Molecular analysis of a large subtelomeric nucleotide-binding-site-leucine-rich-repeat family in two representative genotypes of the major gene pools of Phaseolus vulgaris.
In common bean, the B4 disease resistance gene cluster is a complex cluster localized at the end of linkage group (LG) B4, containing at least three R specificities to the fungus Colletotrichum lindemuthianum. To investigate the evolution of this R cluster since the divergence of Andean and Mesoamerican gene pools, DNA sequences were characterized from two representative genotypes of the two major gene pools of common bean (BAT93: Mesoamerican; JaloEEP558: Andean). Sequences encoding 29 B4-CC nucleotide-binding-site-leucine-rich-repeat (B4-CNL) genes were determined-12 from JaloEEP558 and 17 from BAT93. Although sequence exchange events were identified, phylogenetic analyses revealed that they were not frequent enough to lead to homogenization of B4-CNL sequences within a haplotype. Genetic mapping based on pulsed-field gel electrophoresis separation confirmed that the B4-CNL family is a large family specific to one end of LG B4 and is present at two distinct blocks separated by 26 cM. Fluorescent in situ hybridization on meiotic pachytene chromosomes revealed that two B4-CNL blocks are located in the subtelomeric region of the short arm of chromosome 4 on both sides of a heterochromatic block (knob), suggesting that this peculiar genomic environment may favor the proliferation of a large R gene cluster.
Geffroy
Valérie
V
Plate-Forme 4-Intégration et Analyse Génomiques, Génopole, Institut Pasteur, 75724 Paris, Cedex 15, France. valerie.geffroy@u-psud.fr
Macadré
Catherine
C
David
Perrine
P
Pedrosa-Harand
Andrea
A
Sévignac
Mireille
M
Dauga
Catherine
C
Langin
Thierry
T
D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D020231:Colletotrichum / Q000472:pathogenicity; D017124:Conserved Sequence; D019143:Evolution, Molecular; D017343:Genes, Plant; D018745:Genome, Plant; D005838:Genotype; D017404:In Situ Hybridization, Fluorescence; D000090263:Leucine-Rich Repeat Proteins; D008969:Molecular Sequence Data; D005810:Multigene Family; D027805:Phaseolus / Q000145:classification / Q000235:genetics* / Q000382:microbiology; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics; D011506:Proteins / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D016615:Telomere / Q000235:genetics
D000090263:Leucine-Rich Repeat Proteins; D010940:Plant Proteins; D011506:Proteins