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1.
BMC Plant Biol ; 24(1): 794, 2024 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-39169281

RESUMO

BACKGROUND: The theory of Condition Dependent Sex predicts that - everything else being equal - less fit individuals would outcross at higher rates compared with fitter ones. Here we used the mixed mating plant Lamium amplexicaule, capable of producing both self-pollinating closed flowers (CL), alongside open flowers (CH) that allow cross pollination to test it. We investigated the effects of abiotic stress - salt solution irrigation - on the flowering patterns of plants and their offspring. We monitored several flowering and vegetative parameters, including the number and distribution of flowers, CH fraction, and plant size. RESULTS: We found that stressed plants show an increased tendency for self-pollination and a deficit in floral and vegetative development. However, when parentally primed, stressed plants show a milder response. Un-stressed offspring of stressed parents show reversed responses and exhibit an increased tendency to outcross, and improve floral and vegetative development. CONCLUSIONS: In summary, we found that stress affects the reproduction strategy in the plants that experienced the stress and in subsequent offspring through F2 generation. Our results provide experimental evidence supporting a transgenerational extension to the theories of fitness associate sex and dispersal, where an individual's tendency for sex and dispersal may depend on the stress experienced by its parents.


Assuntos
Flores , Polinização , Reprodução , Flores/fisiologia , Flores/crescimento & desenvolvimento , Lamiales/fisiologia , Lamiales/crescimento & desenvolvimento , Estresse Fisiológico
2.
J Exp Bot ; 74(15): 4324-4348, 2023 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-37155961

RESUMO

Endosperm is a key nutritive tissue that supports the developing embryo or seedling, and serves as a major nutritional source for human and livestock feed. In sexually-reproducing flowering plants, it generally develops after fertilization. However, autonomous endosperm (AE) formation (i.e. independent of fertilization) is also possible. Recent findings of AE loci/ genes and aberrant imprinting in native apomicts, together with a successful initiation of parthenogenesis in rice and lettuce, have enhanced our understanding of the mechanisms bridging sexual and apomictic seed formation. However, the mechanisms driving AE development are not well understood. This review presents novel aspects related to AE development in sexual and asexual plants underlying stress conditions as the primary trigger for AE. Both application of hormones to unfertilized ovules and mutations that impair epigenetic regulation lead to AE development in sexual Arabidopsis thaliana, which may point to a common pathway for both phenomena. Apomictic-like AE development under experimental conditions can take place due to auxin-dependent gene expression and/or DNA methylation.


Assuntos
Arabidopsis , Asteraceae , Humanos , Endosperma/genética , Epigênese Genética , Sementes , Reprodução , Arabidopsis/genética
3.
Proc Natl Acad Sci U S A ; 117(52): 33700-33710, 2020 12 29.
Artigo em Inglês | MEDLINE | ID: mdl-33376225

RESUMO

Cytosine (DNA) methylation in plants regulates the expression of genes and transposons. While methylation in plant genomes occurs at CG, CHG, and CHH sequence contexts, the comparative roles of the individual methylation contexts remain elusive. Here, we present Physcomitrella patens as the second plant system, besides Arabidopsis thaliana, with viable mutants with an essentially complete loss of methylation in the CG and non-CG contexts. In contrast to A. thaliana, P. patens has more robust CHH methylation, similar CG and CHG methylation levels, and minimal cross-talk between CG and non-CG methylation, making it possible to study context-specific effects independently. Our data found CHH methylation to act in redundancy with symmetric methylation in silencing transposons and to regulate the expression of CG/CHG-depleted transposons. Specific elimination of CG methylation did not dysregulate transposons or genes. In contrast, exclusive removal of non-CG methylation massively up-regulated transposons and genes. In addition, comparing two exclusively but equally CG- or CHG-methylated genomes, we show that CHG methylation acts as a greater transcriptional regulator than CG methylation. These results disentangle the transcriptional roles of CG and non-CG, as well as symmetric and asymmetric methylation in a plant genome, and point to the crucial role of non-CG methylation in genome regulation.


Assuntos
Bryopsida/genética , Metilação de DNA/genética , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Mutação/genética , Elementos de DNA Transponíveis/genética , Epigenoma , Inativação Gênica , Modelos Genéticos , Regulação para Cima/genética
4.
BMC Bioinformatics ; 22(1): 495, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34645386

RESUMO

BACKGROUND: Circular RNA (circRNA) is an emerging class of RNA molecules attracting researchers due to its potential for serving as markers for diagnosis, prognosis, or therapeutic targets of cancer, cardiovascular, and autoimmune diseases. Current methods for detection of circRNA from RNA sequencing (RNA-seq) focus mostly on improving mapping quality of reads supporting the back-splicing junction (BSJ) of a circRNA to eliminate false positives (FPs). We show that mapping information alone often cannot predict if a BSJ-supporting read is derived from a true circRNA or not, thus increasing the rate of FP circRNAs. RESULTS: We have developed Circall, a novel circRNA detection method from RNA-seq. Circall controls the FPs using a robust multidimensional local false discovery rate method based on the length and expression of circRNAs. It is computationally highly efficient by using a quasi-mapping algorithm for fast and accurate RNA read alignments. We applied Circall on two simulated datasets and three experimental datasets of human cell-lines. The results show that Circall achieves high sensitivity and precision in the simulated data. In the experimental datasets it performs well against current leading methods. Circall is also substantially faster than the other methods, particularly for large datasets. CONCLUSIONS: With those better performances in the detection of circRNAs and in computational time, Circall facilitates the analyses of circRNAs in large numbers of samples. Circall is implemented in C++ and R, and available for use at https://www.meb.ki.se/sites/biostatwiki/circall and https://github.com/datngu/Circall.


Assuntos
RNA Circular , RNA , Humanos , RNA/genética , Splicing de RNA , RNA-Seq , Análise de Sequência de RNA
5.
Biochim Biophys Acta ; 1859(7): 860-70, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27179444

RESUMO

Packaging of eukaryotic DNA largely depends on histone modifications that affect the accessibility of DNA to transcriptional regulators, thus controlling gene expression. The Polycomb group (PcG) chromatin remodeling complex deposits a methyl group on lysine 27 of histone 3 leading to repressed gene expression. Plants encode homologs of the Enhancer of zeste (E(z)), a component of the PcG complex from Drosophila, one of which is a SET domain protein designated CURLY LEAF (CLF). Although this SET domain protein exhibits a strong correlation with the presence of the H3K27me3 mark in plants, the methyl-transferase activity and specificity of its SET domain have not been directly tested in-vivo. Using the evolutionary early-diverged land plant model species Physcomitrella patens we show that abolishment of a single copy gene PpCLF, as well as an additional member of the PcG complex, FERTILIZATION-INDEPENDENT ENDOSPERM (PpFIE), results in a specific loss of tri-methylation of H3K27. Using site-directed mutagenesis of key residues, we revealed that H3K27 tri-methylation is mediated by the SET domain of the CLF protein. Moreover, the abolishment of H3K27me3 led to enhanced expression of transcription factor genes. This in turn led to the development of fertilization-independent sporophyte-like structures, as observed in PpCLF and PpFIE null mutants. Overall, our results demonstrate the role of PpCLF as a SET protein in tri-methylation of H3K27 in-vivo and the importance of this modification in regulating the expression of transcription factor genes involved in developmental programs of P. patens.


Assuntos
Bryopsida/crescimento & desenvolvimento , Bryopsida/genética , Histona-Lisina N-Metiltransferase/fisiologia , Histonas/metabolismo , Proteínas do Grupo Polycomb/fisiologia , Sequência de Aminoácidos , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Histona Metiltransferases , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/química , Proteínas de Homeodomínio/fisiologia , Lisina/metabolismo , Metilação , Dados de Sequência Molecular , Folhas de Planta/genética , Folhas de Planta/metabolismo , Plantas Geneticamente Modificadas , Homologia de Sequência de Aminoácidos
6.
J Exp Bot ; 67(21): 6111-6123, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27811080

RESUMO

Polycomb group (PcG) proteins are evolutionarily conserved chromatin modifiers that regulate developmental pathways in plants. PcGs form nuclear multi-subunit Polycomb Repressive Complexes (PRCs). The PRC2 complex mediates gene repression via methylation of lysine 27 on histone H3, which consequently leads to chromatin condensation. In Arabidopsis thaliana, several PRC2 complexes with different compositions were identified, each controlling a particular developmental program.The core subunit FIE is crucial for PRC2 function throughout the plant life cycle, yet accurate information on its spatial and temporal localization was absent. This study focused on identifying FIE accumulation patterns, using microscopy and biochemical approaches. Analysing endogenous FIE and transgenic gFIE-green fluorescent protein fusion protein (gFIE-GFP) showed that FIE accumulates in the nuclei of every cell type examined. Interestingly, gFIE-GFP, as well as the endogenous FIE, also localized to the cytoplasm in all examined tissues. In both vegetative and reproductive organs, FIE formed cytoplasmic high-molecular-mass complexes, in parallel to the nuclear PRC2 complexes. Moreover, size-exclusion chromatography and bimolecular fluorescence complementation assays indicated that in inflorescences FIE formed a cytoplasmic complex with MEA, a PRC2 histone methyltransferase subunit. In contrast, CLF and SWN histone methyltransferases were strictly nuclear. Presence of PRC2 subunits in cytoplasmic complexes has not been previously described in plants. Our findings are in agreement with accumulating evidence demonstrating cytoplasmic localization and function of PcGs in metazoa. The cytosolic accumulation of PRC2 components in plants supports the model that PcGs have alternative non-nuclear functions that go beyond chromatin methylation.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Citoplasma/metabolismo , Proteínas Repressoras/metabolismo , Cromatina/metabolismo , Cromatografia em Gel , Imunoprecipitação , Microscopia Confocal , Plantas Geneticamente Modificadas , Complexo Repressor Polycomb 2
7.
Plant Mol Biol ; 88(4-5): 387-400, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25944663

RESUMO

DNA methylation has a crucial role in plant development regulating gene expression and silencing of transposable elements. Maintenance DNA methylation in plants occurs at symmetrical (m)CG and (m)CHG contexts ((m) = methylated) and is maintained by DNA METHYLTRANSFERASE 1 (MET1) and CHROMOMETHYLASE (CMT) DNA methyltransferase protein families, respectively. While angiosperm genomes encode for several members of MET1 and CMT families, the moss Physcomitrella patens, serving as a model for early divergent land plants, carries a single member of each family. To determine the function of P. patens PpMET we generated ΔPpmet deletion mutant which lost (m)CG and unexpectedly (m)CCG methylation at loci tested. In order to evaluate the extent of (m)CCG methylation by MET1, we reexamined the Arabidopsis thaliana Atmet1 mutant methylome and found a similar pattern of methylation loss, suggesting that maintenance of DNA methylation by MET1 is conserved through land plant evolution. While ΔPpmet displayed no phenotypic alterations during its gametophytic phase, it failed to develop sporophytes, indicating that PpMET plays a role in gametogenesis or early sporophyte development. Expression array analysis revealed that the deletion of PpMET resulted in upregulation of two genes and multiple repetitive sequences. In parallel, expression analysis of the previously reported ΔPpcmt mutant showed that lack of PpCMT triggers overexpression of genes. This overexpression combined with loss of (m)CHG and its pleiotropic phenotype, implies that PpCMT has an essential evolutionary conserved role in the epigenetic control of gene expression. Collectively, our results suggest functional conservation of MET1 and CMT families during land plant evolution. A model describing the relationship between MET1 and CMT in CCG methylation is presented.


Assuntos
Bryopsida/genética , Bryopsida/metabolismo , DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA , Proteínas de Plantas/metabolismo , Oxirredutases do Álcool , Sequência de Bases , Bryopsida/crescimento & desenvolvimento , DNA (Citosina-5-)-Metiltransferases/genética , Metilação de DNA/genética , DNA de Plantas/genética , DNA de Plantas/metabolismo , Epigênese Genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Modelos Biológicos , Dados de Sequência Molecular , Mutação , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas
8.
Plant Mol Biol ; 84(6): 719-35, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24370935

RESUMO

C-5 DNA methylation is an essential mechanism controlling gene expression and developmental programs in a variety of organisms. Though the role of DNA methylation has been intensively studied in mammals and Arabidopsis, little is known about the evolution of this mechanism. The chromomethylase (CMT) methyltransferase family is unique to plants and was found to be involved in DNA methylation in Arabidopsis, maize and tobacco. The moss Physcomitrella patens, a model for early terrestrial plants, harbors a single homolog of the CMT protein family designated as PpCMT. Our phylogenetic analysis suggested that the CMT family is unique to embryophytes and its earliest known member PpCMT belongs to the CMT3 subfamily. Thus, P. patens may serve as a model to study the ancient functions of the CMT3 family. We have generated a ΔPpcmt deletion mutant which demonstrated that PpCMT is essential for P. patens protonema and gametophore development and is involved in CHG methylation as demonstrated at four distinct genomic loci. PpCMT protein accumulation pattern correlated with proliferating cells and was sub-localized to the nucleus as predicted from its function. Taken together, our results suggested that CHG DNA methylation mediated by CMT has been employed early in land plant evolution to control developmental programs during both the vegetative and reproductive haploid phases along the plant life cycle.


Assuntos
Bryopsida/enzimologia , DNA (Citosina-5-)-Metiltransferases/genética , Epigênese Genética , Regulação da Expressão Gênica de Plantas , Sequência de Aminoácidos , Evolução Biológica , Bryopsida/citologia , Bryopsida/genética , Bryopsida/crescimento & desenvolvimento , DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA , Dosagem de Genes , Dados de Sequência Molecular , Fenótipo , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Proteínas Recombinantes de Fusão , Alinhamento de Sequência , Análise de Sequência de DNA , Deleção de Sequência , Transgenes
9.
PLoS One ; 18(3): e0279688, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36888585

RESUMO

The Snf2 chromatin remodeler, DECREASE IN DNA METHYLATION 1 (DDM1) facilitates DNA methylation. In flowering plants, DDM1 mediates methylation in heterochromatin, which is targeted primarily by MET1 and CMT methylases and is necessary for silencing transposons and for proper development. DNA methylation mechanisms evolved throughout plant evolution, whereas the role of DDM1 in early terrestrial plants remains elusive. Here, we studied the function of DDM1 in the moss, Physcomitrium (Physcomitrella) patens, which has robust DNA methylation that suppresses transposons and is mediated by a MET1, a CMT, and a DNMT3 methylases. To elucidate the role of DDM1 in P. patens, we have generated a knockout mutant and found DNA methylation to be strongly disrupted at any of its sequence contexts. Symmetric CG and CHG sequences were affected stronger than asymmetric CHH sites. Furthermore, despite their separate targeting mechanisms, CG (MET) and CHG (CMT) methylation were similarly depleted by about 75%. CHH (DNMT3) methylation was overall reduced by about 25%, with an evident hyper-methylation activity within lowly-methylated euchromatic transposon sequences. Despite the strong hypomethylation effect, only a minute number of transposons were transcriptionally activated in Ppddm1. Finally, Ppddm1 was found to develop normally throughout the plant life cycle. These results demonstrate that DNA methylation is strongly dependent on DDM1 in a non-flowering plant; that DDM1 is required for plant-DNMT3 (CHH) methylases, though to a lower extent than for MET1 and CMT enzymes; and that distinct and separate methylation pathways (e.g. MET1-CG and CMT-CHG), can be equally regulated by the chromatin and that DDM1 plays a role in it. Finally, our data suggest that the biological significance of DDM1 in terms of transposon regulation and plant development, is species dependent.


Assuntos
Proteínas de Arabidopsis , Bryopsida , Metilação de DNA , Bryopsida/metabolismo , Cromatina/metabolismo , Metiltransferases/genética , Heterocromatina/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Arabidopsis/genética
10.
Biochim Biophys Acta ; 1809(8): 395-406, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21664995

RESUMO

Polycomb Group (PcG) proteins form an epigenetic "memory system", conserved in both plants and animals, controlling global gene expression during development via histone modifications. The role of PcG proteins in plants was primarily explored in Arabidopsis thaliana, where PcG regulation of developmental processes was demonstrated throughout the plant life cycle. Our knowledge about the PcG machinery in terrestrial plants other than Arabidopsis began to accumulate only in recent years. In this review we summarize recent emerging data on the evolution and diversification of PcG mechanisms in various phyla, from early-diverging plants, including members of the Chlorophyte algae, through bryophytes and flowering plants. We describe the compositions of the PcG gene families, their so-far studied expression profiles, and finally summarize commonalities vs. differences among PcG functions across the various species. This article is part of a Special Issue entitled: Epigenetic control of cellular and developmental processes in plants.


Assuntos
Proteínas de Plantas/genética , Plantas/genética , Proteínas Repressoras/genética , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/fisiologia , Evolução Biológica , Epigênese Genética , Filogenia , Desenvolvimento Vegetal , Fenômenos Fisiológicos Vegetais , Proteínas do Grupo Polycomb , Reprodução/genética , Reprodução Assexuada/genética
11.
PLoS Biol ; 6(8): e194, 2008 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-18700816

RESUMO

Parental genomic imprinting causes preferential expression of one of the two parental alleles. In mammals, differential sex-dependent deposition of silencing DNA methylation marks during gametogenesis initiates a new cycle of imprinting. Parental genomic imprinting has been detected in plants and relies on DNA methylation by the methyltransferase MET1. However, in contrast to mammals, plant imprints are created by differential removal of silencing marks during gametogenesis. In Arabidopsis, DNA demethylation is mediated by the DNA glycosylase DEMETER (DME) causing activation of imprinted genes at the end of female gametogenesis. On the basis of genetic interactions, we show that in addition to DME, the plant homologs of the human Retinoblastoma (Rb) and its binding partner RbAp48 are required for the activation of the imprinted genes FIS2 and FWA. This Rb-dependent activation is mediated by direct transcriptional repression of MET1 during female gametogenesis. We have thus identified a new mechanism required for imprinting establishment, outlining a new role for the Retinoblastoma pathway, which may be conserved in mammals.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Impressão Genômica , Proteína do Retinoblastoma/genética , Arabidopsis/genética , Proteínas de Arabidopsis/biossíntese , Proteínas de Arabidopsis/genética , DNA (Citosina-5-)-Metiltransferases/biossíntese , Metilação de DNA , Regulação para Baixo , Epigênese Genética , Gametogênese , Regulação da Expressão Gênica de Plantas , Proteínas de Homeodomínio/biossíntese , Humanos , N-Glicosil Hidrolases/genética , N-Glicosil Hidrolases/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Transativadores/genética , Transativadores/metabolismo , Fatores de Transcrição/biossíntese
12.
Curr Biol ; 16(5): 486-92, 2006 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-16527743

RESUMO

Fertilization in flowering plants initiates the development of the embryo and endosperm, which nurtures the embryo. A few genes subjected to imprinting are expressed in endosperm from their maternal allele, while their paternal allele remains silenced. Imprinting of the FWA gene involves DNA methylation. Mechanisms controlling imprinting of the Polycomb group (Pc-G) gene MEDEA (MEA) are not yet fully understood. Here we report that MEA imprinting is regulated by histone methylation. This epigenetic chromatin modification is mediated by several Pc-G activities during the entire plant life cycle. We show that Pc-G complexes maintain MEA transcription silenced throughout vegetative life and male gametogenesis. In endosperm, the maternal allele of MEA encodes an essential component of a Pc-G complex, which maintains silencing of the paternal MEA allele. Hence, we conclude that a feedback loop controls MEA imprinting. This feedback loop ensures a complete maternal control of MEA expression from both parental alleles and might have provided a template for evolution of imprinting in plants.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Impressão Genômica , Proteínas Repressoras/fisiologia , Arabidopsis/embriologia , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/metabolismo , Montagem e Desmontagem da Cromatina , Imunoprecipitação da Cromatina , Inativação Gênica , Histonas/metabolismo , Metilação , Modelos Genéticos , Proteínas do Grupo Polycomb , Processamento de Proteína Pós-Traducional , Proteínas Repressoras/metabolismo , Sementes/genética , Sementes/metabolismo
13.
Nat Commun ; 10(1): 2552, 2019 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-31171796

RESUMO

The original version of this Article contained an error in Fig. 5, in which the evolutionary origin of DRM2 was incorrectly placed prior to the divergence between gymnosperms and angiosperms . The correct evolutionary origin of DRM2 should be in angiosperms. In addition, in the "Percent methylation change" section of the Methods, Equation 1 was incorrect. This has been corrected in both the PDF and HTML versions of the Article.An amendment to this paper has been published and can be accessed via a link at the top of the paper.

14.
Nat Commun ; 10(1): 1613, 2019 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-30962443

RESUMO

To properly regulate the genome, cytosine methylation is established by animal DNA methyltransferase 3 s (DNMT3s). While altered DNMT3 homologs, Domains rearranged methyltransferases (DRMs), have been shown to establish methylation via the RNA directed DNA methylation (RdDM) pathway, the role of true-plant DNMT3 orthologs remains elusive. Here, we profile de novo (RPS transgene) and genomic methylation in the basal plant, Physcomitrella patens, mutated in each of its PpDNMTs. We show that PpDNMT3b mediates CG and CHH de novo methylation, independently of PpDRMs. Complementary de novo CHG methylation is specifically mediated by the CHROMOMETHYLASE, PpCMT. Intragenomically, PpDNMT3b functions preferentially within heterochromatin and is affected by PpCMT. In comparison, PpDRMs target active-euchromatic transposons. Overall, our data resolve how DNA methylation in plants can be established in heterochromatin independently of RdDM; suggest that DRMs have emerged to target euchromatin; and link DNMT3 loss in angiosperms to the initiation of heterochromatic CHH methylation by CMT2.


Assuntos
Bryopsida/fisiologia , DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA/fisiologia , Heterocromatina/genética , Proteínas de Plantas/metabolismo , DNA (Citosina-5-)-Metiltransferases/genética , Evolução Molecular , Redes e Vias Metabólicas/fisiologia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Seleção Genética/fisiologia
15.
Sci Rep ; 9(1): 6299, 2019 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-31004098

RESUMO

Theory predicts that less fit individuals would disperse more often than fitter ones (Fitness Associated Dispersal, FAD hypothesis). To test this prediction under laboratory conditions, an entire life cycle of Lamium amplexicaule plants and the preferences of its dispersal agent, Messor ebeninus ants, were tracked. Characterization of individual L. amplexicaule plant revealed high variability in spot cover on the surface of the seeds, where less fit plants produce "unspotted seeds" (see Fig. 1 in Introduction). Unspotted L. amplexicaule seeds showed higher variation in germination time and lower germination rate. Moreover, M. ebeninus ants preferably collected these unspotted seeds. Our results show that low fitness L. amplexicaule plants produce seeds with higher potential for dispersal, supporting the FAD hypothesis in a plant-animal system.


Assuntos
Lamiaceae/fisiologia , Dispersão de Sementes/fisiologia , Sementes/fisiologia , Animais , Formigas/fisiologia
17.
Science ; 357(6346): 93-97, 2017 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-28684525

RESUMO

Wheat (Triticum spp.) is one of the founder crops that likely drove the Neolithic transition to sedentary agrarian societies in the Fertile Crescent more than 10,000 years ago. Identifying genetic modifications underlying wheat's domestication requires knowledge about the genome of its allo-tetraploid progenitor, wild emmer (T. turgidum ssp. dicoccoides). We report a 10.1-gigabase assembly of the 14 chromosomes of wild tetraploid wheat, as well as analyses of gene content, genome architecture, and genetic diversity. With this fully assembled polyploid wheat genome, we identified the causal mutations in Brittle Rachis 1 (TtBtr1) genes controlling shattering, a key domestication trait. A study of genomic diversity among wild and domesticated accessions revealed genomic regions bearing the signature of selection under domestication. This reference assembly will serve as a resource for accelerating the genome-assisted improvement of modern wheat varieties.


Assuntos
Produtos Agrícolas/genética , Domesticação , Genes de Plantas , Tetraploidia , Triticum/genética , Evolução Biológica , Mutação , Melhoramento Vegetal , Sintenia
18.
Trends Plant Sci ; 8(9): 439-45, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-13678911

RESUMO

Cell identity and differentiation are determined by patterns of regulatory gene expression. Spatially and temporally regulated homeotic gene expression defines segment identities along the anterior-posterior axis of animal embryos. Polycomb group (PcG) proteins form a cellular memory system that maintains the repressed state of homeotic gene expression. Conserved PcG proteins control multiple aspects of Arabidopsis development and maintain homeotic gene repression. In animals, PcG proteins repress their target genes by modifying histone tails through deacetylation and methylation, generating a PcG-specific histone code that recruits other chromatin remodeling proteins to establish a stable, heritable mechanism of epigenetic expression control. Plant PcG proteins might function through a similar biochemical mechanism owing to their conserved structural and functional relationship to animal PcG proteins.


Assuntos
Farinha , Flores/fisiologia , Desenvolvimento Vegetal , Proteínas de Plantas/fisiologia , Proteínas Repressoras/fisiologia , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Plantas/genética , Plantas/genética , Proteínas do Grupo Polycomb , Proteínas Repressoras/genética , Reprodução
19.
Nat Plants ; 2: 15209, 2016 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-27250874

RESUMO

Plants characteristically alternate between haploid gametophytic and diploid sporophytic stages. Meiosis and fertilization respectively initiate these two different ontogenies(1). Genes triggering ectopic embryo development on vegetative sporophytic tissues are well described(2,3); however, a genetic control of embryo development from gametophytic tissues remains elusive. Here, in the moss Physcomitrella patens we show that ectopic overexpression of the homeobox gene BELL1 induces embryo formation and subsequently reproductive diploid sporophytes from specific gametophytic cells without fertilization. In line with this, BELL1 loss-of-function mutants have a wild-type phenotype, except that their egg cells are bigger and unable to form embryos. Our results identify BELL1 as a master regulator for the gametophyte-to-sporophyte transition in P. patens and provide mechanistic insights into the evolution of embryos that can generate multicellular diploid sporophytes. This developmental innovation facilitated the colonization of land by plants about 500 million years ago(4) and thus shaped our current ecosystems.


Assuntos
Bryopsida/genética , Genes Homeobox/genética , Bryopsida/embriologia , Bryopsida/fisiologia , Diploide , Células Germinativas Vegetais/fisiologia , Haploidia , Reprodução Assexuada
20.
Methods Mol Biol ; 655: 347-58, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20734272

RESUMO

Protein function is often mediated by the formation of stable or transient complexes. Here we present a method for testing protein-protein interactions in plants designated bimolecular fluorescence complementation (BiFC). The advantages of BiFC are its simplicity, reliability, and the ability to observe protein-protein interactions in different cellular compartments including membranes. BiFC is based on splitting the yellow fluorescent protein (YFP) into two nonoverlapping N-terminal (YN) and C-terminal (YC) fragments. Each fragment is cloned in-frame with a gene of interest, enabling expression of a fusion protein. Reconstitution of the fluorescing YFP chromophore takes place upon interaction of protein pairs that are coexpressed in the same cells.


Assuntos
Proteínas de Plantas/metabolismo , Plantas/metabolismo , Mapeamento de Interação de Proteínas/métodos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Fluorescência , Expressão Gênica , Vetores Genéticos , Immunoblotting/métodos , Imunoprecipitação/métodos , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Microscopia de Fluorescência/métodos , Folhas de Planta/genética , Folhas de Planta/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/isolamento & purificação , Plantas/genética , Rhizobium/genética
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