Promoter elements of rice susceptibility genes are bound and activated by specific TAL effectors from the bacterial blight pathogen, Xanthomonas oryzae pv. oryzae

New Phytol. 2010 Sep;187(4):1048-1057. doi: 10.1111/j.1469-8137.2010.03217.x. Epub 2010 Mar 19.

Abstract

*Plant pathogenic bacteria of the genus Xanthomonas inject transcription activator-like effector (TALe) proteins that bind to and activate host promoters, thereby promoting disease or inducing plant defense. TALes bind to corresponding UPT (up-regulated by TALe) promoter boxes via tandemly arranged 34/35-amino acid repeats. Recent studies uncovered the TALe code in which two amino acid residues of each repeat define specific pairing to UPT boxes. *Here we employed the TALe code to predict potential UPT boxes in TALe-induced host promoters and analyzed these via beta-glucuronidase (GUS) reporter and electrophoretic mobility shift assays (EMSA). *We demonstrate that the Xa13, OsTFX1 and Os11N3 promoters from rice are induced directly by the Xanthomonas oryzae pv. oryzae TALes PthXo1, PthXo6 and AvrXa7, respectively. We identified and functionally validated a UPT box in the corresponding rice target promoter for each TALe and show that box mutations suppress TALe-mediated promoter activation. Finally, EMSA demonstrate that code-predicted UPT boxes interact specifically with corresponding TALes. *Our findings show that variations in the UPT boxes of different rice accessions correlate with susceptibility or resistance of these accessions to the bacterial blight pathogen.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids
  • Bacterial Proteins / metabolism*
  • Gene Expression Regulation, Plant*
  • Genes, Plant*
  • Glucuronidase / metabolism
  • Host-Pathogen Interactions / genetics
  • Oryza / genetics*
  • Oryza / metabolism
  • Plant Diseases / genetics
  • Plant Diseases / microbiology*
  • Promoter Regions, Genetic / physiology
  • Transcription Factors
  • Transcriptional Activation
  • Up-Regulation
  • Xanthomonas / pathogenicity*

Substances

  • Amino Acids
  • Bacterial Proteins
  • Transcription Factors
  • Glucuronidase