Genetic and molecular characterization of the I locus of Phaseolus vulgaris.
The I locus of the common bean, Phaseolus vulgaris, controls the development of four different phenotypes in response to inoculation with Bean common mosaic virus, Bean common mosaic necrosis virus, several other related potyviruses, and one comovirus. We have generated a high-resolution linkage map around this locus and have aligned it with a physical map constructed with BAC clones. These clones were obtained from a library of the cultivar "Sprite," which carries the dominant allele at the I locus. We have identified a large cluster of TIR-NBS-LRR sequences associated within this locus, which extends over a distance >425 kb. Bean cultivars from the Andean or Mesoamerican gene pool that contain the dominant allele share the same haplotypes as revealed by gel blot hybridizations with a TIR probe. In contrast, beans with a recessive allele display simpler and variable haplotypes. A survey of wild accessions from Argentina to Mexico showed that this multigene family has expanded significantly during evolution and domestication. RNA gel blot analysis indicated that the TIR family of genes plays a role in the response to inoculations with BCMV or BCMNV.
Vallejos
C Eduardo
CE
Department of Horticultural Sciences, University of Florida, Gainesville 32611-0690, USA. vallejos@ufl.edu
Astua-Monge
Gustavo
G
Jones
Valerie
V
Plyler
Tammy R
TR
Sakiyama
Ney S
NS
Mackenzie
Sally A
SA
D000595:Amino Acid Sequence; D020440:Gene Duplication; D008040:Genetic Linkage; D005819:Genetic Markers; D008969:Molecular Sequence Data; D005810:Multigene Family; D027805:Phaseolus / Q000235:genetics* / Q000502:physiology / Q000821:virology; D010942:Plant Viruses / Q000502:physiology; D019105:Random Amplified Polymorphic DNA Technique; D011995:Recombination, Genetic
D005819:Genetic Markers