied in vivo through seed dressing and tuber soaking at their respective MIC concentrations, CuO-NPs and MgO-NPs significantly reduced the incidence of brown rot disease to 71.2% and 69.4%, respectively, compared to 43.0% and 39.5% in bulk CuSO₄ and bulk MgSO₄ treatments, respectively. Furthermore, CuO-NPs and MgO-NPs significantly increased the yield, total chlorophyll content, and enzyme efficiency of potato plants compared with the infected control plants. TEM revealed that the bacterial cytomembrane was severely damaged by nanomechanical forces after interaction with CuO-NPs and MgO-NPs, as evidenced by lipid peroxidation and ultrastructural investigations.

CONCLUSION

The results of this study suggest that CuO-NPs and MgO-NPs can be used as intelligent agents to manage plant pathogens in agriculture. The use of metal oxide nanoparticles could provide a risk-free alternative for treating plant diseases, which are currently one of the biggest challenges faced by the potato industry in Egypt. The significant increase in yield, photosynthetic pigments, enzymatic activity, and total phenol-promoted resistance to R. solanacearum in potato plants treated with CuO-NPs and MgO-NPs compared to infected control plants highlights the potential benefits for the potato industry in Egypt. Further investigations are needed to explore using metal oxide nanoparticles for treating other plant diseases.

Biological activities and ecological aspects of Limonium pruinosum (L.) collected from Wadi Hof Eastern Desert, Egypt, as a promising attempt for potential medical applications

Very few researchers have focused on the biological efficacy of Limonium plants. In this concern, no investigations were commenced to delve into the in vitro and ex vivo biological actions of Limonium pruinosum in Egypt. Therefore, this work aims to assess for the first time the antimicrobial, antioxidant, and antitumor activities of Limonium pruinosum extract in addition to studying its ability to suppress the transcription of cell cycle–stimulating genes. L. pruinosum ethyl acetate extract exhibits considerable antibacterial and antibiofilm activity versus E. coli ATCC 25922 and Staphylococcus aureus ATCC 25923. Results revealed that L. pruinosum exerts antioxidant effectiveness concerning DPPH, nitric oxide (NO), and hydroxyl radical (OH) scavenging ability with an IC50 (35.88 ± 2.2, 51.31 ± 1.06, and 65.87 ± 1.19 μg/mL) respectively. The results proved the effectiveness of L. pruinosum in closing wounds in gastric epithelial cells (GES-1) by (79.9343 ± 1.98%) compared with control (68.3637 ± 2.32%) in 48 h. Additionally, L. pruinosum had anticancer activity contrary to breast cancer MCF-7 and liver cancer HepG-2 cell lines with IC50 values of 96.73 ± 2.18 and 81.81 ± 0.99 μg/mL, respectively, while it had no cytotoxic activity against (Wi-38) normal cells. Also, L. pruinosum extract provoked considerable early- and late-apoptotic cell populations and was effective in inducing cell death of MCF-7. Our findings evoked that L. pruinosum has promising antibacterial, antioxidant, and wound healing activities and a good breast tumor suppressor arresting the cell cycle-stimulating genes, which may be an auspicious approach for the treatment of breast cancer.

Assessment of probiotic efficacy and anticancer activities of Lactiplantibacillus plantarum ESSG1 (MZ683194.1) and Lactiplantibacillus pentosus ESSG2 (MZ683195.1) isolated from dairy products

Resistance to antibiotics is on the rise, and its indiscriminate usage has resulted in human and animal management constraints. In the research for an innovative treatment to diminish antimicrobial resistance, lactic acid bacteria (LAB) throw light on diminishing this problem in public health. As a result, this paper looked at the efficacy of LAB isolates and their active metabolites to combat pathogens, reduce antibiotic use in clinical settings, and explore the anticancer potential of 8 strains of LAB isolated from dairy products. Antifungal and antibacterial potential of LAB isolates against selected crop pathogenic fungi and food pathogenic bacteria had been estimated. Results revealed that all isolates exert antioxidant efficacy relating to DPPH, NO scavenging ability, reducing power, superoxide anion, hydroxyl radical, and anti-lipid peroxidation potential. Additionally, 12B isolate exert the highest anticancer upshot with IC₅₀ values of 43.98 ± 0.4; 36.7 ± 0.6, 43.1 ± 0.8, and 35.1 ± 0.3 μg/ml, versus Caco-2, MCF-7, HepG-2, and PC3 cell lines respectively, whereas 13B isolate significantly had the highest selectivity index between peripheral blood mononuclear cells (PBMCs) and the tested human cancer cell lines compared to 5-fluorouracil. 13B was the most apoptosis-dependent death inducer for all human cancer cell lines besides exerting the lowest percentage of apoptosis against PBMCs suggesting its safety against PBMCs. The most promising strains 12B and 13B were identified by 16S rRNA sequencing as Lactiplantibacillus plantarum ESSG1 (MZ683194.1) and Lactiplantibacillus pentosus ESSG2 (MZ683195.1). LAB and their extracts are superb substitutive, safe, and efficient antimicrobial, antioxidant, and antitumor curative agents.

Enhanced Production, Cloning, and Expression of a Xylanase Gene from Endophytic Fungal Strain Trichoderma harzianum kj831197.1: Unveiling the In Vitro Anti-Fungal Activity against Phytopathogenic Fungi

Trichoderma sp. is extensively applied as a beneficial fungus for the management of plant diseases, plant growth promotion, induced resistance, and plays an important role in global sustainable agriculture. This study aimed to enhance the production of microbial xylanase in high titer from the endophytic fungus Trichoderma harzianum kj831197.1, and the cloning of xylanase genes in E. coli DH5α using a pUC19 vector. A combination of glucose, 0.1 mM, Tween 80 with lactose, and 2 mM galactose combined with malt extract boostedthe enzyme production. Xylanase production was maximized at a pH of 5.0, temp. of 30 °C, and agitation of 150 rpm in the presence of malt extract and bagasse as the best nitrogen source and waste, respectively, using submerged fermentation. The molecular weight of highly purified xylanase was 32 KDa, identified using SDS-PAGE. The xylanase gene of T. harzianum kj831197.1 was screened in fungal DNA using definite primers specified in the gene bank database. The identified region was excised using restriction enzymes HindIII and EcoRI and cloned into a pUC19 plasmid vector. Optimization of fermentation conditions improved xylanase production about 23.9-fold.The antifungal efficacy of xylanase toward different phytopathogenic fungi was determined. The highest inhibition was against Corynespora cassiicola, Alternaria sp., Fusarium oxysporum, and Botrytis fabae. This study offered an economical, simple, and efficient method using Trichoderma harzianum kj831197.1 for the production of the xylanase enzyme via the submerged fermentation method.

Immunomodulatory Efficacy-Mediated Anti-HCV and Anti-HBV Potential of Kefir Grains; Unveiling the In Vitro Antibacterial, Antifungal, and Wound Healing Activities

The utilization of fermented foods with health-promoting properties is becoming more popular around the world. Consequently, kefir, a fermented milk beverage made from kefir grains, was shown in numerous studies to be a probiotic product providing significant health benefits. Herein, we assessed the antibacterial and antifungal potential of kefir against a variety of pathogenic bacteria and fungi. This study also showed the effectiveness of kefir in healing wounds in human gastric epithelial cells (GES-1) by (80.78%) compared with control (55.75%) within 48 h. The quantitative polymerase chain reaction (qPCR) results of kefir-treated HCV- or HBV- infected cells found that 200 µg/mL of kefir can eliminate 92.36% of HCV and 75.71% of HBV relative to the untreated infected cells, whereas 800 µg/mL (the highest concentration) completely eradicated HCV and HBV. Moreover, the estimated IC₅₀ values of kefir, at which HCV and HBV were eradicated by 50%, were 63.84 ± 5.81 µg/mL and 224.02 ± 14.36 µg/mL, correspondingly. Kefir can significantly suppress the elevation of TNF-α and upregulate IL-10 and INF-γ in both treated HCV- and HBV-infected cells. High-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) analysis of kefir revealed the presence of numerous active metabolites which mainly contribute to the antimicrobial, antiviral, and immunomodulatory activities. This study demonstrated, for the first time, the anti-HBV efficacy of kefir while also illustrating the immunomodulatory impact in the treated HBV-infected cells. Accordingly, kefir represents a potent antiviral agent against both viral hepatitis C and B, as well as having antimicrobial and wound healing potential.