The barley Mlo gene: a novel control element of plant pathogen resistance

Cell. 1997 Mar 7;88(5):695-705. doi: 10.1016/s0092-8674(00)81912-1.


Mutation-induced recessive alleles (mlo) of the barley Mlo locus confer a leaf lesion phenotype and broad spectrum resistance to the fungal pathogen, Erysiphe graminis f. sp. hordei. The gene has been isolated using a positional cloning approach. Analysis of 11 mutagen-induced mlo alleles revealed mutations leading in each case to alterations of the deduced Mlo wild-type amino acid sequence. Susceptible intragenic recombinants, isolated from mlo heteroallelic crosses, show restored Mlo wild-type sequences. The deduced 60 kDa protein is predicted to be membrane-anchored by at least six membrane-spanning helices. The findings are compatible with a dual negative control function of the Mlo protein in leaf cell death and in the onset of pathogen defense; absence of Mlo primes the responsiveness for the onset of multiple defense functions.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Blotting, Northern
  • Blotting, Southern
  • Cell Death / genetics
  • Chromosome Mapping
  • DNA, Plant / analysis
  • Gene Expression Regulation, Plant / genetics
  • Genes, Plant*
  • Genetic Markers
  • Genotype
  • Hordeum / cytology
  • Hordeum / genetics*
  • Hordeum / microbiology
  • Molecular Sequence Data
  • Mutation / physiology
  • Mycoplasma
  • Plant Proteins / genetics*
  • Polymorphism, Restriction Fragment Length
  • Promoter Regions, Genetic / physiology*
  • RNA, Messenger / analysis
  • RNA, Plant / analysis
  • Recombinant Proteins


  • DNA, Plant
  • Genetic Markers
  • MLO protein, Hordeum vulgare
  • Plant Proteins
  • RNA, Messenger
  • RNA, Plant
  • Recombinant Proteins

Associated data

  • GENBANK/Z83834