Selenium induced selenocysteine methyltransferase gene expression and antioxidant enzyme activities in Astragalus chrysochlorus

Abstract

-Astragalus sp. are used in folk medicine because of their biological activities and are known for the ability to accumulate high levels of selenium (Se). The purpose of this study was to explore gene expression of selenocysteine methyltransferase (SMT), responsible for forming MeSeCys, and activities of ascorbate peroxidase (APX), peroxidase (POX), catalase (CAT) and glutathione reductase (GR) enzymes in callus tissues of Astragalus chrysochlorus growing in different Se-containing media. Quantitative real-time polymerase chain reaction assay was done for quantifi cation of SMT gene transcript and it was normalized to actin gene. It was found that transcript level of callus tissues grown at 5.2 μM and 26.4 μM Se-enriched media was lower than that of the control callus. In contrast, a high level of Se (132.3 μM) in the medium caused an approximately 4.26 times higher level of SMT transcript in callus than the control. APX, POX, CAT and GR enzymes were all effected by different Se concentrations. While POX and APX activities were higher then control, CAT and GR activities decreased. These results show that an increase of SMT gene expression led to a rise in APX and POX, but a suppression of CAT and GR enzymes activities in Astragalus chrysochlorus. This suggests that Se could be involved in the antioxidant metabolism in Astragalus chrysochlorus.

Comparative transcriptomics provides novel insights into the mechanisms of selenium tolerance in the hyperaccumulator plant Cardamine hupingshanensis

“…Selenium is chemically similar to sulfur and is assimilated by plants via the same metabolic pathways 76 , 77 . Most plants nonspecifically take up selenate from the environment by means of sulfate transporters and assimilate selenate into organic forms of Se via S metabolic pathways 7 .…”

An Overview of Hazardous Impacts of Soil Salinity in Crops, Tolerance Mechanisms, and Amelioration through Selenium Supplementation

“…In this regard, the application of Se has been found to reduce the harmful effects of salinity and support the growth of maize (Zea mays L.), tomato (Solanum lycopersicum L.), and garlic (Allium sativum L.) through enhanced photosynthetic performance [29,30,122,129]. Moreover, enhanced growth and nutritional qualities of spinach (Spinacia oleracea L.), ryegrass (Lolium perenne L.), wheat (Triticum aestivum L.), and mung bean (Vigna radiate L.) have also been reported by exogenously applied Se under stressed and non-stressed conditions [22,106,142,146]. Further, a lower Na + concentration and higher K + /Na + ratio was observed in selenite-treated plants as compared to untreated plants [27].…”

Selenium Modulates the Level of Auxin to Alleviate the Toxicity of Cadmium in Tobacco

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