title: Selenium speciation in wheat grain varies in the presence of nitrogen and sulphur fertilisers.
abstract: This study investigated whether selenium species in wheat grains could be altered by exposure to different combinations of nitrogen (N) and sulphur (S) fertilisers in an agronomic biofortification experiment. Four Australian wheat cultivars (Mace, Janz, Emu Rock and Magenta) were grown in a glasshouse experiment and exposed to 3 mg Se kg-1soil as selenate (SeVI). Plants were also exposed to 60 mg N kg-1soil as urea and 20 mg S kg-1soil as gypsum in a factorial design (N + S + Se; N + Se; S + Se; Se only). Plants were grown to maturity with grain analysed for total Se concentrations via ICP-MS and Se species determined via HPLC-ICP-MS. Grain Se concentrations ranged from 22 to 70 µg Se g-1grain (dry mass). Selenomethionine (SeMet), Se-methylselenocystine (MeSeCys), selenohomolanthionine (SeHLan), plus a large concentration of uncharacterised Se species were found in the extracts from grains. SeMet was the major Se species identified accounting for between 9 and 24 µg Se g-1grain. Exposure to different N and S fertiliser combinations altered the SeMet content of Mace, Janz and Emu Rock grain, but not that of Magenta. MeSeCys and SeHLan were found in far lower concentrations (<4 µg Se g-1grain). A large component of the total grain Se was uncharacterisable (>30 % of total grain Se) in all samples. When N fertiliser was applied (with or without S), the proportion of uncharacterisable Se increased between 60 and 70 % of the total grain Se. The data presented here indicate that it is possible to alter the content of individual Se species in wheat grains via biofortification combined with manipulation of N and S fertiliser regimes. This has potential significance in alleviating or combating both Se deficiency and Se toxicity effects in humans.
authors.affiliation: CSIRO Agriculture, Centre for Environment and Life Sciences, Underwood Avenue, Floreat, WA, 6014, Australia. Elliott.Duncan@unisa.edu.au.|Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, University Drive, Bruce, ACT, 2601, Australia. Elliott.Duncan@unisa.edu.au.|Future Industries Institute, University of South Australia, Mawson Lakes Campus, Mawson Lakes, SA, 5095, Australia. Elliott.Duncan@unisa.edu.au.
authors.forename: Elliott G
authors.initials: EG
authors.lastname: Duncan
authors.affiliation: Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, University Drive, Bruce, ACT, 2601, Australia.
authors.forename: William A
authors.initials: WA
authors.lastname: Maher
authors.affiliation: Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, University Drive, Bruce, ACT, 2601, Australia.
authors.forename: Rajani
authors.initials: R
authors.lastname: Jagtap
authors.affiliation: Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, University Drive, Bruce, ACT, 2601, Australia.
authors.forename: Frank
authors.initials: F
authors.lastname: Krikowa
authors.affiliation: CSIRO Agriculture, Centre for Environment and Life Sciences, Underwood Avenue, Floreat, WA, 6014, Australia.
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Roper
authors.affiliation: CSIRO Agriculture, Centre for Environment and Life Sciences, Underwood Avenue, Floreat, WA, 6014, Australia.
authors.forename: Cathryn A
authors.initials: CA
authors.lastname: O'Sullivan
mesh_terms: D001315:Australia; D000072759:Biofortification; D003553:Cystine / Q000031:analogs & derivatives / Q000032:analysis; D005308:Fertilizers; D006710:Homocysteine / Q000031:analogs & derivatives / Q000032:analysis; D006801:Humans; D009584:Nitrogen / Q000494:pharmacology*; D016566:Organoselenium Compounds / Q000032:analysis; D012643:Selenium / Q000032:analysis* / Q000737:chemistry; D012645:Selenomethionine / Q000032:analysis; D013455:Sulfur / Q000494:pharmacology*; D014908:Triticum / Q000737:chemistry* / Q000187:drug effects*
chemical_list: C558639:4,4'-selenobis(2-aminobutanoic acid); D005308:Fertilizers; D016566:Organoselenium Compounds; D006710:Homocysteine; C009226:selenocystine; D003553:Cystine; D013455:Sulfur; D012645:Selenomethionine; D012643:Selenium; D009584:Nitrogen
keywords: Biofortification; Selenate; Selenohomolanthionine; Selenomethionine