Selenite uptake by Medicago sativa L. roots

Abstract

This study aimed to examine selenite uptake in Medicago sativa L. Potted alfalfa plants were grown in sterilized quartz sand and exposed to 1 and 10 μM selenite for 21 days.Thirty-day-old seedlings and excised roots were used to determine the mechanism of selenite uptake in alfalfa. The following patterns of Selenium (Se) distribution in roots were as follows: lateral roots > taproots and subcellular fraction (I) > fraction (III) > fraction (II). With increasing pH, Se uptake in roots decreased markedly. The dosedependent Se net uptake at pH 5.5 followed the Michaelis-Menten kinetics. Addition of phosphate decreased Se uptake in the excised roots (P < 0.05), whereas a deficiency in phosphate increased Se uptake (P < 0.05). The results indicate that alfalfa mainly absorbed selenium through lateral roots. Selenite uptake by alfalfa root depended on pH, with the preferential form absorption of as H 2 SeO 3 > HSeO 3 1À > SeO 3 2À . A portion of selenite was absorbed actively and may be mediated by phosphate transporter.

Mechanistic characterization of waterborne selenite uptake in the water flea, Daphnia magna, indicates water chemistry affects toxicity in coal mine-impacted waters

“…The inhibition of selenite uptake at low concentrations (≤4 μM; 316 μg l −1 ) by phosphate addition to the test water indicated that this anion was a key competitor. This hypothesis that selenite uptake likely occurs through a phosphate transporter is consistent with studies on selenite uptake in plants and yeast ( Lazard et al, 2010 ; Araie et al, 2011 ; Zhang et al, 2014 ; Vriens et al, 2016 ; Wang et al, 2019 ; Bai et al, 2022 ). The finding of selenite uptake in D. magna via a phosphate transporter is further supported by the effect of application of the phosphate transporter inhibitor PFA/foscarnet, wherein increased levels of this blocker reduced selenite uptake.…”

“…For example, in human erythrocytes, selenite uptake is likely achieved by the bicarbonate/chloride anion exchanger (AE1 or Band 3 or SLC4A1; Kaur et al, 2020 ), while McDermott et al (2016) suggested selenite uptake was associated with ZIP8 (SLC39A8) and was transported into a variety of mammalian cells along with zinc and bicarbonate as part of an electroneutral transport process. In plants, considerable research links selenite uptake to phosphate transporters ( Zhang et al, 2014 ; Wang et al, 2019 ; Bai et al, 2022 ), and evidence also exists for phosphate transporter-mediated selenite uptake in yeast ( Lazard et al, 2010 ) and in phytoplankton ( Araie et al, 2011 ), although in both groups alternative pathways have also been suggested (monocarboxylate transporters in yeast; McDermott et al, 2010 ; sulphate and nitrate transporters in phytoplankton; Morlon et al, 2006 ). In the bacterium Escherichia coli , selenite uptake is proposed to be achieved by a sulphate transporter ( Lindblow-Kull et al, 1985 ).…”

Molecular Mechanisms of the Effects of Sodium Selenite on the Growth, Nutritional Quality, and Species of Organic Selenium in Dandelions

“…Vegetable crops are Horticulturae 2024, 10, 209 2 of 23 the main source of dietary Se intake for the human body, so planting Se-rich crops is of great significance for supplementing Se to the human body [9]. Se is mainly utilized by plants in the form of inorganic salts, such as selenite (SeIV) and selenate (SeVI), which are absorbed within the plant through sulfate transporters, and selenite enters the plant through active transport mediated by phosphate transporters [10,11]. Earlier studies in mustard showed that PHO1-H8 promoted the absorption of Na 2 SeO 3 by mustard roots, while SULTR 3;3 and SULTR 4;1 promoted the transport of Se from the roots to shoots and chloroplasts.…”