Overexpression of AtCpNifS Enhances Selenium Tolerance and Accumulation in Arabidopsis

• Published in: Plant physiology (Bethesda) 2005-11, Vol.139 (3), p.1518-1528
• Main Authors: Van Hoewyk, Douglas, Garifullina, Gulnara F, Ackley, Ashley R, Abdel-Ghany, Salah E, Marcus, Matthew A, Fakra, Sirine, Ishiyama, Keiki, Inoue, Eri, Pilon, Marinus, Takahashi, Hideki, Pilon-Smits, Elizabeth A.H
• Format: Article
• Language: English
• Subjects: Adaptation to environment and cultivation conditions; Agronomy. Soil science and plant productions; Arabidopsis - drug effects; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Biological and medical sciences; Chloroplasts; Environmental Stress and Adaptation to Stress; Enzymes; Fundamental and applied biological sciences. Psychology; Gene Expression; Gene Expression Profiling; Gene Expression Regulation, Plant; gene overexpression; Genes; Genetics and breeding of economic plants; microarray technology; Oligonucleotide Array Sequence Analysis; plant biochemistry; plant genetics; plant physiology; plant proteins; Plant roots; Plant Roots - drug effects; Plant Shoots - drug effects; Plants; Plants, Genetically Modified; Protein metabolism; Seedlings - drug effects; Selenium; Selenium - metabolism; Selenium - pharmacology; Sulfates; Sulfur; Sulfur - metabolism; Transcription, Genetic; Transgenic plants; Varietal selection. Specialized plant breeding, plant breeding aims
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.105.068684

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[superscript 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.