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1.
Mol Genet Genomics ; 295(1): 47-54, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31420737

RESUMO

Stem trichomes and seed fibers originate from epidermal cells and partially share a regulatory pathway at the molecular level. In Gossypium barbadense, two insertions of a Ty1 long-terminal repeat-retrotransposon [transposable element TE1 and TE2] in a homeodomain-leucine zipper gene (HD1) result in glabrous stems. The primers used to identify the TE insertions in G. barbadense were applied to screen for the same events in 81 modern G. hirsutum varieties and 31 wild races. Three wild races were found carrying the same TEs as G. barbadense. However, the TE insertions in two of these wild races occurred at different sites (4th exon), therefore, named TE3, while the TE in the other wild race occurred at the same site as TE2. An RNA sequencing and qRT-PCR analysis indicated that the loss of HD1 function was caused by the TE insertion. Genetic mapping revealed a strong association between glabrous stems and TE3 insertions, confirming that HD1 is a critical gene for stem trichome initiation in G. hirsutum, as in G. barbadense. Using the long-terminal repeat sequence as a query to search against the Texas Marker-1 reference genome sequence, we found that the TE occurred after tetraploid cotton formation and evolved at different rates in G. hirsutum and G. barbadense. Interestingly, at least three independent insertion events of the same retrotransposon occurred preferentially in the A sub-genome's HD1 gene, but not in the D sub-genome of G. hirsutum or G. barbadense, suggesting that an unknown TE insertion mechanism and resultant gene function changes may have hastened cotton speciation.


Assuntos
Proteínas de Arabidopsis/genética , Gossypium/genética , Histona Desacetilases/genética , Mutagênese Insercional/genética , Caules de Planta/genética , Retroelementos/genética , Sequências Repetidas Terminais/genética , Tricomas/genética , Mapeamento Cromossômico/métodos , Regulação da Expressão Gênica de Plantas/genética , Genoma de Planta/genética , Zíper de Leucina/genética , Fenótipo , Filogenia , Tetraploidia
2.
Pest Manag Sci ; 76(1): 95-102, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31251461

RESUMO

BACKGROUND: Bidens subalternans (greater beggarticks) is a tetraploid and troublesome weed infesting annual crops in most tropical regions of the world. A glyphosate-resistant (GR) B. subalternans biotype was detected in a soybean field from Paraguay. A series of physiological and molecular analyses were conducted to elucidate its resistance mechanisms. RESULTS: The GR biotype had a high level of resistance (> 15-fold LD50 ), relative to a glyphosate-susceptible (GS) biotype. Shikimate accumulation was up to ten-fold greater for GS compared with GR. We found no differences in sensitivity when plants were treated and kept under lower (10/4 °C) or higher temperatures (25/20 °C). GS and GR had the same relative EPSPS gene copy number, and similar glyphosate absorption and translocation rates. Neither biotype metabolized glyphosate. A double amino acid substitution (TIPT - Thr102Ile and Pro106Thr) was found in only one EPSPS allele from one of the two EPSPS homoeologs present in tetraploid GR B. subalternans. CONCLUSION: This is the first report of a TIPT double mutation conferring high levels of glyphosate resistance in a weed species. The presence of both wild-type and TIPT mutant EPSPS on the polyploid genome of GR B. subalternans may offset a potential fitness cost, requiring additional research to confirm the absence of deleterious effects. © 2019 Society of Chemical Industry.


Assuntos
Bidens , 3-Fosfoshikimato 1-Carboxiviniltransferase , Glicina/análogos & derivados , Resistência a Herbicidas , Herbicidas , Mutação , Tetraploidia
3.
Syst Biol ; 69(1): 91-109, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31127939

RESUMO

Disentangling phylogenetic relationships proves challenging for groups that have evolved recently, especially if there is ongoing reticulation. Although they are in most cases immediately isolated from diploid relatives, sets of sibling allopolyploids often hybridize with each other, thereby increasing the complexity of an already challenging situation. Dactylorhiza (Orchidaceae: Orchidinae) is a genus much affected by allopolyploid speciation and reticulate phylogenetic relationships. Here, we use genetic variation at tens of thousands of genomic positions to unravel the convoluted evolutionary history of Dactylorhiza. We first investigate circumscription and relationships of diploid species in the genus using coalescent and maximum likelihood methods, and then group 16 allotetraploids by maximum affiliation to their putative parental diploids, implementing a method based on genotype likelihoods. The direction of hybrid crosses is inferred for each allotetraploid using information from maternally inherited plastid RADseq loci. Starting from age estimates of parental taxa, the relative ages of these allotetraploid entities are inferred by quantifying their genetic similarity to the diploids and numbers of private alleles compared with sibling allotetraploids. Whereas northwestern Europe is dominated by young allotetraploids of postglacial origins, comparatively older allotetraploids are distributed further south, where climatic conditions remained relatively stable during the Pleistocene glaciations. Our bioinformatics approach should prove effective for the study of other naturally occurring, nonmodel, polyploid plant complexes.


Assuntos
Orchidaceae/classificação , Orchidaceae/genética , Filogenia , Diploide , Europa (Continente) , Tetraploidia
4.
BMC Plant Biol ; 19(1): 471, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31694540

RESUMO

BACKGROUND: Meiosis of newly formed allopolyploids frequently encounter perturbations induced by the merging of divergent and hybridizable genomes. However, to date, the meiotic properties of allopolyploids with dysploid parental karyotypes have not been studied in detail. The allotetraploid Cucumis ×hytivus (HHCC, 2n = 38) was obtained from interspecific hybridization between C. sativus (CC, 2n = 14) and C. hystrix (HH, 2n = 24) followed by chromosome doubling. The results of this study thus offer an excellent opportunity to explore the meiotic properties of allopolyploids with dysploid parental karyotypes. RESULTS: In this report, we describe the meiotic properties of five chromosomes (C5, C7, H1, H9 and H10) and two genomes in interspecific hybrids and C. ×hytivus (the 4th and 14th inbred family) through oligo-painting and genomic in situ hybridization (GISH). We show that 1) only two translocations carrying C5-oligo signals were detected on the chromosomes C2 and C4 of one 14th individual by the karyotyping of eight 4th and 36 14th plants based on C5- and C7-oligo painting, and possible cytological evidence was observed in meiosis of the 4th generation; 2) individual chromosome have biases for homoeologous pairing and univalent formation in F1 hybrids and allotetraploids; 3) extensive H-chromosome autosyndetic pairings (e.g., H-H, 25.5% PMCs) were observed in interspecific F1 hybrid, whereas no C-chromosome autosyndetic pairings were observed (e.g. C-C); 4) the meiotic properties of two subgenomes have significant biases in allotetraploids: H-subgenome exhibits higher univalent and chromosome lagging frequencies than C-subgenome; and 5) increased meiotic stability in the S14 generation compared with the S4 generation, including synchronous meiosis behavior, reduced incidents of univalent and chromosome lagging. CONCLUSIONS: These results suggest that the meiotic behavior of two subgenomes has dramatic biases in response to interspecific hybridization and allopolyploidization, and the meiotic behavior harmony of subgenomes is a key subject of meiosis evolution in C. ×hytivus. This study helps to elucidate the meiotic properties and evolution of nascent allopolyploids with the dysploid parental karyotypes.


Assuntos
Cromossomos de Plantas , Cucumis/genética , Meiose/genética , Tetraploidia , Coloração Cromossômica , Hibridização Genética , Hibridização in Situ Fluorescente/métodos , Cariótipo , Translocação Genética
5.
Nat Commun ; 10(1): 4834, 2019 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-31645568

RESUMO

Tetraploidisation is considered a common event in the evolution of chromosomal instability (CIN) in cancer cells. The current model for how tetraploidy drives CIN in mammalian cells is that a doubling of the number of centrioles that accompany the genome doubling event leads to multipolar spindle formation and chromosome segregation errors. By exploiting the unusual scenario of mouse blastomeres, which lack centrioles until the ~64-cell stage, we show that tetraploidy can drive CIN by an entirely distinct mechanism. Tetraploid blastomeres assemble bipolar spindles dictated by microtubule organising centres, and multipolar spindles are rare. Rather, kinetochore-microtubule turnover is altered, leading to microtubule attachment defects and anaphase chromosome segregation errors. The resulting blastomeres become chromosomally unstable and exhibit a dramatic increase in whole chromosome aneuploidies. Our results thus reveal an unexpected mechanism by which tetraploidy drives CIN, in which the acquisition of chromosomally-unstable microtubule dynamics contributes to chromosome segregation errors following tetraploidisation.


Assuntos
Anáfase , Blastômeros/metabolismo , Instabilidade Cromossômica/genética , Segregação de Cromossomos , Cinetocoros/metabolismo , Microtúbulos/metabolismo , Tetraploidia , Animais , Centríolos , Embrião de Mamíferos/embriologia , Camundongos , Centro Organizador dos Microtúbulos/metabolismo , Mitose , Neoplasias/genética , Fuso Acromático
6.
Theor Appl Genet ; 132(12): 3265-3276, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31529271

RESUMO

KEY MESSAGE: Su1-Ph1, which we previously introgressed into wheat from Aegilops speltoides, is a potent suppressor of Ph1 and a valuable tool for gene introgression in tetraploid wheat. We previously introgressed Su1-Ph1, a suppressor of the wheat Ph1 gene, from Aegilops speltoides into durum wheat cv Langdon (LDN). Here, we evaluated the utility of the introgressed suppressor for inducing introgression of alien germplasm into durum wheat. We built LDN plants heterozygous for Su1-Ph1 that simultaneously contained a single LDN chromosome 5B and a single Ae. searsii chromosome 5Sse, which targeted them for recombination. We genotyped 28 BC1F1 and 84 F2 progeny with the wheat 90-K Illumina single-nucleotide polymorphism assay and detected extensive recombination between the two chromosomes, which we confirmed by non-denaturing fluorescence in situ hybridization (ND-FISH). We constructed BC1F1 and F2 genetic maps that were 65.31 and 63.71 cM long, respectively. Recombination rates between the 5B and 5Sse chromosomes were double the expected rate computed from their meiotic pairing, which we attributed to selection against aneuploid gametes. Recombination rate between 5B and 5Sse was depressed compared to that between 5B chromosomes in the proximal region of the long arm. We integrated ND-FISH signals into the genetic map and constructed a physical map, which we used to map a 172,188,453-bp Ph1 region. Despite the location of the region in a low-recombination region of the 5B chromosome, we detected three crossovers in it. Our data show that Su1-Ph1 is a valuable tool for gene introgression and gene mapping based on recombination between homoeologous chromosomes in wheat.


Assuntos
Aegilops/genética , Melhoramento Vegetal , Recombinação Genética , Triticum/genética , Mapeamento Cromossômico , Cromossomos de Plantas , Genes de Plantas , Tetraploidia
7.
Nat Commun ; 10(1): 4388, 2019 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-31558727

RESUMO

Meiosis is a conserved tenet of sexual reproduction in eukaryotes, yet this program is seemingly absent from many extant species. In the human fungal pathogen Candida albicans, mating of diploid cells generates tetraploid products that return to the diploid state via a non-meiotic process of depolyploidization known as concerted chromosome loss (CCL). Here, we report that recombination rates are more than three orders of magnitude higher during CCL than during normal mitotic growth. Furthermore, two conserved 'meiosis-specific' factors play central roles in CCL as SPO11 mediates DNA double-strand break formation while both SPO11 and REC8 regulate chromosome stability and promote inter-homolog recombination. Unexpectedly, SPO11 also promotes DNA repair and recombination during normal mitotic divisions. These results indicate that C. albicans CCL represents a 'parameiosis' that blurs the conventional boundaries between mitosis and meiosis. They also reveal parallels with depolyploidization in mammalian cells and provide potential insights into the evolution of meiosis.


Assuntos
Candida albicans/genética , Diploide , Recombinação Homóloga/genética , Meiose/genética , Tetraploidia , Candidíase/microbiologia , Cromossomos Fúngicos/genética , Dano ao DNA , Endodesoxirribonucleases/genética , Endodesoxirribonucleases/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Humanos , Mitose/genética , Recombinases Rec A/genética , Recombinases Rec A/metabolismo , Reparo de DNA por Recombinação
8.
BMC Plant Biol ; 19(1): 359, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31419945

RESUMO

BACKGROUND: The genetic and genomic basis of flowering time and biomass yield in alfalfa (Medicago sativa L.) remains poorly understood mainly due to the autopolyploid nature of the species and the lack of adequate genomic resources. We constructed linkage maps using genotyping-by-sequencing (GBS) based single dose allele (SDA) SNP and mapped alfalfa timing of flowering (TOF), spring yield (SY), and cumulative summer biomass (CSB) in a pseudo-testcross F1 population derived from a fall dormant (3010) and a non-dormant (CW 1010) cultivars. We analyzed the quantitative trait loci (QTL) to identify conserved genomic regions and detected molecular markers and potential candidate genes associated with the traits to improve alfalfa and provide genomic resources for the future studies. RESULTS: This study showed that both fall dormant and non-dormant alfalfa cultivars harbored QTL for early and late flowering, suggesting that flowering time in alfalfa is not an indicator of its fall dormancy (FD) levels. A weak phenotypic correlation between the flowering time and fall dormancy (FD) in F1 and checks also corroborated that alfalfa FD and TOF are not the predictors of one another. The relationship between flowering time and alfalfa biomass yield was not strong, but the non-dormant had relatively more SY than dormant. Therefore, selecting superior alfalfa cultivars that are non-dormant, winter-hardy, and early flowering would allow for an early spring harvest with enhanced biomass. In this study, we found 25 QTL for TOF, 17 for SY and six QTL for CSB. Three TOF related QTL were stable and four TOF QTL were detected in the corresponding genomic locations of the flowering QTL of M. truncatula, an indication of possible evolutionarily conserved regions. The potential candidate genes for the SNP sequences of QTL regions were identified for all three traits and these genes would be potential targets for further molecular studies. CONCLUSIONS: This research showed that variation in alfalfa flowering time after spring green up has no association with dormancy levels. Here we reported QTL, markers, and potential candidate genes associated with spring flowering time and biomass yield of alfalfa, which constitute valuable genomic resources for improving these traits via marker-assisted selection (MAS).


Assuntos
Biomassa , Flores/crescimento & desenvolvimento , Medicago sativa/fisiologia , Fenótipo , Locos de Características Quantitativas/genética , Tetraploidia , Flores/genética , Traços de História de Vida , Medicago sativa/genética , Medicago sativa/crescimento & desenvolvimento
9.
Plant Mol Biol ; 101(4-5): 355-371, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31401729

RESUMO

KEY MESSAGE: Protoplasts can be used for genome editing using several different CRISPR systems, either separately or simultaneously, and that the resulting mutations can be recovered in regenerated non-chimaeric plants. Protoplast transfection and regeneration systems are useful platforms for CRISPR/Cas mutagenesis and genome editing. In this study, we demonstrate the use of Cpf1 (Cas12a) and nCas9-activation-induced cytidine deaminase (nCas9-Target-AID) systems to mutagenize Nicotiana tabacum protoplasts and to regenerate plants harboring the resulting mutations. We analyzed 20 progeny plants of Cas12a-mediated phytoene desaturase (PDS) mutagenized regenerants, as well as regenerants from wild-type protoplasts, and confirmed that their genotypes were inherited in a Mendelian manner. We used a Cas9 nickase (nCas9)-cytidine deaminase to conduct C to T editing of the Ethylene receptor 1 (ETR1) gene in tobacco protoplasts and obtained edited regenerates. It is difficult to obtain homozygous edits of polyploid genomes when the editing efficiency is low. A second round of mutagenesis of partially edited regenerants (a two-step transfection protocol) allowed us to derive ETR1 fully edited regenerants without the need for sexual reproduction. We applied three different Cas systems (SaCas9, Cas12a, and nCas9-Traget AID) using either a one-step or a two-step transfection platform to obtain triply mutated and/or edited tobacco regenerants. Our results indicate that these three Cas systems can function simultaneously within a single cell.


Assuntos
Edição de Genes/métodos , Tabaco/genética , Proteínas de Bactérias/genética , Sistemas CRISPR-Cas , Francisella/genética , Homozigoto , Proteínas de Plantas/genética , Tetraploidia
10.
Am J Bot ; 106(7): 906-921, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31283844

RESUMO

PREMISE: Although polyploidy commonly occurs in angiosperms, not all polyploidization events lead to successful lineages, and environmental conditions could influence cytotype dynamics and polyploid success. Low soil nitrogen and/or phosphorus concentrations often limit ecosystem primary productivity, and changes in these nutrients might differentially favor some cytotypes over others, thereby influencing polyploid establishment. METHODS: We grew diploid, established tetraploid, and neotetraploid Chamerion angustifolium (fireweed) in a greenhouse under low and high soil nitrogen and phosphorus conditions and different competition treatments and measured plant performance (height, biomass, flower production, and root bud production) and insect damage responses. By comparing neotetraploids to established tetraploids, we were able to examine traits and responses that might directly arise from polyploidization before they are modified by natural selection and/or genetic drift. RESULTS: We found that (1) neopolyploids were the least likely to survive and flower and experienced the most herbivore damage, regardless of nutrient conditions; (2) both neo- and established tetraploids had greater biomass and root bud production under nutrient-enriched conditions, whereas diploid biomass and root bud production was not significantly affected by nutrients; and (3) intra-cytotype competition more negatively affected diploids and established tetraploids than it did neotetraploids. CONCLUSIONS: Following polyploidization, biomass and clonal growth might be more immediately affected by environmental nutrient availabilities than plant survival, flowering, and/or responses to herbivory, which could influence competitive dynamics. Specifically, polyploids might have competitive and colonizing advantages over diploids under nutrient-enriched conditions favoring their establishment, although establishment may also depend upon the density and occurrences of other related cytotypes in a population.


Assuntos
Herbivoria , Nitrogênio/metabolismo , Onagraceae/fisiologia , Fósforo/metabolismo , Tetraploidia , Animais , Biomassa , Flores/crescimento & desenvolvimento , Insetos , Raízes de Plantas/crescimento & desenvolvimento
11.
Plant Genome ; 12(2)2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31290929

RESUMO

Potato ( L.) breeders often use dihaploids, which are 2× progeny derived from 4× autotetraploid parents. Dihaploids can be used in diploid crosses to introduce new genetic material into breeding germplasm that can be integrated into tetraploid breeding through the use of unreduced gametes in 4× by 2× crosses. Dihaploid potatoes are usually produced via pollination by haploid inducer lines known as in vitro pollinators (IVP). In vitro pollinator chromosomes are selectively degraded from initially full hybrid embryos, resulting in 2× seed. During this process, somatic translocation of IVP DNA may occur. In this study, a genome-wide approach was used to identify such events and other chromosome-scale abnormalities in a population of 95 dihaploids derived from a cross between potato cultivar Superior and the haploid inducing line IVP101. Most Superior dihaploids showed translocation rates of <1% at 16,947,718 assayable sites, yet two dihaploids showed translocation rates of 1.86 and 1.60%. Allelic ratios at translocation sites suggested that most translocations occurred in individual cell lineages and were thus not present in all cells of the adult plants. Translocations were enriched in sites associated with high gene expression and H3K4 dimethylation and H4K5 acetylation, suggesting that they tend to occur in regions of open chromatin. The translocations likely result as a consequence of double-stranded break repair in the dihaploid genomes via homologous recombination during which IVP chromosomes are used as templates. Additionally, primary trisomy was observed in eight individuals. As the trisomic chromosomes were derived from Superior, meiotic nondisjunction may be common in potato.


Assuntos
Cromossomos de Plantas , Diploide , Melhoramento Vegetal , Solanum tuberosum/genética , Translocação Genética , Tetraploidia
12.
BMC Plant Biol ; 19(1): 303, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31291892

RESUMO

BACKGROUND: Polyploidy and hybridization are ubiquitous in Rubus L., a large and taxonomically challenging genus. Chinese Rubus are mainly concentrated into two major sections, the diploid Idaeobatus and the polyploid Malachobatus. However, it remains unclear to be auto- or allo- polyploid origin of polyploids in Rubus. We investigated the homoeologs and the structure of the GBSSI-1 (granule-bound starch synthase I) gene in 140 Rubus individuals representing 102 taxa in 17 (out of the total 24) subsections of 7 (total of 12) sections at different ploidy levels. RESULTS: Based on the gene structure and sequence divergence, we defined three gene variants, GBSSI-1a, GBSSI-1b, and GBSSI-1c. When compared with GBSSI-1a, both GBSSI-1b and GBSSI-1c have a shorter fourth intron, and GBSSI-1c had an additional deletion in the fifth intron. For diploids, either GBSSI-1a or GBSSI-1b was detected in 56 taxa consisting of 82 individuals from sect. Idaeobatus, while both alleles existed in R. pentagonus and R. peltatus. Both homoeologs GBSSI-1a and GBSSI-1b were identified in 39 taxa (48 individuals) of Malachobatus polyploids. They were also observed in two sect. Dalibardastrum taxa, in one sect. Chamaebatus taxon, and in three taxa from sect. Cylactis. Interestingly, all three homoeologs were observed in the three tetraploid taxa. Phylogenetic trees and networks suggested two clades (I and II), corresponding to GBSSI-1a, and GBSSI-1b/1c sequences, respectively. GBSSI-1 homoeologs from the same polyploid individual were resolved in different well-supported clades, and some of these homoelogs were more closely related to homoelogs in other species than they were to each other. This implied that the homoeologs of these polyploids were donated by different ancestral taxa, indicating their allopolyploid origin. Two kinds of diploids hybridized to form most allotetraploid species. The early-divergent diploid species with GBSSI-1a or -1b emerged before polyploid formation in the evolutionary history of Rubus. CONCLUSION: This study provided new insights into allopolyploid origin and evolution from diploid to polyploid within the genus Rubus at the molecular phylogenetic level, consistent with the taxonomic treatment by Yü et al. and Lu.


Assuntos
Rubus/genética , Sintase do Amido/genética , Núcleo Celular/enzimologia , Diploide , Evolução Molecular , Hibridização Genética , Filogenia , Poliploidia , Rubus/enzimologia , Tetraploidia
13.
Theor Appl Genet ; 132(11): 3009-3022, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31317234

RESUMO

Powdery mildew is a severe disease in wheat. In barley, durable resistance exists, based on non-functionality of the Mlo gene. As a model to analyse the effects of mutagenesis in the homoeologous Mlo genes of wheat, we developed mlo-based powdery mildew resistance in tetraploid durum wheat. To obtain Mlo mutations, we screened a TILLING population developed in tetraploid wheat "Kronos" for which the captured exome sequence of  > 1500 lines is available. This resulted in 23 mutants for Mlo-A1 and 26 non-redundant mutants for Mlo-B1. Two Mlo-A1 and four Mlo-B1 mutants were crossed to obtain eight F2 mutant lines that showed a range of phenotypes from susceptibility to full resistance. Pot experiments under semi-field conditions confirmed the resistance levels for six of the mutants without any signs of adverse pleiotropic effects. Resistance ranking was similar across six powdery mildew isolates, indicating no isolate specificity of the mlo-based resistance. The effect of mutations in the Mlo-B1 gene was stronger than in the Mlo-A1 gene, probably reflecting differences in wild-type Mlo gene expression levels. Strong partial resistance effects were observed with single mlo-B1 mutations hence, revealing a dosage effect of mlo mutant alleles. Two of the four mlo-B1 mutations (W163* and P335L) were very strong; however, the highest combined effect was observed with the MloA-P335S/MloB-P335L combination, suggesting that non-functional, but full-length Mlo proteins might have the strongest effect compared with nonsense mutations. Our results show that mlo-based resistance might offer possibilities to introduce durable protection in tetraploid wheat against powdery mildew.


Assuntos
Ascomicetos/patogenicidade , Resistência à Doença/genética , Doenças das Plantas/genética , Tetraploidia , Triticum/genética , Alelos , Genes de Plantas , Fenótipo , Doenças das Plantas/microbiologia , Triticum/microbiologia
14.
Oncogene ; 38(33): 6083-6094, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31270395

RESUMO

Oncogenesis is considered to result from chromosomal instability, in addition to oncogene and tumor-suppressor alterations. Intermediate to aneuploidy and chromosomal instability, genome doubling is a frequent event in tumor development but the mechanisms driving tetraploidization and its impact remain unexplored. Cell fusion, one of the pathways to tetraploidy, is a physiological process involved in mesenchymal cell differentiation. Besides simple genome doubling, cell fusion results in the merging of two different genomes that can be destabilized upon proliferation. By testing whether cell fusion is involved in mesenchymal oncogenesis, we provide evidence that it induces genomic instability and mediates tumor initiation. After a latency period, the tumor emerges with the cells most suited for its development. Furthermore, hybrid tumor genomes were stabilized after this selection process and were very close to those of human pleomorphic mesenchymal tumors. Thus genome restructuring triggered by cell fusion may account for the chromosomal instability involved in oncogenesis.


Assuntos
Aneuploidia , Transformação Celular Neoplásica/genética , Instabilidade Cromossômica/fisiologia , Células Híbridas/citologia , Células Híbridas/metabolismo , Neoplasias/genética , Animais , Fusão Celular , Células Cultivadas , Instabilidade Genômica , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos Transgênicos , Neoplasias/patologia , Tetraploidia
15.
Am J Bot ; 106(8): 1116-1125, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31334845

RESUMO

PREMISE: Although autopolyploidy is common among dominant Great Plains grasses, the distribution of cytotypes within a given species is typically poorly understood. This study aims to establish the geographic distribution of cytotypes within buffalograss (Buchloë dactyloides) and to assess whether individual cytotypes have differing ecological tolerances. METHODS: A range-wide set of 578 B. dactyloides individuals was obtained through field collecting and sampling from herbarium specimens. The cytotype of each sample was estimated by determining allele numbers at 13 simple sequence repeat loci, a strategy that was assessed by comparing estimated to known cytotype in 79 chromosome-counted samples. Ecological differentiation between the dominant tetraploid and hexaploid cytotypes was assessed with analyses of macroclimatic variables. RESULTS: Simple sequence repeat variation accurately estimated cytotype in 89% of samples from which a chromosome count had been obtained. Applying this approach to samples of unknown ploidy established that diploids and pentaploids are rare, with the common tetraploid and hexaploid cytotypes generally occurring in sites to the north/west (tetraploid) or south/east (hexaploid) portions of the species range. Both MANOVA and niche modeling approaches identified significant but subtle differences in macroclimatic conditions at the set of locations occupied by these two dominant cytotypes. CONCLUSIONS: Incorporating chromosome count vouchers and cytotype-estimated herbarium records allowed us to perform the largest study of cytotype niche differentiation to date. Buffalograss cytotypes differ greatly in frequency, the common tetraploid and hexaploid cytotypes are non-randomly distributed, and these two cytotypes are subtly ecologically differentiated.


Assuntos
Diploide , Poliploidia , Humanos , Ploidias , Poaceae , Tetraploidia
16.
Theor Appl Genet ; 132(10): 2881-2898, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31312850

RESUMO

KEY MESSAGE: Using COS markers, the study reveals homeologous relationships between tetraploid Agropyron cristatum and bread wheat to support alien introgression breeding of wheat. Crested wheatgrass (Agropyron cristatum L. Gaertn.) is a wild relative of wheat that possesses many genes that are potentially useful in wheat improvement. The species comprises a complex of diploid, tetraploid and hexaploid forms. In this study, wheat-A. cristatum chromosome, telosome and translocation lines were used to characterize syntenic relationships between tetraploid A. cristatum and bread wheat. Prior to mapping COS markers, the cytogenetic stock lines were characterized for fertility and by FISH and GISH for karyotype stability. Out of 328 COS markers selected for the study, 279 consistently amplified products in tetraploid A. cristatum, and, out of these, 139 were polymorphic between tetraploid crested wheatgrass and wheat. Sixty-nine markers were found to be suitable for the detection of tetraploid A. cristatum chromosomes 1P-6P in wheat, ranging from 6 to 17 markers per chromosome. BLASTn of the source ESTs resulted in significant hits for 67 markers on the wheat pseudomolecules. Generally, COS markers of the same homeologous group were detected on similar arms in both Agropyron and wheat. However, some intragenomic duplications and chromosome rearrangements were detected in tetraploid A. cristatum. These results provide new insights into the structure and evolution of the tetraploid A. cristatum genome and will facilitate the exploitation of the wild species for introgression breeding of bread wheat.


Assuntos
Agropyron/genética , Pão/análise , Marcadores Genéticos , Genoma de Planta/genética , Hibridização Genética , Tetraploidia , Triticum/genética , Agropyron/crescimento & desenvolvimento , Mapeamento Cromossômico , Cromossomos de Plantas , Genótipo , Translocação Genética , Triticum/crescimento & desenvolvimento
17.
Genes (Basel) ; 10(6)2019 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-31234429

RESUMO

Class III peroxidases (PODs), commonly known as secretable class III plant peroxidases, are plant-specific enzymes that play critical roles in not only plant growth and development but also the responses to biotic and abiotic stress. In this study, we identified 198 nonredundant POD genes, designated GhPODs, with 180 PODs being predicted to secrete into apoplast. These POD genes were divided into 10 sub-groups based on their phylogenetic relationships. We performed systematic bioinformatic analysis of the POD genes, including analysis of gene structures, phylogenetic relationships, and gene expression profiles. The GhPODs are unevenly distributed on both upland cotton sub-genome A and D chromosomes. Additionally, these genes have undergone 15 segmental and 12 tandem duplication events, indicating that both segmental and tandem duplication contributed to the expansion of the POD gene family in upland cotton. Ka/Ks analysis suggested that most duplicated GhPODs experienced negative selection, with limited functional divergence during the duplication events. High-throughput RNA-seq data indicated that most highly expressed genes might play significant roles in root, stem, leaf, and fiber development. Under K or P deficiency conditions, PODs showed different expression patterns in cotton root and leaf. This study provides useful information for further functional analysis of the POD gene family in upland cotton.


Assuntos
Gossypium/genética , Peroxidases/genética , Filogenia , Proteínas de Plantas/genética , Sequência de Aminoácidos/genética , Cromossomos de Plantas/genética , Sequência Conservada/genética , Duplicação Gênica/genética , Regulação da Expressão Gênica de Plantas , Genoma de Planta/genética , Gossypium/enzimologia , Família Multigênica/genética , Estresse Fisiológico/genética , Tetraploidia
18.
Sheng Wu Gong Cheng Xue Bao ; 35(5): 910-918, 2019 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-31223009

RESUMO

Parthenogenetic embryonic stem cells (pESCs) derived from bi-maternal genomes do not have competency of tetraploid complementation, due to lacking of paternal imprinting genes. To make pESCs possess fully development potentials and similar pluripotency to zygote-derived ESCs, we knocked out one allelic gene of the two essential maternal imprinting genes (H19 and IG) in their differentially methylated regions (DMR) via CRISPR/Cas9 system and obtained double knock out (DKO) pESCs. Maternal pESCs had similar morphology, expression levels of pluripotent makers and in vitro neural differentiation potentials to zygotes-derived ESCs. Besides that, DKO pESCs could contribute to full-term fetuses through tetraploid complementation, proving that they held fully development potentials. Derivation of DKO pESCs provided a type of major histocompatibility complex (MHC) matched pluripotent stem cells, which would benefit research in regenerative medicine.


Assuntos
Células-Tronco Embrionárias , Partenogênese , Células-Tronco Pluripotentes , Tetraploidia , Animais , Técnicas de Inativação de Genes , Impressão Genômica , Camundongos , Medicina Regenerativa
19.
BMC Genomics ; 20(1): 514, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31226927

RESUMO

BACKGROUND: Polyploidization, pervasive among higher plant species, enhances adaptation to water deficit, but the physiological and molecular advantages need to be investigated widely. Long non-coding RNAs (lncRNAs) are involved in drought tolerance in various crops. RESULTS: Herein, we demonstrate that tetraploidy potentiates tolerance to drought stress in cassava (Manihot esculenta Crantz). Autotetraploidy reduces transpiration by lesser extent increasing of stomatal density, smaller stomatal aperture size, or greater stomatal closure, and reducing accumulation of H2O2 under drought stress. Transcriptome analysis of autotetraploid samples revealed down-regulation of genes involved in photosynthesis under drought stress, and less down-regulation of subtilisin-like proteases involved in increasing stomatal density. UDP-glucosyltransferases were increased more or reduced less in dehydrated leaves of autotetraploids compared with controls. Strand-specific RNA-seq data (validated by quantitative real time PCR) identified 2372 lncRNAs, and 86 autotetraploid-specific lncRNAs were differentially expressed in stressed leaves. The co-expressed network analysis indicated that LNC_001148 and LNC_000160 in autotetraploid dehydrated leaves regulated six genes encoding subtilisin-like protease above mentioned, thereby result in increasing the stomatal density to a lesser extent in autotetraploid cassava. Trans-regulatory network analysis suggested that autotetraploid-specific differentially expressed lncRNAs were associated with galactose metabolism, pentose phosphate pathway and brassinosteroid biosynthesis, etc. CONCLUSION: Tetraploidy potentiates tolerance to drought stress in cassava, and LNC_001148 and LNC_000160 mediate drought tolerance by regulating stomatal density in autotetraploid cassava.


Assuntos
Aclimatação/genética , Manihot/genética , RNA Longo não Codificante/fisiologia , RNA de Plantas/fisiologia , Secas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Manihot/fisiologia , Fotossíntese/genética , Estômatos de Plantas/genética , Estômatos de Plantas/fisiologia , Estresse Fisiológico , Tetraploidia
20.
Am J Bot ; 106(7): 984-995, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31188481

RESUMO

PREMISE: When two populations of related cytotypes grow in sympatry, the rarer cytotype tends to be excluded due to a frequency-dependent mating disadvantage. Evolutionary models predict that polyploids, which are typically the rarer cytotype upon first formation, should have higher relative fitness and/or higher selfing rates to establish and then coexist with diploid parents. METHODS: Performance during early recruitment was compared among three co-occurring rupicolous fern species: the allotetraploid Cheilanthes tinaei and its diploid ancestors, C. hispanica and C. maderensis. In culture experiments, fresh spores and samples of soil spore banks were tested for variation among cytotypes in germination, survival, fecundity, and mating system of gametophytes. RESULTS: Compared with its diploid parents, C. tinaei fresh spores had higher abortion percentages, lower dispersal ability as a result of its larger spores, and similar vigor at germination. For gametophytes from soil spore banks, C. tinaei had high survival similar to C. maderensis, but its sex expression resembled that of C. hispanica, with a high proportion of males. Patterns of sporophyte formation by females and bisexuals indicate that the polyploid does not have an increased gametophytic selfing rate. Gametophytes were larger in C. tinaei, but its reproductive success (sporophyte formation) was intermediate relative to diploids. CONCLUSIONS: Our results show no evidence of higher selfing or fitness advantage of the allopolyploid over both diploid parents at any stage of early recruitment. These two unexpected findings suggest that further factors, such as niche differentiation, play a more important role in cytotype coexistence.


Assuntos
Aptidão Genética , Germinação , Pteridaceae/fisiologia , Esporos/fisiologia , Tetraploidia , Fertilidade , Pteridaceae/citologia , Esporos/citologia
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