title: Identification of wheat chromosomal regions containing expressed resistance genes.
abstract: The objectives of this study were to isolate and physically localize expressed resistance (R) genes on wheat chromosomes. Irrespective of the host or pest type, most of the 46 cloned R genes from 12 plant species share a strong sequence similarity, especially for protein domains and motifs. By utilizing this structural similarity to perform modified RNA fingerprinting and data mining, we identified 184 putative expressed R genes of wheat. These include 87 NB/LRR types, 16 receptor-like kinases, and 13 Pto-like kinases. The remaining were seven Hm1 and two Hs1(pro-1) homologs, 17 pathogenicity related, and 42 unique NB/kinases. About 76% of the expressed R-gene candidates were rare transcripts, including 42 novel sequences. Physical mapping of 121 candidate R-gene sequences using 339 deletion lines localized 310 loci to 26 chromosomal regions encompassing approximately 16% of the wheat genome. Five major R-gene clusters that spanned only approximately 3% of the wheat genome but contained approximately 47% of the candidate R genes were observed. Comparative mapping localized 91% (82 of 90) of the phenotypically characterized R genes to 18 regions where 118 of the R-gene sequences mapped.
authors.affiliation: Department of Crop and Soil Science, Washington State University, Pullman, Washington 99164, USA.
authors.forename: Muharrem
authors.initials: M
authors.lastname: Dilbirligi
authors.forename: Mustafa
authors.initials: M
authors.lastname: Erayman
authors.forename: Devinder
authors.initials: D
authors.lastname: Sandhu
authors.forename: Deepak
authors.initials: D
authors.lastname: Sidhu
authors.forename: Kulvinder S
authors.initials: KS
authors.lastname: Gill
mesh_terms: D001483:Base Sequence; D032461:Chromosomes, Plant / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics; D017343:Genes, Plant; D010641:Phenotype; D020161:Physical Chromosome Mapping; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology / Q000469:parasitology; D018749:RNA, Plant / Q000235:genetics / Q000302:isolation & purification; D014908:Triticum / Q000235:genetics*
chemical_list: D018744:DNA, Plant; D018749:RNA, Plant