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1.
Methods Mol Biol ; 2288: 145-162, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34270010

RESUMO

Culture of isolated microspores is a widely used method to obtain haploid and doubled haploid plants for many crop species. This protocol describes the steps necessary to obtain a large number of microspore derived embryos for pakchoi (Brassica rapa L. ssp. chinensis) and zicaitai (Brassica rapa L. ssp. сhinensis Hanelt var. purpuraria Kitam).


Assuntos
Brassica rapa/crescimento & desenvolvimento , Brassica rapa/genética , Melhoramento Vegetal/métodos , Brassica rapa/ultraestrutura , Cloroplastos/ultraestrutura , Cromossomos de Plantas/ultraestrutura , Produtos Agrícolas/genética , Produtos Agrícolas/crescimento & desenvolvimento , Meios de Cultura/química , Diploide , Germinação/genética , Haploidia , Homozigoto , Microscopia de Fluorescência , Biologia Molecular/métodos , Ploidias , Pólen/genética , Pólen/crescimento & desenvolvimento , Técnicas de Cultura de Tecidos
2.
Plant J ; 106(3): 588-600, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33788333

RESUMO

Polyploidy has played a crucial role in plant evolution, development and function. Synthetic autopolyploid represents an ideal system to investigate the effects of polyploidization on transcriptional regulation. In this study, we deciphered the impact of genome duplication at phenotypic and molecular levels in watermelon. Overall, 88% of the genes in tetraploid watermelon followed a >1:1 dosage effect, and accordingly, differentially expressed genes were largely upregulated. In addition, a great number of hypomethylated regions (1688) were identified in an isogenic tetraploid watermelon. These differentially methylated regions were localized in promoters and intergenic regions and near transcriptional start sites of the identified upregulated genes, which enhances the importance of methylation in gene regulation. These changes were reflected in sophisticated higher-order chromatin structures. The genome doubling caused switching of 108 A and 626 B compartments that harbored genes associated with growth, development and stress responses.


Assuntos
Cromatina/ultraestrutura , Citrullus/genética , Duplicação Gênica/genética , Regulação da Expressão Gênica de Plantas/genética , Cromatina/genética , Cromatina/metabolismo , Cromossomos de Plantas/genética , Cromossomos de Plantas/metabolismo , Cromossomos de Plantas/ultraestrutura , Citrullus/metabolismo , Epigenoma/genética , Estudos de Associação Genética , Genoma de Planta/genética , Poliploidia , Tetraploidia
3.
Int J Mol Sci ; 21(5)2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32143437

RESUMO

Actin-depolymerizing factor (ADF) is a small class of actin-binding proteins that regulates the dynamics of actin in cells. Moreover, it is well known that the plant ADF family plays key roles in growth, development and defense-related functions. Results: Thirteen maize (Zea mays L., ZmADFs) ADF genes were identified using Hidden Markov Model. Phylogenetic analysis indicated that the 36 identified ADF genes in Physcomitrella patens, Arabidopsis thaliana, Oryza sativa japonica, and Zea mays were clustered into five groups. Four pairs of segmental genes were found in the maize ADF gene family. The tissue-specific expression of ZmADFs and OsADFs was analyzed using microarray data obtained from the Maize and Rice eFP Browsers. Five ZmADFs (ZmADF1/2/7/12/13) from group V exhibited specifically high expression in tassel, pollen, and anther. The expression patterns of 13 ZmADFs in seedlings under five abiotic stresses were analyzed using qRT-PCR, and we found that the ADFs mainly responded to heat, salt, drought, and ABA. Conclusions: In our study, we identified ADF genes in maize and analyzed the gene structure and phylogenetic relationships. The results of expression analysis demonstrated that the expression level of ADF genes was diverse in various tissues and different stimuli, including abiotic and phytohormone stresses, indicating their different roles in plant growth, development, and response to external stimulus. This report extends our knowledge to understand the function of ADF genes in maize.


Assuntos
Destrina/genética , Regulação da Expressão Gênica de Plantas , Estresse Fisiológico , Zea mays/genética , Actinas/metabolismo , Arabidopsis/genética , Bryopsida/genética , Cromossomos de Plantas/ultraestrutura , Destrina/metabolismo , Secas , Perfilação da Expressão Gênica , Estudos de Associação Genética , Genoma de Planta , Análise de Sequência com Séries de Oligonucleotídeos , Oryza/genética , Filogenia , Reguladores de Crescimento de Plantas/metabolismo , Pólen/química
4.
Mutat Res ; 846: 403080, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31585628

RESUMO

Loss of genetic integrity can occur during the long-term conservation of seeds. We have studied these effects in seeds of rice (Oryza sativa L.) and common bean (Phaseolus vulgaris L.) exposed to accelerated aging (elevated temperature and moisture) conditions. Tests of first count, germination, and germination speed index were performed to measure physiological quality; cytogenetic tests and comet assay were used to evaluate genetic integrity. With aging, we observed a decrease in mitotic index and an increase in the frequency of chromosomal alterations in root cells of imbibed seeds, as well as increased DNA damage (comet assay) in dry and imbibed seed embryos of both species. The comet assay can be a useful technique for measuring genetic integrity in seed conservation programs.


Assuntos
Genes de Plantas , Oryza/genética , Phaseolus/genética , Preservação Biológica/métodos , Banco de Sementes , Sementes/genética , Cromossomos de Plantas/ultraestrutura , Ensaio Cometa , Análise Citogenética , Dano ao DNA , Regulação da Expressão Gênica de Plantas , Germinação , Umidade , Índice Mitótico , Raízes de Plantas/citologia , Especificidade da Espécie , Temperatura , Fatores de Tempo
5.
Biosci Biotechnol Biochem ; 83(4): 666-674, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30585123

RESUMO

Asparagus (Asparagus officinalis) has several traits that make it a useful model for cytogenetic studies, however, few studies of the meiosis process have been made in asparagus. Here, we present in detail an atlas of male meiosis in asparagus, from preleptotene to telophase II. The meiosis process in asparagus is largely similar to those of the well-characterized model plants Arabidopsis thaliana, Zea mays, and Oryza sativa. However, most asparagus prophase I meiotic chromosomes show a strongly aggregated morphology, and this phenotype persists through the pachytene stage, highlighting a property in the control of chromosome migration and distribution in asparagus. Further, we observed no obvious banding of autofluorescent dots between divided nuclei of asparagus meiocytes, as one would expect in Arabidopsis. This description of wild-type asparagus meiosis will serve as a reference for the analyses of meiotic mutants, as well as for comparative studies among difference species. Abbreviations: DAPI: 4',6-diamidino-2-phenylindole; FISH: fluorescence in situ hybridization; PBS: phosphate-buffered saline; PMC: pollen mother cell; SEM: Scanning Electron Microscope.


Assuntos
Asparagus (Planta)/ultraestrutura , Cromossomos de Plantas/ultraestrutura , Meiose , Células Vegetais/ultraestrutura , Pólen/ultraestrutura , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/ultraestrutura , Asparagus (Planta)/genética , Asparagus (Planta)/crescimento & desenvolvimento , Núcleo Celular/metabolismo , Núcleo Celular/ultraestrutura , Cromossomos de Plantas/química , Flores/genética , Flores/crescimento & desenvolvimento , Flores/ultraestrutura , Hibridização in Situ Fluorescente , Microscopia Eletrônica de Varredura , Células Vegetais/metabolismo , Pólen/genética , Pólen/crescimento & desenvolvimento
6.
Chromosoma ; 128(1): 31-39, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30483879

RESUMO

Chromosome pairing in meiosis usually starts in the vicinity of the telomere attachment to the nuclear membrane and congregation of telomeres in the leptotene bouquet is believed responsible for bringing homologue pairs together. In a heterozygote for an inversion of a rye (Secale cereale L.) chromosome arm in wheat, a distal segment of the normal homologue is capable of chiasmate pairing with its counterpart in the inverted arm, located near the centromere. Using 3D imaging confocal microscopy, we observed that some telomeres failed to be incorporated into the bouquet and occupied various positions throughout the entire volume of the nucleus, including the centromere pole. Rye telomeres appeared ca. 21 times more likely to fail to be included in the telomere bouquet than wheat telomeres. The frequency of the out-of-bouquet rye telomere position in leptotene was virtually identical to the frequency of telomeres deviating from Rabl's orientation in the nuclei of somatic cells, and was similar to the frequency of synapsis of the normal and inverted chromosome arms, but lower than the MI pairing frequency of segments of these two arms normally positioned across the volume of the nucleus. Out-of-position placement of the rye telomeres may be responsible for reduced MI pairing of rye chromosomes in hybrids with wheat and their disproportionate contribution to aneuploidy, but appears responsible for initiating chiasmate pairing of distantly positioned segments of homology in an inversion heterozygote.


Assuntos
Inversão Cromossômica , Cromossomos de Plantas/ultraestrutura , Prófase Meiótica I , Secale/genética , Telômero/ultraestrutura , Triticum/genética , Núcleo Celular/genética , Núcleo Celular/ultraestrutura , Centrômero/química , Centrômero/ultraestrutura , Quimera/genética , Pareamento Cromossômico , Cromossomos de Plantas/química , Heterozigoto , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Imageamento Tridimensional/métodos , Hibridização in Situ Fluorescente , Microscopia Confocal , Células Vegetais/metabolismo , Células Vegetais/ultraestrutura , Secale/ultraestrutura , Especificidade da Espécie , Telômero/química , Triticum/ultraestrutura
7.
Exp Mol Med ; 50(8): 1-12, 2018 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-30154456

RESUMO

An important event enabling meiotic prophase I to proceed is the close juxtaposition of conjoined chromosome axes of homologs and their assembly via an array of transverse filaments and meiosis-specific axial elements into the synaptonemal complex (SC). During meiosis, recombination requires the establishment of a platform for recombinational interactions between the chromosome axes and their subsequent stabilization. This is essential for ensuring crossover recombination and proper segregation of homologous chromosomes. Thus, well-established SCs are essential for supporting these processes. The regulation of recombination intermediates on the chromosome axis/SC and dynamic positioning of double-strand breaks are not well understood. Here, using super-resolution microscopy (structured illumination microscopy), we determined the localization of the replication protein A (RPA) complex on the chromosome axes in the early phase of leptonema/zygonema and within the CEs of SC in the pachynema during meiotic prophase in mouse spermatocytes. RPA, which marks the intermediate steps of pairing and recombination, appears in large numbers and is positioned on the chromosome axes at the zygonema. In the pachynema, RPA foci are reduced but do not completely disappear; instead, they are placed between lateral elements. Our results reveal the precise structure of SC and localization dynamics of recombination intermediates on meiocyte chromosomes undergoing homolog pairing and meiotic recombination.


Assuntos
Cromossomos de Mamíferos/genética , Imageamento Tridimensional , Mamíferos/metabolismo , Meiose , Microscopia/métodos , Proteína de Replicação A/metabolismo , Animais , Arabidopsis/ultraestrutura , Pareamento Cromossômico , Cromossomos de Plantas/ultraestrutura , Reparo do DNA , Histonas/metabolismo , Camundongos Endogâmicos C57BL , Polimerização , Complexo Sinaptonêmico
8.
BMC Plant Biol ; 18(1): 110, 2018 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-29879904

RESUMO

BACKGROUND: The chromosome-specific probe is a fundamental tool of chromosome painting and has been commonly applied in mammalian species. The technology, however, has not been widely applied in plants due to a lack of methodologies for probe development. Identification and labeling of a large number of oligonucleotides (oligos) specific to a single chromosome offers us an opportunity to establish chromosome-specific probes in plants. However, never before has whole chromosome painting been performed in rice. RESULTS: We developed a pooled chromosome 9-specific probe in rice, which contains 25,000 oligos based on the genome sequence of a japonica rice (Oryza sativa L., AA, 2n = 2× = 24). Chromosome 9 was easily identified in both japonica and indica rice using this chromosome 9-painting probe. The probe was also successfully used to identify and characterize chromosome 9 in additional lines of O. sativa, a translocation line, two new aneuploids associated with chromosome 9 and a wild rice (Oryza eichingeri A. Peter, CC, 2n = 2× = 24). CONCLUSION: The study reveals that a pool of oligos specific to a chromosome is a useful tool for chromosome painting in rice.


Assuntos
Coloração Cromossômica/métodos , Cromossomos de Plantas/genética , Oryza/genética , Aneuploidia , Aberrações Cromossômicas , Cromossomos de Plantas/ultraestrutura , Genoma de Planta/genética , Hibridização in Situ Fluorescente , Sondas de Oligonucleotídeos/genética , Translocação Genética/genética
9.
PLoS One ; 13(4): e0195710, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29672536

RESUMO

A quantitative pachytene chromosome map of rice (Oryza sativa L.) was developed using imaging methods. The map depicts not only distribution patterns of chromomeres specific to pachytene chromosomes, but also the higher order information of chromosomal structures, such as heterochromatin (condensed regions), euchromatin (decondensed regions), the primary constrictions (centromeres), and the secondary constriction (nucleolar organizing regions, NOR). These features were image analyzed and quantitatively mapped onto the map by Chromosome Image Analyzing System ver. 4.0 (CHIAS IV). Correlation between H3K9me2, an epigenetic marker and formation and/or maintenance of heterochromatin, thus was, clearly visualized. Then the pachytene chromosome map was unified with the existing somatic chromosome and linkage maps by physically mapping common DNA markers among them, such as a rice A genome specific tandem repeat sequence (TrsA), 5S and 45S ribosomal RNA genes, five bacterial artificial chromosome (BAC) clones, four P1 bacteriophage artificial chromosome (PAC) clones using multicolor fluorescence in situ hybridization (FISH). Detailed comparison between the locations of the DNA probes on the pachytene chromosomes using multicolor FISH, and the linkage map enabled determination of the chromosome number and short/long arms of individual pachytene chromosomes using the chromosome number and arm assignment designated for the linkage map. As a result, the quantitative pachytene chromosome map was unified with two other major rice chromosome maps representing somatic prometaphase chromosomes and genetic linkages. In conclusion, the unification of the three rice maps serves as an indispensable basic information, not only for an in-depth comparison between genetic and chromosomal data, but also for practical breeding programs.


Assuntos
Mapeamento Cromossômico/métodos , Cromossomos de Plantas/genética , Oryza/genética , Cromossomos de Plantas/ultraestrutura , DNA de Plantas/genética , Ligação Genética , Heterocromatina/genética , Heterocromatina/metabolismo , Histonas/metabolismo , Hibridização in Situ Fluorescente , Oryza/metabolismo , Oryza/ultraestrutura , Estágio Paquíteno/genética , Mapeamento Físico do Cromossomo/métodos , Proteínas de Plantas/metabolismo , Transcrição Genética
10.
Genome ; 61(5): 311-322, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29447453

RESUMO

Plant glutathione S-transferases (GSTs) are integral to normal plant metabolism and biotic and abiotic stress tolerance. The GST gene family has been characterized in diverse plant species using molecular biology and bioinformatics approaches. In the current study, in silico analysis identified 44 GSTs in Vigna radiata. Of the total 44 GSTs identified, chromosomal locations of 31 GSTs were confirmed. The pI value of GST proteins ranged from 5.10 to 9.40. The predicted molecular weights ranged from 13.12 to 50 kDa. Subcellular localization analysis revealed that all GSTs were predominantly localized in the cytoplasm. The active site amino acids were confirmed to be serine in tau, phi, theta, zeta, and TCHQD; cysteine in lambda, DHAR, and omega; and tyrosine in EF1G. The gene architecture conformed to the two-exon/one-intron and three-exon/two-intron organization in the case of tau and phi classes, respectively. MEME analysis identified 10 significantly conserved motifs with the width of 8-50 amino acids. The motifs identified were either specific to a specific GST class or were shared by multiple GST classes. The results of the current study will be of potential importance in the characterization of the GST gene family in V. radiata, an economically important leguminous crop.


Assuntos
Cromossomos de Plantas/química , Regulação da Expressão Gênica de Plantas , Glutationa Transferase/genética , Proteínas de Plantas/genética , Vigna/genética , Sequência de Aminoácidos , Domínio Catalítico , Mapeamento Cromossômico , Cromossomos de Plantas/ultraestrutura , Biologia Computacional/métodos , Éxons , Ontologia Genética , Glutationa Transferase/metabolismo , Íntrons , Isoenzimas/genética , Isoenzimas/metabolismo , Anotação de Sequência Molecular , Peso Molecular , Filogenia , Proteínas de Plantas/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Vigna/classificação , Vigna/enzimologia
11.
Plant Cell Rep ; 37(1): 11-16, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29032424

RESUMO

DNA methylation and histone modifications are epigenetic changes on a DNA molecule that alter the three-dimensional (3D) structure locally as well as globally, impacting chromatin looping and packaging on a larger scale. Epigenetic marks thus inform higher-order chromosome organization and placement in the nucleus. Conventional epigenetic marks are joined by chromatin modifiers like cohesins, condensins and membrane-anchoring complexes to support particularly 3D chromosome organization. The most popular consequences of epigenetic modifications are gene expression changes, but chromatin modifications have implications beyond this, particularly in actively dividing cells and during sexual reproduction. In this opinion paper, we will focus on epigenetic mechanisms and chromatin modifications during meiosis as part of plant sexual reproduction where 3D management of chromosomes and re-organization of chromatin are defining features and prime tasks in reproductive cells, not limited to modulating gene expression. Meiotic chromosome organization, pairing and synapsis of homologous chromosomes as well as distribution of meiotic double-strand breaks and resulting crossovers are presumably highly influenced by epigenetic mechanisms. Special mobile small RNAs have been described in anthers, where these so-called phasiRNAs seem to direct DNA methylation in meiotic cells. Intriguingly, many of the mentioned developmental processes make use of epigenetic changes and small RNAs in a manner other than gene expression changes. Widening our approaches and opening our mind to thinking three-dimensionally regarding epigenetics in plant development holds high promise for new discoveries and could give us a boost for further knowledge.


Assuntos
Cromatina/metabolismo , Regulação da Expressão Gênica de Plantas , Plantas/genética , Cromatina/química , Cromatina/genética , Cromossomos de Plantas/ultraestrutura , Epigênese Genética , Histonas , Meiose , Células Vegetais/fisiologia , Desenvolvimento Vegetal/genética , Polinização , Processamento de Proteína Pós-Traducional , RNA de Plantas/genética
12.
Cytogenet Genome Res ; 153(2): 105-116, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29232688

RESUMO

In wild plant populations, chromosome rearrangements lead to the wide intraspecific polymorphisms in the abundance and patterns of highly repetitive DNA. However, despite the large amount of accumulated data, the impact of the complex repetitive DNA fraction on genome reorganization and functioning and the mechanisms balancing and maintaining the structural integrity of the genome are not fully understood. Homologous recombination is thought to play a key role in both genome reshuffling and stabilization, while the contribution of nonhomologous recombination seems to be undervalued. Here, tandem repeat patterns and dynamics during pollen mother cell development were addressed, with a focus on the meiotic recombination that determines chromosome/genome repatterning and stabilization under cross-pollination and artificial hybridization in wild goatgrass, Aegilops speltoides. Native plants from contrasting allopatric populations and artificially created intraspecific hybrids were investigated using a FISH approach. Cytogenetic analysis uncovered a wide spectrum of genotype- and cell-specific chromosomal rearrangements, suggesting intensive repatterning of both parental and hybrid genomes. The data obtained provide evidence that repetitive elements serve as overabundant and ubiquitous resources for maintaining chromosome architecture/genome integrity through homologous and nonhomologous recombination at the intraorganismal level, and genotype-specific repatterning underlies intrapopulation polymorphisms and intraspecific diversification in the wild.


Assuntos
Cromossomos de Plantas/genética , DNA de Plantas/genética , Poaceae/genética , Sequências de Repetição em Tandem/genética , Cromossomos de Plantas/ultraestrutura , Cruzamentos Genéticos , Genoma de Planta , Genótipo , Recombinação Homóloga , Hibridização Genética , Hibridização in Situ Fluorescente , Meiose , Metagenômica , Polimorfismo Genético , Turquia
13.
BMC Plant Biol ; 17(1): 153, 2017 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-28899358

RESUMO

BACKGROUND: Most data concerning chromosome organization have been acquired from studies of a small number of model organisms, the majority of which are mammals. In plants with large genomes, the chromosomes are significantly larger than the animal chromosomes that have been studied to date, and it is possible that chromosome condensation in such plants was modified during evolution. Here, we analyzed chromosome condensation and decondensation processes in order to find structural mechanisms that allowed for an increase in chromosome size. RESULTS: We found that anaphase and telophase chromosomes of plants with large chromosomes (average 2C DNA content exceeded 0.8 pg per chromosome) contained chromatin-free cavities in their axial regions in contrast to well-characterized animal chromosomes, which have high chromatin density in the axial regions. Similar to animal chromosomes, two intermediates of chromatin folding were visible inside condensing (during prophase) and decondensing (during telophase) chromosomes of Nigella damascena: approximately 150 nm chromonemata and approximately 300 nm fibers. The spatial folding of the latter fibers occurs in a fundamentally different way than in animal chromosomes, which leads to the formation of chromosomes with axial chromatin-free cavities. CONCLUSION: Different compaction topology, but not the number of compaction levels, allowed for the evolution of increased chromosome size in plants.


Assuntos
Cromossomos de Plantas/ultraestrutura , Nigella damascena/genética , Nigella damascena/ultraestrutura , Cromatina/ultraestrutura , Montagem e Desmontagem da Cromatina , Estruturas Cromossômicas , Cromossomos de Plantas/fisiologia , DNA de Plantas , Tamanho do Genoma , Genoma de Planta , Mitose
14.
Cytogenet Genome Res ; 152(3): 158-165, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28810257

RESUMO

Whole-genome shotgun reads were analyzed to determine the repeat sequence composition in the genome of black mustard, Brassica nigra (L.) Koch. The analysis showed that satellite DNA sequences are very abundant in the black mustard genome. The distribution pattern of 7 new tandem repeats (BnSAT13, BnSAT28, BnSAT68, BnSAT76, BnSAT114, BnSAT180, and BnSAT200) on black mustard chromosomes was visualized using fluorescence in situ hybridization (FISH). The FISH signals of BnSAT13 and BnSAT76 provided useful cytogenetic markers; their position and fluorescence intensity allowed for unambiguous identification of all 8 somatic metaphase chromosomes. A karyotype showing the location and fluorescence intensity of these tandem repeat sequences together with the position of rDNAs and centromeric retrotransposons of Brassica (CRB) was constructed. The establishment of the FISH-based karyotype in B. nigra provides valuable information that can be used in detailed analyses of B. nigra accessions and derived allopolyploid Brassica species containing the B genome.


Assuntos
DNA de Plantas/genética , Hibridização in Situ Fluorescente/métodos , Cariótipo , Mostardeira/genética , Sequências de Repetição em Tandem/genética , Centrômero , Cromossomos de Plantas/genética , Cromossomos de Plantas/ultraestrutura , DNA Ribossômico/genética , DNA Satélite/genética , Marcadores Genéticos , Genoma de Planta , Metáfase , Microscopia de Fluorescência , Retroelementos
15.
PLoS One ; 12(8): e0183341, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28854212

RESUMO

Mitotic prophase chromosome condensation plays an essential role in nuclear division being therefore regulated by highly conserved mechanisms. However, degrees of chromatin condensation in prophase-prometaphase cells may vary along the chromosomes resulting in specific condensation patterns. We examined different condensation patterns (CPs) of prophase and prometaphase chromosomes and investigated their relationship with genome size and distribution of histone H4 acetylated at lysine 5 (H4K5ac) in 17 plant species. Our results showed that most species with small genomes (2C < 5 pg) (Arachis pusilla, Bixa orellana, Costus spiralis, Eleutherine bulbosa, Indigofera campestris, Phaseolus lunatus, P. vulgaris, Poncirus trifoliata, and Solanum lycopersicum) displayed prophase chromosomes with late condensing terminal regions that were highly enriched in H4K5ac, and early condensing regions with apparently non-acetylated proximal chromatin. The species with large genomes (Allium cepa, Callisia repens, Araucaria angustifolia and Nothoscordum pulchellum) displayed uniformly condensed and acetylated prophase/prometaphase chromosomes. Three species with small genomes (Eleocharis geniculata, Rhynchospora pubera, and R. tenuis) displayed CP and H4K5ac labeling patterns similar to species with large genomes, whereas a forth species (Emilia sonchifolia) exhibited a gradual chromosome labeling, being more acetylated in the terminal regions and less acetylated in the proximal ones. The nucleolus organizer chromatin was the only chromosomal region that in prometaphase or metaphase could be hyperacetylated, hypoacetylated or non-acetylated, depending on the species. Our data indicate that the CP of a plant chromosome complement is influenced but not exclusively determined by nuclear and chromosomal DNA contents, whereas the CP of individual chromosomes is clearly correlated with H4K5ac distribution.


Assuntos
Cromossomos de Plantas/metabolismo , Genoma de Planta , Histonas/metabolismo , Proteínas de Plantas/metabolismo , Plantas/genética , Processamento de Proteína Pós-Traducional , Acetilação , Montagem e Desmontagem da Cromatina , Cromossomos de Plantas/ultraestrutura , Tamanho do Genoma , Heterocromatina/metabolismo , Heterocromatina/ultraestrutura , Histonas/genética , Cariotipagem , Proteínas de Plantas/genética , Plantas/metabolismo , Prometáfase , Prófase , Especificidade da Espécie
16.
Genome ; 60(3): 216-227, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28156137

RESUMO

Fluorescence in situ hybridization (FISH) was used to determine the physical location of the (AC)10 microsatellite in metaphase chromosomes of six diploid species (AA or CC genomes), two tetraploid species (AACC genome), and five cultivars of two hexaploid species (AACCDD genome) of the genus Avena, a genus in which genomic relationships remain obscure. A preferential distribution of the (AC)10 microsatellite in the pericentromeric and interstitial regions was seen in both the A- and D-genome chromosomes, while in C-genome chromosomes the majority of signals were located in the pericentromeric heterochromatic regions. New large chromosome rearrangements were detected in two polyploid species: an intergenomic translocation involving chromosomes 17AL and 21DS in Avena sativa 'Araceli' and another involving chromosomes 4CL and 21DS in the analyzed cultivars of Avena byzantina. The latter 4CL-21DS intergenomic translocation differentiates clearly between A. sativa and A. byzantina. Searches for common hybridization patterns on the chromosomes of different species revealed chromosome 10A of Avena magna and 21D of hexaploid oats to be very similar in terms of the distribution of 45S and Am1 sequences. This suggests a common origin for these chromosomes and supports a CCDD rather than an AACC genomic designation for this species.


Assuntos
Avena/genética , Cromossomos de Plantas/genética , Rearranjo Gênico , Repetições de Microssatélites , Sequências Repetitivas de Ácido Nucleico , Cromossomos de Plantas/ultraestrutura , DNA de Plantas/genética , DNA Ribossômico/genética , Diploide , Genoma de Planta , Hibridização in Situ Fluorescente , Cariotipagem , Mitose , Hibridização de Ácido Nucleico , Poliploidia , Temperatura , Translocação Genética
17.
PLoS One ; 12(1): e0170618, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28118403

RESUMO

Brachypodium distachyon (Brachypodium) is now intensively utilized as a model grass species in various biological studies. Its favorable cytological features create a unique foundation for a convenient system in mutagenesis, thereby potentially enabling the 'hot spots' and 'cold spots' of DNA damage in its genome to be analyzed. The aim of this study was to analyze the involvement of 5S rDNA, 25S rDNA, the Arabidopsis-type (TTTAGGG)n telomeric sequence and the Brachypodium-originated centromeric BAC clone CB33J12 in the micronuclei formation in Brachypodium root tip cells that were subjected to the chemical clastogenic agent maleic hydrazide (MH). To the best of our knowledge, this is the first use of a multicolor fluorescence in situ hybridization (mFISH) with four different DNA probes being used simultaneously to study plant mutagenesis. A quantitative analysis allowed ten types of micronuclei, which were characterized by the presence or absence of specific FISH signal(s), to be distinguished, thus enabling some specific rules governing the composition of the MH-induced micronuclei with the majority of them originating from the terminal regions of chromosomes, to be identified. The application of rDNA sequences as probes showed that 5S rDNA-bearing chromosomes are involved in micronuclei formation more frequently than the 25S rDNA-bearing chromosomes. These findings demonstrate the promising potential of Brachypodium to be a useful model organism to analyze the effects of various genotoxic agents on the plant nuclear genome stability, especially when the complex FISH-based and chromosome-specific approaches such as chromosome barcoding and chromosome painting will be applied in future studies.


Assuntos
Brachypodium/genética , Coloração Cromossômica/métodos , Cromossomos de Plantas/efeitos dos fármacos , Hidrazida Maleica/farmacologia , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Testes para Micronúcleos/métodos , Mutagênese , Mutagênicos/farmacologia , Brachypodium/efeitos dos fármacos , Centrômero/efeitos dos fármacos , Centrômero/ultraestrutura , Cromossomos Artificiais Bacterianos/efeitos dos fármacos , Cromossomos de Plantas/ultraestrutura , Sondas de DNA , DNA Ribossômico/genética , Genoma de Planta , Germinação , Interfase , Mitose , Raízes de Plantas , RNA de Plantas/biossíntese , RNA de Plantas/genética , Sementes/efeitos dos fármacos , Telômero/efeitos dos fármacos , Telômero/ultraestrutura
18.
Cytogenet Genome Res ; 153(4): 223-231, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29439256

RESUMO

Sacred lotus is a basal eudicot plant that has been cultivated in Asia for over 7,000 years for its agricultural, ornamental, religious, and medicinal importance. A notable characteristic of lotus is the seed longevity. Extensive endeavors have been devoted to dissect its genome assembly, including the variety China Antique, which germinated from a 1,300-year-old seed. Here, cytogenetic markers representing the 10 largest megascaffolds, which constitute approximately 70% of the lotus genome assembly, were developed. These 10 megascaffolds were then anchored to the corresponding lotus chromosomes by fluorescence in situ hybridization using these cytogenetic markers, and a set of chromosome-specific cytogenetic markers that could unambiguously identify each of the 8 chromosomes was generated. Karyotyping was conducted, and a nomenclature based on chromosomal length was established for the 8 chromosomes of China Antique. Comparative karyotyping revealed relatively conserved chromosomal structures between China Antique and 3 modern cultivars. Interestingly, significant variations in the copy number of 45S rDNA were detected between China Antique and modern cultivars. Our results provide a comprehensive view on the chromosomal structure of sacred lotus and will facilitate further studies and the genome assembly of lotus.


Assuntos
Cromossomos de Plantas , Nelumbo/genética , China , Cromossomos de Plantas/classificação , Cromossomos de Plantas/genética , Cromossomos de Plantas/ultraestrutura , DNA de Plantas/genética , DNA Ribossômico/genética , Dosagem de Genes , Genes de Plantas , Marcadores Genéticos , Hibridização in Situ Fluorescente , Cariotipagem/métodos , Nelumbo/citologia , Melhoramento Vegetal , RNA de Plantas/genética , RNA Ribossômico/genética , Especificidade da Espécie , Terminologia como Assunto , Tailândia
19.
Tsitol Genet ; 50(1): 68-79, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27266187

RESUMO

A review article on B chromosomes (Bs) in angiosperms is documented considering occurrence, morphology, polymorphic B forms, divisional phase heterogeneity, chromatin organization and gene content, sequence composition, origin, evolutionary aspects and significant role on host with an objective to foresee the evolutionary perspectives as it still remains an enigma. Irrespective of the origin of Bs, it seems that they have attained the following modifications, namely, insertion of centromeric and telomeric sequences, structural reorganization and procuring mitotic and meiotic drives but shows genetic inertness and present in the host as selfish DNA. In the context, few questions are raised. Further, scientific quest may unravel the unexplored information about Bs to ascertain its evolutionary perspectives, if any.


Assuntos
Cromossomos de Plantas/ultraestrutura , Genoma de Planta , Magnoliopsida/ultraestrutura , Meiose , Cromatina/genética , Cromossomos de Plantas/genética , DNA de Plantas , Epigênese Genética , Evolução Molecular , Magnoliopsida/genética , Polimorfismo Genético , Especificidade da Espécie
20.
Sci Rep ; 6: 27161, 2016 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-27255216

RESUMO

Two chromosomal structures, known as monocentric and holocentric chromosomes, have evolved in eukaryotes. Acentric fragments of monocentric chromosomes are unequally distributed to daughter cells and/or lost, while holocentric fragments are inherited normally. In monocentric species, unequal distribution should generate chimeras of cells with different nuclear DNA content. We investigated whether such differences in monocentric species are detectable by flow cytometry (FCM) as (i) a decreased nuclear DNA content and (ii) an increased coefficient of variance (CV) of the G1 peak after gamma radiation-induced fragmentation. We compared 13 monocentric and 9 holocentric plant species. Unexpectedly, monocentrics and holocentrics did not differ with respect to parameters (i) and (ii) in their response to gamma irradiation. However, we found that the proportion of G2 nuclei was highly elevated in monocentrics after irradiation, while holocentrics were negligibly affected. Therefore, we hypothesize that DNA-damaging agents induce cell cycle arrest leading to endopolyploidy only in monocentric and not (or to much lesser extent) in holocentric plants. While current microscope-dependent methods for holocentrism detection are unreliable for small and numerous chromosomes, which are common in holocentrics, FCM can use somatic nuclei. Thus, FCM may be a rapid and reliable method of high-throughput screening for holocentric candidates across plant phylogeny.


Assuntos
Núcleo Celular/ultraestrutura , Cromossomos de Plantas/ultraestrutura , Plantas/genética , Núcleo Celular/genética , Núcleo Celular/efeitos da radiação , Cromossomos de Plantas/efeitos da radiação , Citometria de Fluxo , Microscopia , Filogenia , Plantas/efeitos da radiação , Plantas/ultraestrutura
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