Silver-based nanomaterials for plant diseases management: Today and future perspectives

et al. 2022

Plants

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Cadmium (Cd) and nickel (Ni) are two of the most toxic metals, wreaking havoc on human health and agricultural output. Furthermore, high levels of Cd and Ni in the soil environment, particularly in the root zone, may slow plant development, resulting in lower plant biomass. On the other hand, endophytic bacteria offer great promise for reducing Cd and Ni. Moreover, they boost plants’ resistance to heavy metal stress. Different bacterium strains were isolated from tomato roots. These isolates were identified as Micrococcus luteus and Enterobacter cloacae using 16SrDNA and were utilized to investigate their involvement in mitigating the detrimental effects of heavy metal stress. The two bacterial strains can solubilize phosphorus and create phytohormones as well as siderophores. Therefore, the objective of this study was to see how endophytic bacteria (Micrococcus luteus and Enterobactercloacae) affected the mitigation of stress from Cd and Ni in tomato plants grown in 50 μM Cd or Ni-contaminated soil. According to the findings, Cd and Ni considerably lowered growth, biomass, chlorophyll (Chl) content, and photosynthetic properties. Furthermore, the content of proline, phenol, malondialdehyde (MDA), H2O2, OH, O2, the antioxidant defense system, and heavy metal (HM) contents were significantly raised under HM-stress conditions. However, endophytic bacteria greatly improved the resistance of tomato plants to HM stress by boosting enzymatic antioxidant defenses (i.e., catalase, peroxidase, superoxide dismutase, glutathione reductase, ascorbate peroxidase, lipoxygenase activity, and nitrate reductase), antioxidant, non-enzymatic defenses, and osmolyte substances such as proline, mineral content, and specific regulatory defense genes. Moreover, the plants treated had a higher value for bioconcentration factor (BCF) and translocation factor (TF) due to more extensive loss of Cd and Ni content from the soil. To summarize, the promotion of endophytic bacterium-induced HM resistance in tomato plants is essentially dependent on the influence of endophytic bacteria on antioxidant capacity and osmoregulation.

Section: Discussionsupporting

confidence: 94%

Alleviation of Cadmium and Nickel Toxicity and Phyto-Stimulation of Tomato Plant L. by Endophytic Micrococcus luteus and Enterobacter cloacae

Badawy

Hmed

et al. 2022

Plants

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“…These polysaccharides in algal extracts could Vol. : (0123456789) boost germination and root (Mohamed et al 2021) due to their biological activities as a stimulator of defense responses in plants (Dawood et al 2022a, b). Moreover, the different extracts of the present work nearly showed characteristic bands of indoles viz., 3296-3405, 1538-1541, 1654-1658, 1454-1455, and 720 cm −1 .…”

Section: Discussionmentioning

confidence: 99%

N- or/and P-deprived Coccomyxa chodatii SAG 216–2 extracts instigated mercury tolerance of germinated wheat seedlings

et al. 2022

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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.

“…More than 20% of the world's soils are affected by salt stress, and the extent of these soils is constantly expanding due to anthropogenic activities and climate change (Sofy et al 2021b). Environmental stresses are thought to be responsible for half of all crop losses, posing a severe danger to global food security (Mohamed et al 2021a). In addition, food production must be boosted by 70% by the end of 2050 as a result of the significant increase in the world population (Agha et al 2021).…”

Section: Introductionmentioning

confidence: 99%

“…One of the most harmful salinity impacts is oxidative damage induced by a considerable concentration of reactive oxygen species (ROS) (Saddiq et al 2021). The accumulation of ROS promotes the oxidation of proteins and lipids (Sofy et al 2021a). It obstructs normal cellular activity by causing the malfunction of critical cellular organelles, such as chloroplasts (Nigam et al 2022).…”

Section: Introductionmentioning

confidence: 99%

“…Phaseolus vulgaris L. is a useful legume crop in Egypt and many other nations (Mohamed et al 2021b). Furthermore, P. vulgaris provides roughly half of the world's grain legumes, providing a high amount of protein and nutrients in human nutrition that are critical for human health (Mohamed et al 2021a). Furthermore, common beans are considered a salt-sensitive crop and suffer from yield reductions in soil containing salinity levels of less than 2 d Sm −1 (Assimakopoulou et al 2015).…”

Section: Introductionmentioning

confidence: 99%

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Hydrogen Sulfide Modulates Salinity Stress in Common Bean Plants by Maintaining Osmolytes and Regulating Nitric Oxide Levels and Antioxidant Enzyme Expression

Mohamed

et al. 2022

J Soil Sci Plant Nutr

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The purpose of the present study is to investigate the role of hydrogen sulfide (H2S), 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 H2S relieved salt stress by decreasing growth inhibition and photosynthetic characteristics, and increasing osmolyte contents (proline and glycine betaine). Furthermore, H2S 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 H2S application increased the endogenous level of H2S, which was accompanied by an increase in nitric oxide concentration. H2S, in particular, maintained sodium (Na+) and potassium (K+) homeostasis in the presence of excess NaCl. In general, H2S 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 H2S to common bean plants could protect them from salinity stress by maintaining the Na+/K+ balance, boosting endogenous H2S and nitric oxide levels, and preventing oxidative damage by increasing antioxidant activity.