The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Isidro Ovandomedina - One of the best experts on this subject based on the ideXlab platform.
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sex expression and floral diversity in jatropha curcas a population study in its Center of Origin
PeerJ, 2016Co-Authors: Maria De Lourdes Adrianoanaya, Edilma Perezcastillo, Miguel Salvadorfigueroa, Sonia Ruizgonzalez, Alfredo Vazquezovando, Julieta Grajalesconesa, Isidro OvandomedinaAbstract:Sex expression and floral morphology studies are central to understand breeding behavior and to define the productive potential of plant genotypes. In particular, the new bioenergy crop Jatropha curcas L. has been classified as a monoecious species. Nonetheless, there is no information about its reproductive diversity in the Mesoamerican region, which is considered its Center of Origin and diversification. Thus, we determined sex expression and floral morphology in J. curcas populations from southern Mexico and Guatemala. Our results showed that most of J. curcas specimens had typical inflorescences with separate sexes (monoecious); meanwhile, the rest were atypical (gynoecious, androecious, andromonoecious, androgynomonoecious). The most important variables to group these populations, based on a discriminant analysis, were: male flower diameter, female petal length and male nectary length. From southern Mexico “Guerrero” was the most diverse population, and “Centro” had the highest variability among the populations from Chiapas. A cluster analysis showed that the accessions from southern Mexico were grouped without showing any correlation with the geographical Origin, while those accessions with atypical sexuality were grouped together. To answer the question of how informative are floral morphological traits compared to molecular markers, we perform a Mantel correlation test between the distance matrix generated in this study and the genetic distance matrix (AFLP) previously reported for the same accessions. We found significant correlation between data at the level of accessions. Our results contribute to design genetic improvement programs by using sexually and morphologically contrasting plants from the Center of Origin.
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reproductive biology of the biofuel plant jatropha curcas in its Center of Origin
PeerJ, 2016Co-Authors: Manuel Rinconrabanales, Miguel Salvadorfigueroa, Alfredo Vazquezovando, Laura I Vargaslopez, Lourdes Adrianoanaya, Isidro OvandomedinaAbstract:In this work, we studied the main characteristics of flowering, reproductive system and diversity of pollinators for the biofuel plant Jatropha curcas (L.) in a site of tropical southeastern Mexico, within its Center of Origin. The plants were monoecious with inflorescences of unisexual flowers. The male flowers produced from 3062-5016 pollen grains (266-647 per anther). The plants produced fruits with both geitonogamy and xenogamy, although insect pollination significantly increased the number and quality of fruits. A high diversity of flower visiting insects (36 species) was found, of which nine were classified as efficient pollinators. The native stingless bees Scaptotrigona mexicana (Guerin-Meneville) and Trigona (Tetragonisca) angustula (Latreille) were the most frequent visitors and their presence coincided with the hours when the stigma was receptive. It is noteworthy that the female flowers open before the male flowers, favoring xenogamy, which may explain the high genetic variability reported in J. curcas for this region of the world.
Niklaus J. Grünwald - One of the best experts on this subject based on the ideXlab platform.
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Genome-wide increased copy number is associated with emergence of super-fit clones of the Irish potato famine pathogen Phytophthora infestans
bioRxiv, 2019Co-Authors: Brian J. Knaus, Shankar Shakya, Javier F. Tabima, Howard S. Judelson, Niklaus J. GrünwaldAbstract:Abstract The plant pathogen that caused the Irish potato famine, Phytophthora infestans, continues to reemerge globally. These modern epidemics are caused by clonally reproducing lineages. In contrast, a sexual mode of reproduction is observed at its Center of Origin in Mexico. We conducted a comparative genomic analysis of 47 high coverage genomes to infer changes in genic copy number. We included samples from sexual populations at the Center of Origin as well as several dominant clonal lineages sampled worldwide. We conclude that sexual populations at the Center of Origin are diploid as was the lineage that caused the famine, while modern clonal lineages showed increased copy number (3x). Copy number variation (CNV) was found genome-wide and did not to adhere to the two-speed genome hypothesis. Although previously reported, tetraploidy was not found in any of the genomes evaluated. We propose a model of super-fit clone emergence supported by the epidemiological record (e.g., EU_13_A2, US-11, US-23) whereby higher copy number provides fitness leading to replacement of prior clonal lineages.
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Variation in Genetic Diversity of Phytophthora infestans Populations in Mexico from the Center of Origin Outwards
Plant Disease, 2018Co-Authors: Shankar Shakya, Meredith M. Larsen, Mercedes María Cuenca-condoy, Héctor Lozoya-saldaña, Niklaus J. GrünwaldAbstract:The Toluca valley, located in central Mexico, is thought to be the Center of Origin of the potato late blight pathogen Phytophthora infestans. We characterized over 500 individuals of P. infestans sampled from populations with a geographical distance of more than 400 km in six regions adjacent to the Toluca valley in three states including Michoacan, Mexico, and Tlaxcala. Our sampling occurred on a predominant east to west gradient and showed significant genetic differentiation. The most western sampling location found in Michoacan was most differentiated from the other populations. Populations from San Geronimo, Juchitepec, and Tlaxcala clustered together and appeared to be in linkage equilibrium. This work provides a finer understanding of gradients of genetic diversity in populations of P. infestans at the Center of Origin.
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selection for fungicide resistance within a growing season in field populations of phytophthora infestans at the Center of Origin
Phytopathology, 2006Co-Authors: Niklaus J. Grünwald, Anne K Sturbaum, Gaspar Romero Montes, Edith Garay Serrano, Hector LozoyasaldanaAbstract:Grunwald, N. J., Sturbaum, A. K., Romero Montes, G., Garay Serrano, E., Lozoya-Saldana, H., and Fry, W. E. 2006. Selection for fungicide resistance within a growing season in field populations of Phytophthora infestans at the Center of Origin. Phytopathology 96:1397-1403. The central highlands of Mexico should provide an optimal testing ground for evaluating the potential threat of selection for resistance to fungicides in the population of Phytophthora infestans. We evaluated the hypotheses that exposure to the fungicides azoxystrobin, cymoxanil, dimethomorph, fluazinam, mancozeb, metalaxyl, and propamocarb hydrochloride would lead to (i) a shift in the sensitivity distributions (i.e., selection) and (ii) a lower genotypic diversity of the population. We compared populations from unsprayed plots with populations that had been exposed to several applications of each of the fungicides within a single field season. This study provides novel baseline data and shows that the Toluca valley P. infestans population has a wide range of sensitivities to the fungicides fluazinam, cymoxanil, dimethomorph, metalaxyl, and propamocarb. Directional selection toward resistance combined with a reduction in genetic diversity of the P. infestans population was observed only for the fungicide metalaxyl. The results obtained provide direct experimental support for continuing vigilance regarding further
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the biology of phytophthora infestans at its Center of Origin
Annual Review of Phytopathology, 2005Co-Authors: Niklaus J. Grünwald, W G FlierAbstract:The central highlands of Mexico are considered to be a Center of genetic diversity for both the potato late blight pathogen and for tuber-bearing Solanum spp. Recent work conducted in Mexico and South America sheds new light on the biology and evolution of Phytophthora infestans and other related Phytophthora pathogens. It now appears that Mexican Solanum species, which coevolved with P. infestans and were previously known for providing a source of R-genes, also provide a source of quantitative, rate-reducing resistance that is highly effective, stable, and durable. It is now apparent that Mexico is the Center of Origin not only of the potato late blight pathogen P. infestans, but also of several related Phytophthora species including P. mirabilis, P. ipomoeae, and possibly P. phaseoli. We close with the hypothesis that these Phytophthora species evolved sympatrically from one ancestral host through adaptive radiation onto their respective four host families.
Gerald Seiler - One of the best experts on this subject based on the ideXlab platform.
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High infraspecific diversity of wild sunflowers (Helianthus annuus L.) naturally developed in central Argentina
Flora: Morphology Distribution Functional Ecology of Plants, 2010Co-Authors: Miguel Cantamutto, Ivana Fernandez Moroni, Daniel Alvarez, Alejandro Presotto, Mónica Poverene, Gerald SeilerAbstract:The sunflower's wild relative Helianthus annuus L. is a non-native invader in several regions of the world. It was introduced as an experimental forage plant in central Argentina six decades ago where it probably escaped and developed extended populations coexisting with the sunflower crop. If the invasive taxon was diffused without modifications, it would be expected to have phenotypic similarities with its parental sources. Nine populations representative of different geographic regions of central Argentina were compared with 17 populations from the USA (Center of Origin) in a common garden study at Bahía Blanca, Argentina using 47 phenotypic traits. The nine invasive wild populations were differentiated among themselves and from the native populations by plant form and life cycle traits, oil composition, inflorescence, and achene morphology. Populations from both continents shared traits related to domesticated sunflower, such as bract width over 0.8 cm, but the frequency of this trait was higher in populations from Argentina. The high variability of wild H. annuus populations from Argentina did not reveal any founder effects. The diversity found in the invasive populations reflected about three-fourths of the phenotypic variability of those from the Center of Origin, even though the environmental conditions of the Argentine habitats represented only half of the variability present in the North American habitats. The current findings demonstrated that the invasive wild sunflower populations have developed within few decades a high degree of variability, which could be a source of a novel biodiversity useful as a genetic resource for sunflower crop improvement. © 2010 Elsevier GmbH.
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.
Miguel Cantamutto - One of the best experts on this subject based on the ideXlab platform.
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High infraspecific diversity of wild sunflowers (Helianthus annuus L.) naturally developed in central Argentina
Flora: Morphology Distribution Functional Ecology of Plants, 2010Co-Authors: Miguel Cantamutto, Ivana Fernandez Moroni, Daniel Alvarez, Alejandro Presotto, Mónica Poverene, Gerald SeilerAbstract:The sunflower's wild relative Helianthus annuus L. is a non-native invader in several regions of the world. It was introduced as an experimental forage plant in central Argentina six decades ago where it probably escaped and developed extended populations coexisting with the sunflower crop. If the invasive taxon was diffused without modifications, it would be expected to have phenotypic similarities with its parental sources. Nine populations representative of different geographic regions of central Argentina were compared with 17 populations from the USA (Center of Origin) in a common garden study at Bahía Blanca, Argentina using 47 phenotypic traits. The nine invasive wild populations were differentiated among themselves and from the native populations by plant form and life cycle traits, oil composition, inflorescence, and achene morphology. Populations from both continents shared traits related to domesticated sunflower, such as bract width over 0.8 cm, but the frequency of this trait was higher in populations from Argentina. The high variability of wild H. annuus populations from Argentina did not reveal any founder effects. The diversity found in the invasive populations reflected about three-fourths of the phenotypic variability of those from the Center of Origin, even though the environmental conditions of the Argentine habitats represented only half of the variability present in the North American habitats. The current findings demonstrated that the invasive wild sunflower populations have developed within few decades a high degree of variability, which could be a source of a novel biodiversity useful as a genetic resource for sunflower crop improvement. © 2010 Elsevier GmbH.
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high infraspecific diversity of wild sunflowers helianthus annuus l naturally developed in central argentina
Flora, 2010Co-Authors: Miguel Cantamutto, Daniel Alvarez, Alejandro Presotto, Mónica Poverene, Ivana Fernandez Moroni, Gerald J SeilerAbstract:Abstract The sunflower's wild relative Helianthus annuus L. is a non-native invader in several regions of the world. It was introduced as an experimental forage plant in central Argentina six decades ago where it probably escaped and developed extended populations coexisting with the sunflower crop. If the invasive taxon was diffused without modifications, it would be expected to have phenotypic similarities with its parental sources. Nine populations representative of different geographic regions of central Argentina were compared with 17 populations from the USA (Center of Origin) in a common garden study at Bahia Blanca, Argentina using 47 phenotypic traits. The nine invasive wild populations were differentiated among themselves and from the native populations by plant form and life cycle traits, oil composition, inflorescence, and achene morphology. Populations from both continents shared traits related to domesticated sunflower, such as bract width over 0.8 cm, but the frequency of this trait was higher in populations from Argentina. The high variability of wild H. annuus populations from Argentina did not reveal any founder effects. The diversity found in the invasive populations reflected about three-fourths of the phenotypic variability of those from the Center of Origin, even though the environmental conditions of the Argentine habitats represented only half of the variability present in the North American habitats. The current findings demonstrated that the invasive wild sunflower populations have developed within few decades a high degree of variability, which could be a source of a novel biodiversity useful as a genetic resource for sunflower crop improvement.
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PHENOTYPIC DIVERSITY IN WILD Helianthus annuus FROM ARGENTINA
Helia, 2009Co-Authors: Alejandro Presotto, Miguel Cantamutto, Mónica Poverene, Gerald J SeilerAbstract:SUMMARY Wild Helianthus annuus populations naturalized in central Argentina have spread since their introduction from the Center of Origin in North America. Phenotypic characterization based on 45 morphological and phenological descriptors of nine populations from different geographic regions of Argentina and 17 populations from the USA provided by the US Department of Agriculture germplasm bank at Ames, Iowa, was obtained by growing populations in an experiment field. Wild populations from Argentina reflected part of the phenotypic variability of populations from the Center of Origin, but showed adaptation to local conditions which allows differentiation between populations from each continent. All traits showed a continuous range, with majority of extreme values occurring in populations from North America. The populations that showed similarities for one group of descriptors differed in other traits, revealing the existence of different phenotypes. Helianthus annuus populations established in Argentina could be considered a differentiated genetic resource, containing new combinations and traits absent in North American populations, such as the life cycle length in the Diamante population of 180 days and longer, the longest of any population studied.