24-Epibrassinolide modulates primary metabolites, antioxidants, and phytochelatins in Acutodesmus obliquus exposed to lead stress

Abstract

Aquatic organisms are exposed to many stressors, e.g., heavy metals. Brassinosteroids, a plant hormone group, can effectively stimulate plants to defend against the negative impact of a heavy metal. The present study was conducted with an aim to find out the influence of 24-epibrassinolide (EBL) on Acutodesmus obliquus treated with 0.01 and 500 μM of lead (Pb) ions during 7 days of cultivation. Pb has a toxic effect on algal cultures because it limits both the growth and development and induces oxidative stress. Simultaneously, 1 μM EBL was involved in protecting algal cells against the toxic effect of Pb. Despite the presence of Pb, EBL significantly increased the number of algal cells and their metabolite content (e.g., proteins, monosaccharides, chlorophylls, carotenes, and xanthophylls). Cultures treated concurrently with EBL and Pb were characterized by a reduction in their content of endogenous Pb, H 2 O 2 , and malondialdehyde. Also, EBL increased the activity of catalase, ascorbate peroxidase, superoxide dismutase, glutathione reductase, and the content of ascorbate and glutathione. EBL increased the phytochelatin synthase activity, thereby enhancing the production of phytochelatins accountable for both binding and detoxification of Pb. These results indicate the influence of EBL on the inhibitory effect of Pb in A. obliquus. These findings help to clarify the role of BRs in the algal adaptation to the prevailing stressful conditions.

Melatonin Involved in Protective Effects against Cadmium Stress in Wolffia arrhiza

“…The influence of heavy metals on chlorophylls and carotenoids with separated xanthophyll content was studied in algae and agricultural uses. Similar to our results, Pb caused a decrease in pigment amount in Acutodesmus obliquus [ 50 , 51 ]. In the current work, the reduced level of pigments was observed under the influence of Cd.…”

“…The retention times of GSH and PCs were established using their standards. The wavelengths of excitation and emission were 380 and 470 nm, respectively [ 51 , 81 ].…”

Co-Application of 24-Epibrassinolide and Titanium Oxide Nanoparticles Promotes Pleioblastus pygmaeus Plant Tolerance to Cu and Cd Toxicity by Increasing Antioxidant Activity and Photosynthetic Capacity and Reducing Heavy Metal Accumulation and Translocation

“…The reduction in plant growth by heavy metal toxicity is related to the number of intercellular metal ions bound to the surface of the cell [86,87]. Our results showed that EBL could increase the plant biomass and plant growth under heavy metal toxicity, which could be related to the role of EBL in the reduction in intercellular metal ions, a phenomenon that has been confirmed in a study on A. obliquus [63]. However, the role of EBL in plant growth regulation during the stimulation of plant defense mechanisms can also be considered.…”

“…Conversely, EBL has the ability to positively alter the membrane structure and membrane stability in plants exposed to stresses, such as heavy metals, which leads to a reduction in membrane lipid peroxidation [62]. In one study, the level of EBL was observed to diminish the concentrations of H 2 O 2 and MDA (20-60% reductions) in plants under Pb stress [63]. In another study, EBL diminished the oxidative toxicity in cowpea under Cd by reducing lipid peroxidation, MDA content, and electrolytes [64,65].…”

Ionic homeostasis and redox metabolism upregulated by 24‐epibrassinolide are crucial for mitigating nickel excess in soybean plants, enhancing photosystem II efficiency and biomass

“…The chelation of the metal ions by phytochelatins is one of the mechanisms for heavy metal detoxification in plants (Talarek‐karwel et al . 2020). Phytochelatins are cysteine‐rich polypeptides derived from glutathione (Batista et al .…”