Molecular analysis of three new receptor-like kinase genes from hexaploid wheat and evidence for their participation in the wheat hypersensitive response to stripe rust fungus infection

Plant J. 2007 Nov;52(3):420-34. doi: 10.1111/j.1365-313X.2007.03246.x. Epub 2007 Aug 30.

Abstract

Considerable progress has been made in understanding the function of receptor-like kinase (RLK) genes in model plants. However, much less is known about these genes in crop species. Here we report the characterization of three new wheat RLK genes (TaRLK-R1, 2 and 3). The primary structure of the putative proteins TaRLK-R1, 2 and 3 contained a signal peptide, a cysteine-rich extracellular domain, a transmembrane domain, and a predicted intracellular kinase domain. The fusions between TaRLK-R1, 2 or 3 and the green fluorescence protein (GFP) were targeted to the plasma membrane; such targeting required the signal peptide, extracellular domain and transmembrane domain. Transcription of TaRLK-R1, 2 and 3 was found mainly in the green organs, and was regulated by light. Transcript levels of TaRLK-R1, 2 and 3 increased during the hypersensitive reaction (HR) to stripe rust fungus. In addition, the TaRLK-R3 transcript level was also upregulated by abiotic stresses. Further experiments revealed that the recombinant kinase domain of TaRLK-R3 exhibited auto-phosphorylation activity in vitro. Knocking down the transcript levels of TaRLK-R1, 2 or 3 individually or all together by virus-induced gene silencing compromised the wheat HR to stripe rust fungus. The demonstration of TaRLK-R1, 2 and 3 as positive contributors in the wheat HR to stripe rust fungus suggests a new direction for further functional studies of this important family of RLK genes, and may facilitate the breeding of wheat varieties resistant to stripe rust disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Basidiomycota* / growth & development
  • Basidiomycota* / immunology
  • Gene Silencing
  • Genes, Plant*
  • Immunity, Innate
  • Light
  • Molecular Sequence Data
  • Osmotic Pressure
  • Oxidative Stress
  • Phosphorylation
  • Phosphotransferases / chemistry
  • Phosphotransferases / genetics*
  • Phosphotransferases / metabolism
  • Phylogeny
  • Plant Diseases / immunology*
  • Plant Proteins / chemistry
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Protein Serine-Threonine Kinases / chemistry
  • Protein Serine-Threonine Kinases / genetics*
  • Protein Serine-Threonine Kinases / metabolism
  • Receptors, Cell Surface / chemistry
  • Receptors, Cell Surface / genetics*
  • Receptors, Cell Surface / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Sequence Alignment
  • Transcription, Genetic
  • Triticum / enzymology
  • Triticum / genetics*
  • Triticum / immunology
  • Triticum / microbiology

Substances

  • Plant Proteins
  • Receptors, Cell Surface
  • Recombinant Fusion Proteins
  • Phosphotransferases
  • Protein Serine-Threonine Kinases

Associated data

  • GENBANK/AY327452
  • GENBANK/DQ270234
  • GENBANK/DQ270235
  • GENBANK/DQ270236
  • GENBANK/DQ270237