Resistance to Colletotrichum lindemuthianum in Phaseolus vulgaris: a case study for mapping two independent genes

Theor Appl Genet. 2008 Feb;116(3):407-15. doi: 10.1007/s00122-007-0678-y. Epub 2007 Dec 4.

Abstract

Anthracnose, caused by the hemibiotrophic fungal pathogen Colletotrichum lindemuthianum is a devastating disease of common bean. Resistant cultivars are economical means for defense against this pathogen. In the present study, we mapped resistance specificities against 7 C. lindemuthianum strains of various geographical origins revealing differential reactions on BAT93 and JaloEEP558, two parents of a recombinant inbred lines (RILs) population, of Meso-american and Andean origin, respectively. Six strains revealed the segregation of two independent resistance genes. A specific numerical code calculating the LOD score in the case of two independent segregating genes (i.e. genes with duplicate effects) in a RILs population was developed in order to provide a recombination value (r) between each of the two resistance genes and the tested marker. We mapped two closely linked Andean resistance genes (Co-x, Co-w) at the end of linkage group (LG) B1 and mapped one Meso-american resistance genes (Co-u) at the end of LG B2. We also confirmed the complexity of the previously identified B4 resistance gene cluster, because four of the seven tested strains revealed a resistance specificity near Co-y from JaloEEP558 and two strains identified a resistance specificity near Co-9 from BAT93. Resistance genes found within the same cluster confer resistance to different strains of a single pathogen such as the two anthracnose specificities Co-x and Co-w clustered at the end of LG B1. Clustering of resistance specificities to multiple pathogens such as fungi (Co-u) and viruses (I) was also observed at the end of LG B2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromosome Mapping
  • Colletotrichum / physiology*
  • Genes, Plant*
  • Genotype
  • Immunity, Innate / genetics*
  • Immunity, Innate / immunology
  • Inbreeding
  • Likelihood Functions
  • Lod Score
  • Phaseolus / genetics*
  • Phaseolus / microbiology*
  • Phenotype
  • Plant Diseases / genetics
  • Plant Diseases / immunology*
  • Plant Diseases / microbiology*