The calmodulin-binding transcription factor OsCBT suppresses defense responses to pathogens in rice

Mol Cells. 2009 May 31;27(5):563-70. doi: 10.1007/s10059-009-0081-4. Epub 2009 May 15.

Abstract

We previously isolated the OsCBT gene, which encodes a calmodulin (CaM)-binding protein, from a rice expression library constructed from fungal elicitor-treated rice suspension cells. In order to understand the function of OsCBT in rice, we isolated and characterized a T-DNA insertion mutant allele named oscbt-1. The oscbt-1 mutant exhibits reduced levels of OsCBT transcripts and no significant morphological changes compared to wild-type plant although the growth of the mutant is stunted. However, oscbt-1 mutants showed significant resistance to two major rice pathogens. The growth of the rice blast fungus Magnaporthe grisea, as well as the bacterial pathogen Xanthomonas oryzae pv. oryzae was significantly suppressed in oscbt-1 plants. Histochemical analysis indicated that the hypersensitive-response was induced in the oscbt-1 mutant in response to compatible strains of fungal pathogens. OsCBT expression was induced upon challenge with fungal elicitor. We also observed significant increase in the level of pathogenesis-related genes in the oscbt-1 mutant even under pathogen-free condition. Taken together, the results support an idea that OsCBT might act as a negative regulator on plant defense.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calmodulin-Binding Proteins / genetics
  • Calmodulin-Binding Proteins / immunology
  • Calmodulin-Binding Proteins / metabolism*
  • Cell Growth Processes / genetics
  • DNA, Bacterial
  • Gene Expression Regulation, Plant
  • Gene Library
  • Immune Tolerance
  • Immunity / genetics
  • Magnaporthe / growth & development
  • Magnaporthe / immunology
  • Magnaporthe / pathogenicity
  • Mutant Proteins / genetics
  • Mutant Proteins / immunology
  • Mutant Proteins / metabolism*
  • Oryza / genetics*
  • Oryza / immunology
  • Oryza / microbiology
  • Plant Proteins / genetics
  • Plant Proteins / immunology
  • Plant Proteins / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / immunology
  • Transcription Factors / metabolism*
  • Xanthomonas / growth & development
  • Xanthomonas / immunology*
  • Xanthomonas / pathogenicity

Substances

  • Calmodulin-Binding Proteins
  • DNA, Bacterial
  • Mutant Proteins
  • Plant Proteins
  • T-DNA
  • Transcription Factors