Methyl jasmonate alleviates cadmium toxicity in Solanum nigrum by regulating metal uptake and antioxidative capacity

The principal intent of the investigation was to examine the influence of joint application of methyl jasmonate (MeJA, 10 μM) and a nitric oxide–donor sodium nitroprusside (SNP, 100 μM) to wheat plants grown under cadmium (Cd as CdCl2, 100 μM) stress. Cd stress suppressed plant growth, chlorophylls (Chl), and PSII maximum efficiency (Fv/Fm), but it elevated leaf and root Cd, and contents of leaf proline, phytochelatins, malondialdehyde, and hydrogen peroxide, as well as the activity of lipoxygenase. MeJA and SNP applied jointly or singly improved the concentrations of key antioxidant biomolecules, e.g., reduced glutathione and ascorbic acid and the activities of the key oxidative defense system enzymes such as catalase, superoxide dismutase, dehydroascorbate reductase, glutathione S-transferase, and glutathione reductase. Exogenously applied MeJA and SNP jointly or singly also improved nitrogen metabolism by activating the activities of glutamine synthetase, glutamate synthase, and nitrate and nitrite reductases. Compared with individual application of MeJA or SNP, the combined application of both showed better effect in terms of improving plant growth and key metabolic processes and reducing tissue Cd content, suggesting a putative interactive role of both compounds in alleviating Cd toxicity in wheat plants.Main findingsThe main findings are that exogenous application of methyl jasmonate and nitric oxide–donor sodium nitroprusside alleviated the cadmium (Cd)–induced adverse effects on growth of wheat plants grown under Cd by modulating key physiological processes and up-regulating enzymatic antioxidants and the ascorbic acid–glutathione cycle–related enzymes.

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Metal complexation by histidine-rich peptides confers protective roles against cadmium stress inEscherichia colias revealed by proteomics analysis

PeerJ ◽

10.7717/peerj.5245 ◽

2018 ◽

Vol 6 ◽

pp. e5245 ◽

Cited By ~ 3

Author(s):

Patcharee Isarankura-Na-Ayudhya ◽

Chadinee Thippakorn ◽

Supitcha Pannengpetch ◽

Sittiruk Roytrakul ◽

Chartchalerm Isarankura-Na-Ayudhya ◽

...

Keyword(s):

Gel Electrophoresis ◽

Metal Uptake ◽

Cadmium Toxicity ◽

Surface Membrane ◽

Cadmium Stress ◽

Cellular Responses ◽

Metal Complexation ◽

Two Dimensional ◽

Cadmium Ions ◽

In Cells

The underlying mechanism and cellular responses of bacteria against toxic cadmium ions is still not fully understood. Herein,Escherichia coliTG1 expressing hexahistidine-green fluorescent protein (His6GFP) and cells expressing polyhistidine-fused to the outer membrane protein A (His-OmpA) were applied as models to investigate roles of cytoplasmic metal complexation and metal chelation at the surface membrane, respectively, upon exposure to cadmium stress. Two-dimensional gel electrophoresis (2-DE) and two-dimensional difference in gel electrophoresis (2D-DIGE) in conjunction with mass spectrometry-based protein identification had successfully revealed the low level expression of antioxidative enzymes and stress-responsive proteins such as manganese-superoxide dismutase (MnSOD; +1.65 fold), alkyl hydroperoxide reductase subunit C (AhpC; +1.03 fold) and DNA starvation/stationary phase protection protein (Dps; −1.02 fold) in cells expressing His6GFP in the presence of 0.2 mM cadmium ions. By contrarily, cadmium exposure led to the up-regulation of MnSOD of up to +7.20 and +3.08 fold in TG1-carrying pUC19 control plasmid and TG1 expressing native GFP, respectively, for defensive purposes against Cd-induced oxidative cell damage. Our findings strongly support the idea that complex formation between cadmium ions and His6GFP could prevent reactive oxygen species (ROS) caused by interaction between Cd2+and electron transport chain. This coincided with the evidence that cells expressing His6GFP could maintain their growth pattern in a similar fashion as that of the control cells even in the presence of harmful cadmium. Interestingly, overexpression of either OmpA or His-OmpA inE. colicells has also been proven to confer protection against cadmium toxicity as comparable to that observed in cells expressing His6GFP. Blockage of metal uptake as a consequence of anchored polyhistidine residues on surface membrane limited certain amount of cadmium ions in which some portion could pass through and exert their toxic effects to cells as observed by the increased expression of MnSOD of up to +9.91 and +3.31 fold in case of TG1 expressing only OmpA and His-OmpA, respectively. Plausible mechanisms of cellular responses and protein mapping in the presence of cadmium ions were discussed. Taken together, we propose that the intracellular complexation of cadmium ions by metal-binding regions provides more efficiency to cope with cadmium stress than the blockage of metal uptake at the surface membrane. Such findings provide insights into the molecular mechanism and cellular adaptation against cadmium toxicity in bacteria.

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