Selenium metabolism and factors affecting selenium accumulation in plants

Selenium (Se) is an essential micronutrient for animal and human nutrition that plays an indispensable role in various physiological processes. However, Se at high concentration is toxic to all living organisms. Se is not considered an essential element for plants, but the ability of some plants to accumulate and transform Se into bioactive compounds has important implications for human nutrition and health, and for the environment. The element Se is necessary for the synthesis of the amino acid selenocysteine, which is involved in the formation of approximately 25-35 selenoproteins in humans. Selenoproteins play important roles in antioxidant function, thyroid hormone metabolism, reproduction, and immune responses. Se biological forms like selenocysteine and selenomethionine are the key constituents of glutathione peroxidases, thioredoxin reductase, and iodothyronine deiodinase, which is crucial in the healthy functioning of the endocrine system and plays a great role in various physiological processes. Despite its importance, Se deficiency is now recognized as a significant detriment to human health and continues to be a global challenge, affecting an estimated more than a billion people, particularly in regions where food crops are grown in Se-deficient soils. Since plants are the main sources of dietary Se for human and animal consumption worldwide, understanding the mechanism of selenium metabolism and selenium accumulation in plants is of great importance to increase Se content in plants. Therefore, the objective of this study is to understand the mechanisms of Se metabolism and factors affecting Se accumulation in plants, focusing on the model plant Arabidopsis thaliana. In this study, wild-type (WT) accessions of Arabidopsis (Arabidopsis thaliana) (L.) Heynh. Ecotype Columbia 0 (Col‐0) and three single mutant lines GGCT, GGT, and GGT4 were grown in a controlled growth chamber. After two weeks of plant growth, a concentration of 100 μM of sodium selenate was applied for the study. Certain parameters, such as phenotypic measurements, SPAD values (chlorophyll contents), leaf fresh weight, leaf dry weight, dry matter content were determined. The statistical analysis was conducted by a generalized additive model using R Studio. ANOVA results showed that the addition of Se to the plants improves the plant growth, improves chlorophyll content, and improves plant health and yield compared to the control treatments. Similarly, plants treated with Se had more Se tolerance as compared to the control. While our findings are more aligned with the existing literature on Se metabolism and factors affecting Se accumulation in plants, further research supported by molecular studies and gene expression using technologies like proteomics, metabolomics, and transcriptomics across a range of plant species is needed. This research will provide insights into the selenium metabolic pathways and its accumulation in plants, which could lead to novel biofortification strategies with the aim to improve crop nutritional quality and address selenium deficiency in human diets.