title: Evolution of the rice Xa21 disease resistance gene family.
abstract: The rice disease resistance gene Xa21, encoding a receptor-like kinase, is a member of a multigene family. Sequence analysis of seven family members revealed two distinct classes of genes. One member from each class encodes a receptor kinase-like open reading frame. The other five members encode truncated open reading frames of the predicted receptor kinase. A highly conserved 233-bp sequence (HC) was also identified among the seven family members. Recombination at the HC region between family members apparently resulted in the precise swapping of promoter regions. Large sequence duplications were generated by a presumed unequal crossover event in intergenic regions. Insertions of transposon-like sequences truncated two of the predicted open reading frames. A model for amplification and diversification of the Xa21 gene family is presented.
authors.affiliation: Department of Plant Pathology, University of California, Davis 95616, USA. pcronald@ucdavis.edu
authors.forename: W Y
authors.initials: WY
authors.lastname: Song
authors.forename: L Y
authors.initials: LY
authors.lastname: Pi
authors.forename: G L
authors.initials: GL
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Gardner
authors.forename: T
authors.initials: T
authors.lastname: Holsten
authors.forename: P C
authors.initials: PC
authors.lastname: Ronald
mesh_terms: D000595:Amino Acid Sequence; D001482:Base Composition; D001483:Base Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004251:DNA Transposable Elements; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D017343:Genes, Plant; D008957:Models, Genetic; D008969:Molecular Sequence Data; D005810:Multigene Family; D012275:Oryza / Q000201:enzymology / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D011995:Recombination, Genetic
chemical_list: D004251:DNA Transposable Elements; D018744:DNA, Plant; D010940:Plant Proteins; C097148:Xa21 protein, Oryza sativa; D017346:Protein Serine-Threonine Kinases