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1.
Genetics ; 221(3)2022 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-35639938

RESUMO

Many studies have quantified the distribution of heterozygosity and relatedness in natural populations, but few have examined the demographic processes driving these patterns. In this study, we take a novel approach by studying how population structure affects both pairwise identity and the distribution of heterozygosity in a natural population of the self-incompatible plant Antirrhinum majus. Excess variance in heterozygosity between individuals is due to identity disequilibrium, which reflects the variance in inbreeding between individuals; it is measured by the statistic g2. We calculated g2 together with FST and pairwise relatedness (Fij) using 91 SNPs in 22,353 individuals collected over 11 years. We find that pairwise Fij declines rapidly over short spatial scales, and the excess variance in heterozygosity between individuals reflects significant variation in inbreeding. Additionally, we detect an excess of individuals with around half the average heterozygosity, indicating either selfing or matings between close relatives. We use 2 types of simulation to ask whether variation in heterozygosity is consistent with fine-scale spatial population structure. First, by simulating offspring using parents drawn from a range of spatial scales, we show that the known pollen dispersal kernel explains g2. Second, we simulate a 1,000-generation pedigree using the known dispersal and spatial distribution and find that the resulting g2 is consistent with that observed from the field data. In contrast, a simulated population with uniform density underestimates g2, indicating that heterogeneous density promotes identity disequilibrium. Our study shows that heterogeneous density and leptokurtic dispersal can together explain the distribution of heterozygosity.


Assuntos
Antirrhinum , Genética Populacional , Variação Genética , Heterozigoto , Humanos , Endogamia , Repetições de Microssatélites
2.
Evolution ; 76(5): 1091-1093, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35165891

RESUMO

Marrot et al. used snapdragon plants on a small island to experimentally investigate how spatial structure influences the evolution of biological communities. Using a spline-based fitness function, they studied the varying relationships between traits under selection and driving environmental factors in snapdragons. The authors found that environmental heterogeneity, even on a small spatial scale, may provide several fitness optima on the fitness landscape, paving the way for coexistence of diverse phenotypes. In the absence of sufficient gene flow, this could also lead to microgeographic adaptations.


Assuntos
Antirrhinum , Adaptação Fisiológica , Fluxo Gênico , Plantas , Seleção Genética
3.
New Phytol ; 233(3): 1426-1439, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34170548

RESUMO

Parallel evolution of similar morphologies in closely related lineages provides insight into the repeatability and predictability of evolution. In the genus Antirrhinum (snapdragons), as in other plants, a suite of morphological characters are associated with adaptation to alpine environments. We tested for parallel trait evolution in Antirrhinum by investigating phylogenetic relationships using restriction-site associated DNA (RAD) sequencing. We then associated phenotypic information to our phylogeny to reconstruct the patterns of morphological evolution and related this to evidence for hybridisation between emergent lineages. Phylogenetic analyses showed that the alpine character syndrome is present in multiple groups, suggesting that Antirrhinum has repeatedly colonised alpine habitats. Dispersal to novel environments happened in the presence of intraspecific and interspecific gene flow. We found support for a model of parallel evolution in Antirrhinum. Hybridisation in natural populations, and a complex genetic architecture underlying the alpine morphology syndrome, support an important role of natural selection in maintaining species divergence in the face of gene flow.


Assuntos
Antirrhinum , Antirrhinum/genética , Evolução Biológica , Fluxo Gênico , Fenótipo , Filogenia , Seleção Genética
4.
Evolution ; 76(3): 658-666, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34535895

RESUMO

Spatial variation in natural selection is expected to shape phenotypic variation of wild populations and drive their evolution. Although evidence of phenotypic divergence across populations experiencing different selection regimes is abundant, investigations of intrapopulation variation in selection pressures remain rare. Fine-grained spatial environmental heterogeneity can be expected to influence selective forces within a wild population and thereby alter its fitness function by producing multiple fitness optima at a fine spatial scale. Here, we tested this hypothesis in a wild population of snapdragon plants living on an extremely small island in southern France (about 7500 m2 ). We estimated the spline-based fitness function linking individuals' fitness and five morphological traits in interaction with three spatially variable ecological drivers. We found that selection acting on several traits varied both in magnitude and direction in response to environmental variables at the scale of a meter. Our findings illustrate how different phenotypes can be selected at different locations within a population in response to environmental variation. Investigating spatial variation in selection within a population, in association with ecological conditions, represents an opportunity to identify putative ecological drivers of selection in the wild.


Assuntos
Antirrhinum , França , Fenótipo , Plantas , Seleção Genética
5.
J Evol Biol ; 35(2): 322-332, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34897875

RESUMO

Experimental studies on local adaptation rarely investigate how different environmental variables might modify signals of adaptation or maladaptation. In plant common garden experiments, signals of adaptation or maladaptation to elevation are usually investigated in open habitats under full light. However, most plants inhabit heterogeneous habitats where environmental conditions differ. Understorey microhabitats are common and differ in terms of tree shade, temperature, water availability, microbiota, allelochemicals etc. Germination is a fitness-related trait of major importance for the adaptation of plants to contrasted climate conditions. It is affected by shade in snapdragon plants (Antirrhinum majus) and many other plant species. Here, we tested for the reproducibility of signals extrapolated from germination results between open and understorey microhabitats in two parapatric snapdragon plant subspecies (A. m. striatum and A. m. pseudomajus) characterized by a similar elevation range by using common garden experiments at different elevations. Signals observed under one microhabitat systematically differed in the other. Most scenarios could be inferred, with signals either shifting, appearing or disappearing between different environments. Our findings imply that caution should be taken when extrapolating the evolutionary significance of these types of experimental signals because they are not stable from one local environmental condition to the next. Forecasting the ability of plants to adapt to environmental changes based on common garden and reciprocal transplant experiments must account for the multivariate nature of the environment.


Assuntos
Antirrhinum , Adaptação Fisiológica , Germinação , Plantas/genética , Reprodutibilidade dos Testes
6.
Chemosphere ; 281: 130753, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34015651

RESUMO

Dissipation and transformation of cyantraniliprole, a new diamide class of insecticides, were investigated under greenhouse conditions, using snapdragon (Antirrhinum majus) as the model plant. Dissipation of cyantraniliprole in treated leaves was found to be dependent upon application methods (foliar spray versus soil drench) and doses (high versus low dose), with the parent insecticide being the major residue at various sampling points. A high-dose foliar application resulted in pesticide residue of 6.7-23.8 µg/g foliar fresh weight over 8 weeks of treatments, while in soil drench treatment the residue varied from 0.8 to 1.4 µg/g. However, the residue contents were similar between the two application methods at a low application dose. The transformation pathways of cyantraniliprole were primarily intramolecular rearrangements, with IN-J9Z38 being the major metabolite across treatments. Several other metabolites were also identified, some of which were unique to the application methods. Out of total 26 metabolites tentatively identified in this study, 10 metabolites were unique to foliar application, while six metabolites were unique to soil drench. In addition to plant-mediated biotransformation, photodegradation of the parent compound was identified as a potential mechanism in foliar application.


Assuntos
Antirrhinum , Inseticidas , Resíduos de Praguicidas , Diamida , Inseticidas/análise , Resíduos de Praguicidas/análise , Pirazóis , ortoaminobenzoatos/análise
7.
New Phytol ; 231(2): 849-863, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33616943

RESUMO

Floral pigmentation patterning is important for pollinator attraction as well as aesthetic appeal. Patterning of anthocyanin accumulation is frequently associated with variation in activity of the Myb, bHLH and WDR transcription factor complex (MBW) that regulates anthocyanin biosynthesis. Investigation of two classic mutants in Antirrhinum majus, mutabilis and incolorata I, showed they affect a gene encoding a bHLH protein belonging to subclade bHLH-2. The previously characterised gene, Delila, which encodes a bHLH-1 protein, has a bicoloured mutant phenotype, with residual lobe-specific pigmentation conferred by Incolorata I. Both Incolorata I and Delila induce expression of the anthocyanin biosynthetic gene DFR. Rosea 1 (Myb) and WDR1 proteins compete for interaction with Delila, but interact positively to promote Incolorata I activity. Delila positively regulates Incolorata I and WDR1 expression. Hierarchical regulation can explain the bicoloured patterning of delila mutants, through effects on both regulatory gene expression and the activity of promoters of biosynthetic genes like DFR that mediate MBW regulation. bHLH-1 and bHLH-2 proteins contribute to establishing patterns of pigment distribution in A. majus flowers in two ways: through functional redundancy in regulating anthocyanin biosynthetic gene expression, and through differences between the proteins in their ability to regulate genes encoding transcription factors.


Assuntos
Antirrhinum , Antocianinas , Antirrhinum/genética , Antirrhinum/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Flores/genética , Flores/metabolismo , Regulação da Expressão Gênica de Plantas , Pigmentação/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
8.
Genes (Basel) ; 12(2)2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33557416

RESUMO

The phenotypic plasticity of plants in response to change in their light environment, and in particularly, to shade is a schoolbook example of ecologically relevant phenotypic plasticity with evolutionary adaptive implications. Epigenetic variation is known to potentially underlie plant phenotypic plasticity. Yet, little is known about its role in ecologically and evolutionary relevant mechanisms shaping the diversity of plant populations in nature. Here we used a reference-free reduced representation bisulfite sequencing method for non-model organisms (epiGBS) to investigate changes in DNA methylation patterns across the genome in snapdragon plants (Antirrhinum majus L.). We exposed plants to sunlight versus artificially induced shade in four highly inbred lines to exclude genetic confounding effects. Our results showed that phenotypic plasticity in response to light versus shade shaped vegetative traits. They also showed that DNA methylation patterns were modified under light versus shade, with a trend towards global effects over the genome but with large effects found on a restricted portion. We also detected the existence of a correlation between phenotypic and epigenetic variation that neither supported nor rejected its potential role in plasticity. While our findings imply epigenetic changes in response to light versus shade environments in snapdragon plants, whether these changes are directly involved in the phenotypic plastic response of plants remains to be investigated. Our approach contributed to this new finding but illustrates the limits in terms of sample size and statistical power of population epigenetic approaches in non-model organisms. Pushing this boundary will be necessary before the relationship between environmentally induced epigenetic changes and phenotypic plasticity is clarified for ecologically relevant mechanisms with evolutionary implications.


Assuntos
Adaptação Fisiológica/genética , Antirrhinum/genética , Metilação de DNA/genética , Epigênese Genética/genética , Adaptação Fisiológica/efeitos da radiação , Antirrhinum/efeitos da radiação , Metilação de DNA/efeitos da radiação , Epigênese Genética/efeitos da radiação , Variação Genética/efeitos da radiação , Fenótipo , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Luz Solar
9.
Naturwissenschaften ; 108(5): 44, 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34519874

RESUMO

The timing of volatile organic compound (VOC) emission by flowering plants often coincides with pollinator foraging activity. Volatile emission is often considered to be paced by environmental variables, such as light intensity, and/or by circadian rhythmicity. The question arises as to what extent pollinators themselves provide information about their presence, in keeping with their long co-evolution with flowering plants. Bumblebees are electrically charged and provide electrical stimulation when visiting plants, as measured via the depolarisation of electric potential in the stem of flowers. Here we test the hypothesis that the electric charge of foraging bumblebees increases the floral volatile emissions of bee pollinated plants. We investigate the change in VOC emissions of two bee-pollinated plants (Petunia integrifolia and Antirrhinum majus) exposed to the electric charge typical of foraging bumblebees. P. integrifolia slightly increases its emissions of a behaviorally and physiologically active compound in response to visits by foraging bumblebees, presenting on average 121 pC of electric charge. We show that for P. integrifolia, strong electrical stimulation (600-700 pC) promotes increased volatile emissions, but this is not found when using weaker electrical charges more representative of flying pollinators (100 pC). Floral volatile emissions of A. majus were not affected by either strong (600-700 pC) or weak electric charges (100 pC). This study opens a new area of research whereby the electrical charge of flying insects may provide information to plants on the presence and phenology of their pollinators. As a form of electroreception, this sensory process would bear adaptive value, enabling plants to better ensure that their attractive chemical messages are released when a potential recipient is present.


Assuntos
Antirrhinum , Petunia , Compostos Orgânicos Voláteis , Animais , Abelhas , Flores , Polinização
10.
Mol Ecol ; 29(16): 3010-3021, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32652730

RESUMO

Phenotypic divergence among natural populations can be explained by natural selection or by neutral processes such as drift. Many examples in the literature compare putatively neutral (FST ) and quantitative genetic (QST ) differentiation in multiple populations to assess their evolutionary signature and identify candidate traits involved with local adaptation. Investigating these signatures in closely related or recently diversified species has the potential to shed light on the divergence processes acting at the interspecific level. Here, we conducted this comparison in two subspecies of snapdragon plants (eight populations of Antirrhinum majus pseudomajus and five populations of A. m. striatum) in a common garden experiment. We also tested whether altitude was involved with population phenotypic divergence. Our results identified candidate phenological and morphological traits involved with local adaptation. Most of these traits were identified in one subspecies but not the other. Phenotypic divergence increased with altitude for a few biomass-related traits, but only in A. m. striatum. These traits therefore potentially reflect A. m. striatum adaptation to altitude. Our findings imply that adaptive processes potentially differ at the scale of A. majus subspecies.


Assuntos
Antirrhinum , Genética Populacional , Variação Genética , Repetições de Microssatélites , Fenótipo , Característica Quantitativa Herdável , Seleção Genética
11.
Genes (Basel) ; 11(4)2020 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-32268578

RESUMO

In the plant kingdom, the flower is one of the most relevant evolutionary novelties. Floral symmetry has evolved multiple times from the ancestral condition of radial to bilateral symmetry. During evolution, several transcription factors have been recruited by the different developmental pathways in relation to the increase of plant complexity. The MYB proteins are among the most ancient plant transcription factor families and are implicated in different metabolic and developmental processes. In the model plant Antirrhinum majus, three MYB transcription factors (DIVARICATA, DRIF, and RADIALIS) have a pivotal function in the establishment of floral dorsoventral asymmetry. Here, we present an updated report of the role of the DIV, DRIF, and RAD transcription factors in both eudicots and monocots, pointing out their functional changes during plant evolution. In addition, we discuss the molecular models of the establishment of flower symmetry in different flowering plants.


Assuntos
Antirrhinum/genética , Evolução Molecular , Flores/anatomia & histologia , Fatores de Transcrição/genética , Antirrhinum/crescimento & desenvolvimento , Flores/genética , Regulação da Expressão Gênica de Plantas/genética , Filogenia , Proteínas de Plantas/genética
12.
Curr Biol ; 30(8): 1357-1366.e4, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32109395

RESUMO

Most angiosperms produce trichomes-epidermal hairs that have protective or more specialized roles. Trichomes are multicellular in almost all species and, in the majority, secretory. Despite the importance of multicellular trichomes for plant protection and as a source of high-value products, the mechanisms that control their development are only poorly understood. Here, we investigate the control of multicellular trichome patterns using natural variation within the genus Antirrhinum (snapdragons), which has evolved hairy alpine-adapted species or lowland species with a restricted trichome pattern multiple times in parallel. We find that a single gene, Hairy (H), which is needed to repress trichome fate, underlies variation in trichome patterns between all Antirrhinum species except one. We show that H encodes a novel epidermis-specific glutaredoxin and that the pattern of trichome distribution within individuals reflects the location of H expression. Phylogenetic and functional tests suggest that H gained its trichome-repressing role late in the history of eudicots and that the ancestral Antirrhinum had an active H gene and restricted trichome distribution. Loss of H function was involved in an early divergence of alpine and lowland Antirrhinum lineages, and the alleles underlying this split were later reused in parallel evolution of alpines from lowland ancestors, and vice versa. We also find evidence for an evolutionary reversal from a widespread to restricted trichome distribution involving a suppressor mutation and for a pleiotropic effect of H on plant growth that might constrain the evolution of trichome pattern.


Assuntos
Antirrhinum/genética , Evolução Biológica , Glutarredoxinas/genética , Proteínas de Plantas/genética , Tricomas/crescimento & desenvolvimento , Antirrhinum/crescimento & desenvolvimento , Glutarredoxinas/antagonistas & inibidores , Mutação , Proteínas de Plantas/antagonistas & inibidores , Tricomas/genética
13.
Development ; 147(3)2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-31969326

RESUMO

The bilateral symmetry of flowers is a striking morphological achievement during floral evolution, providing high adaptation potential for pollinators. The symmetry can appear when floral organ primordia developmentally initiate. Primordia initiation at the ventral and dorsal sides of the floral bud is differentially regulated by several factors, including external organs of the flower and CYCLOIDEA (CYC) gene homologues, which are expressed asymmetrically on the dorso-ventral axis. It remains unclear how these factors control the diversity in the number and bilateral arrangement of floral organs. Here, we propose a mathematical model demonstrating that the relative strength of the dorsal-to-ventral inhibitions and the size of the floral stem cell region (meristem) determines the number and positions of the sepal and petal primordia. The simulations reproduced the diversity of monocots and eudicots, including snapdragon Antirrhinum majus and its cyc mutant, with respect to organ number, arrangement and initiation patterns, which were dependent on the inhibition strength. These theoretical results suggest that diversity in floral symmetry is primarily regulated by the dorso-ventral inhibitory field and meristem size during developmental evolution.


Assuntos
Antirrhinum/anatomia & histologia , Arabidopsis/anatomia & histologia , Flores/anatomia & histologia , Flores/genética , Modelos Teóricos , Adaptação Fisiológica/fisiologia , Proteínas de Arabidopsis/genética , Biodiversidade , Padronização Corporal/genética , Proteínas de Ligação a DNA/genética , Evolução Molecular , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Meristema/metabolismo , Filogenia , Proteínas de Plantas/genética , Fatores de Transcrição/genética
14.
Cells ; 8(8)2019 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-31426490

RESUMO

The plant circadian clock controls a large number of internal processes, including growth and metabolism. Scent emission displays a circadian pattern in many species such as the snapdragon. Here we show that knocking down LATE ELONGATED HYPOCOTYL in Antirrhinum majus affects growth and scent emission. In order to gain an understanding of the growth kinetics, we took a phenomic approach using in-house artificial vision systems, obtaining time-lapse videos. Wild type flowers showed a higher growth speed than knockdown plants. The maximal growth rate was decreased by 22% in plants with lower LHY expression. Floral volatiles were differentially affected as RNAi plants showed advanced emission of compounds synthesized from cinnamic acid and delayed emission of metabolites of benzoic acid. The monoterpenes myrcene and ocimene were delayed, whereas the sesquiterpene farnesene was advanced. Overall, transgenic lines showed an altered volatile emission pattern and displayed a modified scent profile. Our results show that AmLHY plays an important role in the quantitative and qualitative control of floral growth and scent emission.


Assuntos
Antirrhinum , Relógios Circadianos/fisiologia , Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/fisiologia , Flores , Proteínas de Plantas/fisiologia , Compostos Orgânicos Voláteis/metabolismo , Antirrhinum/crescimento & desenvolvimento , Antirrhinum/metabolismo , Flores/crescimento & desenvolvimento , Flores/metabolismo , Regulação da Expressão Gênica de Plantas
15.
J Agric Food Chem ; 67(22): 6275-6284, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31083910

RESUMO

Many O-glucuronides exhibiting various pharmacological activities have been found in nature and in drug metabolism. The glucuronidation of bioactive natural products or drugs to generate glucuronides with better activity and druggability is important in drug discovery and research. In this study, by using two uridine diphosphate (UDP)-dependent glucuronosyltransferases (GATs, UGT88D4 and UGT88D7) from plants, we developed two glucuronidation approaches, pure enzyme catalysis in vitro and recombinant whole-cell catalysis in vivo, to efficiently synthesize bioactive O-glucuronides by the glucuronidation of natural products. In total, 14 O-glucuronides with different structures, including flavonoids, anthraquinones, coumarins, and lignans, were obtained, 7 of which were new compounds. Furthermore, one of the biosynthesized O-glucuronides, kaempferol-7- O-ß-d-glucuronide (3a), potently inhibited protein tyrosine phosphatase (PTP) 1B with an IC50 value of 8.02 × 10-6 M. Some of the biosynthesized O-glucuronides also exhibited significant antioxidant activities.


Assuntos
Antirrhinum/enzimologia , Glucuronídeos/química , Glucuronosiltransferase/química , Perilla frutescens/enzimologia , Proteínas de Plantas/química , Antirrhinum/genética , Biocatálise , Estabilidade Enzimática , Glucuronosiltransferase/genética , Glucuronosiltransferase/metabolismo , Cinética , Estrutura Molecular , Perilla frutescens/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Especificidade por Substrato
16.
Genes (Basel) ; 10(4)2019 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-30925802

RESUMO

Genetic and epigenetic variations are commonly known to underlie phenotypic plastic responses to environmental cues. However, the role of epigenetic variation in plastic responses harboring ecological significance in nature remains to be assessed. The shade avoidance response (SAR) of plants is one of the most prevalent examples of phenotypic plasticity. It is a phenotypic syndrome including stem elongation and multiple other traits. Its ecological significance is widely acknowledged, and it can be adaptive in the presence of competition for light. Underlying genes and pathways were identified, but evidence for its epigenetic basis remains scarce. We used a proven and accessible approach at the population level and compared global DNA methylation between plants exposed to regular light and three different magnitudes of shade in seven highly inbred lines of snapdragon plants (Antirrhinum majus) grown in a greenhouse. Our results brought evidence of a strong SAR syndrome for which magnitude did not vary between lines. They also brought evidence that its magnitude was not associated with the global DNA methylation percentage for five of the six traits under study. The magnitude of stem elongation was significantly associated with global DNA demethylation. We discuss the limits of this approach and why caution must be taken with such results. In-depth approaches at the DNA sequence level will be necessary to better understand the molecular basis of the SAR syndrome.


Assuntos
Adaptação Fisiológica/genética , Antirrhinum/genética , Metilação de DNA/genética , Epigênese Genética , Antirrhinum/crescimento & desenvolvimento , Variação Genética/genética , Fenótipo
17.
Nat Plants ; 5(2): 121, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30737515
18.
Nat Plants ; 5(2): 174-183, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30692677

RESUMO

Snapdragon (Antirrhinum majus L.), a member of the Plantaginaceae family, is an important model for plant genetics and molecular studies on plant growth and development, transposon biology and self-incompatibility. Here we report a near-complete genome assembly of A. majus cultivar JI7 (A. majus cv.JI7) comprising 510 Megabases (Mb) of genomic sequence and containing 37,714 annotated protein-coding genes. Scaffolds covering 97.12% of the assembled genome were anchored on eight chromosomes. Comparative and evolutionary analyses revealed that a whole-genome duplication event occurred in the Plantaginaceae around 46-49 million years ago (Ma). We also uncovered the genetic architectures associated with complex traits such as flower asymmetry and self-incompatibility, identifying a unique duplication of TCP family genes dated to around 46-49 Ma and reconstructing a near-complete ψS-locus of roughly 2 Mb. The genome sequence obtained in this study not only provides a representative genome sequenced from the Plantaginaceae but also brings the popular plant model system of Antirrhinum into the genomic age.


Assuntos
Antirrhinum/genética , Genoma de Planta , Proteínas de Plantas/genética , Evolução Biológica , Flores/anatomia & histologia , Flores/genética , Flores/fisiologia , Duplicação Gênica , Anotação de Sequência Molecular , Filogenia , Autoincompatibilidade em Angiospermas/genética
19.
Physiol Plant ; 166(3): 762-771, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30187495

RESUMO

Photoperiodic lighting can promote flowering of long-day plants (LDPs) and inhibit flowering of short-day plants (SDPs). Red (R) and far-red (FR) light regulate flowering through phytochromes, whereas blue light does so primarily through cryptochromes. In contrast, the role of green light in photoperiodic regulation of flowering has been inconsistent in previous studies. We grew four LDP species (two petunia cultivars, ageratum, snapdragon and Arabidopsis) and two SDP species (three chrysanthemum cultivars and marigold) in a greenhouse under truncated 9-h short days with or without 7-h day-extension lighting from green light (peak = 521 nm) at 0, 2, 13 or 25 µmol m-2  s-1 or R + white (W) + FR light at 2 µmol m-2  s-1 . Increasing the green photon flux density from 0 to 25 µmol m-2  s-1 accelerated flowering of all LDPs and delayed flowering of all SDPs. Petunia flowered similarly fast under R + W + FR light and moderate green light but was shorter and developed more branches under green light. To be as effective as R + W + FR light, saturation green photon flux densities were 2 µmol m-2  s-1 for LDP ageratum and SDP marigold and 13 µmol m-2  s-1 for LDP petunia. Snapdragon was the least sensitive to green light. In Arabidopsis, cryptochrome 2 mediated promotion of flowering under moderate green light, whereas both phytochrome B and cryptochrome 2 mediated that under R + W + FR light. We conclude that 7-h day-extension lighting from green light-emitting diodes can control flowering of photoperiodic ornamentals and that in Arabidopsis, cryptochrome 2 mediates promotion of flowering under green light.


Assuntos
Criptocromos/metabolismo , Flores/metabolismo , Luz , Ageratum/metabolismo , Ageratum/efeitos da radiação , Antirrhinum/metabolismo , Antirrhinum/efeitos da radiação , Arabidopsis/metabolismo , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis , Chrysanthemum/metabolismo , Chrysanthemum/efeitos da radiação , Flores/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Fótons , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/efeitos da radiação
20.
Proc Natl Acad Sci U S A ; 115(43): 11006-11011, 2018 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-30297406

RESUMO

Genomes of closely-related species or populations often display localized regions of enhanced relative sequence divergence, termed genomic islands. It has been proposed that these islands arise through selective sweeps and/or barriers to gene flow. Here, we genetically dissect a genomic island that controls flower color pattern differences between two subspecies of Antirrhinum majus, A.m.striatum and A.m.pseudomajus, and relate it to clinal variation across a natural hybrid zone. We show that selective sweeps likely raised relative divergence at two tightly-linked MYB-like transcription factors, leading to distinct flower patterns in the two subspecies. The two patterns provide alternate floral guides and create a strong barrier to gene flow where populations come into contact. This barrier affects the selected flower color genes and tightly-linked loci, but does not extend outside of this domain, allowing gene flow to lower relative divergence for the rest of the chromosome. Thus, both selective sweeps and barriers to gene flow play a role in shaping genomic islands: sweeps cause elevation in relative divergence, while heterogeneous gene flow flattens the surrounding "sea," making the island of divergence stand out. By showing how selective sweeps establish alternative adaptive phenotypes that lead to barriers to gene flow, our study sheds light on possible mechanisms leading to reproductive isolation and speciation.


Assuntos
Flores/genética , Fluxo Gênico/genética , Ilhas Genômicas/genética , Seleção Genética/genética , Antirrhinum/genética , Cromossomos de Plantas/genética , Cor , Especiação Genética , Genoma de Planta/genética
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