Overexpression of AtCpNifS enhances selenium tolerance and accumulation in Arabidopsis.
Selenium (Se) is an essential element for many organisms but is toxic at higher levels. CpNifS is a chloroplastic NifS-like protein in Arabidopsis (Arabidopsis thaliana) that can catalyze the conversion of cysteine into alanine and elemental sulfur (S0) and of selenocysteine into alanine and elemental Se (Se0). We overexpressed CpNifS to investigate the effects on Se metabolism in plants. CpNifS overexpression significantly enhanced selenate tolerance (1.9-fold) and Se accumulation (2.2-fold). CpNifS overexpressors showed significantly reduced Se incorporation into protein, which may explain their higher Se tolerance. Also, sulfur accumulation was enhanced by approximately 30% in CpNifS overexpressors, both on media with and without selenate. Root transcriptome changes in response to selenate mimicked the effects observed under sulfur starvation. There were only a few transcriptome differences between CpNifS-overexpressing plants and wild type, besides the 25- to 40-fold increase in CpNifS levels. Judged from x-ray analysis of near edge spectrum, both CpNifS overexpressors and wild type accumulated mostly selenate (Se(VI)). In conclusion, overexpression of this plant NifS-like protein had a pronounced effect on plant Se metabolism. The observed enhanced Se accumulation and tolerance of CpNifS overexpressors show promise for use in phytoremediation.
Van Hoewyk
Douglas
D
Biology Department, Colorado State University, Fort Collins, CO 80523, USA.
Garifullina
Gulnara F
GF
Ackley
Ashley R
AR
Abdel-Ghany
Salah E
SE
Marcus
Matthew A
MA
Fakra
Sirine
S
Ishiyama
Keiki
K
Inoue
Eri
E
Pilon
Marinus
M
Takahashi
Hideki
H
Pilon-Smits
Elizabeth A H
EA
D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D020411:Oligonucleotide Array Sequence Analysis; D018517:Plant Roots / Q000187:drug effects; D018520:Plant Shoots / Q000187:drug effects; D030821:Plants, Genetically Modified; D036226:Seedlings / Q000187:drug effects; D012643:Selenium / Q000378:metabolism* / Q000494:pharmacology*; D013455:Sulfur / Q000378:metabolism; D014158:Transcription, Genetic
D029681:Arabidopsis Proteins; C472234:At1g08490 protein, Arabidopsis; D013455:Sulfur; D012643:Selenium