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Didier Tharreau - One of the best experts on this subject based on the ideXlab platform.
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south east asia is the Center of origin Diversity and dispersion of the rice blast fungus magnaporthe oryzae
New Phytologist, 2014Co-Authors: Dounia Saleh, Joelle Milazzo, Henri Adreit, Elisabeth Fournier, Didier TharreauAbstract:Summary Inferring invasion routes and identifying reservoirs of Diversity of plant pathogens are essential in proposing new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the world-wide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. In order to investigate the Centers of Diversity, origin and migration of M. oryzae on rice, we analyzed the genetic Diversity of 55 populations from 15 countries. Three genetic clusters were identified world-wide. Asia was the Center of Diversity and the origin of most migrations to other continents. In Asia, two Centers of Diversity were revealed in the Himalayan foothills: South China–Laos–North Thailand, and western Nepal. Sexual reproduction persisted only in the South China–Laos–North Thailand region, which was identified as the putative Center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies.
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South‐East Asia is the Center of origin, Diversity and dispersion of the rice blast fungus, Magnaporthe oryzae
New Phytologist, 2013Co-Authors: Dounia Saleh, Joelle Milazzo, Henri Adreit, Elisabeth Fournier, Didier TharreauAbstract:Summary Inferring invasion routes and identifying reservoirs of Diversity of plant pathogens are essential in proposing new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the world-wide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. In order to investigate the Centers of Diversity, origin and migration of M. oryzae on rice, we analyzed the genetic Diversity of 55 populations from 15 countries. Three genetic clusters were identified world-wide. Asia was the Center of Diversity and the origin of most migrations to other continents. In Asia, two Centers of Diversity were revealed in the Himalayan foothills: South China–Laos–North Thailand, and western Nepal. Sexual reproduction persisted only in the South China–Laos–North Thailand region, which was identified as the putative Center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies.
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South-East Asia is the Center of origin, Diversity and dispersion of the rice blast fungus, Magnaporthe oryzae.
The New phytologist, 2013Co-Authors: Dounia Saleh, Joelle Milazzo, Henri Adreit, Elisabeth Fournier, Didier TharreauAbstract:Inferring invasion routes and identifying reservoirs of Diversity of plant pathogens are essential in proposing new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the world-wide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. In order to investigate the Centers of Diversity, origin and migration of M. oryzae on rice, we analyzed the genetic Diversity of 55 populations from 15 countries. Three genetic clusters were identified world-wide. Asia was the Center of Diversity and the origin of most migrations to other continents. In Asia, two Centers of Diversity were revealed in the Himalayan foothills: South China-Laos-North Thailand, and western Nepal. Sexual reproduction persisted only in the South China-Laos-North Thailand region, which was identified as the putative Center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies. (Resume d'auteur)
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Origin, structure and migration of Magnaporthe oryzae populations pathogenic on rice : DP-2
2013Co-Authors: Dounia Saleh, Joelle Milazzo, Henri Adreit, Elisabeth Fournier, Didier TharreauAbstract:Inferring invasion routes and identifying reservoirs of Diversity of plant pathogens are essential to propose new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the worldwide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. To investigate the Centers of Diversity, of origin and of migration of M. oryzae on rice, we analyzed the genetic Diversity of fifty-five samples from fifteen countries. Three genetic clusters were identified worldwide. Asia was the Center of Diversity and the origin of most migrations to other continents. In Asia, two Centers of Diversity were revealed in the Himalayan foothills: South China-Laos-North Thailand, and Western Nepal. Sexual reproduction persisted only in the South China-Laos-North Thailand region, which was identified as the putative Center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies. (Texte integral)
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World population structure of the rice blast fungus, Magnaporthe oryzae
2008Co-Authors: Didier Tharreau, Elisabeth Fournier, Dodelys Andriantsimialona, - Santoso, Dwinita Utami, Marc-henri Lebrun, Jean-loup NotteghemAbstract:Magnaporthe oryzae is a heterothallic fungus reproducing clonally in the field. The Diversity and structure of populations of this pathogen of rice was described in many countries during the last 20 years. The expected clonal structure of the populations has been illustrated in various studies. But, relationships between the different populations was hardly testable mainly due to the choice of molecular markers. We recently developed a set of 18 microsatellite markers for population studies (Adreit et al. 2007). We used these markers to genotype more than 1,700 isolates from 40 countries. This sample included reference isolates from previous studies and real populations (1 site, 1 year). The world population structure show evidence for some geographic structuration. However, local adaptation and intercontinental migration are (or were) also common. A structure in three major genetic groups is observed. Two groups correspond to isolates of mating type Mat1.1 and Mat1.2 respectively. The third group gathers isolates of both mating types. Diversity is higher in Asia and more precisely in the countries of the Himalayan foothills. This area is the only one where female fertile isolates (able to produce perithecia and ascospores in vitro) were identified. Both mating types are also present in these populations. Whether sexual reproduction is (was) taking place in this region will be tested. The area of the Himalayan foothills is a Center of Diversity and is a good candidate for the Center of origin of the rice blast fungus.
Antonio Figueira - One of the best experts on this subject based on the ideXlab platform.
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High levels of genetic divergence and inbreeding in populations of cupuassu (Theobroma grandiflorum)
Tree Genetics & Genomes, 2007Co-Authors: Rafael M. Alves, Alexandre M. Sebbenn, Angela S. Artero, Charles Clement, Antonio FigueiraAbstract:Theobroma grandiflorum (cupuassu) is an important fruit tree native to the Brazilian Amazon. Establishing the genetic Diversity and structure of populations is critical to define long-term strategies for cupuassu conservation presently threatened by rapid deforestation. Three natural populations collected at the putative Center of Diversity, three groups of accessions established at a germplasm collection, and one derived from commercial plantings were analyzed. The genetic Diversity was assessed using 21 polymorphic microsatellite loci originally developed for Theobroma cacao , disclosing a total of 113 alleles. The estimated genetic Diversity parameters averaged over cupuassu populations ( A = 3.53 alleles per locus; H _e = 0.426; H _o = 0.346) were lower than the values reported for other Neotropical tree species. The three natural populations presented a positive and significant fixation index ( f ), ranging from 0.133 to 0.234. Cupuassu apparently adhered to a general pattern of genetic Diversity structure of some Neotropical tree species occurring at low densities, with a low intrapopulation genetic Diversity and important levels of endogamy, possibly due to biparental inbreeding derived from the presence of spatial genetic structure in the populations. A high level of genetic divergence was detected among the natural populations ( θ _p = 0.301), a strong differentiation caused by limited gene flow, and suggesting that human interference in spreading and/or stimulating plantings might have had a smaller effect than expected. The approximate location of the T. grandiflorum Center of Diversity could not be confirmed by analyzing natural populations from the putative region.
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genetic Diversity and natural population structure of cacao theobroma cacao l from the brazilian amazon evaluated by microsatellite markers
Conservation Genetics, 2006Co-Authors: Maria Lorena Sereno, Roland Vencovsky, Antonio FigueiraAbstract:A sample of 94 accessions of Theobroma cacao L. (cacao), representing four populations from the Brazilian Amazon (Acre, Rondonia, lower Amazon and upper Amazon) were analyzed using microsatellite markers to assess the genetic Diversity and the natural population structure. From the 19 microsatellite loci tested, 11 amplified scorable products, revealing a total of 49 alleles, including two monomorphic loci. The Brazilian upper Amazon population contained the largest genetic Diversity, with the most polymorphic loci, the highest observed heterozygosity; and the majority of rare alleles, thereby this region might be con- sidered part of the Center of Diversity of the species. The observed heterozygosity for all the Brazilian populations (Ho=0.347) was comparable with values reported for other similar upper Amazon Forastero cacao populations, with the Acre and Rondonia displaying the lowest values. The lower Amazon popu- lation, traditionally defined as highly homozygous, presented an unexpectedly high observed heterozygosity (Ho=0.372), disclosing rare and distinct alleles, with large identity with the upper Amazon population. It was hypothesized that part of the lower Amazon population might derive from successive natural or intentional introduction of planting material from other provenances, mainly upper Amazon. Most of the loci exhibited a lower observed heterozygosity than expected, suggesting that self-pollination might be more common than usually assumed in cacao, but excess of homozygotes might also derive from sub-grouping (Wahlund effect) or from sampling related individuals. Most of the gene Diversity was found to occur within groups, with small differentiation between the four Brazilian Amazon populations, typical of species with high gene flow. Abbreviations: AFLP - amplified fragment length polymorphism; bp - base pairs; CAB - Cacao Amazon Brazil; cDNA - complementary DNA; CIRAD - ''Centre de Cooperation Internationale en Recherche Agronomique pour le Developpement''; CTAB - hexadecytrimethyl ammonium bromide; dNTPs - de- oxyribonucleotides; EDTA - ethylenediaminetetraacetic acid; ERJOH - ''Estacao de Recursos Geneticos do Cacau JoseHaroldo''; RAPD - random amplified polymorphic DNA; rDNA - ribosomal DNA; RFLP - restriction fragment length polymorphism
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Genetic Diversity and Natural Population Structure of Cacao (Theobroma cacao L.) from the Brazilian Amazon Evaluated by Microsatellite Markers
Conservation Genetics, 2006Co-Authors: Maria Lorena Sereno, Roland Vencovsky, Paulo S. B. Albuquerque, Antonio FigueiraAbstract:A sample of 94 accessions of Theobroma cacao L. (cacao), representing four populations from the Brazilian Amazon (Acre, Rondônia, lower Amazon and upper Amazon) were analyzed using microsatellite markers to assess the genetic Diversity and the natural population structure. From the 19 microsatellite loci tested, 11 amplified scorable products, revealing a total of 49 alleles, including two monomorphic loci. The Brazilian upper Amazon population contained the largest genetic Diversity, with the most polymorphic loci, the highest observed heterozygosity; and the majority of rare alleles, thereby this region might be considered part of the Center of Diversity of the species. The observed heterozygosity for all the Brazilian populations ( H _o = 0.347) was comparable with values reported for other similar upper Amazon Forastero cacao populations, with the Acre and Rondônia displaying the lowest values. The lower Amazon population, traditionally defined as highly homozygous, presented an unexpectedly high observed heterozygosity ( H _o = 0.372), disclosing rare and distinct alleles, with large identity with the upper Amazon population. It was hypothesized that part of the lower Amazon population might derive from successive natural or intentional introduction of planting material from other provenances, mainly upper Amazon. Most of the loci exhibited a lower observed heterozygosity than expected, suggesting that self-pollination might be more common than usually assumed in cacao, but excess of homozygotes might also derive from sub-grouping (Wahlund effect) or from sampling related individuals. Most of the gene Diversity was found to occur within groups, with small differentiation between the four Brazilian Amazon populations, typical of species with high gene flow.
S. Coertze - One of the best experts on this subject based on the ideXlab platform.
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First Report of Phytophthora cryptogea on Osteospermum spp. in South Africa.
Plant Disease, 2007Co-Authors: A. Mcleod, S. CoertzeAbstract:Osteospermum is the largest genus of the tribe Calendulea of the Compositae (Asteraceae) and has a Center of Diversity in South Africa with approximately 40 known species in the Cape Province (3). This indigenous plant genus is also a popular floricultural crop grown in South Africa because of drought and high temperature tolerance. Two diseased Osteospermum sp. samples were submitted by commercial nurseries to the Stellenbosch University Plant Disease Clinic. Both samples showed similar symptoms including black lesions on the lower stem, petioles, and the base of lower leaves. Isolations were made from roots, stems, and petioles following surface disinfestation of the lesions and plating on potato dextrose agar (PDA), water agar, PARP, and PARPH (1). The only microorganism that was consistently isolated from all lesions was a species of Phytophthora, from which single hyphal tip cultures were prepared. The cultures were identified morphologically as Phytophthora cryptogea Pethybridge & Lafferty. Morpholo...
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first report of phytophthora cryptogea on osteospermum spp in south africa
Plant Disease, 2007Co-Authors: A. Mcleod, S. CoertzeAbstract:Osteospermum is the largest genus of the tribe Calendulea of the Compositae (Asteraceae) and has a Center of Diversity in South Africa with approximately 40 known species in the Cape Province (3). This indigenous plant genus is also a popular floricultural crop grown in South Africa because of drought and high temperature tolerance. Two diseased Osteospermum sp. samples were submitted by commercial nurseries to the Stellenbosch University Plant Disease Clinic. Both samples showed similar symptoms including black lesions on the lower stem, petioles, and the base of lower leaves. Isolations were made from roots, stems, and petioles following surface disinfestation of the lesions and plating on potato dextrose agar (PDA), water agar, PARP, and PARPH (1). The only microorganism that was consistently isolated from all lesions was a species of Phytophthora, from which single hyphal tip cultures were prepared. The cultures were identified morphologically as Phytophthora cryptogea Pethybridge & Lafferty. Morphological characteristics and cardinal growth temperatures followed Levesque and de Cock (2). Distinctive morphological characteristics included abundant hyphal swellings in sterile soil extract and hemp seed water cultures, nonpapil-lated, persistent, internally proliferating, obpyriform sporangia having mean dimensions of 36 × 26 μm and mean length/breadth ratios that ranged from 1.30 to 1.53 (1). Cultures had a petaloid pattern on PDA and no growth at 35°C that distinguished it from Phytophthora drechsleri (1). Analyses and comparison of the internal transcribed spacer (ITS) regions of isolate STE-U 6133 (GenBank Accession No. GI DQ479410) supported the P. cryptogea identification. STE-U 6133 has been deposited in the Stellenbosch University culture collection. Pathogenicity of isolate STE-U 6133 was tested on six plants of Osteospermum jucundum (Phill.) T. Norl. and O. ecklonis (DC.) Norl. in individual containers. Inoculum was grown on V8 agar for 7 days, and 10-mm culture disks were incubated in a filter (0.2 μm) sterilized 1% soil extract solution (1). The disks were vortexed vigorously and filtered through miracloth (Calbiochem Corp., La Jolla, CA) to remove agar disks and excess mycelium. The inoculum concentration was adjusted to 104 sporangia/ml and incubated at 4°C for 4 h. Six plants were inoculated with a 10-ml suspension of sporangia and zoospores by pipetting the suspension at the collar of each plant. Another six plants were treated with water as controls. The inoculated plants were kept at temperatures ranging from 22 to 25°C and were watered until saturation every second day. Initial symptoms were black lesions on the lower stem and petiole bases developing 14 to 18 days after inoculation, followed by wilting of some plants. Control plants remained healthy. Isolations from symptomatic plants yielded only P. cryptogea of which pure cultures were established, completing Koch's postulate. The experiment was repeated with similar results. To our knowledge, this is the first report of P. cryptogea as a pathogen of O. jucundum and O. ecklonis in South Africa. P. cryptogea has been reported as a pathogen on Osteospermum spp. in other countries (4). References: (1) D. C. Erwin et al. Phytophthora Diseases Worldwide. The American Phytopathological Society. St. Paul, MN, 1996. (2) C. A. Levesque and A. W. A. M. de Cock. Stud. Mycol. 50:481, 2004. (3) B. Nordenstam. Edinb. J. Bot. 60:259, 2003. (4) D. J. Stamps. Phytophthora cryptogea. IMI Description of Fungi and Bacteria. No. 60:Sheet 592. CAB International, Wallingford, UK, 1978.
Dounia Saleh - One of the best experts on this subject based on the ideXlab platform.
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south east asia is the Center of origin Diversity and dispersion of the rice blast fungus magnaporthe oryzae
New Phytologist, 2014Co-Authors: Dounia Saleh, Joelle Milazzo, Henri Adreit, Elisabeth Fournier, Didier TharreauAbstract:Summary Inferring invasion routes and identifying reservoirs of Diversity of plant pathogens are essential in proposing new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the world-wide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. In order to investigate the Centers of Diversity, origin and migration of M. oryzae on rice, we analyzed the genetic Diversity of 55 populations from 15 countries. Three genetic clusters were identified world-wide. Asia was the Center of Diversity and the origin of most migrations to other continents. In Asia, two Centers of Diversity were revealed in the Himalayan foothills: South China–Laos–North Thailand, and western Nepal. Sexual reproduction persisted only in the South China–Laos–North Thailand region, which was identified as the putative Center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies.
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South‐East Asia is the Center of origin, Diversity and dispersion of the rice blast fungus, Magnaporthe oryzae
New Phytologist, 2013Co-Authors: Dounia Saleh, Joelle Milazzo, Henri Adreit, Elisabeth Fournier, Didier TharreauAbstract:Summary Inferring invasion routes and identifying reservoirs of Diversity of plant pathogens are essential in proposing new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the world-wide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. In order to investigate the Centers of Diversity, origin and migration of M. oryzae on rice, we analyzed the genetic Diversity of 55 populations from 15 countries. Three genetic clusters were identified world-wide. Asia was the Center of Diversity and the origin of most migrations to other continents. In Asia, two Centers of Diversity were revealed in the Himalayan foothills: South China–Laos–North Thailand, and western Nepal. Sexual reproduction persisted only in the South China–Laos–North Thailand region, which was identified as the putative Center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies.
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South-East Asia is the Center of origin, Diversity and dispersion of the rice blast fungus, Magnaporthe oryzae.
The New phytologist, 2013Co-Authors: Dounia Saleh, Joelle Milazzo, Henri Adreit, Elisabeth Fournier, Didier TharreauAbstract:Inferring invasion routes and identifying reservoirs of Diversity of plant pathogens are essential in proposing new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the world-wide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. In order to investigate the Centers of Diversity, origin and migration of M. oryzae on rice, we analyzed the genetic Diversity of 55 populations from 15 countries. Three genetic clusters were identified world-wide. Asia was the Center of Diversity and the origin of most migrations to other continents. In Asia, two Centers of Diversity were revealed in the Himalayan foothills: South China-Laos-North Thailand, and western Nepal. Sexual reproduction persisted only in the South China-Laos-North Thailand region, which was identified as the putative Center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies. (Resume d'auteur)
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Origin, structure and migration of Magnaporthe oryzae populations pathogenic on rice : DP-2
2013Co-Authors: Dounia Saleh, Joelle Milazzo, Henri Adreit, Elisabeth Fournier, Didier TharreauAbstract:Inferring invasion routes and identifying reservoirs of Diversity of plant pathogens are essential to propose new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the worldwide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. To investigate the Centers of Diversity, of origin and of migration of M. oryzae on rice, we analyzed the genetic Diversity of fifty-five samples from fifteen countries. Three genetic clusters were identified worldwide. Asia was the Center of Diversity and the origin of most migrations to other continents. In Asia, two Centers of Diversity were revealed in the Himalayan foothills: South China-Laos-North Thailand, and Western Nepal. Sexual reproduction persisted only in the South China-Laos-North Thailand region, which was identified as the putative Center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies. (Texte integral)
Joelle Milazzo - One of the best experts on this subject based on the ideXlab platform.
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south east asia is the Center of origin Diversity and dispersion of the rice blast fungus magnaporthe oryzae
New Phytologist, 2014Co-Authors: Dounia Saleh, Joelle Milazzo, Henri Adreit, Elisabeth Fournier, Didier TharreauAbstract:Summary Inferring invasion routes and identifying reservoirs of Diversity of plant pathogens are essential in proposing new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the world-wide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. In order to investigate the Centers of Diversity, origin and migration of M. oryzae on rice, we analyzed the genetic Diversity of 55 populations from 15 countries. Three genetic clusters were identified world-wide. Asia was the Center of Diversity and the origin of most migrations to other continents. In Asia, two Centers of Diversity were revealed in the Himalayan foothills: South China–Laos–North Thailand, and western Nepal. Sexual reproduction persisted only in the South China–Laos–North Thailand region, which was identified as the putative Center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies.
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South‐East Asia is the Center of origin, Diversity and dispersion of the rice blast fungus, Magnaporthe oryzae
New Phytologist, 2013Co-Authors: Dounia Saleh, Joelle Milazzo, Henri Adreit, Elisabeth Fournier, Didier TharreauAbstract:Summary Inferring invasion routes and identifying reservoirs of Diversity of plant pathogens are essential in proposing new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the world-wide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. In order to investigate the Centers of Diversity, origin and migration of M. oryzae on rice, we analyzed the genetic Diversity of 55 populations from 15 countries. Three genetic clusters were identified world-wide. Asia was the Center of Diversity and the origin of most migrations to other continents. In Asia, two Centers of Diversity were revealed in the Himalayan foothills: South China–Laos–North Thailand, and western Nepal. Sexual reproduction persisted only in the South China–Laos–North Thailand region, which was identified as the putative Center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies.
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South-East Asia is the Center of origin, Diversity and dispersion of the rice blast fungus, Magnaporthe oryzae.
The New phytologist, 2013Co-Authors: Dounia Saleh, Joelle Milazzo, Henri Adreit, Elisabeth Fournier, Didier TharreauAbstract:Inferring invasion routes and identifying reservoirs of Diversity of plant pathogens are essential in proposing new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the world-wide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. In order to investigate the Centers of Diversity, origin and migration of M. oryzae on rice, we analyzed the genetic Diversity of 55 populations from 15 countries. Three genetic clusters were identified world-wide. Asia was the Center of Diversity and the origin of most migrations to other continents. In Asia, two Centers of Diversity were revealed in the Himalayan foothills: South China-Laos-North Thailand, and western Nepal. Sexual reproduction persisted only in the South China-Laos-North Thailand region, which was identified as the putative Center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies. (Resume d'auteur)
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Origin, structure and migration of Magnaporthe oryzae populations pathogenic on rice : DP-2
2013Co-Authors: Dounia Saleh, Joelle Milazzo, Henri Adreit, Elisabeth Fournier, Didier TharreauAbstract:Inferring invasion routes and identifying reservoirs of Diversity of plant pathogens are essential to propose new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the worldwide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. To investigate the Centers of Diversity, of origin and of migration of M. oryzae on rice, we analyzed the genetic Diversity of fifty-five samples from fifteen countries. Three genetic clusters were identified worldwide. Asia was the Center of Diversity and the origin of most migrations to other continents. In Asia, two Centers of Diversity were revealed in the Himalayan foothills: South China-Laos-North Thailand, and Western Nepal. Sexual reproduction persisted only in the South China-Laos-North Thailand region, which was identified as the putative Center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies. (Texte integral)