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

Abstract

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.

Antibiotic consumption in hospitals during COVID-19 pandemic: a comparative study

“…These findings are consistent with other studies. In addition, the results demonstrated an increase in the use of azithromycin in 2020, consistent with other studies reporting increased use of azithromycin during the COVID-19 pandemic, especially in combination with hydroxychloroquine [26,32,[33][34][35]. This could be due to physicians' prior experience with azithromycin for respiratory infections, or it could be related to widespread off-label usage of azithromycin for the treatment of COVID-19 in other countries.…”

“…This drop-in usage may be attributed to the increased use of other antibiotics such as azithromycin. However, other studies have reported a positive incremental change in third and fourth generation cephalosporin and lincosamide consumption [26][27][28][29][30]. This may be related to differences in race, variations in the most common infections, and the development of resistance in treated patients.…”

“…However, other studies do not support the use of azithromycin to treat patients diagnosed with mild to moderate COVID-19 because it did not lead to a reduction in the risk of subsequent hospital readmissions or deaths [39]. Studies have shown that azithromycin alone, or in combination with hydroxychloroquine is ineffective in treating COVID-19 patients admitted to hospitals [26,[40][41][42][43].…”

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

“…As the toxicity of mercury is increasing globally, it is critical to take serious action to limit its pollution and prevent its accumulation in highly consumed crops as wheat. Although several approaches, such as phytoremediation, soil remediation, and heavy-metal-resistant cultivars, may help to reduce heavy metal deposition in crops, their effectiveness is limited (Rizwan et al 2012;Badawy et al 2022). Hu et al (2020) found that synthesized or natural-sourced elicitors are highly effective approaches to minimizing heavy metal toxicity in plants.…”

Secondary metabolites, hormonal homeostasis, and antioxidant enzymes of Moringa oleifera in response to white or violet Light Emitting Diodes (LEDs) combined with cytokinins under tissue culture conditions

“…An appropriate plant growth promoter is moringa leaf extract, which is rich in K, Ca, Fe, amino acids, carotenoids, phenols, ascorbate, and growth-regulating hormones (Basra et al, 2009;Ragaey et al, 2022). Plant defense against oxidative stress depends on antioxidants like ascorbic acid and glutathione, which are abundant in the chloroplasts of the moringa plant and other cellular compartments (Badawy et al, 2022;Sofy et al, 2021). According to Lee et al, (2008), the combined action of red and blue light may boost the accumulation of bioactive substances such as total polyphenols, anthocyanins, and flavonoids for all the antioxidant components thus tested.…”