Physiological Function of Selenium in Plants

The global understanding of selenium(Se)in plant biology mainly comes from the fields of medicine and animal science,while the research on Se in plant biology in the field of plant science lags behind.This paper summarized the physiological functions of Se in plants.These studies indicate that Se can promote plant seed development and growth and plant photosynthesis,increase plant economic yield and quality,and enhance plant antioxidant capacity and resistance to stress.However,its effects have a"dual"character,and its concentration or dosage range is very narrow.At appropriate concentrations,Se has an important impact on the physiological processes of plants and is a beneficial element for many plants to maintain health and good growth and development.

Enhanced protective effect of selenium-biofortified peptide RYNA(Se)MNDYT compared with its native peptide RYNAMNDYT in lipopolysaccharide-injured murine gut microbiota

Selenopeptides may be a valuable bioactive compound to promote gut microbiota-targeted therapeutic methods for intestinal disease and hepatopathy.However,limited information is available on the utilization of selenopeptides by gut microbiota,especially Selenium(Se)function.For this purpose,the present study aimed to investigate the protective effect of selenopeptide(RYNA(Se)MNDYT,Se-P2,purity of≥95%)and its original peptide(RYNAMNDYT,P2,purity of≥95%)in vivo by the microbiota-metabolite axis and further analyze the potential contribution of Se biofortification to Se-P2 bioactivity.The results showed that Se-P2 exhibits a higher protective effect on lipopolysaccharide(LPS)-induced inflammation than P2,including pathology of the colon and liver,which suggested that the bioactivity of P2 was promoted by the organic combination of Se.Notably,gut microbiota composition tended to be a healthy structure by Se-P2 pretreatment in LPS-injured mice,which had a positive effect on LPS-induced gut microbiota dysbacteriosis.Additionally,only Se-P2 promoted an increase in the relative abundance of Lactobacillus,Alistipes,and Roseburia and a decrease in the relative abundance of Akkermansia,Erysipelatoclostridium,and Bacteroides in LPS-injured mice.The changes in gut microbiota were obviously correlated with the changes in metabolites and affected the metabolic pathways of valine,leucine,isoleucine,phenylalanine,tyrosine,and tryptophan biosynthesis and phenylalanine metabolism.This may be one of the key reasons for Se-P2 to exert bioactivity through the microbiota-metabolite axis.Furthermore,Se-biofortification in Se-enriched Cordyceps militaris affected the parental proteins of Se-P2 to modulate mitogen-activated protein kinase,GPI anchored protein,and carbohydrate metabolism,translation,folding,sorting and degradation,which may contribute to the bioactivity of Se-P2.Our study provides information on the effect of Se on selenopeptides in vivo,which further promotes the prospective applications of selenopeptides as dietary supplements.

Selenium-oxidizing Agrobacterium sp.T3F4 decreases arsenic uptake by Brassica rapa L.under a native polluted soil

Toxic arsenic(As)and trace element selenium(Se)are transformed by microorganisms but their complex interactions in soil-plant systems have not been fully understood.An Asand Se-oxidizing bacterium,Agrobacterium sp.T3F4,was applied to a native seleniferous As-polluted soil to investigate As/Se uptake by the vegetable Brassica rapa L.and As-Se interaction as mediated by strain T3F4.The Se content in the aboveground plants was significantly enhanced by 34.1%,but the As content was significantly decreased by 20.5% in the T3F4-inoculated pot culture compared to the control(P<0.05).Similar result was shown in treatment with additional 5 mg/kg of Se(IV)in soil.In addition,the As contents in roots were significantly decreased by more than 35% under T3F4 or Se(IV)treatments(P<0.05).Analysis of As-Se-bacterium interaction in a soil simulation experiment showed that the bioavailability of Se significantly increased and As was immobilized with the addition of the T3F4strain(P<0.05).Furthermore,an As/Se co-exposure hydroponic experiment demonstrated that As uptake and accumulation in plants was reduced by increasing Se(IV)concentrations.The 50% growth inhibition concentration(IC50)values for As in plants were increased about one-fold and two-fold under co-exposure with 5 and 10μmol/L Se(IV),respectively.In conclusion,strain T3F4 improves Se uptake but decreases As uptake by plants via oxidation of As and Se,resulting in decrease of soil As bioavailability and As/Se competitive absorption by plants.This provides a potential bioremediation strategy for Se biofortification and As immobilization in As-polluted soil.