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Loren H Rieseberg - One of the best experts on this subject based on the ideXlab platform.
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gene flow in argentinian Sunflowers as revealed by genotyping by sequencing data
Evolutionary Applications, 2018Co-Authors: Ana Mondon, Gregory L. Owens, Miguel Cantamutto, Monica Poverene, Loren H RiesebergAbstract:Gene flow can have several different applied consequences, ranging from extinction to the escape of transgenes to the evolution of weedy or invasive lineages. Here, we describe patterns of hybridization and gene flow involving domesticated and wild Sunflowers in Argentina. To address the risks of introgression of variants from the cultivated Sunflower into invasive wild Helianthus, we used genotyping by sequencing (GBS) to genotype 182 samples from 11 sites in Argentina, along with previously published data from samples from the native range (North America), to determine the native source populations of the Argentinian samples and to detect admixture. We unexpectedly discovered two distinctive forms of H. petiolaris in Argentina, one from H. petiolaris subsp. petiolaris as expected, but the other from an unknown source. Extensive admixture was observed among Argentinian Sunflowers, largely confirming phenotypic predictions. While many hybrids are F1s, there were signals consistent with introgression from the domesticated Sunflower into H. petiolaris. Whether this introgression is incidental or a causal driver of invasiveness is not yet clear, but it seems likely that genes found in the domesticated Sunflower genome (whether engineered or not) will quickly find their way into wild Argentinian Sunflower populations. This article is protected by copyright. All rights reserved.
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genomics of homoploid hybrid speciation diversity and transcriptional activity of long terminal repeat retrotransposons in hybrid Sunflowers
Philosophical Transactions of the Royal Society B, 2014Co-Authors: Sebastien Renaut, Heather C Rowe, Loren H Rieseberg, Mark C UngererAbstract:Hybridization is thought to play an important role in plant evolution by introducing novel genetic combinations and promoting genome restructuring. However, surprisingly little is known about the impact of hybridization on transposable element (TE) proliferation and the genomic response to TE activity. In this paper, we first review the mechanisms by which homoploid hybrid species may arise in nature. We then present hybrid Sunflowers as a case study to examine transcriptional activity of long terminal repeat retrotransposons in the annual Sunflowers Helianthus annuus , Helianthus petiolaris and their homoploid hybrid derivatives ( H. paradoxus , H. anomalus and H. deserticola ) using high-throughput transcriptome sequencing technologies (RNAseq). Sampling homoploid hybrid Sunflower taxa revealed abundant variation in TE transcript accumulation. In addition, genetic diversity for several candidate genes hypothesized to regulate TE activity was characterized. Specifically, we highlight one candidate chromatin remodelling factor gene with a direct role in repressing TE activity in a hybrid species. This paper shows that TE amplification in hybrid lineages is more idiosyncratic than previously believed and provides a first step towards identifying the mechanisms responsible for regulating and repressing TE expansions.
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Hybridization and the colonization of novel habitats by annual Sunflowers
Genetica, 2007Co-Authors: Loren H Rieseberg, Seung Chul Kim, Briana L. Gross, Rebecca A Randell, Christian Lexer, Kenneth D Whitney, Keith ClayAbstract:Although invasive plant species often have a hybrid ancestry, unambiguous evidence that hybridization has stimulated the evolution of invasive behaviors has been difficult to come by. Here, we briefly review how hybridization might contribute to the colonization of novel habitats, range expansions, and invasiveness and then describe work on hybrid Sunflowers that forges a direct link between hybridization and ecological divergence. We first discuss the invasion of Texas by the common Sunflower and show that the introgression of chromosomal segments from a locally adapted species may have facilitated range expansion. We then present evidence that the colonization of sand dune, desert floor, and salt marsh habitats by three hybrid Sunflower species was made possible by selection on extreme or "transgressive" phenotypes generated by hybridization. This body of work corroborates earlier claims regarding the role of hybridization in adaptive evolution and provides an experimental and conceptual framework for ongoing studies in this area.
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a bt transgene reduces herbivory and enhances fecundity in wild Sunflowers
Ecological Applications, 2003Co-Authors: Allison A. Snow, Diana E Wolf, Diana Pilson, N Pleskac, Michael Reagon, M. J. Paulsen, Loren H Rieseberg, Sarena M. SelboAbstract:Gene flow from transgenic crops can introduce novel traits into related spe- cies, but the ecological importance of this process is unknown. Here, we report the first empirical evidence that wild plants can benefit from a bacterial transgene under uncaged, natural conditions. Cultivated Sunflower ( Helianthus annuus) is known to hybridize fre- quently with wild Sunflower ( H. annuus) in the western and midwestern United States. We studied a crop-developed Bacillus thuringiensis(Bt) transgene, cry1Ac, in backcrossed wild Sunflower populations. Lepidopteran damage on transgenic plants was strongly reduced relative to control plants at our two study sites, while damage by several weevil and fly species was unaffected. Our results suggest that reduced herbivory caused transgenic plants to produce an average of 55% more seeds per plant relative to nontransgenic controls at the field site in Nebraska. A similar but nonsignificant trend was seen at the site in Colorado (14% more seeds per plant). In a greenhouse experiment the transgene had no effect on fecundity, suggesting that it was not associated with a fitness cost. If Bt Sunflowers are released commercially, we expect that Bt genes will spread to wild and weedy populations, limit damage from susceptible herbivores on these plants, and increase seed production when these herbivores are common.
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Genetic mapping in Sunflowers
Advances in Cellular and Molecular Biology of Plants, 2001Co-Authors: Steven J. Knapp, Simon Berry, Loren H RiesebergAbstract:Cultivated Sunflower (Helianthus annuus L.) is a member of the subtribe Helianthinae of the Compositae (Asteraceae) family (Seiler and Rieseberg 1997). The genus is a polyploid complex, with diploid, tetraploid and hexaploid species, and a basic chromosome number of 17 (Heiser and Smith 1955). There are 12 annual diploid species and 37 perennial species. North America is the center of diversity for Sunflowers. Sunflowers were first cultivated by Native Americans in 1000 BC, were introduced into Europe in the sixteenth century, and were first grown as a source of edible oil in nineteenth century Russia. Russian plant breeders increased Sunflower seed oil concentrations from 330g/kg up to as much as 550g/kg between 1940 and 1965 and developed the first high oil cultivars (Putt 1997). These cultivars dramatically transformed Sunflower as an oilseed crop and they have been widely used in the development of modern-day cultivars and hybrids — a significant fraction of the diversity in elite inbred lines traces to high-oil germplasm developed in Russia (Korell et al. 1992; Cheres and Knapp 1998).
Guillermo H Crapiste - One of the best experts on this subject based on the ideXlab platform.
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temperature dependent diffusion coefficient of oil from different Sunflower seeds during extraction with hexane
Journal of Food Engineering, 2011Co-Authors: Ethel E Perez, Amalia A Carelli, Guillermo H CrapisteAbstract:Abstract Oil extraction from confectionery, oilseed and wild Sunflower seeds with n -hexane was investigated by laboratory tests carried out in a stirred batch extractor at several temperatures (40, 50 and 60 °C). The rates of extraction were determined from ground Sunflower seeds (particle sizes between 0.420 and 1.000 mm). The oil yield in the extract increased with higher contact time and extraction temperature in all the cases. Equilibrium constants at 50 °C for different solvent–ground seed ratios are reported. A mathematical model of oil extraction from seeds of Sunflowers, based on a modified diffusive process in spherical geometry of particles, was proposed. The analysis of significance of the coefficient of fitting regression models showed significant differences between temperatures for each genotype and between genotypes at each temperature. The resulting diffusion coefficient ranged from 1.34 × 10 −12 to 1.87 × 10 −12 m 2 /s for confectionery, 2.06 × 10 −12 to 5.03 × 10 −12 m 2 /s for oilseed, and 9.06 × 10 −13 to 1.18 × 10 −12 m 2 /s for wild Sunflower. The temperature dependence of the diffusion coefficient was represented by an Arrhenius-type equation for each Sunflower seed studied. Activation energy values of 13.74, 33.95 and 11.32 kJ/mol were obtained for confectionery, oilseed and wild Sunflower, respectively.
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temperature dependent diffusion coefficient of oil from different Sunflower seeds during extraction with hexane
Journal of Food Engineering, 2011Co-Authors: Ethel E Perez, Amalia A Carelli, Guillermo H CrapisteAbstract:Abstract Oil extraction from confectionery, oilseed and wild Sunflower seeds with n -hexane was investigated by laboratory tests carried out in a stirred batch extractor at several temperatures (40, 50 and 60 °C). The rates of extraction were determined from ground Sunflower seeds (particle sizes between 0.420 and 1.000 mm). The oil yield in the extract increased with higher contact time and extraction temperature in all the cases. Equilibrium constants at 50 °C for different solvent–ground seed ratios are reported. A mathematical model of oil extraction from seeds of Sunflowers, based on a modified diffusive process in spherical geometry of particles, was proposed. The analysis of significance of the coefficient of fitting regression models showed significant differences between temperatures for each genotype and between genotypes at each temperature. The resulting diffusion coefficient ranged from 1.34 × 10 −12 to 1.87 × 10 −12 m 2 /s for confectionery, 2.06 × 10 −12 to 5.03 × 10 −12 m 2 /s for oilseed, and 9.06 × 10 −13 to 1.18 × 10 −12 m 2 /s for wild Sunflower. The temperature dependence of the diffusion coefficient was represented by an Arrhenius-type equation for each Sunflower seed studied. Activation energy values of 13.74, 33.95 and 11.32 kJ/mol were obtained for confectionery, oilseed and wild Sunflower, respectively.
Marie-Helene Muller - One of the best experts on this subject based on the ideXlab platform.
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How to escape from crop-to-weed gene flow: phenological variation and isolation-by-time within weedy Sunflower populations.
New Phytologist, 2015Co-Authors: Marie Roumet, Muriel Latreille, Camille NOILHAN, Jacques David, Marie-Helene MullerAbstract:The evolution of crop-related weeds may be constrained by recurrent gene flow from the crop. However, flowering time variation within weedy populations may open the way for weed adaptation by allowing some weeds to escape from this constraint. We investigated this link between phenology, gene flow and adaptation in weedy Sunflower populations that have recently emerged in Europe from crop-wild hybridization. We studied jointly flowering phenology and genetic diversity for 15 microsatellite loci in six cultivated Sunflower (Helianthus annuus) fields infested by weedy Sunflower populations. The flowering overlap of cultivated and weedy Sunflowers varied between and within populations: some weedy individuals were found to be completely isolated from the crop, the frequency of these plants being higher in populations from highly infested fields. Within weedy populations, we detected a pattern of isolation-by-time: the genetic divergence between individuals was positively correlated with their divergence in flowering period. In addition, earlier weeds, which flowered synchronously with the crop, were genetically more similar than late-flowering weeds to the cultivated varieties. Overall, our results suggest that crop-to-weed gene flow occurred, but was limited by divergent phenologies. We discuss the roles of weed adaptation and population history in the generation of this partial reproductive isolation.
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Les tournesols adventices : un exemple d’évolution d’une mauvaise-herbe apparentée àune espèce cultivée – Synthèse des recherches menées sur les populations adventices de tournesol en France depuis 2004
Oléagineux, Corps Gras, Lipides, 2015Co-Authors: Marie-Helene Muller, Marie Roumet, Vincent LecomteAbstract:Evolution of a crop-related weed: Synthesis of researches conducted on weedy Sunflower populations in France since 2004 Weedy Sunflowers have been officially reported in South-Western France in 2004. They display a combination of phenotypic traits of the wild and domesticated forms of the species and infest between 15 and 20% of fields of Sunflower crop in this area, although at variable levels. When the infestation is strong, it affects seed yield and oil quality. Molecular studies showed that weedy Sunflowers most probably resulted from accidental crop-wild hybridization during the seed production process and from the introduction of the resulting hybrids into commercial seed lots. Multiple independent introductions were at the source of the number of infested fields observed nowadays. The temporal dynamics of the infestation of a field and the detailed conditions for its success remain largely unknown. The flowering synchrony between crops and weeds is substantial, even if a variable fraction of the weeds (15-55%) flower completely outside the crop flowering period. Molecular survey of adult weedy plants and their progenies showed that crop-toweed gene flow occurs, at a rate that can reach 35 %on average, at the peak of the crop flowering period. We draw perspectives on the durability of herbicide-tolerant Sunflower varieties as a solution to control these weeds, and call for more studies tackling weed management from an evolutionary lens.
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Les tournesols adventices : un exemple d’évolution d’une mauvaise-herbe apparentée à une espèce cultivée – Synthèse des recherches menées sur les populations adventices de tournesol en France depuis 2004
Oléagineux Corps Gras Lipides, 2012Co-Authors: Marie-Helene Muller, Marie Roumet, Vincent LecomteAbstract:Evolution of a crop-related weed: Synthesis of researches conducted on weedy Sunflower populations in France since 2004 Weedy Sunflowers have been officially reported in South-Western France in 2004. They display a combination of phenotypic traits of the wild and domesticated forms of the species and infest between 15 and 20% of fields of Sunflower crop in this area, although at variable levels. When the infestation is strong, it affects seed yield and oil quality. Molecular studies showed that weedy Sunflowers most probably resulted from accidental crop-wild hybridization during the seed production process and from the introduction of the resulting hybrids into commercial seed lots. Multiple independent introductions were at the source of the number of infested fields observed nowadays. The temporal dynamics of the infestation of a field and the detailed conditions for its success remain largely unknown. The flowering synchrony between crops and weeds is substantial, even if a variable fraction of the weeds (15-55%) flower completely outside the crop flowering period. Molecular survey of adult weedy plants and their progenies showed that crop-toweed gene flow occurs, at a rate that can reach 35 %on average, at the peak of the crop flowering period. We draw perspectives on the durability of herbicide-tolerant Sunflower varieties as a solution to control these weeds, and call for more studies tackling weed management from an evolutionary lens.
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Occurrence, distribution and distinctive morphological traits of weedy Helianthus annuus L. populations in Spain and France
Genetic Resources and Crop Evolution, 2009Co-Authors: Marie-Helene Muller, Florent Delieux, J.m. Fernandez-martınez, B. Garric, V. Lecombe, V. Anglade, M. Leflon, C. Motard, R. SeguraAbstract:We made a first descriptive study of weedy Sunflowers infesting Sunflower crop fields in one Spanish and three French regions. Overall, weedy Sunflowers affected around 15% of Sunflower fields. Infested fields were most often dispersed over the study areas without evident geographical clustering. In France, five weedy populations were surveyed more intensively. They were composed of a large diversity of morphotypes showing a combination of typical wild and domesticated traits in proportions that differed between populations. Yield losses reached 50% in heavily infested patches. Our results suggest that weedy Sunflowers may have arisen through the hybridization of cultivated and wild Sunflower, potentially during the seed production process. Such crop-wild hybrids would have been introduced recurrently into fields through the seed lots, where they evolved to locally invasive weedy populations
Ethel E Perez - One of the best experts on this subject based on the ideXlab platform.
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temperature dependent diffusion coefficient of oil from different Sunflower seeds during extraction with hexane
Journal of Food Engineering, 2011Co-Authors: Ethel E Perez, Amalia A Carelli, Guillermo H CrapisteAbstract:Abstract Oil extraction from confectionery, oilseed and wild Sunflower seeds with n -hexane was investigated by laboratory tests carried out in a stirred batch extractor at several temperatures (40, 50 and 60 °C). The rates of extraction were determined from ground Sunflower seeds (particle sizes between 0.420 and 1.000 mm). The oil yield in the extract increased with higher contact time and extraction temperature in all the cases. Equilibrium constants at 50 °C for different solvent–ground seed ratios are reported. A mathematical model of oil extraction from seeds of Sunflowers, based on a modified diffusive process in spherical geometry of particles, was proposed. The analysis of significance of the coefficient of fitting regression models showed significant differences between temperatures for each genotype and between genotypes at each temperature. The resulting diffusion coefficient ranged from 1.34 × 10 −12 to 1.87 × 10 −12 m 2 /s for confectionery, 2.06 × 10 −12 to 5.03 × 10 −12 m 2 /s for oilseed, and 9.06 × 10 −13 to 1.18 × 10 −12 m 2 /s for wild Sunflower. The temperature dependence of the diffusion coefficient was represented by an Arrhenius-type equation for each Sunflower seed studied. Activation energy values of 13.74, 33.95 and 11.32 kJ/mol were obtained for confectionery, oilseed and wild Sunflower, respectively.
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temperature dependent diffusion coefficient of oil from different Sunflower seeds during extraction with hexane
Journal of Food Engineering, 2011Co-Authors: Ethel E Perez, Amalia A Carelli, Guillermo H CrapisteAbstract:Abstract Oil extraction from confectionery, oilseed and wild Sunflower seeds with n -hexane was investigated by laboratory tests carried out in a stirred batch extractor at several temperatures (40, 50 and 60 °C). The rates of extraction were determined from ground Sunflower seeds (particle sizes between 0.420 and 1.000 mm). The oil yield in the extract increased with higher contact time and extraction temperature in all the cases. Equilibrium constants at 50 °C for different solvent–ground seed ratios are reported. A mathematical model of oil extraction from seeds of Sunflowers, based on a modified diffusive process in spherical geometry of particles, was proposed. The analysis of significance of the coefficient of fitting regression models showed significant differences between temperatures for each genotype and between genotypes at each temperature. The resulting diffusion coefficient ranged from 1.34 × 10 −12 to 1.87 × 10 −12 m 2 /s for confectionery, 2.06 × 10 −12 to 5.03 × 10 −12 m 2 /s for oilseed, and 9.06 × 10 −13 to 1.18 × 10 −12 m 2 /s for wild Sunflower. The temperature dependence of the diffusion coefficient was represented by an Arrhenius-type equation for each Sunflower seed studied. Activation energy values of 13.74, 33.95 and 11.32 kJ/mol were obtained for confectionery, oilseed and wild Sunflower, respectively.
Ivana Imerovski - One of the best experts on this subject based on the ideXlab platform.
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Massive haplotypes underlie ecotypic differentiation in Sunflowers
Nature, 2020Co-Authors: Marco Todesco, Gregory L. Owens, Jeansebastien Legare, Shaghayegh Soudi, Kaichi Huang, Katherine L Ostevik, Emily B M Drummond, Natalia Bercovich, Dylan O. Burge, Ivana ImerovskiAbstract:Species often include multiple ecotypes that are adapted to different environments^ 1 . However, it is unclear how ecotypes arise and how their distinctive combinations of adaptive alleles are maintained despite hybridization with non-adapted populations^ 2 – 4 . Here, by resequencing 1,506 wild Sunflowers from 3 species ( Helianthus annuus , Helianthus petiolaris and Helianthus argophyllus ), we identify 37 large (1–100 Mbp in size), non-recombining haplotype blocks that are associated with numerous ecologically relevant traits, as well as soil and climate characteristics. Limited recombination in these haplotype blocks keeps adaptive alleles together, and these regions differentiate Sunflower ecotypes. For example, haplotype blocks control a 77-day difference in flowering between ecotypes of the silverleaf Sunflower H. argophyllus (probably through deletion of a homologue of FLOWERING LOCUS T ( FT )), and are associated with seed size, flowering time and soil fertility in dune-adapted Sunflowers. These haplotypes are highly divergent, frequently associated with structural variants and often appear to represent introgressions from other—possibly now-extinct—congeners. These results highlight a pervasive role of structural variation in ecotypic adaptation. Resequencing analyses of three species of wild Sunflower identify large non-recombining haplotype blocks that correlate with ecologically relevant traits, soil and climate characteristics, and that differentiate species ecotypes.
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Massive haplotypes underlie ecotypic differentiation in Sunflowers
Nature, 2020Co-Authors: Marco Todescov, Gregory L. Owens, Jeansebastien Legare, Shaghayegh Soudi, Kaichi Huang, Katherine L Ostevik, Emily B M Drummond, Natalia Bercovich, Dylan O., Ivana ImerovskiAbstract:Species often include multiple ecotypes that are adapted to different environments 1. However, it is unclear how ecotypes arise and how their distinctive combinations of adaptive alleles are maintained despite hybridization with non-adapted populations 2-4. Here, by resequencing 1,506 wild Sunflowers from 3 species (Helianthus annuus, Helianthus petiolaris and Helianthus argophyllus), we identify 37 large (1-100 Mbp in size), non-recombining haplotype blocks that are associated with numerous ecologically relevant traits, as well as soil and climate characteristics. Limited recombination in these haplotype blocks keeps adaptive alleles together, and these regions differentiate Sunflower ecotypes. For example, haplotype blocks control a 77-day difference in flowering between ecotypes of the silverleaf Sunflower H. argophyllus (probably through deletion of a homologue of FLOWERING LOCUS T (FT)), and are associated with seed size, flowering time and soil fertility in dune-adapted Sunflowers. These haplotypes are highly divergent, frequently associated with structural variants and often appear to represent introgressions from other-possibly now-extinct-congeners. These results highlight a pervasive role of structural variation in ecotypic adaptation. Local adaptation is common in species that experience different environments across their range, often resulting in the formation of ecotypes-ecological races with distinct morphological and/or physiological characteristics that provide an environment-specific fitness advantage. Despite the prevalence of ecotypic differentiation, much remains to be understood about the genetic basis and evolutionary mechanisms that underlie its establishment and maintenance. In particular , a longstanding evolutionary question-dating to criticisms of Darwin's theories by his contemporaries 4-concerns how such ecological divergence can occur when challenged by hybridization with non-adapted populations 2. Local adaptation typically requires alleles at multiple loci that contribute to increased fitness in the same environment ; however, different ecotypes are often geographically close and interfertile, and hybridization between them should break up adaptive allelic combinations 3. To better understand the genetic basis of local adaptation and ecotypic differentiation, we conducted an in-depth study of genetic, phenotypic and environmental variation in three annual Sunflower species, each of which includes multiple reproductively compatible ecotypes. Two species (H. annuus and H. petiolaris) have broad, overlapping distributions across North America. Helianthus annuus, the common Sunflower, is generally found on mesic soils, but can grow in a variety of disturbed or extreme habitats, including semi-desert or frequently flooded areas. An especially well-characterized ecotype (formally known as H. annuus subsp. texanus) is adapted to the higher temperatures and herbivore pressures in Texas (USA) 5. Helianthus petiolaris, the prairie Sunflower, prefers sandier soils; ecotypes of this species are adapted to sand sheets and dunes 6. The third species-H. argophyllus, the silverleaf Sunflower-is endemic to southern Texas and includes both an early-flowering, coastal-island ecotype and a late-flowering inland ecotype 7. Population structure of wild Sunflowers In a common garden experiment, we grew 10 plants from each of 151 populations of the 3 species, selected from across their native range (Fig. 1a); for each of these populations, we collected corresponding soil samples. We generated extensive records of developmental and morphological traits, and resequenced the genomes of 1,401 individual plants. We resequenced an additional 105 H. annuus plants to fill gaps in geographical coverage, as well as 12 outgroup taxa (Supplementary Table 1). Sunflower genomes are relatively large (H. annuus, 3.5 Gbp; https://doi.