The Experts below are selected from a list of 402 Experts worldwide ranked by ideXlab platform
Philip M. Gilmartin - One of the best experts on this subject based on the ideXlab platform.
-
Primula Vulgaris primrose genome assembly annotation and gene expression with comparative genomics on the heterostyly supergene
Scientific Reports, 2018Co-Authors: Philip M. Gilmartin, Jonathan M. Cocker, Jonathan Wright, Sarah Dyer, David Swarbreck, Mario CaccamoAbstract:Primula Vulgaris (primrose) exhibits heterostyly: plants produce self-incompatible pin- or thrum-form flowers, with anthers and stigma at reciprocal heights. Darwin concluded that this arrangement promotes insect-mediated cross-pollination; later studies revealed control by a cluster of genes, or supergene, known as the S (Style length) locus. The P. Vulgaris S locus is absent from pin plants and hemizygous in thrum plants (thrum-specific); mutation of S locus genes produces self-fertile homostyle flowers with anthers and stigma at equal heights. Here, we present a 411 Mb P. Vulgaris genome assembly of a homozygous inbred long homostyle, representing ~87% of the genome. We annotate over 24,000 P. Vulgaris genes, and reveal more genes up-regulated in thrum than pin flowers. We show reduced genomic read coverage across the S locus in other Primula species, including P. veris, where we define the conserved structure and expression of the S locus genes in thrum. Further analysis reveals the S locus has elevated repeat content (64%) compared to the wider genome (37%). Our studies suggest conservation of S locus genetic architecture in Primula, and provide a platform for identification and evolutionary analysis of the S locus and downstream targets that regulate heterostyly in diverse heterostylous species.
-
Agrobacterium-mediated transformation systems of Primula Vulgaris
BMC, 2018Co-Authors: Sadiye Hayta, Mark A. Smedley, Wendy A. Harwood, Philip M. GilmartinAbstract:Abstract Background Genetic transformation is a valuable tool and an important procedure in plant functional genomics contributing to gene discovery, allowing powerful insights into gene function and genetically controlled characteristics. Primulaceae species provide one of the best-known examples of heteromorphic flower development, a breeding system which has attracted considerable attention, including that of Charles Darwin. Molecular approaches, including plant transformation give the best opportunity to define and understand the role of genes involved in floral heteromorphy in the common primrose, Primula Vulgaris, along with other Primula species. Results Two transformation systems have been developed in P. Vulgaris. The first system, Agrobacterium-mediated vacuum infiltration of seedlings, enables the rapid testing of transgenes, transiently in planta. GUS expression was observed in the cotyledons, true leaves, and roots of Primula seedlings. The second system is based on Agrobacterium tumefaciens infection of pedicel explants with an average transformation efficiency of 4.6%. This transformation system, based on regeneration and selection of transformants within in vitro culture, demonstrates stable transgene integration and transmission to the next generation. Conclusion The two transformation systems reported here will aid fundamental research into important traits in Primula. Although, stable integration of transgenes is the ultimate goal for such analyses, transient gene expression via Agrobacterium-mediated DNA transfer, offers a simple and fast method to analyse transgene functions. The second system describes, for the first time, stable Agrobacterium-mediated transformation of Primula Vulgaris, which will be key to characterising the genes responsible for the control of floral heteromorphy
-
On the origins of observations of heterostyly in Primula
The New phytologist, 2015Co-Authors: Philip M. GilmartinAbstract:In 1862, Charles Darwin published his landmark study on the different forms of flower in Primula; he coined the term distyly and subsequently expanded his studies to other species, including those with tristyly. Darwin is widely recognized as the first to study pin and thrum flowers in Primula, and to provide an explanation for the functional significance of the two floral morphs. Our laboratory is pursuing the genes that underpin floral heteromorphy in Primula, work influenced by Darwin's observations. One day, while appreciating a print of Primula Vulgaris from William Curtis' Flora Londinensis, I was struck by the fact that I was looking at images of dimorphic Primula flowers captured in a late-1700s copper-plate engraving that predated Darwin's observations by over 70 yr. This realization triggered a journey into archives of botanical texts, herbals and florilegia from the 16(th) to 19(th) Centuries, and correspondence archives, in search of earlier documents that could have influenced Darwin and the origins of an idea. Darwin was not the first to observe floral heteromorphy in Primula, but he was the first to realize the significance of the two floral morphs. Darwin's insight and exposition of purpose have underpinned all consequent work on the subject.
-
hose in hose an s locus linked mutant of Primula Vulgaris is caused by an unstable mutation at the globosa locus
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Brigitta Dudas, Margaret A Webster, Holly Cook, Brendan Davies, Philip M. GilmartinAbstract:Hose in Hose mutants of primrose and cowslip have been cultivated since the early 17th century and show dominant homeotic conversion of sepals to petals. The phenotype shows variable penetrance and expressivity and is linked to the S locus, which controls floral heteromorphy in Primula species. Here we demonstrate that the homeotic conversion of sepals to petals in Hose in Hose is associated with up-regulation of both Primula B-function MADS box genes PvDef and PvGlo in the first floral whorl. We have defined a restriction fragment length polymorphism associated with PvGlo that cosegregates with the Hose in Hose phenotype and have also identified and characterized a retrotransposon insertion in the PvGlo promoter which is associated with the up-regulated expression of PvGlo. Excision of this retrotransposon, associated with epigenetic changes at the locus, causes reversion toward normal calyces and restores wild-type flower development. These data define the molecular basis of the Hose in Hose mutation and provide an explanation for its long-documented phenotypic instability.
-
analysis of late stage flower development in Primula Vulgaris reveals novel differences in cell morphology and temporal aspects of floral heteromorphy
New Phytologist, 2006Co-Authors: Margaret A Webster, Philip M. GilmartinAbstract:• Heterostyly in Primula is characterized by the development of long-styled pin and short-styled thrum flowers, with anthers midway down the corolla tube in pin flowers, and at its mouth in thrum flowers. Other differences include pollen size and stigmatic papillae length. Several linked genes at the S locus control these differences. • In this study we have analyzed pin and thrum flowers through the temporal development of heteromorphy. • These studies indicate that the S locus linked genes that orchestrate heteromorphic flower development act in coordination, but with different temporal and spatial dynamics. • Style length is differentiated by longer style cells in pin than thrum. However, our studies on cell shape and size within the corolla tube show that a different mechanism mediates the dissimilar elevation of anthers between pin and thrum types. These studies have also revealed that upper corolla tube cells in thrum flowers are wider than those in pin flowers. This results in a larger corolla tube mouth in thrum flowers and represents a new and previously undocumented heteromorphic variation between pin and thrum flowers.
Ludwig Triest - One of the best experts on this subject based on the ideXlab platform.
-
outbreeding depression and breeding system evolution in small remnant populations of Primula Vulgaris consequences for genetic rescue
Conservation Genetics, 2018Co-Authors: Henrik S H Barmentlo, Patrick P G Meirmans, S H Luijten, Ludwig Triest, Gerard OostermeijerAbstract:Many species suffer from anthropogenic habitat fragmentation. The resulting small and isolated populations are more prone to extinction due to, amongst others, genetic erosion, inbreeding depression and Allee-effects. Genetic rescue can help mitigate such problems, but might result in outbreeding depression. We evaluated offspring fitness after selfing and outcrossing within and among three very small and isolated remnant populations of the heterostylous plant Primula Vulgaris. We used greenhouse-grown offspring from these populations to test several fitness components. One population was fixed for the pin-morph, and was outcrossed with another population in the field to obtain seeds. Genetic diversity of parent and offspring populations was studied using microsatellites. Morph and population-specific heterosis, inbreeding and outbreeding depression were observed for fruit and seed set, seed weight and cumulative fitness. Highest fitness was observed in the field-outcrossed F1-population, which also showed outbreeding depression following subsequent between-population (back)crossing. Despite outbreeding depression, fitness was still relatively high. Inbreeding coefficients indicated that the offspring were more inbred than their parent populations. Offspring heterozygosity and inbreeding coefficients correlated with observed fitness. One population is evolving homostyly, showing a thrum morph with an elongated style and high autonomous fruit and seed set. This has important implications for conservation strategies such as genetic rescue, as the mating system will be altered by the introduction of homostyles.
-
does the surrounding matrix influence corridor effectiveness for pollen dispersal in farmland
Perspectives in Plant Ecology Evolution and Systematics, 2014Co-Authors: Anja Van Geert, Ludwig Triest, Fabienne Van RossumAbstract:Recent decades have seen a shift in agricultural land use from pasture to arable combined with increased use of fertilisers and pesticides. In this quite hostile landscape matrix, pollinator movements between native vegetation remnants may be impeded. Linear landscape elements (LLEs) in farmland can function as biological corridors by facilitating pollinator movements and pollen flow between fragmented plant populations. The type of landscape matrix surrounding LLEs and plant populations, and LLE habitat quality may influence the effectiveness of LLEs as corridors for pollen dispersal through the availability of floral resources and nesting opportunities for pollinators. Using fluorescent dyes as pollen analogues, we investigated dye dispersal patterns between fragmented populations of the rare insect-pollinated Primula Vulgaris connected by existing LLEs. We examined how dye deposition on P. Vulgaris and within LLEs (on other co-flowering insect-pollinated species) could be influenced by the surrounding matrix type (pasture, arable field), the recipient population traits of P. Vulgaris (flowering population size, flower display, flowering plant density and co-flowering floral resources) and by LLE traits (LLE length and co-flowering floral resources). Dye dispersal through corridors was significantly higher when the landscape matrix surrounding P. Vulgaris recipient populations and LLEs consisted of pastures rather than arable fields (or a mix of both), even after accounting for differences in floral resources. A higher cover and diversity of insect-pollinated plants increased dye deposition when co-flowering within small P. Vulgaris populations, but led to dye loss within LLEs. Large P. Vulgaris populations appeared more attractive thereby increasing heterospecific dye deposition in the LLEs. Our study shows that farming practices shifting from pastures to maize arable fields have a negative impact on dye dispersal patterns, and so possibly affect pollen dispersal of P. Vulgaris, likely through a reduced pollinator service. Corridor effectiveness depends on the type of surrounding matrix, and the abundance of floral resources directly influences dye dispersal patterns. Preserving the remaining pastureland is essential, but restoring rich flowering vegetation at field boundaries and along LLEs may also promote corridor effectiveness for pollen dispersal.
-
do linear landscape elements in farmland act as biological corridors for pollen dispersal
Journal of Ecology, 2010Co-Authors: Anja Van Geert, Fabienne Van Rossum, Ludwig TriestAbstract:Summary 1. Habitat fragmentation in agricultural landscapes has reduced the population sizes of many plant species while increasing their spatial isolation. Restoration or maintenance of the connectivity by gene flow between the fragmented patches may be determinant to sustaining viable populations, especially for insect-pollinated species. Functional biological corridors facilitating pollen flow between remnants in a human-dominated matrix might achieve this. 2. Dye dispersal was investigated for the extremely fragmented insect-pollinated herb Primula Vulgaris, using fluorescent dye particles as pollen analogues, in a study site comprising 20 populations, of which 13 pairs were physically connected by a linear landscape elements (LLEs, ditches), and 11 pairs were not connected by an LLE. The dye deposition events were used to fit a model of pollen dispersal at the landscape level. We examined whether existing LLEs in the intensively used agricultural landscape act as functional corridors for pollen dispersal. The effects of LLE length and size and plant density of the recipient population on the dispersal patterns were tested. 3. Dye dispersal showed a leptokurtic decay distribution, with 80% of the dye transfers occurring at less than 85.1 m, and a maximal distance of 1010.8 m. The mean distance travelled by fluorescent dye particles based on the dye dispersal model was δ = 87 m. 4. Dye dispersal between populations was found to be significantly higher when populations were connected by an LLE, than when populations were unconnected. For the group of population pairs connected by an LLE, dye deposition significantly decreased with the distance to dye source, but was not related to recipient population size and plant density. 5. Synthesis. Our study is, to our knowledge, the first to demonstrate that existing LLEs in an intensively used farmland may act as functional biological corridors facilitating pollen dispersal through pollinator movements. The maintenance or restoration of a network of populations connected by LLEs, but also by other landscape structures (e.g. population relays in vegetation patches and networks of small elements allowing indirect connections) should be strongly encouraged.
-
genetic consequences of habitat fragmentation in an agricultural landscape on the common Primula veris and comparison with its rare congener p Vulgaris
Conservation Genetics, 2004Co-Authors: Fabienne Van Rossum, Sara Campos De Sousa, Ludwig TriestAbstract:In Flanders (northern Belgium), the common (butlocally rare) P. veris and its rarerelative Primula Vulgaris, twoself-incompatible perennials, mainly occur infragmented habitats of the intensively usedagricultural landscape. We investigated geneticvariation and structure for respectively 30 and27 allozyme loci in 24 and 41 populations ofP. veris and P. Vulgaris, inrelation to species (local) abundance and topopulation size and plant density, and comparedpopulations of linear landscape elements(verges) with non verge populations. Therare P. Vulgaris was geneticallydepauperate compared to the commoner P.veris. Both species showed a geographicalstructure of genetic variation and isolation bydistance. The scattered populations of P.veris from the Westhoek region (polderhabitats) were of smaller size, geneticallydepauperate and showed higher interpopulationdivergence compared to the Voeren region, wherepopulations are densely distributed andhabitats less fragmented. Verge and non vergepopulations showed similar populations sizesand levels of genetic variation. For bothspecies, small populations showed a loss ofgenetic variation, but still maintained highlevels of observed heterozygosity.Within-population plant density negativelyaffected allelic richness in P. veris.Ours results indicate that common species canalso be negatively affected by habitatfragmentation (perhaps even more so than rarespecies) and that verge populations can have ahigh potential conservation value. Both vergeand non-verge populations should be included inconservation efforts.
-
reduced reproductive success in small populations of the self incompatible Primula Vulgaris
Journal of Ecology, 2004Co-Authors: Rein Brys, Ludwig Triest, Hans Jacquemyn, Patrick Endels, Martin Hermy, Fabienne Van Rossum, Luc De Bruyn, Geert De BlustAbstract:Summary 1 Habitat fragmentation and the resulting decline in population size can affect biotic interactions and reproductive success of plant species. We investigated the impact of habitat type, population size, morph type and frequency, plant density, floral display and predation on different reproductive components in 16 populations of the distylous self-incompatible perennial herb, Primula Vulgaris , a rare, declining species in Belgium. 2 Although habitat type accounted for significant variation in population size, we did not find any relation between habitat type and either reproductive and vegetative characteristics. Population size, however, strongly affected reproductive success, such that plants in small populations produced significantly fewer fruits per plant and seeds per fruit, and therefore fewer seeds per plant. 3 No significant difference was found between morph types for any reproductive characteristic, nor an interaction with population size. However, when morph frequency was strongly biased ( ≥ 1 : 3), the proportion of flowers setting fruit and the number of seeds per fruit were significantly lower in individuals of the common morph type. 4 Within populations, individual plants varied tremendously in size and floral display. Total number of fruits per plant significantly increased with floral display, but the highest fruit set per flower was found at intermediate flower number. 5 The proportion of fruit suffering pre-dispersal predation per plant significantly increased with floral display, but this did not offset the potential fitness gains of producing a large display. Furthermore, the absolute number of predated fruits per plant was significantly and positively affected by the interaction of the total number of fruits per plant and the density of the population.
Gerard Oostermeijer - One of the best experts on this subject based on the ideXlab platform.
-
outbreeding depression and breeding system evolution in small remnant populations of Primula Vulgaris consequences for genetic rescue
Conservation Genetics, 2018Co-Authors: Henrik S H Barmentlo, Patrick P G Meirmans, S H Luijten, Ludwig Triest, Gerard OostermeijerAbstract:Many species suffer from anthropogenic habitat fragmentation. The resulting small and isolated populations are more prone to extinction due to, amongst others, genetic erosion, inbreeding depression and Allee-effects. Genetic rescue can help mitigate such problems, but might result in outbreeding depression. We evaluated offspring fitness after selfing and outcrossing within and among three very small and isolated remnant populations of the heterostylous plant Primula Vulgaris. We used greenhouse-grown offspring from these populations to test several fitness components. One population was fixed for the pin-morph, and was outcrossed with another population in the field to obtain seeds. Genetic diversity of parent and offspring populations was studied using microsatellites. Morph and population-specific heterosis, inbreeding and outbreeding depression were observed for fruit and seed set, seed weight and cumulative fitness. Highest fitness was observed in the field-outcrossed F1-population, which also showed outbreeding depression following subsequent between-population (back)crossing. Despite outbreeding depression, fitness was still relatively high. Inbreeding coefficients indicated that the offspring were more inbred than their parent populations. Offspring heterozygosity and inbreeding coefficients correlated with observed fitness. One population is evolving homostyly, showing a thrum morph with an elongated style and high autonomous fruit and seed set. This has important implications for conservation strategies such as genetic rescue, as the mating system will be altered by the introduction of homostyles.
Jonathan M. Cocker - One of the best experts on this subject based on the ideXlab platform.
-
Primula Vulgaris primrose genome assembly annotation and gene expression with comparative genomics on the heterostyly supergene
Scientific Reports, 2018Co-Authors: Philip M. Gilmartin, Jonathan M. Cocker, Jonathan Wright, Sarah Dyer, David Swarbreck, Mario CaccamoAbstract:Primula Vulgaris (primrose) exhibits heterostyly: plants produce self-incompatible pin- or thrum-form flowers, with anthers and stigma at reciprocal heights. Darwin concluded that this arrangement promotes insect-mediated cross-pollination; later studies revealed control by a cluster of genes, or supergene, known as the S (Style length) locus. The P. Vulgaris S locus is absent from pin plants and hemizygous in thrum plants (thrum-specific); mutation of S locus genes produces self-fertile homostyle flowers with anthers and stigma at equal heights. Here, we present a 411 Mb P. Vulgaris genome assembly of a homozygous inbred long homostyle, representing ~87% of the genome. We annotate over 24,000 P. Vulgaris genes, and reveal more genes up-regulated in thrum than pin flowers. We show reduced genomic read coverage across the S locus in other Primula species, including P. veris, where we define the conserved structure and expression of the S locus genes in thrum. Further analysis reveals the S locus has elevated repeat content (64%) compared to the wider genome (37%). Our studies suggest conservation of S locus genetic architecture in Primula, and provide a platform for identification and evolutionary analysis of the S locus and downstream targets that regulate heterostyly in diverse heterostylous species.
-
integration of genetic and physical maps of the Primula Vulgaris s locus and localization by chromosome in situ hybridization
New Phytologist, 2015Co-Authors: Jonathan M. Cocker, Jonathan Wright, Margaret A Webster, Matthew C Smith, Farah Badakshi, Pat HeslopharrisonAbstract:Summary Heteromorphic flower development in Primula is controlled by the S locus. The S locus genes, which control anther position, pistil length and pollen size in pin and thrum flowers, have not yet been characterized. We have integrated S-linked genes, marker sequences and mutant phenotypes to create a map of the P. Vulgaris S locus region that will facilitate the identification of key S locus genes. We have generated, sequenced and annotated BAC sequences spanning the S locus, and identified its chromosomal location. We have employed a combination of classical genetics and three-point crosses with molecular genetic analysis of recombinants to generate the map. We have characterized this region by Illumina sequencing and bioinformatic analysis, together with chromosome in situ hybridization. We present an integrated genetic and physical map across the P. Vulgaris S locus flanked by phenotypic and DNA sequence markers. BAC contigs encompass a 1.5-Mb genomic region with 1 Mb of sequence containing 82 S-linked genes anchored to overlapping BACs. The S locus is located close to the centromere of the largest metacentric chromosome pair. These data will facilitate the identification of the genes that orchestrate heterostyly in Primula and enable evolutionary analyses of the S locus.
Henrik S H Barmentlo - One of the best experts on this subject based on the ideXlab platform.
-
outbreeding depression and breeding system evolution in small remnant populations of Primula Vulgaris consequences for genetic rescue
Conservation Genetics, 2018Co-Authors: Henrik S H Barmentlo, Patrick P G Meirmans, S H Luijten, Ludwig Triest, Gerard OostermeijerAbstract:Many species suffer from anthropogenic habitat fragmentation. The resulting small and isolated populations are more prone to extinction due to, amongst others, genetic erosion, inbreeding depression and Allee-effects. Genetic rescue can help mitigate such problems, but might result in outbreeding depression. We evaluated offspring fitness after selfing and outcrossing within and among three very small and isolated remnant populations of the heterostylous plant Primula Vulgaris. We used greenhouse-grown offspring from these populations to test several fitness components. One population was fixed for the pin-morph, and was outcrossed with another population in the field to obtain seeds. Genetic diversity of parent and offspring populations was studied using microsatellites. Morph and population-specific heterosis, inbreeding and outbreeding depression were observed for fruit and seed set, seed weight and cumulative fitness. Highest fitness was observed in the field-outcrossed F1-population, which also showed outbreeding depression following subsequent between-population (back)crossing. Despite outbreeding depression, fitness was still relatively high. Inbreeding coefficients indicated that the offspring were more inbred than their parent populations. Offspring heterozygosity and inbreeding coefficients correlated with observed fitness. One population is evolving homostyly, showing a thrum morph with an elongated style and high autonomous fruit and seed set. This has important implications for conservation strategies such as genetic rescue, as the mating system will be altered by the introduction of homostyles.