Abstract
In its natural habitat, Astragalus bisulcatus can accumulate up to 0.65% (w/w) selenium (Se) in its shoot dry weight. X-ray absorption spectroscopy has been used to examine the selenium biochemistry of A. bisulcatus. High concentrations of the nonprotein amino acid Se-methylseleno-cysteine (Cys) are present in young leaves of A. bisulcatus, but in more mature leaves, the Se-methylseleno-Cys concentration is lower, and selenate predominates. Seleno-Cys methyltransferase is the enzyme responsible for the biosynthesis of Se-methylseleno-Cys from seleno-Cys and S-methyl-methionine. Seleno-Cys methyltransferase is found to be expressed in A. bisulcatus leaves of all ages, and thus the biosynthesis of Se-methylseleno-Cys in older leaves is limited earlier in the metabolic pathway, probably by an inability to chemically reduce selenate. A comparative study of sulfur (S) and Se in A. bisulcatus using x-ray absorption spectroscopy indicates similar trends for oxidized and reduced Se and S species, but also indicates that the proportions of these differ significantly. These results also indicate that sulfate and selenate reduction are developmentally correlated, and they suggest important differences between S and Se biochemistries.
| Original language | English |
|---|---|
| Pages (from-to) | 1460-1467 |
| Number of pages | 8 |
| Journal | Plant Physiology |
| Volume | 131 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - Mar 2003 |
Keywords
- ray-absorption spectroscopy
- non-accumulator plants
- cancer prevention
- ATP sulfurylase
- selenate uptake
- Indian mustard
- leaf tissue
- amino-acids
- tolerance
- metabolism
Cite this
Chemical form and distribution of selenium and sulfur in the selenium hyperaccumulator Astragalus bisulcatus. / Pickering, I J ; Wright, Carrie; Bubner, B ; Ellis, D ; Persans, M W ; Yu, E Y ; George, G N ; Prince, R C ; Salt, D E .
In: Plant Physiology, Vol. 131, No. 3, 03.2003, p. 1460-1467.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Chemical form and distribution of selenium and sulfur in the selenium hyperaccumulator Astragalus bisulcatus
AU - Pickering, I J
AU - Wright, Carrie
AU - Bubner, B
AU - Ellis, D
AU - Persans, M W
AU - Yu, E Y
AU - George, G N
AU - Prince, R C
AU - Salt, D E
PY - 2003/3
Y1 - 2003/3
N2 - In its natural habitat, Astragalus bisulcatus can accumulate up to 0.65% (w/w) selenium (Se) in its shoot dry weight. X-ray absorption spectroscopy has been used to examine the selenium biochemistry of A. bisulcatus. High concentrations of the nonprotein amino acid Se-methylseleno-cysteine (Cys) are present in young leaves of A. bisulcatus, but in more mature leaves, the Se-methylseleno-Cys concentration is lower, and selenate predominates. Seleno-Cys methyltransferase is the enzyme responsible for the biosynthesis of Se-methylseleno-Cys from seleno-Cys and S-methyl-methionine. Seleno-Cys methyltransferase is found to be expressed in A. bisulcatus leaves of all ages, and thus the biosynthesis of Se-methylseleno-Cys in older leaves is limited earlier in the metabolic pathway, probably by an inability to chemically reduce selenate. A comparative study of sulfur (S) and Se in A. bisulcatus using x-ray absorption spectroscopy indicates similar trends for oxidized and reduced Se and S species, but also indicates that the proportions of these differ significantly. These results also indicate that sulfate and selenate reduction are developmentally correlated, and they suggest important differences between S and Se biochemistries.
AB - In its natural habitat, Astragalus bisulcatus can accumulate up to 0.65% (w/w) selenium (Se) in its shoot dry weight. X-ray absorption spectroscopy has been used to examine the selenium biochemistry of A. bisulcatus. High concentrations of the nonprotein amino acid Se-methylseleno-cysteine (Cys) are present in young leaves of A. bisulcatus, but in more mature leaves, the Se-methylseleno-Cys concentration is lower, and selenate predominates. Seleno-Cys methyltransferase is the enzyme responsible for the biosynthesis of Se-methylseleno-Cys from seleno-Cys and S-methyl-methionine. Seleno-Cys methyltransferase is found to be expressed in A. bisulcatus leaves of all ages, and thus the biosynthesis of Se-methylseleno-Cys in older leaves is limited earlier in the metabolic pathway, probably by an inability to chemically reduce selenate. A comparative study of sulfur (S) and Se in A. bisulcatus using x-ray absorption spectroscopy indicates similar trends for oxidized and reduced Se and S species, but also indicates that the proportions of these differ significantly. These results also indicate that sulfate and selenate reduction are developmentally correlated, and they suggest important differences between S and Se biochemistries.
KW - ray-absorption spectroscopy
KW - non-accumulator plants
KW - cancer prevention
KW - ATP sulfurylase
KW - selenate uptake
KW - Indian mustard
KW - leaf tissue
KW - amino-acids
KW - tolerance
KW - metabolism
U2 - 10.1104/pp.014787
DO - 10.1104/pp.014787
M3 - Article
VL - 131
SP - 1460
EP - 1467
JO - Plant Physiology
JF - Plant Physiology
SN - 0032-0889
IS - 3
ER -