Chloroplast-to-Nucleus Signaling Regulates MicroRNA Biogenesis in Arabidopsis

Dev Cell. 2019 Feb 11;48(3):371-382.e4. doi: 10.1016/j.devcel.2018.11.046. Epub 2018 Dec 27.

Abstract

As integral regulators in plant development and stress response, microRNAs (miRNAs) themselves need to be tightly regulated. Here, we show that tocopherols (vitamin E), lipid-soluble antioxidants synthesized from tyrosine in chloroplasts, positively regulate the biogenesis of miRNAs. Tocopherols are required for the accumulation of 3'-phosphoadenosine 5'-phosphate (PAP), a retrograde inhibitor of the nuclear exoribonucleases (XRN), which may protect primary miRNAs from being degraded and promote mature miRNA production. Such regulation is involved in heat-induced accumulation of miR398 and plant acquisition of heat tolerance. Our study reveals a chloroplast-to-nucleus signaling mechanism that favors miRNA biogenesis under heat and possibly other environmental perturbations.

Keywords: chloroplast; exoribonuclease; heat tolerance; miRNA; microRNA; plastid; retrograde signaling; stress response; tocopherol.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / metabolism
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism
  • Cell Nucleus / metabolism*
  • Chloroplasts / metabolism*
  • Exoribonucleases / metabolism
  • Gene Expression Regulation, Plant / genetics
  • MicroRNAs / metabolism*
  • Signal Transduction / physiology
  • Stress, Physiological / physiology

Substances

  • Arabidopsis Proteins
  • MicroRNAs
  • Adenosine Diphosphate
  • adenosine 3'-phosphate-5'-phosphate
  • Exoribonucleases