Rice OsACDR1 (Oryza sativa accelerated cell death and resistance 1) is a potential positive regulator of fungal disease resistance

Mol Cells. 2009 Nov 30;28(5):431-9. doi: 10.1007/s10059-009-0161-5. Epub 2009 Oct 29.


Rice Oryza sativa accelerated cell death and resistance 1 (OsACDR1) encodes a putative Raf-like mitogen-activated protein kinase kinase kinase (MAPKKK). We had previously reported upregulation of the OsACDR1 transcript by a range of environmental stimuli involved in eliciting defense-related pathways. Here we apply biochemical, gain and loss-of-function approaches to characterize OsACDR1 function in rice. The OsACDR1 protein showed autophosphorylation and possessed kinase activity. Rice plants overexpressing OsACDR1 exhibited spontaneous hypersensitive response (HR)-like lesions on leaves, upregulation of defense-related marker genes and accumulation of phenolic compounds and secondary metabolites (phytoalexins). These transgenic plants also acquired enhanced resistance to a fungal pathogen (Magnaporthe grisea) and showed inhibition of appressorial penetration on the leaf surface. In contrast, loss-offunction and RNA silenced OsACDR1 rice mutant plants showed downregulation of defense-related marker genes expressions and susceptibility to M. grisea. Furthermore, transient expression of an OsACDR1:GFP fusion protein in rice protoplast and onion epidermal cells revealed its localization to the nucleus. These results indicate that OsACDR1 plays an important role in the positive regulation of disease resistance in rice.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Nucleus / enzymology
  • Colony Count, Microbial
  • Gene Expression Regulation, Enzymologic
  • Gene Expression Regulation, Plant
  • Gene Knockout Techniques
  • Immunity, Innate / genetics
  • Immunity, Innate / immunology*
  • MAP Kinase Kinase Kinases / chemistry
  • MAP Kinase Kinase Kinases / genetics
  • MAP Kinase Kinase Kinases / metabolism
  • Magnaporthe / pathogenicity
  • Magnaporthe / physiology*
  • Mutation / genetics
  • Oryza / enzymology*
  • Oryza / genetics
  • Oryza / immunology
  • Oryza / microbiology*
  • Phenols / metabolism
  • Plant Diseases / genetics
  • Plant Diseases / immunology*
  • Plant Diseases / microbiology*
  • Plant Leaves / enzymology
  • Plant Leaves / microbiology
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Protein Transport
  • RNA Interference


  • Phenols
  • Plant Proteins
  • MAP Kinase Kinase Kinases