title: Genome-wide mapping of NBS-LRR genes and their association with disease resistance in soybean.
abstract: BACKGROUND
  R genes are a key component of genetic interactions between plants and biotrophic bacteria and are known to regulate resistance against bacterial invasion. The most common R proteins contain a nucleotide-binding site and a leucine-rich repeat (NBS-LRR) domain. Some NBS-LRR genes in the soybean genome have also been reported to function in disease resistance. In this study, the number of NBS-LRR genes was found to correlate with the number of disease resistance quantitative trait loci (QTL) that flank these genes in each chromosome. NBS-LRR genes co-localized with disease resistance QTL. The study also addressed the functional redundancy of disease resistance on recently duplicated regions that harbor NBS-LRR genes and NBS-LRR gene expression in the bacterial leaf pustule (BLP)-induced soybean transcriptome.
  
  
  RESULTS
  A total of 319 genes were determined to be putative NBS-LRR genes in the soybean genome. The number of NBS-LRR genes on each chromosome was highly correlated with the number of disease resistance QTL in the 2-Mb flanking regions of NBS-LRR genes. In addition, the recently duplicated regions contained duplicated NBS-LRR genes and duplicated disease resistance QTL, and possessed either an uneven or even number of NBS-LRR genes on each side. The significant difference in NBS-LRR gene expression between a resistant near-isogenic line (NIL) and a susceptible NIL after inoculation of Xanthomonas axonopodis pv. glycines supports the conjecture that NBS-LRR genes have disease resistance functions in the soybean genome.
  
  
  CONCLUSIONS
  The number of NBS-LRR genes and disease resistance QTL in the 2-Mb flanking regions of each chromosome was significantly correlated, and several recently duplicated regions that contain NBS-LRR genes harbored disease resistance QTL for both sides. In addition, NBS-LRR gene expression was significantly different between the BLP-resistant NIL and the BLP-susceptible NIL in response to bacterial infection. From these observations, NBS-LRR genes are suggested to contribute to disease resistance in soybean. Moreover, we propose models for how NBS-LRR genes were duplicated, and apply Ks values for each NBS-LRR gene cluster.
authors.affiliation: Department of Plant Science and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, South Korea.
authors.forename: Yang Jae
authors.initials: YJ
authors.lastname: Kang
authors.forename: Kil Hyun
authors.initials: KH
authors.lastname: Kim
authors.forename: Sangrea
authors.initials: S
authors.lastname: Shim
authors.forename: Min Young
authors.initials: MY
authors.lastname: Yoon
authors.forename: Suli
authors.initials: S
authors.lastname: Sun
authors.forename: Moon Young
authors.initials: MY
authors.lastname: Kim
authors.forename: Kyujung
authors.initials: K
authors.lastname: Van
authors.forename: Suk-Ha
authors.initials: SH
authors.lastname: Lee
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D060467:Disease Resistance; D020440:Gene Duplication; D020869:Gene Expression Profiling; D017343:Genes, Plant; D000090263:Leucine-Rich Repeat Proteins; D005810:Multigene Family; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D057865:Plant Immunity / Q000235:genetics*; D018515:Plant Leaves / Q000276:immunology / Q000382:microbiology; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D040641:Quantitative Trait Loci; D013025:Glycine max / Q000235:genetics* / Q000276:immunology* / Q000382:microbiology; D059467:Transcriptome; D053532:Xanthomonas axonopodis / Q000276:immunology / Q000472:pathogenicity
chemical_list: D000090263:Leucine-Rich Repeat Proteins; D011506:Proteins