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.

Abstract

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*

Substances

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