Effect Of Selenium Biofortification On Wheat

Selenium(Se)is a beneficial mineral element for human,animal and plant.Selenium can boosting immune function and has important effects on protecting cardio-cerebrovascular diseases,liver,anti-cancer and anti-aged.For plants,Se can improve plant growth,increase production and plant stress resistance This paper studies the effect of Se-biofortification on wheat grain-related traits,interaction effects among Se accumulation and N accumulation,inhibiting effect on Fusarium head blight(FHB),as well as QTL mapping for Se tolerance in wheat.This study provides a theoretical basis for making better use of Se-biofortification in wheat to answer national Se deficiency and provides new ideals on increasing N fertilizer utilization the innovative control methods of FHB.(1)Pot experiment was conducted and 110 wheat cultivars were collected as materials.Three levels of0,100 and 150mg·kg-1 soil were designed and applied uniformly into soil in before wheat planting The mean 100-kernel weight was 3.78,4.11,and 3.70g,respectively,and the total Se concentration was averaged 2.00,12.46 and 17.35 mg·kg-1,respectively.Se was mainly existed in organic forms,of which Selenomethionin(SeMet)is the predominant form,and then were methylated Selenocysteine(MeSeCys)and selenocysteine(SeCys).Application of Nano-Se fertilizer had either synergistically or antagonistically effects on the accumulation of the tested nutrient elements,but did not on the flour paste viscosity properties.114 cultivars(or lines)were biofortificatied with selenate.Four lever:0?00?200?300mg kg-1 100mL·line-1.The total Se concentration was averaged 1.54,5.70,10.01 and 13.10mg·kg-1 for the four levels of selenate solution respectively.The other mineral elements responded either synergistically or antagonistically to selenate application.In general,selenate decreased the concentrations of Ca,Mg,Cu,Fe,Mn and S,but increased Zn concentration in grains.63 wheat cultivars in Jiangsu Province were biofortifited with Selenate.The results indicated that selenate application(300mg Se·L-1)significantly increased Se concentrations in grains of wheat from 2.13 mg·kg-1 in CK group to 9.13 mg·kg-1 in Se-treated groups.Selenate decreased the concentrations of Cu,Fe,K,Ca,Mg,and S,and increased Zn concentration in grains,but had no effect on Mn and Mg concentration.(2)To evaluate the effect of high Se concentration on wheat,six agronomic traits of wheat were measured.99 wheat accessions included landraces and commercial varieties were potted,treated by 120 mg·kg-1.Wheat 9,OOOSNP infinium associated with the difference of agronomic traits(Se120-Se0),extract three principal components from six difference agronomic traits,use these three principal components associated with 9,000 SNP.A total of 44 SNP were found to be associated with Se tolerance(P<0.01).13 Se tolerance alleles and 8 Se sensitive alleles were identified,such as SNP2565-TT and SNP3597-GG were Se tolerance alleles with lager effect,SNP2949-CC and SNP3584-CC were Se sensitive alleles with lager effect.With the number of Se sensitive alleles increased,Se tolerance of wheat and Se concentration in grain were both decreased.We found 6209 and Youmai3 were representative Se tolerance cultivars while Corrine,Field-H and Jupatecar(34+)were representative Se sensitive cultivars.(3)We designed the greenhouse Se-N experiment of potted plant by using Ning7840 and a self-selected high generation line7001 in 2016 and 2017 to study interaction of Se and N during the growth of wheat.The experimental results show Se application can promote N uptake in wheat and the stimulating effect on promoting N uptake in wheat will be more significant with N concentration increasing.In addition,N application can also promote Se uptake in wheat and the promoting efficiency is associated with N concentration.Detailed results are that N promote Se uptake in wheat at low N concentration while the promote efficiency will be repressed or even show decline at high N concentration compared to the control.N concentration in different organs is grain>leaf>stem,Se concentration in different organs is grain>stem>leaf at low Se concentration while the Se concentration in different organs is leaf>grain>stem at high Se concentration.Thus,this experiment provides the new idea and method for high-efficient of Se fortification and increasing N fertilizer utilization.(4)We designed the vitro experiment and vivo experiment to provide a reference for chemical control of FHB to study the control effect that Se does on FHB in wheat.Vitro experiment in culture shows Se can significantly inhibit the gibberella growth and the production of DON in culture.Besides,the gibberella growth has more vigorous growth and stronger toxin producing ability under the condition of grain compared to the culture without grain.Vivo experiments on plant shows spraying Se can inhibit the gibberella expansion on wheat ear and organic Se(Secys)has optimum efficiency.DON determination was conducted on F.g-inoculated grains which were sprayed with sodium selenite and sodium selenite pentahydrate,and we find both spraying sodium selenite and sodium selenite pentahydrate in both cultivars can significantly decrease DON concentration compared to the control.In conclusion,both the vitro experiment and vivo experiment indicate Se can inhibit the growth and expansion of gibberella and the production of DON.