Identification of an ancestral resistance gene cluster involved in the coevolution process between Phaseolus vulgaris and its fungal pathogen Colletotrichum lindemuthianum

• Published in: Molecular plant-microbe interactions Vol. 12; no. 9; pp. 774 - 784
• Main Authors: Geffroy, V, Sicard, D, Oliveira, J.C.F. de, Sevignac, M, Cohen, S, Gepts, P, Neeman, C, Langin, T, Dron, M
• Format: Journal Article
• Language: English
• Published: St Paul, MN APS Press 01.09.1999; American Phytopathological Society; The American Phytopathological Society
• Subjects: Agronomy. Soil science and plant productions; Amino Acid Sequence; amino acid sequences; Base Sequence; binding sites; Biochemistry, Molecular Biology; Biological and medical sciences; Biological Evolution; chromosome mapping; coevolution; Colletotrichum - pathogenicity; Colletotrichum lindemuthianum; common bean; disease resistance; DNA Primers - genetics; Fabaceae - genetics; Fabaceae - microbiology; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; genbank/af072167; genbank/af072168; gene location; Genes, Plant; genetic resistance; genetic variation; Genetics and breeding of economic plants; Genetics, Population; host plants; inbred lines; Life Sciences; linkage (genetics); mapping; Molecular Sequence Data; Multigene Family; nucleotide sequences; Pest resistance; Phaseolus vulgaris; Phytopathology. Animal pests. Plant and forest protection; plant diseases and disorders; Plant pathogens; Plant Proteins - genetics; Plants, Medicinal; population genetics; provenance; restriction fragment length polymorphism; sympatric species; Variation, races, biotypes, parasitic specialization, genetics; Varietal selection. Specialized plant breeding, plant breeding aims; Virulence; Plant pathogen; Biological evolution; Host specificity; Host agent relation; Genotype; Coevolution; Genetic determinism; Fungus resistance; Fungi; Grain legume; Leguminosae; Phaseolus vulgaris; Dicotyledones; Angiospermae; Colletotrichum lindemuthianum; Spermatophyta; Fungi Imperfecti; Thallophyta; Adaptation; Cultivar; HARICOT
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/MPMI.1999.12.9.774

The recent cloning of plant resistance (R) genes and the sequencing of resistance gene clusters have shed light on the molecular evolution of R genes. However, up to now, no attempt has been made to correlate this molecular evolution with the host-pathogen coevolution process at the population level. Cross-inoculations were carried out between 26 strains of the fungal pathogen Colletotrichum lindemuthianum and 48 Phaseolus vulgaris plants collected in the three centers of diversity of the host species. A high level of diversity for resistance against the pathogen was revealed. Most of the resistance specificities were overcome in sympatric situations, indicating an adaptation of the pathogen to the local host. In contrast, plants were generally resistant to allopatric strains, suggesting that R genes that were efficient against exotic strains but had been overcome locally were maintained in the plant genome. These results indicated that coevolution processes between the two protagonists led to a differentiation for resistance in the three centers of diversity of the host. To improve our understanding of the molecular evolution of these different specificities, a recombinant inbred (RI) population derived from two representative genotypes of the Andean (JaloEEP558) and Mesoamerican (BAT93) gene pools was used to map anthracnose specificities. A gene cluster comprising both Andean (Co-y; Co-z) and Mesoamerican (Co-9) host resistance specificities was identified, suggesting that this locus existed prior to the separation of the two major gene pools of P. vulgaris. Molecular analysis revealed a high level of complexity at this locus. It harbors 11 restriction fragment length polymorphisms when R gene analog (RGA)clones are used. The relationship between the coevolution process and diversification of resistance specificities at resistance gene clusters is discussed.