Analysis of sulfur and selenium assimilation in Astragalus plants with varying capacities to accumulate selenium

Thomas G. Sors, Danielle R. Ellis, G N Na, Brett Lahner, Simon Lee, T Leustek, Ingrid J. Pickering, David Edward Salt

Research output: Contribution to journalArticle

83 Citations (Scopus)

Abstract

Several Astragalus species have the ability to hyperaccumulate selenium (Se) when growing in their native habitat. Given that the biochemical properties of Se parallel those of sulfur (S), we examined the activity of key S assimilatory enzymes ATP sulfurylase (ATPS), APS reductase (APR), and serine acetyltransferase (SAT), as well as selenocysteine methyltransferase (SMT), in eight Astragalus species with varying abilities to accumulate Se. Se hyperaccumulation was found to positively correlate with shoot accumulation of S-methylcysteine (MeCys) and Se-methylselenocysteine (MeSeCys), in addition to the level of SMT enzymatic activity. However, no correlation was observed between Se hyperaccumulation and ATPS, APR, and SAT activities in shoot tissue. Transgenic Arabidopsis thaliana overexpressing both ATPS and APR had a significant enhancement of selenate reduction as a proportion of total Se, whereas SAT overexpression resulted in only a slight increase in selenate reduction to organic forms. In general, total Se accumulation in shoots was lower in the transgenic plants overexpressing ATPS, PaAPR, and SAT. Root growth was adversely affected by selenate treatment in both ATPS and SAT overexpressors and less so in the PaAPR transgenic plants. Such observations support our conclusions that ATPS and APR are major contributors of selenate reduction in planta. However, Se hyperaccumulation in Astragalus is not driven by an overall increase in the capacity of these enzymes, but rather by either an increased Se flux through the S assimilatory pathway, generated by the biosynthesis of the sink metabolites MeCys or MeSeCys, or through an as yet unidentified Se assimilation pathway.

Original languageEnglish
Pages (from-to)785-797
Number of pages13
JournalThe Plant Journal
Volume42
Issue number6
DOIs
Publication statusPublished - Jun 2005

Keywords

  • Se-methylselenocysteine
  • S-methylcysteine
  • hyperaccumulator
  • ATP sulfurylase
  • APS reductase
  • selenocysteine methyltransferase
  • Arabidopsis thaliana
  • serine acetyltransferase
  • 5'-adenylylsulfate reductase
  • Schizosaccharomyces pombe
  • subcellular localization
  • Saccharomyces cerevisiae
  • cysteine synthase
  • sulfate reduction

Cite this

Analysis of sulfur and selenium assimilation in Astragalus plants with varying capacities to accumulate selenium. / Sors, Thomas G.; Ellis, Danielle R.; Na, G N ; Lahner, Brett; Lee, Simon; Leustek, T ; Pickering, Ingrid J.; Salt, David Edward.

In: The Plant Journal, Vol. 42, No. 6, 06.2005, p. 785-797.

Research output: Contribution to journalArticle

Sors, Thomas G. ; Ellis, Danielle R. ; Na, G N ; Lahner, Brett ; Lee, Simon ; Leustek, T ; Pickering, Ingrid J. ; Salt, David Edward. / Analysis of sulfur and selenium assimilation in Astragalus plants with varying capacities to accumulate selenium. In: The Plant Journal. 2005 ; Vol. 42, No. 6. pp. 785-797.
@article{8c817ab6f45f40a2a64adec58b545e27,
title = "Analysis of sulfur and selenium assimilation in Astragalus plants with varying capacities to accumulate selenium",
abstract = "Several Astragalus species have the ability to hyperaccumulate selenium (Se) when growing in their native habitat. Given that the biochemical properties of Se parallel those of sulfur (S), we examined the activity of key S assimilatory enzymes ATP sulfurylase (ATPS), APS reductase (APR), and serine acetyltransferase (SAT), as well as selenocysteine methyltransferase (SMT), in eight Astragalus species with varying abilities to accumulate Se. Se hyperaccumulation was found to positively correlate with shoot accumulation of S-methylcysteine (MeCys) and Se-methylselenocysteine (MeSeCys), in addition to the level of SMT enzymatic activity. However, no correlation was observed between Se hyperaccumulation and ATPS, APR, and SAT activities in shoot tissue. Transgenic Arabidopsis thaliana overexpressing both ATPS and APR had a significant enhancement of selenate reduction as a proportion of total Se, whereas SAT overexpression resulted in only a slight increase in selenate reduction to organic forms. In general, total Se accumulation in shoots was lower in the transgenic plants overexpressing ATPS, PaAPR, and SAT. Root growth was adversely affected by selenate treatment in both ATPS and SAT overexpressors and less so in the PaAPR transgenic plants. Such observations support our conclusions that ATPS and APR are major contributors of selenate reduction in planta. However, Se hyperaccumulation in Astragalus is not driven by an overall increase in the capacity of these enzymes, but rather by either an increased Se flux through the S assimilatory pathway, generated by the biosynthesis of the sink metabolites MeCys or MeSeCys, or through an as yet unidentified Se assimilation pathway.",
keywords = "Se-methylselenocysteine, S-methylcysteine, hyperaccumulator, ATP sulfurylase, APS reductase, selenocysteine methyltransferase, Arabidopsis thaliana, serine acetyltransferase, 5'-adenylylsulfate reductase, Schizosaccharomyces pombe, subcellular localization, Saccharomyces cerevisiae, cysteine synthase, sulfate reduction",
author = "Sors, {Thomas G.} and Ellis, {Danielle R.} and Na, {G N} and Brett Lahner and Simon Lee and T Leustek and Pickering, {Ingrid J.} and Salt, {David Edward}",
year = "2005",
month = "6",
doi = "10.1111/j.1365-313X.2005.02413.x",
language = "English",
volume = "42",
pages = "785--797",
journal = "The Plant Journal",
issn = "0960-7412",
publisher = "Wiley-Blackwell",
number = "6",

}

TY - JOUR

T1 - Analysis of sulfur and selenium assimilation in Astragalus plants with varying capacities to accumulate selenium

AU - Sors, Thomas G.

AU - Ellis, Danielle R.

AU - Na, G N

AU - Lahner, Brett

AU - Lee, Simon

AU - Leustek, T

AU - Pickering, Ingrid J.

AU - Salt, David Edward

PY - 2005/6

Y1 - 2005/6

N2 - Several Astragalus species have the ability to hyperaccumulate selenium (Se) when growing in their native habitat. Given that the biochemical properties of Se parallel those of sulfur (S), we examined the activity of key S assimilatory enzymes ATP sulfurylase (ATPS), APS reductase (APR), and serine acetyltransferase (SAT), as well as selenocysteine methyltransferase (SMT), in eight Astragalus species with varying abilities to accumulate Se. Se hyperaccumulation was found to positively correlate with shoot accumulation of S-methylcysteine (MeCys) and Se-methylselenocysteine (MeSeCys), in addition to the level of SMT enzymatic activity. However, no correlation was observed between Se hyperaccumulation and ATPS, APR, and SAT activities in shoot tissue. Transgenic Arabidopsis thaliana overexpressing both ATPS and APR had a significant enhancement of selenate reduction as a proportion of total Se, whereas SAT overexpression resulted in only a slight increase in selenate reduction to organic forms. In general, total Se accumulation in shoots was lower in the transgenic plants overexpressing ATPS, PaAPR, and SAT. Root growth was adversely affected by selenate treatment in both ATPS and SAT overexpressors and less so in the PaAPR transgenic plants. Such observations support our conclusions that ATPS and APR are major contributors of selenate reduction in planta. However, Se hyperaccumulation in Astragalus is not driven by an overall increase in the capacity of these enzymes, but rather by either an increased Se flux through the S assimilatory pathway, generated by the biosynthesis of the sink metabolites MeCys or MeSeCys, or through an as yet unidentified Se assimilation pathway.

AB - Several Astragalus species have the ability to hyperaccumulate selenium (Se) when growing in their native habitat. Given that the biochemical properties of Se parallel those of sulfur (S), we examined the activity of key S assimilatory enzymes ATP sulfurylase (ATPS), APS reductase (APR), and serine acetyltransferase (SAT), as well as selenocysteine methyltransferase (SMT), in eight Astragalus species with varying abilities to accumulate Se. Se hyperaccumulation was found to positively correlate with shoot accumulation of S-methylcysteine (MeCys) and Se-methylselenocysteine (MeSeCys), in addition to the level of SMT enzymatic activity. However, no correlation was observed between Se hyperaccumulation and ATPS, APR, and SAT activities in shoot tissue. Transgenic Arabidopsis thaliana overexpressing both ATPS and APR had a significant enhancement of selenate reduction as a proportion of total Se, whereas SAT overexpression resulted in only a slight increase in selenate reduction to organic forms. In general, total Se accumulation in shoots was lower in the transgenic plants overexpressing ATPS, PaAPR, and SAT. Root growth was adversely affected by selenate treatment in both ATPS and SAT overexpressors and less so in the PaAPR transgenic plants. Such observations support our conclusions that ATPS and APR are major contributors of selenate reduction in planta. However, Se hyperaccumulation in Astragalus is not driven by an overall increase in the capacity of these enzymes, but rather by either an increased Se flux through the S assimilatory pathway, generated by the biosynthesis of the sink metabolites MeCys or MeSeCys, or through an as yet unidentified Se assimilation pathway.

KW - Se-methylselenocysteine

KW - S-methylcysteine

KW - hyperaccumulator

KW - ATP sulfurylase

KW - APS reductase

KW - selenocysteine methyltransferase

KW - Arabidopsis thaliana

KW - serine acetyltransferase

KW - 5'-adenylylsulfate reductase

KW - Schizosaccharomyces pombe

KW - subcellular localization

KW - Saccharomyces cerevisiae

KW - cysteine synthase

KW - sulfate reduction

U2 - 10.1111/j.1365-313X.2005.02413.x

DO - 10.1111/j.1365-313X.2005.02413.x

M3 - Article

VL - 42

SP - 785

EP - 797

JO - The Plant Journal

JF - The Plant Journal

SN - 0960-7412

IS - 6

ER -