Arabidopsis HFR1 is a potential nuclear substrate regulated by the Xanthomonas type III effector XopD(Xcc8004)

PLoS One. 2015 Feb 3;10(2):e0117067. doi: 10.1371/journal.pone.0117067. eCollection 2015.


XopDXcc8004, a type III effector of Xanthomonas campestris pv. campestris (Xcc) 8004, is considered a shorter version of the XopD, which lacks the N-terminal domain. To understand the functions of XopDXcc8004, in planta, a transgenic approach combined with inducible promoter to analyze the effects of XopDXcc8004 in Arabidopsis was done. Here, the expression of XopDXcc8004, in Arabidopsis elicited the accumulation of host defense-response genes. These molecular changes were dependent on salicylic acid and correlated with lesion-mimic phenotypes observed in XVE::XopDXcc8004 transgenic plants. Moreover, XopDXcc8004 was able to desumoylate HFR1, a basic helix-loop-helix transcription factor involved in photomorphogenesis, through SUMO protease activity. Interestingly, the hfr1-201 mutant increased the expression of host defense-response genes and displayed a resistance phenotype to Xcc8004. These data suggest that HFR1 is involved in plant innate immunity and is potentially regulated by XopDXcc8004.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics*
  • Arabidopsis / immunology
  • Arabidopsis / microbiology
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / immunology*
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / immunology
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / immunology*
  • Gene Expression Regulation, Plant*
  • Host-Pathogen Interactions*
  • Mutation
  • Nuclear Proteins / genetics
  • Nuclear Proteins / immunology*
  • Plant Diseases / genetics*
  • Plant Diseases / immunology
  • Plant Diseases / microbiology
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / immunology
  • Salicylic Acid / immunology
  • Small Ubiquitin-Related Modifier Proteins / immunology
  • Xanthomonas campestris / physiology*


  • Arabidopsis Proteins
  • Bacterial Proteins
  • DNA-Binding Proteins
  • HFR1 protein, Arabidopsis
  • Nuclear Proteins
  • Small Ubiquitin-Related Modifier Proteins
  • Salicylic Acid

Grant support

This work was supported by the Ministry of Science and Technology (NSC 100-2321-B- 005-007-MY3, NSC 103-2911-I-005-301, MOST 103-2321-B-005-020) and Ministry of Education (ATU plan), Taiwan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.