Interaction with a host ubiquitin-conjugating enzyme is required for the pathogenicity of a geminiviral DNA beta satellite

Mol Plant Microbe Interact. 2009 Jun;22(6):737-46. doi: 10.1094/MPMI-22-6-0737.

Abstract

DNA beta is a single-stranded satellite DNA which encodes a single gene, betaC1. To better understand the role of betaC1 in the pathogenicity of DNA beta, a yeast two-hybrid screen of a tomato cDNA library was carried out using betaC1 from Cotton leaf curl Multan virus (CLCuMV) DNA beta as the bait. A ubiquitin-conjugating enzyme, designated SlUBC3, which functionally complemented a yeast mutant deficient in ubiquitin-conjugating enzymes was identified. The authenticity and specificity of the interaction between betaC1 and SlUBC3 was confirmed both in vivo, using a bimolecular fluorescence complementation assay, and in vitro, using a protein-binding assay. Analysis of deletion mutants of the betaC1 protein showed that a myristoylation-like motif is required both for its interaction with SlUBC3 and the induction of DNA-beta-specific symptoms in host plants. The level of polyubiquitinated proteins in transgenic tobacco plants expressing betaC1 was found to be reduced compared with wild-type plants. These results are consistent with the hypothesis that interaction of betaC1 with SlUBC3 is required for DNA-beta-specific symptom induction, and that this is possibly due to downregulation of the host ubiquitin proteasome pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Binding Sites
  • DNA, Satellite / chemistry
  • DNA, Satellite / metabolism
  • DNA, Satellite / physiology*
  • DNA, Viral / chemistry
  • DNA, Viral / metabolism
  • DNA, Viral / physiology*
  • Geminiviridae / genetics
  • Geminiviridae / pathogenicity*
  • Gene Library
  • Molecular Sequence Data
  • Plant Proteins / metabolism*
  • Sequence Alignment
  • Solanum lycopersicum / enzymology*
  • Solanum lycopersicum / genetics
  • Solanum lycopersicum / metabolism
  • Substrate Specificity
  • Two-Hybrid System Techniques
  • Ubiquitin-Conjugating Enzymes / metabolism*
  • Ubiquitination

Substances

  • DNA, Satellite
  • DNA, Viral
  • Plant Proteins
  • Ubiquitin-Conjugating Enzymes

Associated data

  • GENBANK/FJ429328