Exploring the new dimensions of selenium research to understand the underlying mechanism of its uptake, translocation, and accumulation

Abstract

Selenium (Se) is a vital mineral for both plants and animals. It is widely distributed on the earth's crust and is taken up by the plants as selenite or selenate. Plants substantially vary in their physiological response to Se. The amount of Se in edible plants is genetically controlled. Its availability can be determined by measuring its phytoavailability in soil. The low concentration of Se in plants can help them in combating stress, whereas higher concentrations can be detrimental to plant health and in most cases it is toxic. Thus, solving the double‐edged sword problem of nutritional Se deficiency and its elevated concentrations in environment requires a better understanding of Se uptake and metabolism in plants. The studies on Se uptake and metabolism can help in genetic biofortification of Se in plants and also assist in phytoremediation. Moreover, Se uptake and transport, especially biochemical pathways of assimilation and incorporation into proteins, offers striking mechanisms of toxicity and tolerance. These developments have led to a revival of Se research in higher plants with significant break throughs being made in the previous years. This review explores the new dimensions of Se research with major emphasis on key research events related to Se undertaken in last few years. Further, we also discussed future possibilities in Se research for crop improvement.

The Phytoremediation Potential and Physiological Adaptive Response of Tamarix tetrandra Pall. Ex M. Bieb. during the Restoration of Chronosequence Fly Ash Deposits

“…In addition to passive uptake, active uptake of Se (selenite and selenate) is conditioned by mechanisms that are similar to those responsible for sulphur and phosphorus transportation. Thus, the form in which the plant absorbs Se is also partially impacted by differences in phosphate and sulphate concentrations in soil and plants [ 59 ]. In alkaline conditions, like those found at the investigated sites, selenate dominates.…”

“…A reduction in pH favours the dominance of selenite, the uptake of which is an active process mediated by phosphate transporters [ 60 ]. The lower pH of FA at L2, as well as the deficit of bioavailable P in FA at L1, and especially at L2, resulted in increased phosphate transporter activity in tamarisk, which may cause a significant increase in selenite uptake [ 59 ]. In contrast, it was found that an increase in phosphate concentrations in soil decreased Se uptake rates by 20–70% in the herbaceous plants Lolium perenne , Trifolium fragiferrum , Astragalus canadensis , A. bisulcatus and Triticum aestivum [ 61 , 62 , 63 ].…”

Selenium Biofortification: Roles, Mechanisms, Responses and Prospects

“…Transgenic plants have been engineered with greater Se tolerance, Se accumulation or reduced Se volatilization than their non-transgenic counterparts [197]. An example of this is the SeCys methyltransferase gene of Astragalus bisulcatus (two-grooved poison vetch) which was introduced into Arabidopsis thaliana to overexpress Se-methyl SeCys and g-glutamyl methyl SeCys in plant shoots [198], which resulted in an increased accumulation of Se within the plant. Other genes have been successfully targeted by genetic engineering in the last decade, with positive outcomes for Se bio-fortification.…”

Selenate and selenite transporters in proso millet: Genome extensive detection and expression studies under salt stress and selenium

“…Se absorption, transport, and translocation are influenced by a variety of parameters, including the quantity and type of Se in the environment, plant species, medium pH, and the presence of Sulphur and phosphorus ( Rasool et al., 2022 ). Agricultural soils are predominantly richer in selenate than selenite and the selenate being more water soluble is readily absorbed as compared to selenite ( Raina et al., 2021 ). As a result of the chemical analogy of selanate/selenite with sulphate and phosphate, their behavior in metabolism and transport in plants is closely related ( Raina et al., 2021 ).…”

“…Agricultural soils are predominantly richer in selenate than selenite and the selenate being more water soluble is readily absorbed as compared to selenite ( Raina et al., 2021 ). As a result of the chemical analogy of selanate/selenite with sulphate and phosphate, their behavior in metabolism and transport in plants is closely related ( Raina et al., 2021 ). A high concentration of Se seems to promote the pathway of “Starch and sucrose metabolism” as its treatment resulted in the accumulation of both forms of carbohydrates in potato ( Solanum tuberosum L.) ( Turakainen et al., 2004 ).…”