The genetic architecture of resistance

Curr Opin Plant Biol. 2000 Aug;3(4):285-90. doi: 10.1016/s1369-5266(00)00081-9.


Plant resistance genes (R genes), especially the nucleotide binding site leucine-rich repeat (NBS-LRR) family of sequences, have been extensively studied in terms of structural organization, sequence evolution and genome distribution. These studies indicate that NBS-LRR sequences can be split into two related groups that have distinct amino-acid motif organizations, evolutionary histories and signal transduction pathways. One NBS-LRR group, characterized by the presence of a Toll/interleukin receptor domain at the amino-terminal end, seems to be absent from the Poaceae. Phylogenetic analysis suggests that a small number of NBS-LRR sequences existed among ancient Angiosperms and that these ancestral sequences diversified after the separation into distinct taxonomic families. There are probably hundreds, perhaps thousands, of NBS-LRR sequences and other types of R gene-like sequences within a typical plant genome. These sequences frequently reside in 'mega-clusters' consisting of smaller clusters with several members each, all localized within a few million base pairs of one another. The organization of R-gene clusters highlights a tension between diversifying and conservative selection that may be relevant to gene families that are unrelated to disease resistance.

Publication types

  • Review

MeSH terms

  • Amino Acid Motifs
  • Animals
  • Evolution, Molecular
  • Genes, Plant / genetics*
  • Genes, Plant / physiology
  • Genome, Plant
  • Multigene Family / genetics
  • Phylogeny
  • Plant Diseases / genetics*
  • Plant Diseases / microbiology*
  • Plant Diseases / parasitology
  • Plant Proteins / chemistry
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Plants / genetics*
  • Plants / microbiology
  • Plants / parasitology
  • Species Specificity


  • Plant Proteins