Nuclear Localised MORE SULPHUR ACCUMULATION1 Epigenetically Regulates Sulphur Homeostasis in Arabidopsis thaliana

PLoS Genet. 2016 Sep 13;12(9):e1006298. doi: 10.1371/journal.pgen.1006298. eCollection 2016 Sep.


Sulphur (S) is an essential element for all living organisms. The uptake, assimilation and metabolism of S in plants are well studied. However, the regulation of S homeostasis remains largely unknown. Here, we report on the identification and characterisation of the more sulphur accumulation1 (msa1-1) mutant. The MSA1 protein is localized to the nucleus and is required for both S-adenosylmethionine (SAM) production and DNA methylation. Loss of function of the nuclear localised MSA1 leads to a reduction in SAM in roots and a strong S-deficiency response even at ample S supply, causing an over-accumulation of sulphate, sulphite, cysteine and glutathione. Supplementation with SAM suppresses this high S phenotype. Furthermore, mutation of MSA1 affects genome-wide DNA methylation, including the methylation of S-deficiency responsive genes. Elevated S accumulation in msa1-1 requires the increased expression of the sulphate transporter genes SULTR1;1 and SULTR1;2 which are also differentially methylated in msa1-1. Our results suggest a novel function for MSA1 in the nucleus in regulating SAM biosynthesis and maintaining S homeostasis epigenetically via DNA methylation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Active Transport, Cell Nucleus
  • Anion Transport Proteins / genetics
  • Anion Transport Proteins / metabolism
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • Cell Nucleus / metabolism
  • DNA Methylation
  • Epigenesis, Genetic*
  • Glutathione / metabolism
  • Homeostasis*
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • S-Adenosylmethionine / metabolism*


  • Anion Transport Proteins
  • Arabidopsis Proteins
  • MSA1-1 protein, Arabidopsis
  • Nuclear Proteins
  • Sultr1;1 protein, Arabidopsis
  • Sultr1;2 protein, Arabidopsis
  • S-Adenosylmethionine
  • Glutathione

Grants and funding

This work was supported by grants from the U.S. National Science Foundation Arabidopsis 2010 Program (IOB 0419695), U.S. National Science Foundation Plant Genome Research Program (Grant IOS 0701119) and the European Commission (grant PCIG9-GA-2011-291798) to DES. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.