Foliar Application of Nanoclay Promotes Potato (Solanum tuberosum L.) Growth and Induces Systemic Resistance against Potato Virus Y.

Potato virus Y (PVY) is one of the most harmful phytopathogens. It causes big problems for potatoes and other important crops around the world. Nanoclays have been extensively studied for various biomedical applications. However, reports on their interactions with phytopathogens, particularly viral infections, are still limited. In this study, the protective activity of Egyptian nanoclay (CE) and standard nanoclay (CS) against PVY was evaluated on potato (Solanum tuberosum L.) plants. Their physicochemical and morphological properties were examined with scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and energy dispersive spectrometer (EDS). SEM and TEM analyses revealed that CE has a spherical and hexagonal structure ranging from 20 to 80 nm in size, while CS has boulder-like and tubular structures of about 320 nm in size. FTIR and EDS showed that both nanoclay types have different functional groups and contain many vital plant nutrients that are necessary for every stage and process of the plant, including development, productivity, and metabolism. Under greenhouse conditions, a 1% nanoclay foliar application enhanced potato growth, reduced disease symptoms, and reduced PVY accumulation levels compared with non-treated plants. Significant increases in levels of antioxidant enzymes (PPO and POX) and considerable decreases in oxidative stress markers (MDA and H2O2) were also reported. Moreover, a significant increase in the transcriptional levels of defense-related genes (PAL-1, PR-5, and CHI-2) was observed. All experiment and analysis results indicate that the CE type is more effective than the CS type against PVY infection. Based on these results, the foliar applications of nanoclay could be used to manage plant viral infections in a way that is both effective and environmentally friendly. To our knowledge, this is the first report of the antiviral activity of the foliar application of nanoclay against PVY infection.

Plantago lagopus extract as a green fungicide induces systemic resistance against Rhizoctonia root rot disease in tomato plants.

Extensive use of chemical control agents and fungicides typically leads to numerous risks to human health and the environment. Using plant extracts as natural substances represents a dual key for the environment and sustainable food production, as it reduces the input of synthetic pesticides into the environment and/or controls plant pathogens. For the first time, a Plantago lagopus ethanolic extract has been characterized and evaluated for its protective and curative effects against Rhizoctonia solani in tomato plants. The results showed that P. lagopus extract (10 µg/ml) completely inhibited R. solani mycelial growth in vitro. At 20 days of post fungal inoculation, the results demonstrated that using P. lagopus extract (100 µg/ml) in vivo enhanced tomato plant growth by significantly increasing shoot and root parameters in protective and curative treatments. Furthermore, the protective and curative treatments significantly reduced the disease index by 18.66 and 38.66%, respectively. Induction of systemic resistance with upregulation of PR-1 and PR-2 and a significant increase in the transcriptional levels of PR-3 and CHS in all P. lagopus extract-treated tomato plants were reported compared to untreated plants. HPLC analysis showed that the most common polyphenolic components detected in P. lagopus extract were rutin (74206.3 mg/kg), naringenin (2388.74 mg/kg), quercetin (1249.13 mg/kg), and p-hydroxybenzoic acid (1035.87 mg/kg). In addition, the ellagic acid (798.47 mg/kg), vanillic acid (752.55 mg/kg), catechol (648.89 mg/kg), cinnamic acid (332.51 mg/kg), ferulic acid (296.32 mg/kg), benzoic acid (295.95 mg/kg), and chlorogenic acid (116.63 mg/kg) were also reported. Our study is the first to show that P. lagopus extract can help plants fight off R. solani fungal infection. Furthermore, the findings imply that using the P. lagopus extract as a natural biocontrol agent could be a sustainable strategy to manage plant fungal diseases.

Evaluation of the antifungal activity of Rumex vesicarius L. and Ziziphus spina-christi (L) Desf. Aqueous extracts and assessment of the morphological changes induced to certain myco-phytopathogens.

Many Plant extracts had proved a potential antifungal activity against a wide range of phytopathogenic fungi. The aim of this study was to evaluate the antifungal activity of the aqueous extracts of Rumex vesicarius L. and Ziziphus spina-christi (L) Desf. against some fungal species. The effect on growth inhibition, conidia germination, sporogenesis, morphological, and ultrastructural characterizations of fungal growth by scanning and transmission electron microscopes, have been investigated. Both plant extracts exhibited an antifungal activity against Fusarium, Helminthosporium, Alternaria, and Rhizoctonia species, besides, the sporogenesis of Alternaria and Fusarium species was suppressed. Both plants induced severe morphological changes in the hyphal shape and surface. We concluded that the aqueous extracts of these plants had strong antifungal activities. More investigations should be performed to evaluate the possible applications in agriculture and in vivo.

Ziziphus spina-christi leaf extract attenuates mercury chloride-induced testicular dysfunction in rats.

Mercury (Hg) is a heavy metal toxicant, causing several adverse reactions to animals and humans including reproductive dysfunction. The potential protective role of Ziziphus spina-christi leaf extract (ZSCLE) against testicular impairments associated with mercury chloride (HgCl2) exposure in rats was investigated in the current study. Four experimental groups were employed as follows (n = 7): group I served as control, group II was gavaged with ZSCLE (300 mg/kg), group III was administered with HgCl2 (0.4 mg/kg), and group IV was preadministered with ZSCLE 1 h before HgCl2. All groups were treated daily for 28 days. The exposure to HgCl2 caused a marked increase in Hg concentration in the testicular tissue, which was accompanied with a decrease in testis index. A reproductive impairment was recorded following HgCl2 exposure as verified through the decrease in levels of testosterone, luteinizing, and follicle-stimulating hormones. HgCl2 was found to enhance the development of oxidative damage in the testicular tissue as presented by the imbalance between pro-oxidants and antioxidant molecules. In addition, excessive release of tumor necrosis factor-α and interleukin-1ß was recorded in response to HgCl2 intoxication. Furthermore, a disturbance in the apoptotic proteins in favor of the pro-apoptotic proteins was also observed following HgCl2 intoxication. However, ZSCLE administration along with HgCl2 abolished significantly the molecular, biochemical, and histopathological alterations induced by HgCl2 intoxication. Our findings suggest that ZSCLE could be used to mitigate reproductive dysfunction associated with HgCl2 exposure.

Ziziphus spina-christi Leaf Extract Suppressed Mercury Chloride-Induced Nephrotoxicity via Nrf2-Antioxidant Pathway Activation and Inhibition of Inflammatory and Apoptotic Signaling.

Exposure to heavy metals, including mercury chloride (HgCl2), is associated with severe health problems. This study was designed to investigate HgCl2-induced nephrotoxicity and evaluate the protective role of Ziziphus spina-christi leaf extract (ZSCLE). Four randomly selected groups containing seven rats were used. For a period of 28 days, the control group was administered 0.9% saline solution; the second group was administered 300 mg/kg ZSCLE; the third group was administered 0.4 mg/kg HgCl2 dissolved in 0.9% physiological saline solution; and the fourth group was administered an oral supplement of 300 mg/kg ZSCLE one hour after HgCl2 administration. HgCl2 intoxication resulted in Hg accumulation in renal tissue; decreases in body weight, kidney index, and glutathione content and superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activities; increases in creatinine, urea, Kim-1 expression, lipid peroxidation, and nitric oxide production; suppression of the Nrf2-antioxidant response pathway; upregulation of Il1ß, Tnfα, and Nos2; and potentiation of proapoptotic activity. ZSCLE exerted beneficial effects against mercury-induced renal toxicity and significantly reversed these alterations to near normal values. These effects resulted from its chelation and antioxidant, anti-inflammatory, and antiapoptotic activities. ZSCLE may prevent or minimize the pathological changes induced by mercury in the kidney.