title: Diversity in nucleotide binding site-leucine-rich repeat genes in cereals.
abstract: The diversity of the largest group of plant disease resistance genes, the nucleotide binding site-leucine-rich repeat (NBS-LRR) genes, was examined in cereals following polymerase chain reaction (PCR) cloning and database mining. NBS-LRR genes in rice are a large and diverse class with more than 600 genes, at least three to four times the complement of Arabidopsis. Most occur in small families containing one or a few cross-hybridizing members. Unlike in Arabidopsis and other dicots, the class of NBS-LRR genes coding for a Toll and mammalian interleukin-1 receptor (TIR) domain were not amplified during the evolution of the cereals. Genes coding for TIR domains are present in the rice genome, but have diverged from the NBS-LRR genes. Most cereal genes are similar in structure to the members of the non-TIR class of dicots, although many do not code for a coiled-coil domain in their amino termini. One unique class of cereal genes, with ~50 members, codes for proteins similar to the N-termini and NBS domains of resistance genes but does not code for LRR domains. The resistance gene repertoire of grasses has changed from that of dicots in their independent evolution since the two groups diverged. It is not clear whether this reflects a difference in downstream defense signaling pathways.
authors.affiliation: Department of Plant Pathology, Kansas State University, Manhattan, Kansas 66506-5502, USA.
authors.forename: Jianfa
authors.initials: J
authors.lastname: Bai
authors.forename: Lourdes A
authors.initials: LA
authors.lastname: Pennill
authors.forename: Jianchang
authors.initials: J
authors.lastname: Ning
authors.forename: Se Weon
authors.initials: SW
authors.lastname: Lee
authors.forename: Jegadeesan
authors.initials: J
authors.lastname: Ramalingam
authors.forename: Craig A
authors.initials: CA
authors.lastname: Webb
authors.forename: Bingyu
authors.initials: B
authors.lastname: Zhao
authors.forename: Qing
authors.initials: Q
authors.lastname: Sun
authors.forename: James C
authors.initials: JC
authors.lastname: Nelson
authors.forename: Jan E
authors.initials: JE
authors.lastname: Leach
authors.forename: Scot H
authors.initials: SH
authors.lastname: Hulbert
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D016384:Consensus Sequence; D015342:DNA Probes / Q000235:genetics; D002523:Edible Grain / Q000235:genetics*; D018628:Gene Dosage; D017343:Genes, Plant / Q000235:genetics*; D014644:Genetic Variation / Q000235:genetics*; D007438:Introns / Q000235:genetics; D007930:Leucine / Q000235:genetics*; D000090263:Leucine-Rich Repeat Proteins; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D009711:Nucleotides / Q000235:genetics* / Q000378:metabolism*; D016366:Open Reading Frames / Q000235:genetics; D012275:Oryza / Q000235:genetics; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D011506:Proteins / Q000235:genetics*; D020449:Repetitive Sequences, Amino Acid / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D015342:DNA Probes; D000090263:Leucine-Rich Repeat Proteins; D009711:Nucleotides; D011506:Proteins; D007930:Leucine