Selenite Uptake and Transformation in Rice Seedlings (Oryza sativa L.): Response to Phosphorus Nutrient Status

Abstract

Selenite and phosphate share similar uptake mechanisms, as a phosphate transporter is involved in the selenite uptake process. However, the mechanism by which selenium (Se) transformation in plants is mediated by phosphorus (P) remains unclear. In this hydroponic study, the absorption, translocation, and biotransformation of Se in selenitetreated rice (Oryza sativa L.) seedlings were investigated under varying P nutrient status. The results showed that P-deficient cultivation increased the Se concentration in roots with Se-only treatment by 2.1 times relative to that of the P-normal condition. However, co-treating roots with additional P caused the Se concentration to decline by 20 and 73% compared to Se treatment alone under P-normal and P-deficient cultivation, respectively. A similar pattern was also observed in Se uptake by rice roots. With an Se-transfer factor elevated by 4.4 times, the shoot Se concentration was increased by 44% with additional P supply compared to the concentration under Se-only treatment of P deficiency; however, no significant differences were observed regarding P-normal cultivation. P deficiency increased the Se percentage by 28% within the cell wall, but reduced it by 60% in the soluble fraction of Se-only treated roots relative to that of the P-normal condition. Contrarily, compared with the Se-only treatment under P deficiency, additional P supply enhanced Se storage in the root soluble fraction by 1.3 times. The opposite tendency was observed for rice shoots. Moreover, P deficiency reduced the proportion of SeMet by 22%, but increased MeSeCys by 1.3 times in Se-only treated roots compared to those under the P-normal condition. Interestingly, MeSeCys was not detected when additional P was added to the two cultivation conditions. Unlike in the roots, only SeMet was generally detected in the rice shoots. The results demonstrate that the P nutrient status strongly affects the Se biofortification efficiency in rice seedlings by altering the Se subcellular distribution and speciation.

Selenite uptake by Medicago sativa L. roots

“…in tomatoes (Lycopersicon esculentum),Zhang et al (2006) in rice (O. sativa) andLi et al (2010) in wheat (T. aestivum L.). In addition, phosphate and sulfate deficiencies decreased Se accumulation in shoots, which is consistent with the findings ofWang et al (2020), indicating that Se transport form root to shoot may be inhibited by phosphate and sulfate deficiency.5 | CONCLUSIONSLateral roots contained the highest concentration of Se in the root system of alfalfa. Excessive Se was immobilized by cell wall fraction to protect plants from Se toxicity.…”

Uptake Dynamics of Ionic and Elemental Selenium Forms and Their Metabolism in Multiple-Harvested Alfalfa (Medicago sativa L.)

“…Yet, the agronomic biofortification of Se, added as either soil or foliar application, has recently gained extraordinary attention due to its easy, safe, and effective application. Treating growing plants/forages by different chemical Se forms not only increases the total Se content in plant biomass but also alerts the content of several bioactive compounds [ 9 , 31 ].…”

Advances in Research on the Involvement of Selenium in Regulating Plant Ecosystems

“…Selenite can be taken up by the root system through phosphate transporter proteins, such as rice OsPT2 [ 20 ], and transported to other parts of the plant via the xylem, where selenite is rapidly converted into organoselenium compounds [ 21 , 22 , 23 ]. There are other ways for selenite to enter plants; rice, for example, can absorb selenite through aquaporins and the Si influx transporter OsNIP2;1 [ 24 , 25 ].…”