COP1, a negative regulator of photomorphogenesis, positively regulates plant disease resistance via double-stranded RNA binding proteins

PLoS Pathog. 2018 Mar 7;14(3):e1006894. doi: 10.1371/journal.ppat.1006894. eCollection 2018 Mar.

Abstract

The E3 ubiquitin ligase COP1 (Constitutive Photomorphogenesis 1) is a well known component of the light-mediated plant development that acts as a repressor of photomorphogenesis. Here we show that COP1 positively regulates defense against turnip crinkle virus (TCV) and avrRPM1 bacteria by contributing to stability of resistance (R) protein HRT and RPM1, respectively. HRT and RPM1 levels and thereby pathogen resistance is significantly reduced in the cop1 mutant background. Notably, the levels of at least two double-stranded RNA binding (DRB) proteins DRB1 and DRB4 are reduced in the cop1 mutant background suggesting that COP1 affects HRT stability via its effect on the DRB proteins. Indeed, a mutation in either drb1 or drb4 resulted in degradation of HRT. In contrast to COP1, a multi-subunit E3 ligase encoded by anaphase-promoting complex (APC) 10 negatively regulates DRB4 and TCV resistance but had no effect on DRB1 levels. We propose that COP1-mediated positive regulation of HRT is dependent on a balance between COP1 and negative regulators that target DRB1 and DRB4.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / immunology*
  • Arabidopsis / metabolism
  • Arabidopsis / virology
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Carmovirus / immunology*
  • Disease Resistance / immunology*
  • Gene Expression Regulation, Plant
  • Light
  • Morphogenesis
  • Mutation
  • Nicotiana / immunology
  • Nicotiana / virology
  • Plant Development
  • Plant Diseases / immunology*
  • Plant Diseases / virology
  • RNA-Binding Proteins / metabolism*
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / metabolism*

Substances

  • Arabidopsis Proteins
  • DRB4 protein, Arabidopsis
  • HYL1 protein, Arabidopsis
  • RNA-Binding Proteins
  • AT2G32950 protein, Arabidopsis
  • Ubiquitin-Protein Ligases

Grants and funding

This work was supported by grants 0641576 and 0749731 from the National Science Foundation to PK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.