The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Loren H Rieseberg - One of the best experts on this subject based on the ideXlab platform.
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Genetic mapping in Sunflowers
Advances in Cellular and Molecular Biology of Plants, 2020Co-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).
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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, Mónica 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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Gene flow in Argentinian Sunflowers as revealed by genotyping-by-sequencing data
Evolutionary Applications, 2018Co-Authors: Ana Mondon, Gregory L. Owens, Miguel Cantamutto, Mónica 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 sun- flowers in Argentina. To address the risks of introgression of variants from the culti- vated sunflower into invasive wild Helianthus, we used genotyping-by-sequencing (GBS) to genotype 182 samples from 11 sites in Argentina, along with previously pub- lished 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 engi- neered or not) will quickly find their way into wild Argentinian sunflower populations.
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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, Loren H Rieseberg, Heather C Rowe, 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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effective population size is positively correlated with levels of adaptive divergence among annual Sunflowers
Molecular Biology and Evolution, 2011Co-Authors: Jared L Strasburg, Loren H Rieseberg, Nolan C Kane, Andrew R Raduski, Aurelie Bonin, Richard W MichelmoreAbstract:The role of adaptation in the divergence of lineages has long been a central question in evolutionary biology, and as multilocus sequence data sets have become available for a wide range of taxa, empirical estimates of levels of adaptive molecular evolution are increasingly common. Estimates vary widely among taxa, with high levels of adaptive evolution in Drosophila, bacteria, and viruses but very little evidence of widespread adaptive evolution in hominids. Although estimates in plants are more limited, some recent work has suggested that rates of adaptive evolution in a range of plant taxa are surprisingly low and that there is little association between adaptive evolution and effective population size in contrast to patterns seen in other taxa. Here, we analyze data from 35 loci for six sunflower species that vary dramatically in effective population size. We find that rates of adaptive evolution are positively correlated with effective population size in these species, with a significant fraction of amino acid substitutions driven by positive selection in the species with the largest effective population sizes but little or no evidence of adaptive evolution in species with smaller effective population sizes. Although other factors likely contribute as well, in Sunflowers effective population size appears to be an important determinant of rates of adaptive evolution.
Marek Vaculík - One of the best experts on this subject based on the ideXlab platform.
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impact of wheat straw biochar addition to soil on the sorption leaching dissipation of the herbicide 4 chloro 2 methylphenoxy acetic acid and the growth of sunflower helianthus annuus l
Ecotoxicology and Environmental Safety, 2013Co-Authors: Veronika Tatarková, Edgar Hiller, Marek VaculíkAbstract:Abstract Biochar addition to agricultural soils might increase the sorption of herbicides, and therefore, affect other sorption-related processes such as leaching, dissipation and toxicity for plants. In this study, the impact of wheat straw biochar on the sorption, leaching and dissipation in a soil, and toxicity for sunflower of (4-chloro-2-methylphenoxy)acetic acid (MCPA), a commonly used ionizable herbicide, was investigated. The results showed that MCPA sorption by biochar and biochar-amended soil (1.0 wt% biochar) was 82 and 2.53 times higher than that by the non-amended soil, respectively. However, desorption of MCPA from biochar-amended soil was only 1.17 times lower than its desorption in non-amended soil. Biochar addition to soil reduced both MCPA leaching and dissipation. About 35% of the applied MCPA was transported through biochar-amended soil, while up to 56% was recovered in the leachates transported through non-amended soil. The half-life value of MCPA increased from 5.2 d in non-amended soil to 21.5 d in biochar-amended soil. Pot experiments with sunflower (Helianthus annuus L.) grown in MCPA-free, but biochar-amended soil showed no positive effect of biochar on the growth of sunflower in comparison to the non-amended soil. However, biochar itself significantly reduced the content of photosynthetic pigments (chlorophyll a, b) in sunflower. There was no significant difference in the phytotoxic effects of MCPA on Sunflowers between the biochar-amended soil and the non-amended soil. Furthermore, MCPA had no effect on the photosynthetic pigment contents in sunflower.
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Impact of wheat straw biochar addition to soil on the sorption, leaching, dissipation of the herbicide (4-chloro-2-methylphenoxy)acetic acid and the growth of sunflower (Helianthus annuus L.)
Ecotoxicology and Environmental Safety, 2013Co-Authors: Veronika Tatarková, Edgar Hiller, Marek VaculíkAbstract:Biochar addition to agricultural soils might increase the sorption of herbicides, and therefore, affect other sorption-related processes such as leaching, dissipation and toxicity for plants. In this study, the impact of wheat straw biochar on the sorption, leaching and dissipation in a soil, and toxicity for sunflower of (4-chloro-2-methylphenoxy)acetic acid (MCPA), a commonly used ionizable herbicide, was investigated. The results showed that MCPA sorption by biochar and biochar-amended soil (1.0. wt% biochar) was 82 and 2.53 times higher than that by the non-amended soil, respectively. However, desorption of MCPA from biochar-amended soil was only 1.17 times lower than its desorption in non-amended soil. Biochar addition to soil reduced both MCPA leaching and dissipation. About 35% of the applied MCPA was transported through biochar-amended soil, while up to 56% was recovered in the leachates transported through non-amended soil. The half-life value of MCPA increased from 5.2. d in non-amended soil to 21.5 d in biochar-amended soil. Pot experiments with sunflower (Helianthus annuus L.) grown in MCPA-free, but biochar-amended soil showed no positive effect of biochar on the growth of sunflower in comparison to the non-amended soil. However, biochar itself significantly reduced the content of photosynthetic pigments (chlorophyll a, b) in sunflower. There was no significant difference in the phytotoxic effects of MCPA on Sunflowers between the biochar-amended soil and the non-amended soil. Furthermore, MCPA had no effect on the photosynthetic pigment contents in sunflower. © 2013 Elsevier Inc.
Veronika Tatarková - One of the best experts on this subject based on the ideXlab platform.
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impact of wheat straw biochar addition to soil on the sorption leaching dissipation of the herbicide 4 chloro 2 methylphenoxy acetic acid and the growth of sunflower helianthus annuus l
Ecotoxicology and Environmental Safety, 2013Co-Authors: Veronika Tatarková, Edgar Hiller, Marek VaculíkAbstract:Abstract Biochar addition to agricultural soils might increase the sorption of herbicides, and therefore, affect other sorption-related processes such as leaching, dissipation and toxicity for plants. In this study, the impact of wheat straw biochar on the sorption, leaching and dissipation in a soil, and toxicity for sunflower of (4-chloro-2-methylphenoxy)acetic acid (MCPA), a commonly used ionizable herbicide, was investigated. The results showed that MCPA sorption by biochar and biochar-amended soil (1.0 wt% biochar) was 82 and 2.53 times higher than that by the non-amended soil, respectively. However, desorption of MCPA from biochar-amended soil was only 1.17 times lower than its desorption in non-amended soil. Biochar addition to soil reduced both MCPA leaching and dissipation. About 35% of the applied MCPA was transported through biochar-amended soil, while up to 56% was recovered in the leachates transported through non-amended soil. The half-life value of MCPA increased from 5.2 d in non-amended soil to 21.5 d in biochar-amended soil. Pot experiments with sunflower (Helianthus annuus L.) grown in MCPA-free, but biochar-amended soil showed no positive effect of biochar on the growth of sunflower in comparison to the non-amended soil. However, biochar itself significantly reduced the content of photosynthetic pigments (chlorophyll a, b) in sunflower. There was no significant difference in the phytotoxic effects of MCPA on Sunflowers between the biochar-amended soil and the non-amended soil. Furthermore, MCPA had no effect on the photosynthetic pigment contents in sunflower.
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Impact of wheat straw biochar addition to soil on the sorption, leaching, dissipation of the herbicide (4-chloro-2-methylphenoxy)acetic acid and the growth of sunflower (Helianthus annuus L.)
Ecotoxicology and Environmental Safety, 2013Co-Authors: Veronika Tatarková, Edgar Hiller, Marek VaculíkAbstract:Biochar addition to agricultural soils might increase the sorption of herbicides, and therefore, affect other sorption-related processes such as leaching, dissipation and toxicity for plants. In this study, the impact of wheat straw biochar on the sorption, leaching and dissipation in a soil, and toxicity for sunflower of (4-chloro-2-methylphenoxy)acetic acid (MCPA), a commonly used ionizable herbicide, was investigated. The results showed that MCPA sorption by biochar and biochar-amended soil (1.0. wt% biochar) was 82 and 2.53 times higher than that by the non-amended soil, respectively. However, desorption of MCPA from biochar-amended soil was only 1.17 times lower than its desorption in non-amended soil. Biochar addition to soil reduced both MCPA leaching and dissipation. About 35% of the applied MCPA was transported through biochar-amended soil, while up to 56% was recovered in the leachates transported through non-amended soil. The half-life value of MCPA increased from 5.2. d in non-amended soil to 21.5 d in biochar-amended soil. Pot experiments with sunflower (Helianthus annuus L.) grown in MCPA-free, but biochar-amended soil showed no positive effect of biochar on the growth of sunflower in comparison to the non-amended soil. However, biochar itself significantly reduced the content of photosynthetic pigments (chlorophyll a, b) in sunflower. There was no significant difference in the phytotoxic effects of MCPA on Sunflowers between the biochar-amended soil and the non-amended soil. Furthermore, MCPA had no effect on the photosynthetic pigment contents in sunflower. © 2013 Elsevier Inc.
L L Qi - One of the best experts on this subject based on the ideXlab platform.
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diversification of the downy mildew resistance gene pool by introgression of a new gene pl 35 from wild helianthus argophyllus into oilseed and confection Sunflowers helianthus annuus l
Theoretical and Applied Genetics, 2019Co-Authors: L L Qi, G J, Xuehui Li, Gerald J SeilerAbstract:We have mapped a new downy mildew resistance gene, Pl35, derived from wild Helianthus argophyllus to sunflower linkage group 1. New germplasms incorporating the Pl35 gene were developed for both oilseed and confection sunflower Sunflower downy mildew (DM), caused by the oomycete pathogen Plasmopara halstedii, is an economically important and widespread sunflower disease worldwide. Non-race-specific resistance is not available in sunflower, and breeding for DM resistance relies on race-specific resistance to control this disease. The discovery of the novel DM resistance genes is a long-term task due to the highly virulent and aggressive nature of the P. halstedii pathogen, which reduces the effectiveness of resistance genes. The objectives of this study were to: (1) transfer DM resistance from a wild sunflower species Helianthus argophyllus (PI 494576) into cultivated Sunflowers; (2) map the resistance gene; and (3) develop diagnostic single-nucleotide polymorphism (SNP) markers for efficient targeting of the gene in breeding programs. The H. argophyllus accession PI 494576 previously identified with resistance to the most virulent P. halstedii race 777 was crossed with oilseed and confection sunflower in 2012. Molecular mapping using the BC2F2 and BC2F3 populations derived from the cross CONFSCLB1/PI 494576 located a new resistance gene Pl35 on linkage group 1 of the sunflower genome. The new gene Pl35 was successfully transferred from PI 494576 into cultivated Sunflowers. SNP markers flanking Pl35 were surveyed in a validation panel of 548 diversified sunflower lines collected globally. Eleven SNP markers were found to be diagnostic for Pl35 SNP alleles, with four co-segregating with Pl35. The developed oilseed and confection germplasms with diagnostic SNP markers for Pl35 will be very useful resources for breeding of DM resistance in sunflower.
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pl 17 is a novel gene independent of known downy mildew resistance genes in the cultivated sunflower helianthus annuus l
Theoretical and Applied Genetics, 2015Co-Authors: L L Qi, Yunming Long, G J, T J GulyaAbstract:Key message Pl17, a novel downy mildew resistance gene independent of known downy mildew resistance genes in Sunflowers, was genetically mapped to linkage group 4 of the sunflower genome.
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identification of resistance to new virulent races of rust in Sunflowers and validation of dna markers in the gene pool
Phytopathology, 2011Co-Authors: L L Qi, T J Gulya, Gerald J Seiler, Brent S Hulke, Brady A VickAbstract:Qi, L.-L., Gulya, T., Seiler, G. J., Hulke, B. S., and Vick, B. A. 2011. Identification of resistance to new virulent races of rust in Sunflowers and validation of DNA markers in the gene pool. Phytopathology 101:241249. Sunflower rust, caused by Puccinia helianthi, is a prevalent disease in many countries throughout the world. The U.S. Department of Agriculture (USDA)-Agricultural Research Service, Sunflower Research Unit has released rust resistant breeding materials for several decades. However, constantly coevolving rust populations have formed new virulent races to which current hybrids have little resistance. The objectives of this study were to identify resistance to race 336, the predominant race in North America, and to race 777, the most virulent race currently known, and to validate molecular markers known to be linked to rust resistance genes in the sunflower gene pool. A total of 104 entries, including 66 released USDA inbred lines, 14 USDA interspecific germplasm lines, and 24 foreign germplasms, all developed specifically for rust resistance, were tested for their reaction to races 336 and 777. Only 13 of the 104 entries tested were resistant to both races, whereas another six were resistant only to race 336. The interspecific germplasm line, Rf ANN1742, was resistant to both races and was identified as a new rust resistance source. A selection of 24 lines including 19 lines resistant to races 777 and/or 336 was screened with DNA markers linked to rust resistance genes R1, R2, R4u, and R5. The results indicated that the existing resistant lines are diverse in rust resistance genes. Durable genetic resistance through gene pyramiding will be effective for the control of rust.
Edgar Hiller - One of the best experts on this subject based on the ideXlab platform.
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impact of wheat straw biochar addition to soil on the sorption leaching dissipation of the herbicide 4 chloro 2 methylphenoxy acetic acid and the growth of sunflower helianthus annuus l
Ecotoxicology and Environmental Safety, 2013Co-Authors: Veronika Tatarková, Edgar Hiller, Marek VaculíkAbstract:Abstract Biochar addition to agricultural soils might increase the sorption of herbicides, and therefore, affect other sorption-related processes such as leaching, dissipation and toxicity for plants. In this study, the impact of wheat straw biochar on the sorption, leaching and dissipation in a soil, and toxicity for sunflower of (4-chloro-2-methylphenoxy)acetic acid (MCPA), a commonly used ionizable herbicide, was investigated. The results showed that MCPA sorption by biochar and biochar-amended soil (1.0 wt% biochar) was 82 and 2.53 times higher than that by the non-amended soil, respectively. However, desorption of MCPA from biochar-amended soil was only 1.17 times lower than its desorption in non-amended soil. Biochar addition to soil reduced both MCPA leaching and dissipation. About 35% of the applied MCPA was transported through biochar-amended soil, while up to 56% was recovered in the leachates transported through non-amended soil. The half-life value of MCPA increased from 5.2 d in non-amended soil to 21.5 d in biochar-amended soil. Pot experiments with sunflower (Helianthus annuus L.) grown in MCPA-free, but biochar-amended soil showed no positive effect of biochar on the growth of sunflower in comparison to the non-amended soil. However, biochar itself significantly reduced the content of photosynthetic pigments (chlorophyll a, b) in sunflower. There was no significant difference in the phytotoxic effects of MCPA on Sunflowers between the biochar-amended soil and the non-amended soil. Furthermore, MCPA had no effect on the photosynthetic pigment contents in sunflower.
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Impact of wheat straw biochar addition to soil on the sorption, leaching, dissipation of the herbicide (4-chloro-2-methylphenoxy)acetic acid and the growth of sunflower (Helianthus annuus L.)
Ecotoxicology and Environmental Safety, 2013Co-Authors: Veronika Tatarková, Edgar Hiller, Marek VaculíkAbstract:Biochar addition to agricultural soils might increase the sorption of herbicides, and therefore, affect other sorption-related processes such as leaching, dissipation and toxicity for plants. In this study, the impact of wheat straw biochar on the sorption, leaching and dissipation in a soil, and toxicity for sunflower of (4-chloro-2-methylphenoxy)acetic acid (MCPA), a commonly used ionizable herbicide, was investigated. The results showed that MCPA sorption by biochar and biochar-amended soil (1.0. wt% biochar) was 82 and 2.53 times higher than that by the non-amended soil, respectively. However, desorption of MCPA from biochar-amended soil was only 1.17 times lower than its desorption in non-amended soil. Biochar addition to soil reduced both MCPA leaching and dissipation. About 35% of the applied MCPA was transported through biochar-amended soil, while up to 56% was recovered in the leachates transported through non-amended soil. The half-life value of MCPA increased from 5.2. d in non-amended soil to 21.5 d in biochar-amended soil. Pot experiments with sunflower (Helianthus annuus L.) grown in MCPA-free, but biochar-amended soil showed no positive effect of biochar on the growth of sunflower in comparison to the non-amended soil. However, biochar itself significantly reduced the content of photosynthetic pigments (chlorophyll a, b) in sunflower. There was no significant difference in the phytotoxic effects of MCPA on Sunflowers between the biochar-amended soil and the non-amended soil. Furthermore, MCPA had no effect on the photosynthetic pigment contents in sunflower. © 2013 Elsevier Inc.
