Origins of host-specific populations of the blast pathogen Magnaporthe oryzae in crop domestication with subsequent expansion of pandemic clones on rice and weeds of rice

Couch Brett C., Fudal Isabelle, Lebrun Marc-Henri, Tharreau Didier, Valent Barbara, Pham Van Kim, Nottéghem Jean-Loup, Kohn Linda M.. 2005. Origins of host-specific populations of the blast pathogen Magnaporthe oryzae in crop domestication with subsequent expansion of pandemic clones on rice and weeds of rice. Genetics, 170 (2) : 613-630.

Résumé : Rice, as a widely and intensively cultivated crop, should be a target for parasite host shifts and a source for shifts to co-occurring weeds. Magnaporthe oryzae, of the M. grisea species complex. is the most important fungal pathogen of rice, with a high degree of host specificity. On the basis of 10 loci from six of its seven linkage groups. 37 multilocus haplotypes among 497 isolates of M. oryzae from rice and other grasses were identified. Phylogenetic relationships among isolates from rice (Oryza saliva). millet (Setaria spp.), cutgrass (Leersia hexandra), and torpedo grass (Panicum repens) were predominantly tree like. consistent with a lack of recombination, but from other hosts were reticulate, consistent with recombination. The single origin of rice-infecting M. oryzae followed a host shift from a Setaria millet and was closely followed by additional shifts to weeds of rice, cutgrass, and torpedo grass. Two independent estimators of divergence time indicate that these host shills predate the Green Revolution and could he associated with rice domestication. The rice-infecting lineage is characterized by high copy number of the transposable element MGR586 (Pot3) and, except in two haplotypes, by a loss of AVR-Co39. Both mating types have been retained in ancestral, well-distributed rice-infecting haplotypes 10 (mainly temperate) and 14 (mainly tropical). but only one mating type was recovered from several derived, geographically restricted haplotypes. There is evidence of a common origin of both ACE1 virulence genotypes in haplotype 14. Host-haplotype association is evidenced by low pathogenicity on hosts associated with other haplotypes.

Mots-clés Agrovoc : Oryza, Oryza sativa, Magnaporthe grisea, pouvoir pathogène, résistance aux maladies, phylogénie, génotype, recombinaison, domestication

Mots-clés géographiques Agrovoc : États-Unis d'Amérique

Mots-clés complémentaires : Gène de résistance

Classification Agris : H20 - Maladies des plantes
F30 - Génétique et amélioration des plantes

Champ stratégique Cirad : Axe 1 (2005-2013) - Intensification écologique

Auteurs et affiliations

• Couch Brett C., Université de Toronto (CAN)
• Fudal Isabelle, CNRS (FRA)
• Lebrun Marc-Henri, CNRS (FRA)
• Tharreau Didier, CIRAD-AMIS-UMR BGPI (FRA) ORCID: 0000-0003-3961-6120
• Valent Barbara, Kansas State University (USA)
• Pham Van Kim, Can Tho University (VNM)
• Nottéghem Jean-Loup, ENSAM [Ecole nationale supérieure agronomique de Montpellier] (FRA)
• Kohn Linda M., Université de Toronto (CAN)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/528077/)

Métriques

[ Page générée et mise en cache le 2024-12-18 ]