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Mark Van Kleunen - One of the best experts on this subject based on the ideXlab platform.
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adaptive rather than non adaptive evolution of mimulus guttatus in its invasive range
Basic and Applied Ecology, 2008Co-Authors: Markus Fischer, Mark Van KleunenAbstract:Adaptive and non-adaptive evolutionary processes are likely to play important roles in biological invasions but their relative importance has hardly ever been quantified. Moreover, although genetic differences between populations in their native versus invasive ranges may simply reflect different positions along a genetic latitudinal cline, this has rarely been controlled for. To study non-adaptive evolutionary processes in invasion of Mimulus guttatus, we used allozyme analyses on offspring of seven native populations from western North America, and three and four invasive populations from Scotland and New Zealand, respectively. To study quantitative genetic differentiation, we grew 2474 plants representing 17 native populations and the seven invasive populations in a common greenhouse environment under temporarily and permanently wet soil conditions. The absence of allozyme differentiation between the invasive and native range indicates that multiple genotypes had been introduced to Scotland and New Zealand, and suggests that founder effects and genetic drift played small, if any, roles in shaping genetic structure of invasive M. guttatus populations. Plants from the invasive and native range did not differ in phenology, floral traits and sexual and Vegetative Reproduction, and also not in plastic responses to the watering treatments. However, plants from the invasive range produced twice as many flower-bearing upright side branches than the ones from the native populations. Further, with increasing latitude of collection, Vegetative Reproduction of our experimental plants increased while sexual Reproduction decreased. Plants from the invasive and native range shared these latitudinal clines. Because allozymes showed that the relatedness between native and invasive populations did not depend on latitude, this suggests that plants in the invasive regions have adapted to the local latitude. Overall, our study indicates that quantitative genetic variation of M. guttatus in its two invasive regions is shaped by adaptive evolutionary processes rather than by non-adaptive ones. (C) 2007 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved.
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adaptive genetic differentiation in life history traits between populations of mimulus guttatus with annual and perennial life cycles
Evolutionary Ecology, 2007Co-Authors: Mark Van KleunenAbstract:The optimal allocation to sexual and Vegetative Reproduction as well as the optimal values of other life-history characteristics such as phenology, growth and mating system are likely to depend on the life-cycle of the organism. I tested whether plants of Mimulus guttatus originating from temporarily wet populations where the species has an enforced annual life-cycle have higher allocation to sexual Reproduction, lower allocation to Vegetative Reproduction, more rapid phenology, faster growth, and floral traits associated with a self-fertilizing mating system than plants from permanently wet populations where the species has a perennial life-cycle. I grew a total of 1377 plants originating from three populations with an annual life-cycle and 11 populations with a perennial life-cycle in a greenhouse under permanently and temporarily wet conditions. Plants of M. guttatus in permanently wet conditions had significantly more Vegetative Reproduction and tended to have a faster growth than plants in the temporarily wet conditions, indicating plasticity in these life-history traits. Plants from populations with an annual life-cycle invested significantly more in sexual Reproduction and significantly less in Vegetative Reproduction than the ones from populations with a perennial life-cycle. Moreover, this study showed that plants originating from populations with an annual life-cycle have a significantly faster development and floral traits associated with autonomous self-fertilization. In conclusion, this study suggests that there has been adaptive evolution of life history traits of M. guttatus in response to natural watering conditions that determine the life span of the species.
Yukiko Yasui - One of the best experts on this subject based on the ideXlab platform.
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gemma cup associated myb1 an ortholog of axillary meristem regulators is essential in Vegetative Reproduction in marchantia polymorpha
Current Biology, 2019Co-Authors: Yukiko Yasui, Shigeyuki Tsukamoto, Tomomi Sugaya, Ryuichi Nishihama, Quan Wang, Hirotaka Kato, Katsuyuki T Yamato, Hidehiro Fukaki, Tetsuro MimuraAbstract:Summary A variety of plants in diverse taxa can reproduce asexually via Vegetative propagation, in which clonal propagules with a new meristem(s) are generated directly from Vegetative organs. A basal land plant, Marchantia polymorpha, develops clonal propagules, gemmae, on the gametophyte thallus from the basal epidermis of a specialized receptacle, the gemma cup. Here we report an R2R3-MYB transcription factor, designated GEMMA CUP-ASSOCIATED MYB1 (GCAM1), which is an essential regulator of gemma cup development in M. polymorpha. Targeted disruption of GCAM1 conferred a complete loss of gemma cup formation and gemma generation. Ectopic overexpression of GCAM1 resulted in formation of cell clumps, suggesting a function of GCAM1 in suppression of cell differentiation. Although gemma cups are a characteristic gametophyte organ for Vegetative Reproduction in a taxonomically restricted group of liverwort species, phylogenetic and interspecific complementation analyses support the orthologous relationship of GCAM1 to regulatory factors of axillary meristem formation, e.g., Arabidopsis REGULATOR OF AXILLARY MERISTEMS and tomato Blind, in angiosperm sporophytes. The present findings in M. polymorpha suggest an ancient acquisition of a transcriptional regulator for production of asexual propagules in the gametophyte and the use of the regulatory factor for diverse developmental programs, including axillary meristem formation, during land plant evolution.
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the ropgef karappo is essential for the initiation of Vegetative Reproduction in marchantia polymorpha
Current Biology, 2019Co-Authors: Takuma Hiwatashi, Yukiko Yasui, Hideyuki Takami, Masataka Kajikawa, Hiroyuki Kirita, Honzhen Goh, Li Quan Koh, Takehiko KanazawaAbstract:Summary Many plants can reproduce Vegetatively, producing clonal progeny from Vegetative cells; however, little is known about the molecular mechanisms underlying this process. Liverwort (Marchantia polymorpha), a basal land plant, propagates asexually via gemmae, which are clonal plantlets formed in gemma cups on the dorsal side of the Vegetative thallus [ 1 ]. The initial stage of gemma development involves elongation and asymmetric divisions of a specific type of epidermal cell, called a gemma initial, which forms on the floor of the gemma cup [ 2 , 3 ]. To investigate the regulatory mechanism underlying gemma development, we focused on two allelic mutants in which no gemma initial formed; these mutants were named karappo, meaning “empty.” We used whole-genome sequencing of both mutants and molecular genetic analysis to identify the causal gene, KARAPPO (KAR), which encodes a ROP guanine nucleotide exchange factor (RopGEF) carrying a plant-specific ROP nucleotide exchanger (PRONE) catalytic domain. In vitro GEF assays showed that the full-length KAR protein and the PRONE domain have significant GEF activity toward MpROP, the only ROP GTPase in M. polymorpha. Moreover, genetic complementation experiments showed a significant role for the N- and C-terminal variable regions in gemma development. Our investigation demonstrates an essential role for KAR/RopGEF in the initiation of plantlet development from a differentiated cell, which may involve cell-polarity formation and subsequent asymmetric cell division via activation of ROP signaling, implying a similar developmental mechanism in Vegetative Reproduction of various land plants.
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gemma cup associated myb1 an orthologue of axillary meristem regulator is essential for Vegetative Reproduction in a liverwort marchantia polymorpha
Social Science Research Network, 2019Co-Authors: Yukiko Yasui, Shigeyuki Tsukamoto, Tomomi Sugaya, Ryuichi Nishihama, Quan Wang, Katsuyuki T Yamato, Hidehiro Fukaki, Tetsuro Mimura, Hiroyoshi Kubo, Klaus TheresAbstract:A variety of plants in diverse taxa can reproduce asexually via Vegetative propagation, in which clonal propagules with new meristem(s) are generated directly from Vegetative organs. A basal land plant, Marchantia polymorpha, develops clonal propagules, gemmae, on the gametophyte thallus from the basal epidermis of a specialized receptacle, gemma cup. Here we report an R2R3-MYB transcription factor, designated GEMMA CUP-ASSOCIATED MYB 1 (GCAM1), which is an essential regulator of gemma cup development in M. polymorpha. Targeted disruption of GCAM1 conferred a complete loss of gemma cup formation and gemmae generation. Ectopic overexpression of GCAM1 resulted in formation of cell clumps, suggesting a function of GCAM1 in suppression of cell differentiation. Although gemma cups are a characteristic gametophyte organ for Vegetative Reproduction in a taxonomically restricted group of liverwort species, phylogenetic and interspecific complementation analyses supported the orthologous relationship of GCAM1 to regulatory factors for axillary meristem formation, e.g. Arabidopsis RAXs and tomato Blind, in angiosperm sporophytes. The present findings in M. polymorpha suggest an ancient acquisition of a regulatory mechanism for production of new meristems, and the use of the mechanism for diverse developmental programs during land plant evolution.
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the ropgef karappo is essential for the initiation of Vegetative Reproduction in marchantia
Social Science Research Network, 2018Co-Authors: Takuma Hiwatashi, Koh Li Quan, Yukiko Yasui, Hideyuki Takami, Masataka Kajikawa, Hiroyuki Kirita, Mayuko Sato, Mayumi Wakazaki, Katsushi Yamaguchi, Shuji ShigenobuAbstract:Many plants can reproduce Vegetatively, producing clonal progeny from Vegetative cells; however, little is known about the molecular mechanisms underlying this process. Liverwort (Marchantia polymorpha), a basal land plant, propagates asexually via gemmae, which are clonal plantlets formed in gemma cups on the dorsal side of the Vegetative thallus [1]. The initial stage of gemma development involves elongation and asymmetric divisions of a specific type of epidermal cell, called a gemma initial, which forms on the floor of the gemma cup [2, 3]. To investigate the regulatory mechanism underlying gemma development, we focused on two allelic mutants in which no gemma initial formed; these mutants were named karappo, meaning “empty”. We used whole-genome sequencing of both mutants, and molecular genetic analyses to identify the causal gene, KARAPPO (KAR), which encodes a Rop guanine nucleotide exchange factor (RopGEF) carrying a PRONE catalytic domain. In vitro GEF assays showed that the full-length KAR protein and the PRONE domain have significant GEF activity toward MpRop, the only Rop GTPase in M. polymorpha. Moreover, genetic complementation experiments showed a significant role for the N- and C-terminal variable regions in gemma development. Our investigation demonstrated an essential role for KAR/RopGEF in the initiation of plantlet development from a differentiated cell, which may involve cell polarity formation and subsequent asymmetric cell division via activation of Rop signaling, implying a similar developmental mechanism in Vegetative Reproduction of various land plants.
Jurg Stocklin - One of the best experts on this subject based on the ideXlab platform.
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sexual and Vegetative Reproduction of hieracium pilosella l under competition and disturbance a grid based simulation model
Annals of Botany, 2002Co-Authors: E Winkler, Jurg StocklinAbstract:We used a spatially explicit simulation model to examine the relative importance of Vegetative and sexual Reproduction in Hieracium pilosella L. Based on an understanding of the complex life cycle of this species and on data from in situ population dynamics in a calcareous grassland in NW Switzerland, we simulated growth and the relative contribution of clonal Reproduction by stolons and Reproduction by seeds across a gradient of increasing soil fertility. Competition by a clonal grass resulted in nearly complete exclusion of H. pilosella from the more fertile part of the simulation plot. Under low soil fertility, when grass could not survive, H. pilosella largely persisted by Vegetatively produced rosettes. This pattern of a sharp separation of both species was shifted slightly in favour of H. pilosella by introducing random disturbances. Only by adding: (1) long-distance seed dispersal, and (2) facilitation of seedling establishment in the vicinity of grass tussocks in vegetation gaps was a more realistic representation of field observations realised, with rosettes of H. pilosella grown from seeds occasionally distributed within dense grass vegetation. Phenotypic plasticity of stolon length was a decisive factor for the maintenance of H. pilosella populations. We conclude that a mixed strategy of clonal growth and Reproduction by seeds in H. pilosella is necessary to maintain populations of this species in the presence of high interspecific competition and a shortage of open space. a 2002 Annals of Botany Company
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sexual and Vegetative Reproduction of hieracium pilosella l under competition and disturbance a grid based simulation model
Annals of Botany, 2002Co-Authors: Eckart Winkler, Jurg StocklinAbstract:Populationsbiologie We used a spatially explicit simulation model to examine the relative importance of Vegetative and sexual Reproduction in Hieracium pilosella L. Based on an understanding of the complex life cycle of this species and on data from in situ population dynamics in a calcareous grassland in NW Switzerland, we simulated growth and the relative contribution of clonal Reproduction by stolons and Reproduction by seeds across a gradient of increasing soil fertility. Competition by a clonal grass resulted in nearly complete exclusion of H. pilosella from the more fertile part of the simulation plot. Under low soil fertility, when grass could not survive, H. pilosella largely persisted by Vegetatively produced rosettes. This pattern of a sharp separation of both species was shifted slightly in favour of H. pilosella by introducing random disturbances. Only by adding: (1) long-distance seed dispersal, and (2) facilitation of seedling establishment in the vicinity of grass tussocks in vegetation gaps was a more realistic representation of field observations realised, with rosettes of H. pilosella grown from seeds occasionally distributed within dense grass vegetation. Phenotypic plasticity of stolon length was a decisive factor for the maintenance of H. pilosella populations. We conclude that a mixed strategy of clonal growth and Reproduction by seeds in H. pilosella is necessary to maintain populations of this species in the presence of high interspecific competition and a shortage of open space.
Guillermo Goldstein - One of the best experts on this subject based on the ideXlab platform.
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effects of fire on seedling diversity and plant Reproduction sexual vs Vegetative in neotropical savannas differing in tree density
Biotropica, 2014Co-Authors: Ana Salazar, Guillermo GoldsteinAbstract:Little is known about the effects of fire on the structure and species composition of Neotropical savanna seedling communities. Such effects are critical for predicting long-term changes in plant distribution patterns in these ecosystems. We quantified richness and density of seedlings within 144 plots of 1 m2 located along a topographic gradient in long-unburned (fire protected since 1983) and recently burned (September 2005) savannas in Brazil. These savannas differ in tree density and canopy cover. Sites along the gradient, however, did not differ in species composition prior to the fire. In recently burned savannas we also evaluated the contribution of Vegetative Reproduction relative to sexual Reproduction by quantifying richness and density of root suckers. Finally, we tested seed tolerance to pulses of high temperatures-similar to those occurring during fires on the soil surface and below-of five dominant savanna tree species. Seedlings were more abundant and diverse in unburned than in burned savannas. Seedling species composition differed among unburned and burned savannas probably reflecting early differences in root: shoot biomass allocation patterns. In recently burned savannas, root suckers were more abundant and diverse than seedlings. Relatively long exposures (>10 min) of temperatures of 90 °C reduced seed germination in all studied species suggesting a negative effect of fire on germination of seeds located at or aboveground level. Because Vegetative Reproduction contributes more than sexual Reproduction in burned environments, frequent fires are likely to cause major shifts in species composition of Neotropical savanna plant communities, favoring clonally produced recruits along tree density/topographic gradients. © 2014 The Association for Tropical Biology and Conservation.
Markus Fischer - One of the best experts on this subject based on the ideXlab platform.
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simulating the evolution of a clonal trait in plants with sexual and Vegetative Reproduction
Journal of Plant Ecology, 2008Co-Authors: Markus Fischer, Eckart Winkler, Bernhard SchmidAbstract:Aims Phenotypic optimality models neglect genetics. However, especially when heterozygous genotypes are fittest, evolving allele, genotype and phenotype frequencies may not correspond to predicted optima. This was not previously addressed for organisms with complex life histories. Methods Therefore, we modelled the evolution of a fitness-relevant trait of clonal plants, stolon internode length. We explored the likely case of an asymmetric unimodal fitness profile with three model types. In constant selection models (CSMs), which are gametic, but not spatially explicit, evolving allele frequencies in the one-locus and fiveloci cases did not correspond to optimum stolon internode length predicted by the spatially explicit, but not gametic, phenotypic model. This deviation was due to the asymmetry of the fitness profile. Gametic, spatially explicit individual-based (SEIB) modeling allowed us relaxing the CSM assumptions of constant selection with exclusively sexual Reproduction. Important findings For entirely Vegetative or sexual Reproduction, predictions of the gametic SEIB model were close to the ones of spatially explicit nongametic phenotypic models, but for mixed modes of Reproduction they approximated those of gametic, not spatially explicit CSMs. Thus, in contrast to gametic SEIB models, phenotypic models and, especially for few loci, also CSMs can be very misleading. We conclude that the evolution of traits governed by few quantitative trait loci appears hardly predictable by simple models, that genetic algorithms aiming at technical optimization may actually miss the optimum and that selection may lead to loci with smaller effects in derived compared with ancestral lines.
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adaptive rather than non adaptive evolution of mimulus guttatus in its invasive range
Basic and Applied Ecology, 2008Co-Authors: Markus Fischer, Mark Van KleunenAbstract:Adaptive and non-adaptive evolutionary processes are likely to play important roles in biological invasions but their relative importance has hardly ever been quantified. Moreover, although genetic differences between populations in their native versus invasive ranges may simply reflect different positions along a genetic latitudinal cline, this has rarely been controlled for. To study non-adaptive evolutionary processes in invasion of Mimulus guttatus, we used allozyme analyses on offspring of seven native populations from western North America, and three and four invasive populations from Scotland and New Zealand, respectively. To study quantitative genetic differentiation, we grew 2474 plants representing 17 native populations and the seven invasive populations in a common greenhouse environment under temporarily and permanently wet soil conditions. The absence of allozyme differentiation between the invasive and native range indicates that multiple genotypes had been introduced to Scotland and New Zealand, and suggests that founder effects and genetic drift played small, if any, roles in shaping genetic structure of invasive M. guttatus populations. Plants from the invasive and native range did not differ in phenology, floral traits and sexual and Vegetative Reproduction, and also not in plastic responses to the watering treatments. However, plants from the invasive range produced twice as many flower-bearing upright side branches than the ones from the native populations. Further, with increasing latitude of collection, Vegetative Reproduction of our experimental plants increased while sexual Reproduction decreased. Plants from the invasive and native range shared these latitudinal clines. Because allozymes showed that the relatedness between native and invasive populations did not depend on latitude, this suggests that plants in the invasive regions have adapted to the local latitude. Overall, our study indicates that quantitative genetic variation of M. guttatus in its two invasive regions is shaped by adaptive evolutionary processes rather than by non-adaptive ones. (C) 2007 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved.
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effects of intraspecific competition on size variation and reproductive allocation in a clonal plant
Oikos, 2001Co-Authors: Mark Van Kleunen, Markus Fischer, Bernhard SchmidAbstract:Clonal plants grow in diameter rather than height, and therefore competition among genets is likely to be symmetric and to result in smaller variation in size of genets than in non-clonal plants. Moreover, clonal plants can reproduce both sexually and Vegetatively. We studied the effects of density on the size of rosettes and of clones, variation in the size of rosettes and of clones, and allocation to sexual and Vegetative Reproduction in the clonal herb Ranunculus reptans. We grew plants from an artificial population of R. reptans in 32 trays at two densities. After four months, differences in density were still apparent, although clones in the low-density treatment had on average 155% more rosettes and 227% more rooted rosettes than clones in the high-density treatment. The coefficient of variation of these measures of clone size was 15% and 83% higher, respectively, in the low-density treatment. This indicates that intraspecific competition among clones of R. reptans is symmetric and increases the effective population size. Rooted rosettes were larger and varied more in size in the low-density treatment. The relative allocation of the populations to sexual and to Vegetative Reproduction was 19% and 13% higher, respectively, in the high-density treatment. Moreover, seeds produced in the high-density treatment had a 24% higher mass and a 7% higher germination percentage. This suggests that with increasing density, allocation to sexual Reproduction increases more than allocation to Vegetative Reproduction in R. reptans, which corresponds to the response of some other species with a spreading growth form but not of species with a compact growth form. We conclude that intraspecific competition is an important factor in the life-history evolution of R. reptans because intraspecific competition affects its clonal life-history traits and may affect evolutionary processes such as genetic drift and selection through its effect on the effective population size.
