(ToMV) is one of the economically damageable
infecting the tomato in Egypt that has caused significant losses. It is therefore of great interest to trigger systemic resistance to ToMV. In this ...endeavor, we aimed to explore the capacity of ZnO-NPs (zinc oxide nanoparticles) to trigger tomato plant resistance against ToMV. Effects of ZnO-NPs on tomato (
L.) growth indices and antioxidant defense system activity under ToMV stress were investigated. Noticeably that treatment with ZnO-NPs showed remarkably increased growth indices, photosynthetic attributes, and enzymatic and non-enzymatic antioxidants compared to the challenge control. Interestingly, oxidative damage caused by ToMV was reduced by reducing malondialdehyde, H
O
, and O
levels. Overall, ZnO-NPs offer a safe and economic antiviral agent against ToMV.
(CMV) is a deadly plant virus that results in crop-yield losses with serious economic consequences. In recent years, environmentally friendly components have been developed to manage crop diseases as ...alternatives to chemical pesticides, including the use of natural compounds such as glycine betaine (GB) and chitosan (CHT), either alone or in combination. In the present study, the leaves of the cucumber plants were foliar-sprayed with GB and CHT-either alone or in combination-to evaluate their ability to induce resistance against CMV. The results showed a significant reduction in disease severity and CMV accumulation in plants treated with GB and CHT, either alone or in combination, compared to untreated plants (challenge control). In every treatment, growth indices, leaf chlorophylls content, phytohormones (i.e., indole acetic acid, gibberellic acid, salicylic acid and jasmonic acid), endogenous osmoprotectants (i.e., proline, soluble sugars and glycine betaine), non-enzymatic antioxidants (i.e., ascorbic acid, glutathione and phenols) and enzymatic antioxidants (i.e., superoxide dismutase, peroxidase, polyphenol oxidase, catalase, lipoxygenase, ascorbate peroxidase, glutathione reductase, chitinase and β-1,3 glucanase) of virus-infected plants were significantly increased. On the other hand, malondialdehyde and abscisic acid contents have been significantly reduced. Based on a gene expression study, all treated plants exhibited increased expression levels of some regulatory defense genes such as
and
. In conclusion, the combination of GB and CHT is the most effective treatment in alleviated virus infection. To our knowledge, this is the first report to demonstrate the induction of systemic resistance against CMV by using GB.
During the spring of 2019, distinct virus-like symptoms were observed in the Kafr El-Sheikh Governorate in Egypt in naturally infected eggplants. Leaves of affected plants showed interveinal leaf ...chlorosis, net yellow, chlorotic sectors, mottling, blisters, vein enation, necrotic intervention, and narrowing symptoms. The
(AMV) was suspected of to be involved in this disease. Forty plant samples from symptomatic eggplants and 10 leaf samples with no symptoms were collected. The samples were tested by double antibody sandwich ELISA (DAS-ELISA) using AMV-IgG. Six of the 40 symptomatic leaf samples tested positive for AMV, while, DAS-ELISA found no AMV in the 10 leaf samples without symptoms. The AMV Egyptian isolate (AMV-Eggplant-EG) was biologically isolated from the six positive samples tested by DAS-ELISA and from the similar local lesions induced on
and then re-inoculated in healthy
as a source of AMV-Eggplant-EG and confirmed by DAS-ELISA.
(RT-PCR) assay with a pair of primers specific for coat protein (CP) encoding RNA 3 of AMV yielded an amplicon of 666 bp from infected plants of
with AMV-Eggplant-EG. The amplified PCR product was cloned and sequenced. Analysis of the AMV-Eggplant-EG sequence revealed 666 nucleotides (nt) of the complete CP gene (translating 221 amino acid (aa) residues). Analysis of phylogeny for nt and deduced aa sequences of the CP gene using the maximum parsimony method clustered AMV-Eggplant-EG in the lineage of Egyptian isolates (shark-EG, mans-EG, CP2-EG, and FRE-EG) with a high bootstrap value of 88% and 92%, respectively. In addition to molecular studies, melatonin (MTL) and salicylic acid (SA) (100 μM) were used to increase the resistance of eggplant to AMV- infection. Foliar spray with MLT and SA caused a significant increase in the morphological criteria (shoot, root length, number of leaves, leaf area, and leaf biomass), chlorophyll and carotenoid content, antioxidant enzymes, and gene expression of some enzymes compared to the infected plants. On the other hand, treatment with MLT and SA reduced the oxidative damage caused by AMV through the reduction of hydrogen peroxide, superoxide anions, hydroxyl radicals, and malondialdehyde. In conclusion, MLT and SA are eco-friendly compounds and can be used as antiviral compounds.
Viruses pose a serious threat to the sustainable production of economically important crops around the world. In the past 20 years, potato virus Y (PVY) emerged as a relatively new and very serious ...problem in potatoes, even though it is the oldest known plant virus. Multiple strains of the virus cause various symptoms on the leaves and tubers of potatoes, resulting in yield reduction and poor-quality tubers. Consequently, it would be very interesting to learn what causes systemic PVY resistance in plants. Natural compounds such as chitosan (CHT) and phosphorus have been developed as alternatives to chemical pesticides to manage crop diseases in recent years. In the current study, potato leaves were foliar-sprayed with chitosan and phosphorus to assess their ability to induce PVY resistance. Compared to untreated plants, the findings demonstrated a significant decrease in disease severity and PVY accumulation in plants for which CHT and P were applied. Every treatment includes significantly increased growth parameters, chlorophyll content, photosynthetic characteristics, osmoprotectants (glycine betaine, proline, and soluble sugar), non-enzymatic antioxidants (glutathione, phenols, and ascorbic acid), enzymatic antioxidants (peroxidase, superoxide dismutase, lipoxygenase, glutathione reductase, catalase, β-1,3 glucanase, and ascorbate peroxidase), phytohormones (gibberellic acid, indole acetic acid, jasmonic acid, and salicylic acid), and mineral content (phosphorus, nitrogen, and potassium), compared to infected plants. However, compared to PVY infection values, CHT and P treatments showed a significant decrease in malondialdehyde, DPPH, H2O2, O2, OH, and abscisic acid levels. In addition, increased expression levels of some regulatory defense genes, including superoxide dismutase (SOD), ascorbic acid peroxidase (APX), relative pathogenesis-related 1 basic (PR-1b), and relative phenylalanine ammonia-lyase (PAL), were found in all treated plants, compared to PVY-infected plants. Conclusion: Phosphorus is the most effective treatment for alleviating virus infections.
Purpose
This research studies the alleviation potential of N- or/and P- deprived
Coccomyxa chodatii
SAG 216–2 extracts as biostimulants on mercury stress (10 and 30 mg L
−1
) of wheat seedlings.
...Materials
The study includes the interactive effect of mercury and biostimulants on growth, reactive nitrogen and oxygen species, membrane stability, and antioxidant activity in wheat seedlings.
Results
The imposed toxic effects of Hg-stress on the studied parameters were to a great extent less noticeable under different algal extracts, and the magnitude of augmentation was P-deprived extract > P-&N-deprived extract > N-deprived extract > Normal algal extract. Higher Hg-tolerance modulated by algal extracts, especially P-deprived extract, was associated with high antioxidant capacity and ferric reducing power. These activities could instigate the antioxidant system (enzymatic and non-enzymatic) under Hg-stress. Furthermore, the algal extracts broadly alleviated wheat chelating mechanism deterioration by Hg-stress via enhancing phytochelatins, reduced glutathione, and metallothioneins. Thus, the applied algal extracts retarded Hg accumulation in wheat tissues exposed to Hg stress. In addition, the nitrosative stress induced by Hg-stress in terms of high nitric oxide content was minimized by various algal extracts. All these regulations by algal extracts are reflected in high membrane stability as denoted by the reduction of lipid peroxidation, lipoxygenase, and methylglyoxal as a sign of reducing oxidative damage and reactive oxygen species (ROS).
Conclusion
Thus, we recommended using the macronutrient-deprived algal extracts of
Coccomyxa chodatii
SAG 216–2 as potential biostimulants of wheat growth under Hg-stress and may be under other stresses.
Herein, a novel chitosan/silver/Mn0.5Mg0.5Fe2O4 (Cs/Ag/MnMgFe2O4) nanocomposite was synthesized with gamma irradiation assistant. The prepared Cs/Ag/MnMgFe2O4 nanocomposite was characterized via EDX, ...XRD, SEM, UV–vis spectroscopy. To evaluate the effects of soak low and high-dose nanocomposite on physiological parameters, photosynthetic pigments, antioxidant and non-antioxidant enzymes of cabbage under Cd stress, a factorial experiment was conducted based on CRD with five replications. The Cd stress decreased the morphological characteristics and photosynthetic pigments while increasing cabbage's antioxidant and non-antioxidant enzymes. The application of low and high-dose of nanocomposite decreased Cd content in leaves by about 42.86%, 60.48%, and the root by approximately 18.72%, 28.72%, respectively, and translocation factors and tolerance index, H2O2, O2, and malondialdehyde. In contrast, the application of high of the nanocomposite increased the values of SPAD chlorophyll about 27.50%, stomatal conductance about 87.18%, net photosynthetic rate about 44.90%, intercellular CO2 concentration about 32.00%, and transpiration rate about 85.20%, as compared to Cd stress. Furthermore, the application of low and high-dose Cs/Ag/MnMgFe2O4 nanocomposite enhances the antioxidant and non-antioxidant enzymes of the cabbage plant compared to Cd stress. Generally, it was conducted that Cs/Ag/MnMgFe2O4 nanocomposite can be used as a proper tool for increasing cabbage plants under Cd stress.
Broad bean mottle virus (BBMV) infects a wide range of hosts, resulting in significant production reductions. The lack of adequate and effective control methods involves implementing novel BBMV ...control strategies. Herein, we demonstrate the effect of different potassium concentrations (20, 40, and 60 mM) against BBMV in broad bean plants. Potassium could control BBMV infection in broad bean by inhibiting the virus. In addition, infection with BBMV caused a significant decrease in morphological criteria, SPDA, photosynthetic characteristics, phytohormones, and mineral content in broad bean leaves compared to control plants. The levels of reactive oxygen species (ROS) (hydrogen peroxide, hydroxyl radical, and oxygen anion) and ROS scavenging enzymes (catalase, superoxide dismutase, peroxidase, phenylaniline ammonia-lyase, chitinase, and 1,3 - glucanase) increased significantly in plants inoculated with BBMV alone or in the presence of K+. In addition, proline and phenolic compounds increased significantly after being infected with BBMV. In conclusion, treatment with a high potassium concentration (60 mM) alleviates the adverse effect of BBMV on broad bean plants by boosting secondary metabolites, phytohormones, and enzymatic antioxidants.
Bean yellow mosaic virus (BYMV) is the main cause of the mosaic and malformation of many plants, worldwide. Thus, the triggering of plant systemic resistance against BYMV is of great interest. In ...this endeavor, we aimed to explore the capacity of new carboxymethyl chitosan-titania nanobiocomposites (NBCs, NBC1,2) to trigger faba bean plants resistance against BYMV. Effects of NBCs on faba bean (Vicia faba L.) disease severity (DS), growth parameters, and antioxidant defense system activity were investigated under BYMV stress. Noticeably that the DS in NBCs-treated faba bean was significantly reduced compared to untreated plants. Moreover, treatment with NBCs was remarkably increased growth indices, photosynthetic pigments, membrane stability index, and relative water content compared to challenge control. Additionally, enzymatic and non-enzymatic antioxidants and total soluble protein were significantly increased. Contrary, electrolyte leakage, hydrogen peroxide, and lipid peroxidation were reduced. Interestingly that NBC1 has higher efficacy than NBC2 in triggering plant immune-system against BYMV as indicated from DS percentage (DS = 10.66% and 19.33% in case of plants treated with NBC1 and NBC2, respectively). This could be attributed to the higher content of TNPs in NBC1 (21.58%) as compared to NBC2 (14.32%). Overall, NBCs offer safe and economic antiviral agents against BYMV.
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The purpose of the present study is to investigate the role of hydrogen sulfide (H
2
S), in improving resistance to common bean salt stress. Method shows that common bean seeds were soaked in water ...and in two concentrations of sodium hydrosulfide (50 and 100 µM) for 8 h. After 25 days from sowing, the pots were irrigated with water and with two concentrations of NaCl (75 and 150 mM) until the end of the experiment. Results revealed that H
2
S relieved salt stress by decreasing growth inhibition and photosynthetic characteristics, and increasing osmolyte contents (proline and glycine betaine). Furthermore, H
2
S reduced oxidative damage by lowering lipid peroxidation, electrolyte leakage, and reactive oxygen species production such as hydrogen peroxide, hydroxyl radicals, and superoxide anion by increasing non-enzymatic antioxidants such as ascorbic acid and glutathione, as well as enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX), glutathione reductase (GR), and nitrate reductase (NR). Meanwhile, salt stress and H
2
S application increased the endogenous level of H
2
S, which was accompanied by an increase in nitric oxide concentration. H
2
S, in particular, maintained sodium (Na
+
) and potassium (K
+
) homeostasis in the presence of excess NaCl. In general, H
2
S effectively reduced oxidative stress in common bean plants by increasing relative expression levels of copper-zinc superoxide dismutase (
Cu-ZnSOD
),
CAT
, and glutathione S-transferase (
GST
). Applying H
2
S to common bean plants could protect them from salinity stress by maintaining the Na
+
/K
+
balance, boosting endogenous H
2
S and nitric oxide levels, and preventing oxidative damage by increasing antioxidant activity.
Water deficit is a significant environmental stress that has a negative impact on plant growth and yield. In this research, the positive significance of kaolin and SiO
nanoparticles in moderating the ...detrimental effects of water deficit on maize plant growth and yield is investigated. The foliar application of kaolin (3 and 6%) and SiO
NPs (1.5 and 3 mM) solutions increased the growth and yield variables of maize plants grown under normal conditions (100% available water) and drought stress conditions (80 and 60% available water (AW)). In addition, plants treated with SiO
NPs (3 mM) demonstrated increased levels of important osmolytes, such as proline and phenol, and maintained more of their photosynthetic pigments (net photosynthetic rate (PN), stomatal conductance (gs), intercellular CO
concentration (Ci), and transpiration rate (E)) than with other applied treatments under either stress or non-stress conditions. Furthermore, the exogenous foliar application of kaolin and SiO
NPs also reduced the amounts of hydroxyl radicals (OH), superoxide anions (O
), hydrogen peroxide (H
O
), and lipid peroxidation in maize plants experiencing a water deficit. In contrast, the treatments led to an increase in the activity of antioxidant enzymes such as peroxidase (POX), ascorbate peroxidase (APX), glutathione peroxidase (GR), catalase (CAT), and superoxide dismutase (SOD). Overall, our findings indicate the beneficial impact of the application of kaolin and silicon NPs, particularly the impact of SiO
NPs (3 mM) on managing the negative, harmful impacts of soil water deficit stress in maize plants.
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