An Oomycete CRN Effector Reprograms Expression of Plant HSP Genes by Targeting their Promoters

PLoS Pathog. 2015 Dec 29;11(12):e1005348. doi: 10.1371/journal.ppat.1005348. eCollection 2015 Dec.

Abstract

Oomycete pathogens produce a large number of CRN effectors to manipulate plant immune responses and promote infection. However, their functional mechanisms are largely unknown. Here, we identified a Phytophthora sojae CRN effector PsCRN108 which contains a putative DNA-binding helix-hairpin-helix (HhH) motif and acts in the plant cell nucleus. Silencing of the PsCRN108 gene reduced P. sojae virulence to soybean, while expression of the gene in Nicotiana benthamiana and Arabidopsis thaliana enhanced plant susceptibility to P. capsici. Moreover, PsCRN108 could inhibit expression of HSP genes in A. thaliana, N. benthamiana and soybean. Both the HhH motif and nuclear localization signal of this effector were required for its contribution to virulence and its suppression of HSP gene expression. Furthermore, we found that PsCRN108 targeted HSP promoters in an HSE- and HhH motif-dependent manner. PsCRN108 could inhibit the association of the HSE with the plant heat shock transcription factor AtHsfA1a, which initializes HSP gene expression in response to stress. Therefore, our data support a role for PsCRN108 as a nucleomodulin in down-regulating the expression of plant defense-related genes by directly targeting specific plant promoters.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Blotting, Western
  • Chromatin Immunoprecipitation
  • DNA-Binding Proteins / genetics*
  • Electrophoretic Mobility Shift Assay
  • Genes, Plant / genetics
  • Genes, Plant / immunology
  • Heat Shock Transcription Factors
  • Heat-Shock Proteins / genetics*
  • Host-Parasite Interactions / immunology*
  • Microscopy, Fluorescence
  • Molecular Sequence Data
  • Phytophthora / immunology
  • Phytophthora / pathogenicity*
  • Plant Diseases / genetics*
  • Plant Diseases / immunology
  • Plant Diseases / microbiology*
  • Plant Proteins / genetics*
  • Plants, Genetically Modified
  • Real-Time Polymerase Chain Reaction
  • Transcription Factors / genetics*
  • Virulence Factors / immunology

Substances

  • DNA-Binding Proteins
  • Heat Shock Transcription Factors
  • Heat-Shock Proteins
  • Plant Proteins
  • Transcription Factors
  • Virulence Factors

Grant support

This work was supported by: National Natural Science Foundation of China (31371894; 31301613), Natural Science Foundation of Jiangsu Province (BK2012027), and Fundamental Research Funds for the Central Universities (KYTZ201403). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.