Production of Se-methylselenocysteine in transgenic plants expressing selenocysteine methyltransferase

Ellis, Danielle R.; Sors, Thomas G.; Brunk, Dennis G.; Albrecht, Carrie; Orser, Cindy S.; Lahner, Brett; Wood, Karl V.; Harris, Hugh H.; Pickering, Ingrid J.; Salt, David E.

doi:10.1186/1471-2229-4-1

Cited by 224 publications

(83 citation statements)

References 57 publications

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“…The transgenic APS plants also accumulated more Se than the controls [128]. Similarly when SeCys methyltransferase (SMT) was overexpressed in A. thaliana and B. juncea, SMT transgenics showed enhanced Se accumulation predominantly in organic form [129]. Double-transgenic plants (APS X SMT) accumulated up to 9 times higher Se levels than wild type [126].…”

Section: Genetic Biofortificationmentioning

confidence: 97%

Selenium in Soil-Crop-Animal System: A Holistic Perspective to Manage Animal and Human Health

Saha¹

2017

IJAAS

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Selenium (Se) dependent enzymes play important roles in physiological functions such as thyroid hormone metabolism, strengthens anti-oxidant defense system and immune system. However, about 800 million people worldwide are believed to be deficient in Se which is attributed to low Se levels in the soil. This is because Se in plant and animal products in human diet depends upon the available Se in the soil. Deficiency of Se can be prevented or treated by adequate dietary intake or through direct supplementation. There have been reports that patients with dilated cardiomyopathy, HIV viral loads and cancer have responded to Se supplementation. However, food fortification has been found to be more efficient than supplementation. Both agronomic biofortification and genetic biofortification have been used to increase Se content of food crops and animal products. Genetic engineering makes use of key genes of Se hyperaccumulators to increase Se accumulating potential of food crops. Agronomic biofortification increases Se content of food crops by adding Se rich fertilizers to the soil or foliar application of Se. Selenium can also be added to animal diets or feedstuff to increase Se content of meat, eggs, and milk. Although inorganic forms of Se are approved as feed additives, they are less efficient than organic sources such as selenomethionine (SeMet) which is the dominant form in plants and animals. Animal products have been found to have higher Se content than plant products with fish having the highest Se content. Fruits and vegetables have a low content of Se probably because of their low protein content. Recommendations for dietary intake of Se vary with country, age and sex. There are concerns that the present recommended Se daily allowance may not be adequate due to discovery of other selenoenzymes with higher Se requirements than gluthathione peroxidase. There may be a need to review the current recommended daily allowance for Se in order to improve human health.

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Section: Genetic Biofortificationmentioning

confidence: 97%

Selenium in Soil-Crop-Animal System: A Holistic Perspective to Manage Animal and Human Health

Saha¹

2017

IJAAS

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“…The second pathway from SeCys involves the formation of MeSeCys by methylation, 58,59) and MeSeCys is used for the biosynthesis of γ-glutamylmethylselenocysteine (GluMeSeCys).…”

Section: Selenoamino Acids In Se-accumulating Plantsmentioning

confidence: 99%

Selenometabolomics Explored by Speciation

Ogra

Anan

2012

Biological & Pharmaceutical Bulletin

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Selenium (Se) belongs to the same group as sulfur in the periodic table but possesses certain chemical properties characteristic of a metal. It is an essential element in animals but becomes severely toxic when the amount ingested exceeds the required level. On the other hand, Se is not essential in plants although some plants are Se hyperaccumulators. Se changes into several chemical forms when metabolized. Thus, the identification of selenometabolites would enable us to formulate a metabolic chart of Se. Recently, speciation analysis by hyphenated techniques has contributed immensely to the study of selenometabolomes, i.e., the entirety of selenometabolites. Indeed, speciation has unveiled some unique selenometabolites in biological samples. The aim of this review is to present newly identified selenometabolites in animals and plants by speciation using hyphenated techniques and to delineate the perspectives of Se biology and toxicology from the viewpoint of speciation.

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“…The enzyme activities converting MeSeCys to GluMeSeCys and Me 2 Se 2 are not completely characterised in Se accumulators. Abbreviations: APS, adenosine 5 0 -phosphosulfate; APSe, adenosine 5 0 -phosphoselenate; Cys, cysteine; GluMeSeCys, c-glutamyl-methylselenocysteine; MeSeCys, methylselenocysteine; MeSeOCys, methylselenocysteine selenooxide; MeSeMet, methylselenomethionine; Met, methionine; Me 2 Se, dimethyl selenide; Me 2 Se 2 , dimethyl diselenide Transgenic Res (2009) 18:407-424 409 increases in Se uptake and Se tolerance were achieved, but only when the transgenic lines were watered with selenite, and not with selenate (Ellis et al 2004). This is thought to be because the reduction of selenate to selenite by ATPS may be a limiting step in many species (Leustek 1996;Leustek and Saito 1999;Pilon-Smits et al 1999).…”

Section: Introductionmentioning

confidence: 99%

“…Previous work, however, has focused primarily on the development of rapidlygrowing Se-accumulating transgenic plants for the phytoremediation of selenate-contaminated soils (Ellis et al 2004;LeDuc et al 2004LeDuc et al , 2006, where MeSeCys production is part of the mechanism for Se accumulation and volatalization. We are interested in using the SMT gene to develop crop plants that when used for human dietary Se supplementation contain MeSeCys, a compound possessing powerful anticancer properties.…”

Section: Introductionmentioning

confidence: 99%

Accumulation of an organic anticancer selenium compound in a transgenic Solanaceous species shows wider applicability of the selenocysteine methyltransferase transgene from selenium hyperaccumulators

et al. 2008

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Tolerance to high selenium (Se) soils in Se-hyperaccumulating plant species is correlated with the ability to biosynthesise methylselenocysteine (MeSeCys), due to the activity of selenocysteine methyltransferase (SMT). In mammals, inclusion of MeSeCys in the diet reduces the incidence of certain cancers, so increasing the range of crop plants that can produce this compound is an attractive biotechnology target. However, in the non-Se accumulator Arabidopsis, overexpression of SMT does not result in biosynthesis of MeSeCys from selenate because the rate at which selenate is reduced to selenite by ATP sulfurylase (ATPS) is low. This limitation is less problematic in other species of the Brassicaceae that can produce MeSeCys naturally. We investigated the potential for biosynthesis of MeSeCys in other plant families using Nicotiana tabacum L., a member of the Solanaceae. When plants were watered with 200 microM selenate, overexpression of a SMT transgene caused a 2- to 4-fold increase in Se accumulation (resulting in increased numbers of leaf lesions and areas of necrosis), production of MeSeCys (up to 20% of total Se) and generation of volatile dimethyl diselenide derived directly from MeSeCys. Despite the greatly increased accumulation of total Se, this did not result in increased Se toxicity effects on growth. Overexpression of ATPS did not increase Se accumulation from selenate. Accordingly, lines overexpressing both ATPS and SMT did not show a further increase in total Se accumulation or in leaf toxicity symptoms relative to overexpression of SMT alone, but directed a greater proportion of Se into MeSeCys. This work demonstrates that the production of the cancer-preventing compound MeSeCys in plants outside the Brassicaceae is possible. We conclude that while the SMT gene from Se hyperaccumulators can probably be utilised universally to increase the metabolism of Se into MeSeCys, the effects of enhancing ATPS activity will vary depending on the species involved.

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Production of Se-methylselenocysteine in transgenic plants expressing selenocysteine methyltransferase

Cited by 224 publications

References 57 publications

Selenium in Soil-Crop-Animal System: A Holistic Perspective to Manage Animal and Human Health

Selenium in Soil-Crop-Animal System: A Holistic Perspective to Manage Animal and Human Health

Selenometabolomics Explored by Speciation

Accumulation of an organic anticancer selenium compound in a transgenic Solanaceous species shows wider applicability of the selenocysteine methyltransferase transgene from selenium hyperaccumulators

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