Organization of Genes Conferring Resistance to Anthracnose in Common Bean - Translational Genomics for Crop Breeding: Biotic Stress - page 151

Chapter 9

Organization of Genes Conferring Resistance
to Anthracnose in Common Bean

JuanJoseFerreira,AnaCampa,and JamesD.Kelly

Abstract

Anthracnose, caused by the fungus Colletotrichum lindemuthianum (Sacc. & Magnus) Lams.- Scrib, is
one of the most economically important diseases of common bean ( Phaseolus vulgaris L.). The plant-
pathogen interaction is very specific and essentially follows the gene-for-gene model. Many pathogenic
variants or races have been described in this pathogen using the same set of twelve differential cultivars,
standardized resistance tests, and a standardized nomenclature system to name the races. Since the
first anthracnose resistance gene was described early in the twentieth century, twenty resistance
genes (named as Co-) that condition resistance to specific isolates or races of anthracnose pathogenic
on common bean have been described. Although not all characterized resistance genes have been
mapped, those genes that have been mapped reside on seven of eleven bean linkage groups: Pv01,
Pv02, Pv03, Pv04, Pv07, Pv08, and Pv11. Many of these regions are gene clusters that include
genes conditioning resistant reactions to other pathogens such as angular leaf spot, bean rust, bean
common mosaic virus, and halo blight. Genetic and molecular evidence indicates that anthracnose
resistance loci are organized in gene clusters in which individual genes confer resistance to one specific
isolate or race. In this chapter the inheritance patterns of this pathogen are reviewed in detail, and
the limitations of classical genetic analysis based on allelism tests are discussed. Direct or indirect
mapping using molecular markers linked to specific genes or genomic regions is recommended in
the characterization of new resistances genes. In addition, a new system to name the anthracnose
resistances gene(s) considering their position on the genetic map and the specific fungus genotype-
bean genotype interaction is suggested. The C. lindemuthianum-P. vulgaris interaction can be used as
a model to investigate and explain other race-specific resistance interactions in plants.

lus vulgaris L.) causing the disease known as
anthracnose (Bailey et al. 1992). The plant-
pathogen interaction is very specific and it essen-
tially follows the gene-for-gene model (Flor
1955). A large number of physiological races

Introduction

Colletotrichum lindemuthianum (Sacc. & Mag-
nus) Lams.- Scrib. is a hemibiotrophic fungal
pathogen that attacks common bean ( Phaseo-