WorldWideScience

Sample records for apomictic polyploid hawkweeds

  1. Intra-individual polymorphism in diploid and apomictic polyploid hawkweeds (Hieracium, Lactuceae, Asteraceae: disentangling phylogenetic signal, reticulation, and noise

    Directory of Open Access Journals (Sweden)

    Chrtek Jindřich

    2009-09-01

    Full Text Available Abstract Background Hieracium s.str. is a complex species-rich group of perennial herbs composed of few sexual diploids and numerous apomictic polyploids. The existence of reticulation and the near-continuity of morphological characters across taxa seriously affect species determination, making Hieracium one of the best examples of a 'botanist's nightmare'. Consequently, its species relationships have not previously been addressed by molecular methods. Concentrating on the supposed major evolutionary units, we used nuclear ribosomal (ETS and chloroplast (trnT-trnL sequences in order to disentangle the phylogenetic relationships and to infer the origins of the polyploids. Results Despite relatively low interspecific variation, the nuclear data revealed the existence of two major groups roughly corresponding to species with a Western or Eastern European origin. Extensive reticulation was mainly inferred from the character additivity of parental ETS variants. Surprisingly, many diploid species were of hybrid origin whilst several polyploid taxa showed no evidence of reticulation. Intra-individual ETS sequence polymorphism generally exceeded interspecific variation and was either independent of, or additional to, additive patterns accounted for by hybrid origin. Several ETS ribotypes occurred in different hybrid taxa, but never as the only variant in any species analyzed. Conclusion The high level of intra-individual ETS polymorphism prevented straightforward phylogenetic analysis. Characterization of this variation as additive, shared informative, homoplasious, or unique made it possible to uncover the phylogenetic signal and to reveal the hybrid origin of 29 out of 60 accessions. Contrary to expectation, diploid sexuals and polyploid apomicts did not differ in their molecular patterns. The basic division of the genus into two major clades had not previously been intimated on morphological grounds. Both major groups are thought to have survived in

  2. 75 FR 64984 - Availability of an Environmental Assessment for a Biological Control Agent for Hawkweeds

    Science.gov (United States)

    2010-10-21

    ... Assessment for a Biological Control Agent for Hawkweeds AGENCY: Animal and Plant Health Inspection Service... the control of hawkweeds (Hieracium spp.). The environmental assessment considers the effects of, and... States as a biological control agent to reduce the severity of infestations of hawkweeds. We are...

  3. Chromosome studies and genetic analysis of natural and synthetic apomictic model species

    OpenAIRE

    Kantama, L.

    2005-01-01

    Some plants have gained the ability to produce seed without fertilisation. This alternative to sexual reproduction, known as apomixis occurs most frequently in species of the families of the grasses, roses and composites, and mostly in polyploids and is considered one of the ways to escape from hybrid sterility. An impressive number of apomictic mechanisms have so far been described; most of them with different developmental modes of embryo and endosperm. The trait is potential very promising...

  4. Hybrid apomicts trapped in the ecological niches of their sexual ancestors.

    Science.gov (United States)

    Mau, Martin; Lovell, John T; Corral, José M; Kiefer, Christiane; Koch, Marcus A; Aliyu, Olawale M; Sharbel, Timothy F

    2015-05-01

    Asexual reproduction is expected to reduce the adaptive potential to novel or changing environmental conditions, restricting or altering the ecological niche of asexual lineages. Asexual lineages of plants and animals are typically polyploid, an attribute that may influence their genetic variation, plasticity, adaptive potential, and niche breadth. The genus Boechera (Brassicaceae) represents an ideal model to test the relative ecological and biogeographic impacts of reproductive mode and ploidy because it is composed of diploid sexual and both diploid and polyploid asexual (i.e., apomictic) lineages. Here, we demonstrate a strong association between a transcriptionally conserved allele and apomictic seed formation. We then use this allele as a proxy apomixis marker in 1,649 accessions to demonstrate that apomixis is likely to be a common feature across the Boechera phylogeny. Phylogeographic analyses of these data demonstrate (i) species-specific niche differentiation in sexuals, (ii) extensive niche conservation between differing reproductive modes of the same species, (iii) ploidy-specific niche differentiation within and among species, and (iv) occasional niche drift between apomicts and their sexual ancestors. We conclude that ploidy is a substantially stronger and more common driver of niche divergence within and across Boechera species although variation in both traits may not necessarily lead to niche evolution on the species scale.

  5. Hieracium maccoshiana, a new Scottish hawkweed related to H. dovrense (Section Alpestria, Asteraceae

    Directory of Open Access Journals (Sweden)

    Timothy Rich

    2011-05-01

    Full Text Available A new species of hawkweed Hieracium maccoshiana T.C.G.Rich sp. nov. is described. It is related to the Norwegian H. dovrense Fr., but differs in the shape and toothing of the stem leaves and inglabrous-tipped ligules. It is endemic to the county of Sutherland, Scotland where it has been recorded from four sites. A lectotype of H. dovrense is designated.

  6. Hieracium maccoshiana, a new Scottish hawkweed related to H. dovrense (Section Alpestria, Asteraceae).

    Science.gov (United States)

    Rich, Timothy C G

    2011-01-01

    A new species of hawkweed Hieracium maccoshiana T.C.G.Rich sp. nov. is described. It is related to the Norwegian Hieracium dovrense Fr., but differs in the shape and toothing of the stem leaves and in having glabrous-tipped ligules. It is endemic to the county of Sutherland, Scotland where it has been recorded from four sites. A lectotype of Hieracium dovrense is designated.

  7. Elementary apomictic processes in Rubus L.

    Directory of Open Access Journals (Sweden)

    Roman Czapik

    2014-02-01

    Full Text Available Two elementary apomictic processe were found in the examined Rubus species: R. saxatilis developed diplosporous and aposporous embryo sacs, R. caesius - displosporous, apart from meiotic ones. These result; confirmed the wide occurrence of facultative apomixis and intraspecific differentiation of the mode of reproduction within the taxa of the investigated genus.

  8. Polyembryony in non-apomictic citrus genotypes

    Science.gov (United States)

    Aleza, Pablo; Juárez, José; Ollitrault, Patrick; Navarro, Luis

    2010-01-01

    Background and Aims Adventitious embryony from nucellar cells is the mechanism leading to apomixis in Citrus sp. However, singular cases of polyembryony have been reported in non-apomictic genotypes as a consequence of 2x × 4x hybridizations and in vitro culture of isolated nucelli. The origin of the plants arising from the aforementioned processes remains unclear. Methods The genetic structure (ploidy and allelic constitution with microsatellite markers) of plants obtained from polyembryonic seeds arising from 2x × 4x sexual hybridizations and those regenerated from nucellus culture in vitro was systematically analysed in different non-apomictic citrus genotypes. Histological studies were also conducted to try to identify the initiation process underlying polyembryony. Key Results All plants obtained from the same undeveloped seed in 2x × 4x hybridizations resulted from cleavage of the original zygotic embryo. Also, the plants obtained from in vitro nucellus culture were recovered by somatic embryogenesis from cells that shared the same genotype as the zygotic embryos of the same seed. Conclusions It appears that in non-apomictic citrus genotypes, proembryos or embryogenic cells are formed by cleavage of the zygotic embryos and that the development of these adventitious embryos, normally hampered, can take place in vivo or in vitro as a result of two different mechanisms that prevent the dominance of the initial zygotic embryo. PMID:20675656

  9. Freakish patterns – species and species concepts in apomicts

    NARCIS (Netherlands)

    Haveman, R.

    2013-01-01

    Apomict groups keep challenging taxonomists, in classifi cations as well as in more fundamental question about the nature
    of apomictic species. Th e latter question is not just an academic one, because the outcome infl uences practical decisions
    on biodiversity and conservation. A historical

  10. Comparative cyto-embryological investigations of sexual and apomictic dandelions (Taraxacum) and their apomictic hybrids

    NARCIS (Netherlands)

    Van Baarlen, P.; De Jong, J.H.; Van Dijk, P.J.

    2002-01-01

    In the autonomous apomictic Taraxacum offinale (common dandelion), parthenogenetic egg cells develop into embryos and central cells into endosperm without prior fertilisation. Unreduced (2n) megaspores are formed via meiotic diplospory, a nonreductional type of meiosis. In this paper, we describe th

  11. Dynamics of callose deposition and B-1,3-glucanase expression during reproductive events in sexual and apomictic Hieracium

    NARCIS (Netherlands)

    Tucker, M.R.; Paech, N.A.; Willemse, M.T.M.; Koltunow, A.M.G.

    2001-01-01

    Callose accumulates in the walls of cells undergoing megasporogenesis during embryo sac formation in angiosperm ovules. Deficiencies in callose deposition have been observed in apomictic plants and causal linkages between altered callose deposition and apomictic initiation proposed. In apomictic Hie

  12. Identification of genes differentially expressed during apomictic and sexual development in buffelgrass (Pennisetum ciliare)

    Science.gov (United States)

    Apomixis, an asexual method of reproduction through seeds with the absence of meiosis and fertilization holds great potential for plant breeding and hybrid seed production. Buffelgrass, an apomictic forage grass, has well characterized apomictic, facultative and sexual accessions to study apomictic...

  13. Genomic Aspects of Research Involving Polyploid Plants

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaohan [ORNL; Ye, Chuyu [ORNL; Tschaplinski, Timothy J [ORNL; Wullschleger, Stan D [ORNL; Tuskan, Gerald A [ORNL

    2011-01-01

    Almost all extant plant species have spontaneously doubled their genomes at least once in their evolutionary histories, resulting in polyploidy which provided a rich genomic resource for evolutionary processes. Moreover, superior polyploid clones have been created during the process of crop domestication. Polyploid plants generated by evolutionary processes and/or crop domestication have been the intentional or serendipitous focus of research dealing with the dynamics and consequences of genome evolution. One of the new trends in genomics research is to create synthetic polyploid plants which provide materials for studying the initial genomic changes/responses immediately after polyploid formation. Polyploid plants are also used in functional genomics research to study gene expression in a complex genomic background. In this review, we summarize the recent progress in genomics research involving ancient, young, and synthetic polyploid plants, with a focus on genome size evolution, genomics diversity, genomic rearrangement, genetic and epigenetic changes in duplicated genes, gene discovery, and comparative genomics. Implications on plant sciences including evolution, functional genomics, and plant breeding are presented. It is anticipated that polyploids will be a regular subject of genomics research in the foreseeable future as the rapid advances in DNA sequencing technology create unprecedented opportunities for discovering and monitoring genomic and transcriptomic changes in polyploid plants. The fast accumulation of knowledge on polyploid formation, maintenance, and divergence at whole-genome and subgenome levels will not only help plant biologists understand how plants have evolved and diversified, but also assist plant breeders in designing new strategies for crop improvement.

  14. The breeding of two polyploid rice lines with the characteristic of polyploid meiosis stability

    Institute of Scientific and Technical Information of China (English)

    CAI DeTian; HE YuChi; ZHANG DaoSheng; HE GuangCun; ZHU YingGuo; CHEN JianGuo; CHEN DongLing; DAI BingCheng; ZHANG Wei; SONG ZhaoJian; YANG ZhiFan; DU ChaoQun; TANG ZhiQiang

    2007-01-01

    Polyploidization is a basic feature of plant evolution. Nearly all of the main food, cotton and oil crops are polyploid. When ploidy levels increase, yields double; this phenomenon suggested a new strategy of rice breeding that utilizes wide crosses and polyploidization dual advantages to breed super rice.Because low seed set rates in polyploid rice usually makes it difficult to breed, the selection of Ph-liked gene lines was emphasized. After progenies of indica-japonica were identified and selected, two polyploid lines, PMeS-1 and PMeS-2 with Polyploid Meiosis Stability (PMeS) genes were bred. The procedure included seven steps: selecting parents, crossing or multiple crossing, back-crossing, doubling chromosomes, identifying the polyploid, and choosing plants with high seed set rates that can breed themselves into stable lines. The characteristics of PMeS were determined by observing meiotic behaviors and by cross-identification of seed sets. PMeS-1 and PMeS-2, (japonica rice), have several characteristics different from other polyploid rice lines, including a higher rate of seed set (more than 65%, increasing to more than 70% in their F1 offspring); and stable meiotic behaviors (pairing with bivalents and quarivalents nearly without over-quarivalent in prophase, nearly without lagging chromosomes in metaphase and without micronuclei in anaphase and telophase). The latter was obviously different from control polyploid line Dure-4X, which displayed abnormal meiotic behaviors including a higher rate of multivalents, univalents and trivalents in prophase, lagging chromosomes in metaphase and micronuclei in anaphase and telophase. There were also three differences of the breeding method between PMeS lines and normal diploid lines: chromosomes doubling, polyploidism identifying and higher seed set testing. The selection of PMeS lines is the first step in polyploid rice breeding; their use will advance the progress of polyploid rice breeding, which will in turn offer

  15. The breeding of two polyploid rice lines with the characteristic of polyploid meiosis stability

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Polyploidization is a basic feature of plant evolution. Nearly all of the main food, cotton and oil crops are polyploid. When ploidy levels increase, yields double; this phenomenon suggested a new strategy of rice breeding that utilizes wide crosses and polyploidization dual advantages to breed super rice. Because low seed set rates in polyploid rice usually makes it difficult to breed, the selection of Ph-liked gene lines was emphasized. After progenies of indica-japonica were identified and selected, two poly- ploid lines, PMeS-1 and PMeS-2 with Polyploid Meiosis Stability (PMeS) genes were bred. The proce- dure included seven steps: selecting parents, crossing or multiple crossing, back-crossing, doubling chromosomes, identifying the polyploid, and choosing plants with high seed set rates that can breed themselves into stable lines. The characteristics of PMeS were determined by observing meiotic be- haviors and by cross-identification of seed sets. PMeS-1 and PMeS-2, (japonica rice), have several characteristics different from other polyploid rice lines, including a higher rate of seed set (more than 65%, increasing to more than 70% in their F1 offspring); and stable meiotic behaviors (pairing with bi- valents and quarivalents nearly without over-quarivalent in prophase, nearly without lagging chromo- somes in metaphase and without micronuclei in anaphase and telophase). The latter was obviously different from control polyploid line Dure-4X, which displayed abnormal meiotic behaviors including a higher rate of multivalents, univalents and trivalents in prophase, lagging chromosomes in metaphase and micronuclei in anaphase and telophase. There were also three differences of the breeding method between PMeS lines and normal diploid lines: chromosomes doubling, polyploidism identifying and higher seed set testing. The selection of PMeS lines is the first step in polyploid rice breeding; their use will advance the progress of polyploid rice breeding, which will in

  16. Production of tetraploid plants of non apomictic citrus genotypes.

    Science.gov (United States)

    Aleza, Pablo; Juárez, José; Ollitrault, Patrick; Navarro, Luis

    2009-12-01

    Ploidy manipulation in Citrus is a major issue of current breeding programs aiming to develop triploid seedless mandarins to address consumer demands for seedless fruits. The most effective method to obtain triploid hybrids is to pollinate tetraploid non apomictic cultivars with pollen of diploid varieties. Such non apomictic tetraploid lines are not found in the citrus germplasm and need to be created. In this work we describe a new methodology based on in vitro shoot-tip grafting combined with treatment of the micro-grafted shoot-tip with colchicine and oryzalin to achieve chromosome doubling and a dechimerization procedure assisted by flow cytometry. Stable tetraploid plants of Clemenules, Fina and Marisol clementines and Moncada mandarin have been obtained directly from shoot tip grafting combined with colchicine and oryzalin treatments or after dechimerization of mixoploids plants (2x-4x). These stable tetraploid plants have been used in 4x x 2x hybridizations, to recover over 3,250 triploid hybrids in 3 years.

  17. Decidual cell polyploidization necessitates mitochondrial activity.

    Directory of Open Access Journals (Sweden)

    Xinghong Ma

    Full Text Available Cellular polyploidy has been widely reported in nature, yet its developmental mechanism and function remain poorly understood. In the present study, to better define the aspects of decidual cell polyploidy, we isolated pure polyploid and non-polyploid decidual cell populations from the in vivo decidual bed. Three independent RNA pools prepared for each population were then subjected to the Affymetrix gene chip analysis for the whole mouse genome transcripts. Our data revealed up-regulation of 1015 genes and down-regulation of 1207 genes in the polyploid populations, as compared to the non-polyploid group. Comparative RT-PCR and in situ hybridization results indeed confirmed differential expressional regulation of several genes between the two populations. Based on functional enrichment analyses, up-regulated polyploidy genes appeared to implicate several functions, which primarily include cell/nuclear division, ATP binding, metabolic process, and mitochondrial activity, whereas that of down-regulated genes primarily included apoptosis and immune processes. Further analyses of genes that are related to mitochondria and bi-nucleation showed differential and regional expression within the decidual bed, consistent with the pattern of polyploidy. Consistently, studies revealed a marked induction of mitochondrial mass and ATP production in polyploid cells. The inhibition of mitochondrial activity by various pharmacological inhibitors, as well as by gene-specific targeting using siRNA-mediated technology showed a dramatic attenuation of polyploidy and bi-nucleation development during in vitro stromal cell decidualization, suggesting mitochondria play a major role in positive regulation of decidual cell polyploidization. Collectively, analyses of unique polyploidy markers and molecular signaling networks may be useful to further characterize functional aspects of decidual cell polyploidy at the site of implantation.

  18. Transgenerational Effects of Stress Exposure on Offspring Phenotypes in Apomictic Dandelion

    NARCIS (Netherlands)

    Verhoeven, K.J.F.; Gurp, van T.P.

    2012-01-01

    Heritable epigenetic modulation of gene expression is a candidate mechanism to explain parental environmental effects on offspring phenotypes, but current evidence for environment-induced epigenetic changes that persist in offspring generations is scarce. In apomictic dandelions, exposure to various

  19. Transgenerational effects of stress exposure on offspring phenotypes in apomictic dandelion

    NARCIS (Netherlands)

    Verhoeven, K.J.F.; Van Gurp, T.P.

    2012-01-01

    Heritable epigenetic modulation of gene expression is a candidate mechanism to explain parental environmental effects on offspring phenotypes, but current evidence for environment-induced epigenetic changes that persist in offspring generations is scarce. In apomictic dandelions, exposure to various

  20. Determination of Apomictic Fruit Set Ratio in Several Romanian Walnut (Juglans regia L. Cultivars

    Directory of Open Access Journals (Sweden)

    Sina Niculina COSMULESCU

    2012-05-01

    Full Text Available carried out to determine the ability of apomictic fruit setting in twelve Romanian walnut cultivars. ‘Sibisel 44’, ‘Geoagiu 65’, ‘Germisara’, ‘Muscelean’, ‘Sarmis’, ‘Valcor’, ‘Valmit’, ‘Valrex’, ‘Jupanesti’, ‘Velnita’, ‘Orastie’ and ‘Argesean’ cultivars were used in the experiment. Female flowers were isolated with pergament paper bags and the apomictic fruit set was determined 8 weeks after anthesis. The apomixis degree was determined as the number of fruit calculated in relation to the number of isolated flowers. The percentage of apomictic fruit set without pollination in cultivars analyzed is low, ranging from 7.86% (‘Orastie’ cultivar up to 12.46% (‘Jupanesti’ cultivar. The results indicated that apomictic fruit set is insufficient for economical seed and crop production in these Romanian walnut cultivars.

  1. Karyotype evolution in apomictic Boechera and the origin of the aberrant chromosomes.

    Science.gov (United States)

    Mandáková, Terezie; Schranz, M Eric; Sharbel, Timothy F; de Jong, Hans; Lysak, Martin A

    2015-06-01

    Chromosome rearrangements may result in both decrease and increase of chromosome numbers. Here we have used comparative chromosome painting (CCP) to reconstruct the pathways of descending and ascending dysploidy in the genus Boechera (tribe Boechereae, Brassicaceae). We describe the origin and structure of three Boechera genomes and establish the origin of the previously described aberrant Het and Del chromosomes found in Boechera apomicts with euploid (2n = 14) and aneuploid (2n = 15) chromosome number. CCP analysis allowed us to reconstruct the origin of seven chromosomes in sexual B. stricta and apomictic B. divaricarpa from the ancestral karyotype (n = 8) of Brassicaceae lineage I. Whereas three chromosomes (BS4, BS6, and BS7) retained their ancestral structure, five chromosomes were reshuffled by reciprocal translocations to form chromosomes BS1-BS3 and BS5. The reduction of the chromosome number (from x = 8 to x = 7) was accomplished through the inactivation of a paleocentromere on chromosome BS5. In apomictic 2n = 14 plants, CCP identifies the largely heterochromatic chromosome (Het) being one of the BS1 homologues with the expansion of pericentromeric heterochromatin. In apomictic B. polyantha (2n = 15), the Het has undergone a centric fission resulting in two smaller chromosomes - the submetacentric Het' and telocentric Del. Here we show that new chromosomes can be formed by a centric fission and can be fixed in populations due to the apomictic mode of reproduction.

  2. Alterations of reproduction system in a polyploidized cassava interspecific hybrid.

    Science.gov (United States)

    Nassar, Nagib M A; Graciano-Ribeiro, Dalva; Gomes, Paula F; Hashimoto, Danielle Y C

    2010-04-01

    The objective of this research was to examine how much polyploidy may affect seed and root formation in cassava interspecific hybrids Manihot esculenta Crantz xM. oligantha Pax. A polyploid type was induced by colchicine treatment to lateral buds followed by propagating vegetatively arising stems. Cytogenetic and anatomical analyses were made on both polyploid and diploid types. The polyploid type showed extensive chromosome pairing and pollen viability. Multiembryonic ovule frequency increased in polyploid plants. Stalks became woody and propagation through roots difficult, the edible roots increased, however, in size. PMID:20536543

  3. A statistical design for testing apomictic diversification through linkage analysis.

    Science.gov (United States)

    Zeng, Yanru; Hou, Wei; Song, Shuang; Feng, Sisi; Shen, Lin; Xia, Guohua; Wu, Rongling

    2014-03-01

    The capacity of apomixis to generate maternal clones through seed reproduction has made it a useful characteristic for the fixation of heterosis in plant breeding. It has been observed that apomixis displays pronounced intra- and interspecific diversification, but the genetic mechanisms underlying this diversification remains elusive, obstructing the exploitation of this phenomenon in practical breeding programs. By capitalizing on molecular information in mapping populations, we describe and assess a statistical design that deploys linkage analysis to estimate and test the pattern and extent of apomictic differences at various levels from genotypes to species. The design is based on two reciprocal crosses between two individuals each chosen from a hermaphrodite or monoecious species. A multinomial distribution likelihood is constructed by combining marker information from two crosses. The EM algorithm is implemented to estimate the rate of apomixis and test its difference between two plant populations or species as the parents. The design is validated by computer simulation. A real data analysis of two reciprocal crosses between hickory (Carya cathayensis) and pecan (C. illinoensis) demonstrates the utilization and usefulness of the design in practice. The design provides a tool to address fundamental and applied questions related to the evolution and breeding of apomixis.

  4. [Experiment on polyploid induction of Angelica dahurica var. formosana].

    Science.gov (United States)

    Peng, F; Zhou, R; Liu, J

    1999-12-01

    Colchicine solution was applied to the primary adventitious buds of Angelica dahurica var. formosana in vitro to induce the polyploid. Compared with non-treated plantlet, the morphology, microhisology, and chromosome number of treated plantlets are varied. It proved that the polyploid induction was effective. PMID:12571900

  5. Relevance of sexual polyploidization for crop improvement - A review

    NARCIS (Netherlands)

    Ramanna, M.S.; Jacobsen, E.

    2003-01-01

    Colchicine induced polyploids have not directly contributed for crop improvement in the past. On the other hand, the so-called natural polyploids, derived from the functioning of numerically unreduced (2n) gametes have been shown to be more relevant for crop improvement in many cases. Different type

  6. Transgenerational effects of stress exposure on offspring phenotypes in apomictic dandelion.

    Directory of Open Access Journals (Sweden)

    Koen J F Verhoeven

    Full Text Available Heritable epigenetic modulation of gene expression is a candidate mechanism to explain parental environmental effects on offspring phenotypes, but current evidence for environment-induced epigenetic changes that persist in offspring generations is scarce. In apomictic dandelions, exposure to various stresses was previously shown to heritably alter DNA methylation patterns. In this study we explore whether these induced changes are accompanied by heritable effects on offspring phenotypes. We observed effects of parental jasmonic acid treatment on offspring specific leaf area and on offspring interaction with a generalist herbivore; and of parental nutrient stress on offspring root-shoot biomass ratio, tissue P-content and leaf morphology. Some of the effects appeared to enhance offspring ability to cope with the same stresses that their parents experienced. Effects differed between apomictic genotypes and were not always consistently observed between different experiments, especially in the case of parental nutrient stress. While this context-dependency of the effects remains to be further clarified, the total set of results provides evidence for the existence of transgenerational effects in apomictic dandelions. Zebularine treatment affected the within-generation response to nutrient stress, pointing at a role of DNA methylation in phenotypic plasticity to nutrient environments. This study shows that stress exposure in apomictic dandelions can cause transgenerational phenotypic effects, in addition to previously demonstrated transgenerational DNA methylation effects.

  7. Transgenerational effects of stress exposure on offspring phenotypes in apomictic dandelion.

    Science.gov (United States)

    Verhoeven, Koen J F; van Gurp, Thomas P

    2012-01-01

    Heritable epigenetic modulation of gene expression is a candidate mechanism to explain parental environmental effects on offspring phenotypes, but current evidence for environment-induced epigenetic changes that persist in offspring generations is scarce. In apomictic dandelions, exposure to various stresses was previously shown to heritably alter DNA methylation patterns. In this study we explore whether these induced changes are accompanied by heritable effects on offspring phenotypes. We observed effects of parental jasmonic acid treatment on offspring specific leaf area and on offspring interaction with a generalist herbivore; and of parental nutrient stress on offspring root-shoot biomass ratio, tissue P-content and leaf morphology. Some of the effects appeared to enhance offspring ability to cope with the same stresses that their parents experienced. Effects differed between apomictic genotypes and were not always consistently observed between different experiments, especially in the case of parental nutrient stress. While this context-dependency of the effects remains to be further clarified, the total set of results provides evidence for the existence of transgenerational effects in apomictic dandelions. Zebularine treatment affected the within-generation response to nutrient stress, pointing at a role of DNA methylation in phenotypic plasticity to nutrient environments. This study shows that stress exposure in apomictic dandelions can cause transgenerational phenotypic effects, in addition to previously demonstrated transgenerational DNA methylation effects.

  8. Is the aneuploid chromosome in an apomictic Boechera holboellii a genuine B chromosome?

    NARCIS (Netherlands)

    Sharbel, T.F.; Voigt, M.L.; Mitchell-Olds, T.; Kantama, L.; Jong, de J.H.S.G.M.

    2004-01-01

    The Boechera holboellii complex comprises B. holboellii and B. drummondii, both of which can reproduce through sex or apomixis. Sexuality is associated with diploidy, whereas apomictic individuals can either be diploid, aneuploid or triploid. Aneuploid individuals are found in geographically and gen

  9. Biogeographic distribution of polyploidy and B chromosomes in the apomictic Boechera holboellii complex

    NARCIS (Netherlands)

    Sharbel, T.F.; Mitchell-Olds, T.; Dobes, C.; Kantama, L.; Jong, de J.H.S.G.M.

    2005-01-01

    The Boechera holboellii complex comprises B. holboellii and B. drummondii, both of which can reproduce through sex or apomixis. Sexuality is associated with diploid individuals, whereas apomictic individuals are diploid or triploid and may additionally have B chromosomes. Using flow cytometry and ka

  10. Recent advances in understanding of meiosis initiation and the apomictic pathway in plants.

    Science.gov (United States)

    Wang, Chung-Ju R; Tseng, Ching-Chih

    2014-01-01

    Meiosis, a specialized cell division to produce haploid cells, marks the transition from a sporophytic to a gametophytic generation in the life cycle of plants. In angiosperms, meiosis takes place in sporogenous cells that develop de novo from somatic cells in anthers or ovules. A successful transition from the mitotic cycle to the meiotic program in sporogenous cells is crucial for sexual reproduction. By contrast, when meiosis is bypassed or a mitosis-like division occurs to produce unreduced cells, followed by the development of an embryo sac, clonal seeds can be produced by apomixis, an asexual reproduction pathway found in 400 species of flowering plants. An understanding of the regulation of entry into meiosis and molecular mechanisms of apomictic pathway will provide vital insight into reproduction for plant breeding. Recent findings suggest that AM1/SWI1 may be the key gene for entry into meiosis, and increasing evidence has shown that the apomictic pathway is epigenetically controlled. However, the mechanism for the initiation of meiosis during sexual reproduction or for its omission in the apomictic pathway still remains largely unknown. Here we review the current understanding of meiosis initiation and the apomictic pathway and raised several questions that are awaiting further investigation.

  11. Recent advances in understanding of meiosis initiation and the apomictic pathway in plants

    Directory of Open Access Journals (Sweden)

    Chung-Ju Rachel Wang

    2014-09-01

    Full Text Available Meiosis, a specialized cell division to produce haploid cells, marks the transition from a sporophytic to a gametophytic generation in the life cycle of plants. In angiosperms, meiosis takes place in sporogenous cells that develop de novo from somatic cells in anthers or ovules. A successful transition from the mitotic cycle to the meiotic program in sporogenous cells is crucial for sexual reproduction. By contrast, when meiosis is bypassed or a mitosis-like division occurs to produce unreduced cells, followed by the development of an embryo sac, clonal seeds can be produced by apomixis, an asexual reproduction pathway found in 400 species of flowering plants. An understanding of the regulation of entry into meiosis and molecular mechanisms of apomictic pathway will provide vital insight into reproduction for plant breeding. Recent findings suggest that AM1/SWI1 may be the key gene for entry into meiosis, and increasing evidence has shown that the apomictic pathway is epigenetically controlled. However, the mechanism for the initiation of meiosis during sexual reproduction or for its omission in the apomictic pathway still remains largely unknown. Here we review the current understanding of meiosis initiation and the apomictic pathway and raised several questions that are awaiting further investigation.

  12. Polyploidization facilitates biotechnological in vitro techniques in the genus Cucumis.

    Science.gov (United States)

    Skálová, Dagmar; Ondřej, Vladan; Doležalová, Ivana; Navrátilová, Božena; Lebeda, Aleš

    2010-01-01

    Prezygotic interspecific crossability barrier in the genus Cucumis is related to the ploidy level of the species (cucumber (C. sativus), x = 7; muskmelon (C. melo) and wild Cucumis species, x = 12). Polyploidization of maternal plants helps hybridization among other Cucumis species by overcoming prezygotic genetic barriers. The main objective of this paper is to compare the results of several methods supporting interspecific crosses in cucumber without and with polyploidization (comparison between diploid (2x) and mixoploid (2x/4x) cucumber maternal plants). Mixoploid plants were obtained after in vivo and in vitro polyploidization by colchicine and oryzalin. Ploidy level was estimated by flow cytometry. Embryo rescue, in vitro pollination, and isolation of mesophyll protoplast were tested and compared. Positive effect of polyploidization was observed during all experiments presented by higher regeneration capacity of cultivated mixoploid cucumber embryos, ovules, and protoplasts. Nevertheless, the hybrid character of putative hybrid accessions obtained after cross in vivo and in vitro pollination was not confirmed. PMID:21234406

  13. Angiosperm polyploids and their road to evolutionary success

    OpenAIRE

    Fawcett, Jeffrey A.; Van de Peer, Yves; Jeffrey A, FAWCETT

    2010-01-01

    The abundance of polyploidy among flowering plants has long been recognized, and recent studies have uncovered multiple ancient polyploidization events in the evolutionary history of several angiosperm lineages. Once polyploids are formed they must get locally established and then propagate and survive while adapting to different environments and avoiding extinction. This might ultimately lead to their long-term evolutionary success, where their descendant lineages survive for tens of million...

  14. Rapid chromosome evolution in recently formed polyploids in Tragopogon (Asteraceae.

    Directory of Open Access Journals (Sweden)

    K Yoong Lim

    Full Text Available BACKGROUND: Polyploidy, frequently termed "whole genome duplication", is a major force in the evolution of many eukaryotes. Indeed, most angiosperm species have undergone at least one round of polyploidy in their evolutionary history. Despite enormous progress in our understanding of many aspects of polyploidy, we essentially have no information about the role of chromosome divergence in the establishment of young polyploid populations. Here we investigate synthetic lines and natural populations of two recently and recurrently formed allotetraploids Tragopogon mirus and T. miscellus (formed within the past 80 years to assess the role of aberrant meiosis in generating chromosomal/genomic diversity. That diversity is likely important in the formation, establishment and survival of polyploid populations and species. METHODOLOGY/PRINCIPAL FINDINGS: Applications of fluorescence in situ hybridisation (FISH to natural populations of T. mirus and T. miscellus suggest that chromosomal rearrangements and other chromosomal changes are common in both allotetraploids. We detected extensive chromosomal polymorphism between individuals and populations, including (i plants monosomic and trisomic for particular chromosomes (perhaps indicating compensatory trisomy, (ii intergenomic translocations and (iii variable sizes and expression patterns of individual ribosomal DNA (rDNA loci. We even observed karyotypic variation among sibling plants. Significantly, translocations, chromosome loss, and meiotic irregularities, including quadrivalent formation, were observed in synthetic (S(0 and S(1 generations polyploid lines. Our results not only provide a mechanism for chromosomal variation in natural populations, but also indicate that chromosomal changes occur rapidly following polyploidisation. CONCLUSIONS/SIGNIFICANCE: These data shed new light on previous analyses of genome and transcriptome structures in de novo and establishing polyploid species. Crucially our

  15. Wheat Hybridization and Polyploidization Results in Deregulation of Small RNAs

    OpenAIRE

    Kenan-Eichler, Michal; Leshkowitz, Dena; Tal, Lior; Noor, Elad; Melamed-Bessudo, Cathy; Feldman, Moshe; Levy, Avraham A.

    2011-01-01

    Speciation via interspecific or intergeneric hybridization and polyploidization triggers genomic responses involving genetic and epigenetic alterations. Such modifications may be induced by small RNAs, which affect key cellular processes, including gene expression, chromatin structure, cytosine methylation and transposable element (TE) activity. To date, the role of small RNAs in the context of wide hybridization and polyploidization has received little attention. In this work, we performed h...

  16. Molecular Tools for Exploring Polyploid Genomes in Plants

    Directory of Open Access Journals (Sweden)

    Domenico Carputo

    2012-08-01

    Full Text Available Polyploidy is a very common phenomenon in the plant kingdom, where even diploid species are often described as paleopolyploids. The polyploid condition may bring about several advantages compared to the diploid state. Polyploids often show phenotypes that are not present in their diploid progenitors or exceed the range of the contributing species. Some of these traits may play a role in heterosis or could favor adaptation to new ecological niches. Advances in genomics and sequencing technology may create unprecedented opportunities for discovering and monitoring the molecular effects of polyploidization. Through this review, we provide an overview of technologies and strategies that may allow an in-depth analysis of polyploid genomes. After introducing some basic aspects on the origin and genetics of polyploids, we highlight the main tools available for genome and gene expression analysis and summarize major findings. In the last part of this review, the implications of next generation sequencing are briefly discussed. The accumulation of knowledge on polyploid formation, maintenance, and divergence at whole-genome and subgenome levels will not only help plant biologists to understand how plants have evolved and diversified, but also assist plant breeders in designing new strategies for crop improvement.

  17. Asexual genome evolution in the apomictic Ranunculus auricomus complex: examining the effects of hybridization and mutation accumulation.

    Science.gov (United States)

    Pellino, Marco; Hojsgaard, Diego; Schmutzer, Thomas; Scholz, Uwe; Hörandl, Elvira; Vogel, Heiko; Sharbel, Timothy F

    2013-12-01

    Asexual lineages are thought to be prone to extinction because of deleterious mutation accumulation (Muller's ratchet). Here, we analyse genomic effects of hybridity, polyploidy and allelic divergence in apomictic plants, and identify loci under divergent selection among sexual/apomictic lineages. RNAseq was used to sequence the flower-specific transcriptomes of five genotypes of the Ranunculus auricomus complex, representing three sexual and two apomictic reproductive biotypes. The five sequence libraries were pooled and de novo assembly performed, and the resultant assembly was used as a backbone for a subsequent alignment of each separate library. High-quality single-nucleotide (SNP) and insertion-deletion (indel) polymorphisms were mined from each library. Annotated genes for which open reading frames (ORF) could be determined were analysed for signatures of divergent versus stabilizing selection. A comparison between all genotypes supports the hypothesis of Pleistocene hybrid origin of both apomictic genotypes from R. carpaticola and R. cassubicifolius, with subsequent allelic divergence of apomictic lineages (Meselson effect). Pairwise comparisons of nonsynonymous (dN) to synonymous (dS) substitution rate ratios between apomictic and sexual genotypes for 1231 genes demonstrated similar distributions for all comparisons, although 324 genes demonstrated outlier (i.e. elevated) dN/dS ratios. Gene ontology analyses of these outliers revealed significant enrichment of genes associated with reproduction including meiosis and gametogenesis, following predictions of divergent selection between sexual and apomictic reproduction, although no significant signal of genome-wide mutation accumulation could be identified. The results suggest that gene function should be considered in order to understand effects of mutation accumulation in asexual lineages.

  18. Induced polyploidization in Brassica campestris L. (Brassicaceae).

    Science.gov (United States)

    Kumar, G; Dwivedi, K

    2014-01-01

    Present experimental design has been made up to obtain crop with higher ploidy level via synthetic polyploidization. Since ploidy manipulation is generally associated with the obtainment of some increased enviable traits of the crop and also provides them greater adaptability to unfavorable or harsh circumstances as compared to its diploids counterparts. Thus, herein present research autotetraploids of Brassica campestris L. have been lucratively achieved by the application of colchicine. Two methods of treatment were utilized i.e. seed treatment and seedling treatment. No polyploidy could be obtained through seed treatment while seedling treatment responded well towards polyploidy. However, the status of autotetraploidy has been confirmed by cytomorphological investigations of treated plants as against its diploids counterparts. For the purpose, morphological parameters such as increased stomata size, pollen diameter, flower size, reproductive organs whereas reduction in plant height, leaf length, leaf breadth, stomata frequency, number of flowers/inflorescence etc. were appraised. Further, cytological observations were made that had clearly revealed the doubling of genome in the autotetraploids as compared to diploids. Meanwhile, pollen fertility and size of pollen grains were evaluated as well. PMID:24818510

  19. Analysis of conserved microRNAs in floral tissues of sexual and apomictic Boechera species

    Directory of Open Access Journals (Sweden)

    Vogel Heiko

    2011-10-01

    Full Text Available Abstract Background Apomixis or asexual seed formation represents a potentially important agronomic trait whose introduction into crop plants could be an effective way to fix and perpetuate a desirable genotype through successive seed generations. However, the gene regulatory pathways underlying apomixis remain unknown. In particular, the potential function of microRNAs, which are known to play crucial roles in many aspects of plant growth and development, remains to be determined with regards to the switch from sexual to apomictic reproduction. Results Using bioinformatics and microarray validation procedures, 51 miRNA families conserved among angiosperms were identified in Boechera. Microarray assay confirmed 15 of the miRNA families that were identified by bioinformatics techniques. 30 cDNA sequences representing 26 miRNAs could fold back into stable pre-miRNAs. 19 of these pre-miRNAs had miRNAs with Boechera-specific nucleotide substitutions (NSs. Analysis of the Gibbs free energy (ΔG of these pre-miRNA stem-loops with NSs showed that the Boechera-specific miRNA NSs significantly (p ≤ 0.05 enhance the stability of stem-loops. Furthermore, six transcription factors, the Squamosa promoter binding protein like SPL6, SPL11 and SPL15, Myb domain protein 120 (MYB120, RELATED TO AP2.7 DNA binding (RAP2.7, TOE1 RAP2.7 and TCP family transcription factor 10 (TCP10 were found to be expressed in sexual or apomictic ovules. However, only SPL11 showed differential expression with significant (p ≤ 0.05 up-regulation at the megaspore mother cell (MMC stage of ovule development in apomictic genotypes. Conclusions This study constitutes the first extensive insight into the conservation and expression of microRNAs in Boechera sexual and apomictic species. The miR156/157 target squamosa promoter binding protein-like 11 (SPL11 was found differentially expressed with significant (p ≤ 0.05 up-regulation at the MMC stage of ovule development in apomictic

  20. Lessons from natural and artificial polyploids in higher plants.

    Science.gov (United States)

    Hegarty, M; Coate, J; Sherman-Broyles, S; Abbott, R; Hiscock, S; Doyle, J

    2013-01-01

    Polyploidy in higher plants is a major source of genetic novelty upon which selection may act to drive evolution, as evidenced by the widespread success of polyploid species in the wild. However, research into the effects of polyploidy can be confounded by the entanglement of several processes: genome duplication, hybridisation (allopolyploidy is frequent in plants) and subsequent evolution. The discovery of the chemical agent colchicine, which can be used to produce artificial polyploids on demand, has enabled scientists to unravel these threads and understand the complex genomic changes involved in each. We present here an overview of lessons learnt from studies of natural and artificial polyploids, and from comparisons between the 2, covering basic cellular and metabolic consequences through to alterations in epigenetic gene regulation, together with 2 in-depth case studies in Senecio and Glycine. See also the sister article focusing on animals by Arai and Fujimoto in this themed issue. PMID:23816545

  1. Polyploid evolution in Oryza officinalis complex of the genus Oryza

    Directory of Open Access Journals (Sweden)

    Li Changbao

    2009-10-01

    Full Text Available Abstract Background Polyploidization is a prominent process in plant evolution, whereas the mechanism and tempo-spatial process remained poorly understood. Oryza officinalis complex, a polyploid complex in the genus Oryza, could exemplify the issues not only for it covering a variety of ploidy levels, but also for the pantropical geographic pattern of its polyploids in Asia, Africa, Australia and Americas, in which a pivotal genome, the C-genome, witnessed all the polyploidization process. Results Tracing the C-genome evolutionary history in Oryza officinalis complex, this study revealed the genomic relationships, polyploid forming and diverging times, and diploidization process, based on phylogeny, molecular-clock analyses and fluorescent in situ hybridization using genome-specific probes. Results showed that C-genome split with B-genome at ca. 4.8 Mya, followed by a series of speciation of C-genome diploids (ca. 1.8-0.9 Mya, which then partook in successive polyploidization events, forming CCDD tetraploids in ca. 0.9 Mya, and stepwise forming BBCC tetraploids between ca. 0.3-0.6 Mya. Inter-genomic translocations between B- and C-genomes were identified in BBCC tetraploid, O. punctata. Distinct FISH (fluorescent in situ hybridization patterns among three CCDD species were visualized by C-genome-specific probes. B-genome was modified before forming the BBCC tetraploid, O. malampuzhaensis. Conclusion C-genome, shared by all polyploid species in the complex, had experienced different evolutionary history particularly after polyploidization, e.g., inter-genomic exchange in BBCC and genomic invasion in CCDD tetraploids. It diverged from B-genome at 4.8 Mya, then participated in the tetraploid formation spanning from 0.9 to 0.3 Mya, and spread into tropics of the disjunct continents by transcontinentally long-distance dispersal, instead of vicariance, as proposed by this study, given that the continental splitting was much earlier than the C

  2. Polyploidization of glia in neural development links tissue growth to blood-brain barrier integrity.

    Science.gov (United States)

    Unhavaithaya, Yingdee; Orr-Weaver, Terry L

    2012-01-01

    Proper development requires coordination in growth of the cell types composing an organ. Many plant and animal cells are polyploid, but how these polyploid tissues contribute to organ growth is not well understood. We found the Drosophila melanogaster subperineurial glia (SPG) to be polyploid, and ploidy is coordinated with brain mass. Inhibition of SPG polyploidy caused rupture of the septate junctions necessary for the blood-brain barrier. Thus, the increased SPG cell size resulting from polyploidization is required to maintain the SPG envelope surrounding the growing brain. Polyploidization likely is a conserved strategy to coordinate tissue growth during organogenesis, with potential vertebrate examples.

  3. A Parthenogenesis Gene Candidate and Evidence for Segmental Allopolyploidy in Apomictic Brachiaria decumbens.

    Science.gov (United States)

    Worthington, Margaret; Heffelfinger, Christopher; Bernal, Diana; Quintero, Constanza; Zapata, Yeny Patricia; Perez, Juan Guillermo; De Vega, Jose; Miles, John; Dellaporta, Stephen; Tohme, Joe

    2016-07-01

    Apomixis, asexual reproduction through seed, enables breeders to identify and faithfully propagate superior heterozygous genotypes by seed without the disadvantages of vegetative propagation or the expense and complexity of hybrid seed production. The availability of new tools such as genotyping by sequencing and bioinformatics pipelines for species lacking reference genomes now makes the construction of dense maps possible in apomictic species, despite complications including polyploidy, multisomic inheritance, self-incompatibility, and high levels of heterozygosity. In this study, we developed saturated linkage maps for the maternal and paternal genomes of an interspecific Brachiaria ruziziensis (R. Germ. and C. M. Evrard) × B. decumbens Stapf. F1 mapping population in order to identify markers linked to apomixis. High-resolution molecular karyotyping and comparative genomics with Setaria italica (L.) P. Beauv provided conclusive evidence for segmental allopolyploidy in B. decumbens, with strong preferential pairing of homologs across the genome and multisomic segregation relatively more common in chromosome 8. The apospory-specific genomic region (ASGR) was mapped to a region of reduced recombination on B. decumbens chromosome 5. The Pennisetum squamulatum (L.) R.Br. PsASGR-BABY BOOM-like (psASGR-BBML)-specific primer pair p779/p780 was in perfect linkage with the ASGR in the F1 mapping population and diagnostic for reproductive mode in a diversity panel of known sexual and apomict Brachiaria (Trin.) Griseb. and P. maximum Jacq. germplasm accessions and cultivars. These findings indicate that ASGR-BBML gene sequences are highly conserved across the Paniceae and add further support for the postulation of the ASGR-BBML as candidate genes for the apomictic function of parthenogenesis. PMID:27206716

  4. Photoperiod extension enhances sexual megaspore formation and triggers metabolic reprogramming in facultative apomictic Ranunculus auricomus

    Directory of Open Access Journals (Sweden)

    Simone eKlatt

    2016-03-01

    Full Text Available Abstract••Meiosis, the key step of sexual reproduction, persists in facultative apomictic plants functional to some extent. However, it still remains unclear how and why proportions of reproductive pathways vary under different environmental stress conditions. We hypothesized that oxidative stress mediates alterations of developmental pathways. In apomictic plants we expected that megasporogenesis, the stage directly after meiosis, would be more affected than later stages of seed development.•To simulate moderate stress conditions we subjected clone-mates of facultative apomictic Ranunculus auricomus to 10 h photoperiods, reflecting natural conditions, and extended ones (16.5 h. Reproduction mode was screened directly after megasporogenesis (microscope and at seed stage (flow cytometric seed screening. Targeted metabolite profiles were performed with HPLC−DAD to explore if and which metabolic reprogramming was caused by the extended photoperiod.•Prolonged photoperiods resulted in increased frequencies of sexual vs. aposporous initials directly after meiosis, but did not affect frequencies of sexual vs. asexual seed formation. Changes in secondary metabolite profiles under extended photoperiods affected all classes of compounds, and c. 20% of these changes separated the two treatments. Unexpectedly, the renowned antioxidant phenylpropanoids and flavonoids added more to clone-mate variation than to treatment differentiation. Among others, chlorophyll degradation products, non-assigned phenolic compounds and more lipophilic metabolites also contributed to the dissimilarity of the metabolic profiles of plants that had been exposed to the two different photoperiods.•The hypothesis of moderate light stress effects was supported by increased proportions of sexual megaspore development at the expense of aposporous initial formation. The lack of effects at the seed stage confirms the basic assumption that only meiosis and sporogenesis would

  5. A parthenogenesis gene of apomict origin elicits embryo formation from unfertilized eggs in a sexual plant.

    Science.gov (United States)

    Conner, Joann A; Mookkan, Muruganantham; Huo, Heqiang; Chae, Keun; Ozias-Akins, Peggy

    2015-09-01

    Apomixis is a naturally occurring mode of asexual reproduction in flowering plants that results in seed formation without the involvement of meiosis or fertilization of the egg. Seeds formed on an apomictic plant contain offspring genetically identical to the maternal plant. Apomixis has significant potential for preserving hybrid vigor from one generation to the next in highly productive crop plant genotypes. Apomictic Pennisetum/Cenchrus species, members of the Poaceae (grass) family, reproduce by apospory. Apospory is characterized by apomeiosis, the formation of unreduced embryo sacs derived from nucellar cells of the ovary and, by parthenogenesis, the development of the unreduced egg into an embryo without fertilization. In Pennisetum squamulatum (L.) R.Br., apospory segregates as a single dominant locus, the apospory-specific genomic region (ASGR). In this study, we demonstrate that the PsASGR-BABY BOOM-like (PsASGR-BBML) gene is expressed in egg cells before fertilization and can induce parthenogenesis and the production of haploid offspring in transgenic sexual pearl millet. A reduction of PsASGR-BBML expression in apomictic F1 RNAi transgenic plants results in fewer visible parthenogenetic embryos and a reduction of embryo cell number compared with controls. Our results endorse a key role for PsASGR-BBML in parthenogenesis and a newly discovered role for a member of the BBM-like clade of APETALA 2 transcription factors. Induction of parthenogenesis by PsASGR-BBML will be valuable for installing parthenogenesis to synthesize apomixis in crops and will have further application for haploid induction to rapidly obtain homozygous lines for breeding. PMID:26305939

  6. A Parthenogenesis Gene Candidate and Evidence for Segmental Allopolyploidy in Apomictic Brachiaria decumbens.

    Science.gov (United States)

    Worthington, Margaret; Heffelfinger, Christopher; Bernal, Diana; Quintero, Constanza; Zapata, Yeny Patricia; Perez, Juan Guillermo; De Vega, Jose; Miles, John; Dellaporta, Stephen; Tohme, Joe

    2016-07-01

    Apomixis, asexual reproduction through seed, enables breeders to identify and faithfully propagate superior heterozygous genotypes by seed without the disadvantages of vegetative propagation or the expense and complexity of hybrid seed production. The availability of new tools such as genotyping by sequencing and bioinformatics pipelines for species lacking reference genomes now makes the construction of dense maps possible in apomictic species, despite complications including polyploidy, multisomic inheritance, self-incompatibility, and high levels of heterozygosity. In this study, we developed saturated linkage maps for the maternal and paternal genomes of an interspecific Brachiaria ruziziensis (R. Germ. and C. M. Evrard) × B. decumbens Stapf. F1 mapping population in order to identify markers linked to apomixis. High-resolution molecular karyotyping and comparative genomics with Setaria italica (L.) P. Beauv provided conclusive evidence for segmental allopolyploidy in B. decumbens, with strong preferential pairing of homologs across the genome and multisomic segregation relatively more common in chromosome 8. The apospory-specific genomic region (ASGR) was mapped to a region of reduced recombination on B. decumbens chromosome 5. The Pennisetum squamulatum (L.) R.Br. PsASGR-BABY BOOM-like (psASGR-BBML)-specific primer pair p779/p780 was in perfect linkage with the ASGR in the F1 mapping population and diagnostic for reproductive mode in a diversity panel of known sexual and apomict Brachiaria (Trin.) Griseb. and P. maximum Jacq. germplasm accessions and cultivars. These findings indicate that ASGR-BBML gene sequences are highly conserved across the Paniceae and add further support for the postulation of the ASGR-BBML as candidate genes for the apomictic function of parthenogenesis.

  7. Chromosome studies and genetic analysis of natural and synthetic apomictic model species

    NARCIS (Netherlands)

    Kantama, L.

    2005-01-01

    Some plants have gained the ability to produce seed without fertilisation. This alternative to sexual reproduction, known as apomixis occurs most frequently in species of the families of the grasses, roses and composites, and mostly in polyploids and is considered one of the ways to escape from hybr

  8. [Expression of the apomictic potential and selection for apomixis in sorghum line AS-1a].

    Science.gov (United States)

    El'konin, L A; Beliaeva, E V; Fadeeva, I Iu

    2012-01-01

    Expression of elements of apomixis was studied for ten seasons in sorghum line AS-la and its backcross hybrids on the 9E and A3 sterile cytoplasms. Cytoembryological analysis revealed aposporous embryo sacks (apo-ESs), their initial cells, and, rare, parthenogeneic proembryos in ovules of line AS-la and its BC2 and BC3 hybrids on the 9E cytoplasm. The A3 sterile cytoplasm suppressed the development of parthenogenetic proembryos, but did not affect the apo-ES formation. The frequency of apomictic elements increased in seasons with high daily temperatures and total precipitation deficiency in the period when the ovule and megagametophyte developed (r = -0.805, P anthocyan color of coleoptyles and leaves in seedlings. Plants of the maternal type were found in the progenies of these crosses at a frequency of 1.4-28.1%. The genetic structure of the endosperm in grains with maternal-type seedlings was inferred from the electrophoretic patterns of storage proteins (kafirins). The kafirin spectra of grains producing maternal-type seedlings was similar to the spectrum of line AS-la and differed from the spectra of grains producing hybrid seedlings, indicating that the endosperm developed independently when apomictic grains formed in line AS-1a. The results showed that lines with facultative apomixis can be constructed in functionally diploid plants. PMID:22567852

  9. Polyploid induction of Lespedeza formosa by colchicine treatment

    Institute of Scientific and Technical Information of China (English)

    Li Wei; Hu Dong-nan; Li Hui; Chen Xiao-yang

    2007-01-01

    Polyploid induction has been conducted by different colchicines concentrations with seed. hypocotyl and apices of Lespedeza formosa. Morphological variation and amounts of chromosome about the polyploidy have also been analyzed. Results show that the best material for polyploid induction of L. formosa is the new apices from seed germination, with an induction rate of 44. 4% at 0. 1% colchicines concentration and 36 hours of treatment time. Compared with normal diploid plants. the polyploidy plants of L. formosa inducted in our experiments have short stature and stems with thick and wide leaves. Cytological studies show that the changed seedlings,whose morphology has changed dramatically, are tetraploid, with 44 (2n=4x=44)chromosomes in the somatic cells.

  10. Karyomorphometry on three polyploid species of Arum L. (Araceae, Aroideae)

    OpenAIRE

    Turco, Alessio; Medagli,Pietro; Albano, Antonella; D’Emerico, Saverio

    2014-01-01

    Abstract In this study three polyploid Arum Linnaeus, 1753 species from Southern Italy were chromosomally investigated. Arum italicum Miller, 1768 was found to have 2n = 84 chromosomes and a karyotype composed of numerous asymmetric chromosomes. Arum maculatum Linnaeus, 1753 and Arum apulum (Carano) P. C. Boyce, 1993 were found to have 2n = 56 chromosomes. In the examined taxa some chromosome pairs were characterized by the presence of weakly coloured Feulgen-stained segments. The karyotype m...

  11. Hepatocytes Polyploidization and Cell Cycle Control in Liver Physiopathology

    Directory of Open Access Journals (Sweden)

    Géraldine Gentric

    2012-01-01

    Full Text Available Most cells in mammalian tissues usually contain a diploid complement of chromosomes. However, numerous studies have demonstrated a major role of “diploid-polyploid conversion” during physiopathological processes in several tissues. In the liver parenchyma, progressive polyploidization of hepatocytes takes place during postnatal growth. Indeed, at the suckling-weaning transition, cytokinesis failure events induce the genesis of binucleated tetraploid liver cells. Insulin signalling, through regulation of the PI3K/Akt signalling pathway, is essential in the establishment of liver tetraploidization by controlling cytoskeletal organisation and consequently mitosis progression. Liver cell polyploidy is generally considered to indicate terminal differentiation and senescence, and both lead to a progressive loss of cell pluripotency associated to a markedly decreased replication capacity. Although adult liver is a quiescent organ, it retains a capacity to proliferate and to modulate its ploidy in response to various stimuli or aggression (partial hepatectomy, metabolic overload (i.e., high copper and iron hepatic levels, oxidative stress, toxic insult, and chronic hepatitis etc.. Here we review the mechanisms and functional consequences of hepatocytes polyploidization during normal and pathological liver growth.

  12. GISH and BAC-FISH study of apomictic Beta M14

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Apomixis is a means of asexual reproduction by which plants produce embryos without fertilization and meiosis,therefore the embryo is of clonal and maternal origin.Interspecific hybrids between dip-loid B.vulgaris(2n=2x=18)and tetraploid B.corolliflora(2n=4x=36)were established,and then back-crossed with B.vulgaris.Among their offspring,monosomic addition line M14(2n=2x=18+1)was se-lected because of the apomictic phenotype.We documented chromosome transmission from B.corol-liflora into M14 by using genomic in situ hybridization(GISH).Suppression of cross-hybridization by blocking DNA was not necessary,indicating that the investigated Beta genome contains sufficient species-specific DNA,thus enabling the determination of genomic composition of the hybrids.We analyzed BAC microarrays of B.corolliflora chromosome 9 by using fluorescence-specific mRNA of B.vulgaris and Beta M14.BAC clones 16-M11 and 26-L15 were detected as fluorescence-specifics of BAC DNA of Beta M14.Then both BAC clones 16-M11 and 26-L15 were in situ hybridized to M14 chromo-somes.The two hybridized BAC clones were located close to the telomere region of the long arm of a single chromosome 9,and showed hemizygosity.The results of BAC microarrays showed that these developments of embryo and endosperm have conservative expression patterns,indicating that sexual reproduction and apomixis have an interrelated pathway with common regulatory components and that the induction of a modified sexual reproduction program may enable the manifestation of apomixis in Beta species.It would be sufficient for the expression of apomixes with those apomictic-specific genes on chromosome 9 of B.corolliflora.

  13. GISH and BAC-FISH study of apomictic Beta M14

    Institute of Scientific and Technical Information of China (English)

    GE Yan; HE GuangChun; WANG ZhiWei; GUO DeDong; QIN Rui; LI RongTian

    2007-01-01

    Apomixis is a means of asexual reproduction by which plants produce embryos without fertilization and meiosis, therefore the embryo is of clonal and maternal origin. Interspecific hybrids between diploid B. vulgaris (2n=2x=18) and tetraploid B. corolliflora (2n=4x=36) were established, and then backcrossed with B. vulgaris. Among their offspring, monosomic addition line M14 (2n=2x=18+1) was selected because of the apomictic phenotype. We documented chromosome transmission from B. corolliflora into M14 by using genomic in situ hybridization (GISH). Suppression of cross-hybridization by blocking DNA was not necessary, indicating that the investigated Beta genome contains sufficient species-specific DNA, thus enabling the determination of genomic composition of the hybrids. We analyzed BAC microarrays of B. corolliflora chromosome 9 by using fluorescence-specific mRNA of B.vulgaris and Beta M14. BAC clones 16-M11 and 26-L15 were detected as fluorescence-specifics of BAC DNA of Beta M14. Then both BAC clones 16-M11 and 26-L15 were in situ hybridized to M14 chromosomes. The two hybridized BAC clones were located close to the telomere region of the long arm of a single chromosome 9, and showed hemizygosity. The results of BAC microarrays showed that these developments of embryo and endosperm have conservative expression patterns, indicating that sexual reproduction and apomixis have an interrelated pathway with common regulatory components and that the induction of a modified sexual reproduction program may enable the manifestation of apomixis in Beta species. It would be sufficient for the expression of apomixes with those apomictic-specific genes on chromosome 9 of B. corolliflora.

  14. Tetraploidization events by chromosome doubling of nucellar cells are frequent in apomictic citrus and are dependent on genotype and environment

    Science.gov (United States)

    Aleza, Pablo; Froelicher, Yann; Schwarz, Sergio; Agustí, Manuel; Hernández, María; Juárez, José; Luro, François; Morillon, Raphael; Navarro, Luis; Ollitrault, Patrick

    2011-01-01

    Background and Aims Polyploidy is a major component of plant evolution. The citrus gene pool is essentially diploid but tetraploid plants are frequently encountered in seedlings of diploid apomictic genotypes. The main objectives of the present study were to establish the origin of these tetraploid plants and to ascertain the importance of genotypic and environmental factors on tetraploid formation. Methods Tetraploid seedlings from 30 diploid apomictic genotypes were selected by flow cytometry and genotyped with 24 single sequence repeat (SSR) markers to analyse their genetic origin. Embryo rescue was used to grow all embryos contained in polyembryonic seeds of ‘Tardivo di Ciaculli’ mandarin, followed by characterization of the plantlets obtained by flow cytometry and SSR markers to accurately establish the rate of tetraploidization events and their potential tissue location. Inter-annual variations in tetraploid seedling rates were analysed for seven genotypes. Variation in tetraploid plantlet rates was analysed between different seedlings of the same genotype (‘Carrizo’ citrange; Citrus sinensis × Poncirus trifoliata) from seeds collected in different tropical, subtropical and Mediterranean countries. Key Results Tetraploid plants were obtained for all the studied diploid genotypes, except for four mandarins. All tetraploid plants were identical to their diploid maternal line for SSR markers and were not cytochimeric. Significant genotypic and environmental effects were observed, as well as negative correlation between mean temperature during the flowering period and tetraploidy seedling rates. The higher frequencies (20 %) of tetraploids were observed for citranges cultivated in the Mediterranean area. Conclusions Tetraploidization by chromosome doubling of nucellar cells are frequent events in apomictic citrus, and are affected by both genotypic and environmental factors. Colder conditions in marginal climatic areas appear to favour the expression of

  15. Genetic variability in apomictic mangosteen (Garcinia mangostana) and its close relatives (Garcinia spp.) based on ISSR markers

    OpenAIRE

    SOBIR; ROEDHY POERWANTO; EDY SANTOSA; SOALOON SINAGA; ELINA MANSYAH

    2011-01-01

    Sobir, Poerwanto R, Santosa E, Sinaga S, Mansyah E (2011) Genetic variability in apomictic mangosteen (Garcinia mangostana) and its close relatives (Garcinia spp.) based on ISSR markers. Biodiversitas 12: 59-63. In order to reveal phylogenetic relationship of mangosteen and several close relatives (Garcinia spp.), we employed seven ISSR dinucleotide primer systems on eleven close relatives of mangosteen and 28 mangosteen accessions from four islands in Indonesia (Sumatra, Java, Kalimantan and...

  16. Polyploid induction of Allium ascalonicum L. by colchicine

    Directory of Open Access Journals (Sweden)

    SUMINAH

    2002-01-01

    Full Text Available The low production rate of shallot (Allium ascalonicum L. in Indonesia could be caused by rarely excellent cultivars. Colchicine was one of the mutation agents frequently used in plant breeding in order to get polyploidy of cultivars. The aim of this research was to find out the differentiation of morphometric evidences and ploidy of shallot chromosomes induced by colchicines 1%. Preparation was made by squash method and stained by acetocarmine. The results indicated that the amount, length and shape of chromosomes altered by the application of the agent. The polyploids produced could be grouped into tetraploids, pentaploids, hexaploids, octaploids, and nonaploids.

  17. [Induction of polyploid hairy roots and its plant regeneration in Pogostemon cablin].

    Science.gov (United States)

    Shi, Heping; Yu, Wu; Zhang, Guopeng; Tsang, Pokeung Eric; Chow, Cheuk Fai Stephen

    2014-08-01

    Abstract: In order to enhance the content of secondary metabolites patchouli alcohol in Pogostemon cablin, we induced polyploid hairy roots and their plant regeneration, and determined the content of patchouli alcohol through artificial chromosome doubling with colchicine. The highest rate of polyploidy induction was more than 40% when hairy roots were treated with 0.05% colchicine for 36 h. The obtained polyploid hairy roots formed adventitious shoots when cultured in an MS medium with 6-BA 0.2 mg/L and NAA 0.1 mg/L for 60 d. Compared with the control diploid plants, the polyploid hairy root-regenerated plants of P. cablin had more developed root systems, thicker stems, shorter internodes and longer, wider and thicker leaves. Observation of the chromosome number in their root tip cells reveals that the obtained polyploid regenerated plants were tetraploidy, with 128 (4n = 128) chromosomes. The leaves contained around twice as many stomatal guard cells and chloroplasts as the controls, but the stomatal density declined with increasing ploidy. The stomatal density in diploid plants was around 1.67 times of that in polyploid plants. GC-MS analysis shows that the content of patchouli alcholol in the hairy root-derived polyploid plants was about 4.25 mg/g dry weight, which was 2.3 times of that in diploid plants. The present study demonstrates that polyploidization of hairy roots can stimulate the content of patchouli alcholol in medicinal plant of P. cablin. PMID:25507476

  18. Regeneration and Agrobacterium-mediated transformation of the apomictic species Eulaliopsis binata.

    Science.gov (United States)

    Ma, Kai; Hu, Chun Gen; Xu, Bing; Yao, Jia Ling

    2013-09-01

    Protocols for regeneration and Agrobacterium-mediated transformation of the apomictic species Eulaliopsis binata were developed. Initially, seeds of four genotypes of E. binata were incubated on a callus induction Murashige and Skoog (MS) basal medium supplemented with three concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D). It was found that 36.2 % of explants developed highly friable callus on medium containing 3.0 mg l(-1) 2,4-D. Based on frequency of callus induction, the genotype Neixiang was selected for regeneration and transformation. Callus incubated on MS basal medium supplemented with 0.2 mg l(-1) α-naphthalene acetic acid and 6.0 mg l(-1) 6-furfuryl-aminopurine developed shoots. Subsequently, Agrobacterium tumefaciens strain EHA105-harboring a plasmid pCAMBIA1381 carrying a hygromycin phosphotransferase (hpt) resistance gene and a synthetic green fluorescent protein (GFP) gene, both driven by the cauliflower mosaic virus 35S promoter-was used for transformation system. Putative transgenic callus was obtained following two cycles of hygromycin selection. Expression of the transgene(s) in putative transgenic callus was analyzed using the GFP detection. Molecular identification of putative transformed shoots was performed by polymerase chain reaction and Southern blot analysis to confirm presence and integration of the hpt gene.

  19. Evolutionarily advanced ant farmers rear polyploid fungal crops

    DEFF Research Database (Denmark)

    Kooij, Pepijn Wilhelmus; Aanen, D.K.; Schiøtt, Morten;

    2015-01-01

    Innovative evolutionary developments are often related to gene or genome duplications. The crop fungi of attine fungus-growing ants are suspected to have enhanced genetic variation reminiscent of polyploidy, but this has never been quantified with cytological data and genetic markers. We estimated...... the number of nuclei per fungal cell for 42 symbionts reared by 14 species of Panamanian fungus-growing ants. This showed that domesticated symbionts of higher attine ants are polykaryotic with 7-17 nuclei per cell, whereas nonspecialized crops of lower attines are dikaryotic similar to most free......-living basidiomycete fungi. We then investigated how putative higher genetic diversity is distributed across polykaryotic mycelia, using microsatellite loci and evaluating models assuming that all nuclei are either heterogeneously haploid or homogeneously polyploid. Genetic variation in the polykaryotic symbionts...

  20. Phylogeographic surveys and apomictic genetic connectivity in the North Atlantic red seaweed Mastocarpus stellatus.

    Science.gov (United States)

    Li, Jing-Jing; Hu, Zi-Min; Liu, Ruo-Yu; Zhang, Jie; Liu, Shao-Lun; Duan, De-Lin

    2016-01-01

    The North Atlantic red alga Mastocarpus stellatus is characterized by two life histories (sexual-type and direct-type), which correspond to two geographically isolated breeding groups. These features enable M. stellatus to be an interesting model to investigate how environmental shift and apomictic propagation have influenced its population genetic structure, historical demography and distribution dynamic. To test these ideas, we obtained 456 specimens from 15 locations on both sides of the North Atlantic and sequenced portion of the nuclear internal transcribed spacer (ITS), mitochondrial cox2-3 region (COX) and plastid RuBisCo spacer (RLS). Median-joining networks and ML trees inferred from COX and RLS consistently revealed two gene lineages (mtDNA: CN, CS; cpDNA: RN, RS). The concatenated COX and RLS markers yielded three cytotypes: a northern CN-RN, a southern CS-RS and a mixed cytotype CS-RN, which enabled us to roughly separate samples into D (direct-type life-cycle) and S (sexual-type life-cycle) groups (northern CN-RN and mixed cytotype CS-RN=D; southern CS-RS=S). Pairwise FST analysis of the D group revealed a high level of genetic differentiation both along European coasts and across the Atlantic basin. Bayesian skyline plots (BSPs) and IMa analyses indicated that M. stellatus underwent slight demographic expansion at the late-Pleistocene, with the beginning of divergence between lineages dating to c. 0.189Ma (95%HPD: 0.083-0.385Ma). IMa analyses also revealed asymmetric genetic exchange among European populations and a predominant postglacial trans-Atlantic migration from Norway and Galway Bay to North America. Our study highlights the importance of phylogeographic approaches to discover the imprints of climate change, life histories and gene flow in driving population genetic connectivity and biogeographic distribution of intertidal seaweeds in the North Atlantic. PMID:26528630

  1. Use of the SSLP-based method for detection of rare apomictic events in a sexual AtSERK1 transgenic Arabidopsis population

    NARCIS (Netherlands)

    Kantama, L.; Lambert, J.M.; Hu, H.; Jong, de H.; Vries, de S.C.; Russinova, E.

    2006-01-01

    Here we present a screening method to evaluate the potential of genes to transfer aspects of apomixis into sexual crop plants. Based on the assumption that an apomictic progeny is an exact genetic replica of the mother plant we employed a set of single sequence length polymorphism (SSLP) markers to

  2. Selection of reference genes for quantitative real-time PCR expression studies of microdissected reproductive tissues in apomictic and sexual Boechera

    Directory of Open Access Journals (Sweden)

    Amiteye Samuel

    2011-08-01

    Full Text Available Abstract Background Apomixis, a natural form of asexual seed production in plants, is considered to have great biotechnological potential for agriculture. It has been hypothesised that de-regulation of the sexual developmental pathway could trigger apomictic reproduction. The genus Boechera represents an interesting model system for understanding apomixis, having both sexual and apomictic genotypes at the diploid level. Quantitative qRT-PCR is the most extensively used method for validating genome-wide gene expression analyses, but in order to obtain reliable results, suitable reference genes are necessary. In this work we have evaluated six potential reference genes isolated from a 454 (FLX derived cDNA library of Boechera. RNA from live microdissected ovules and anthers at different developmental stages, as well as vegetative tissues of apomictic and sexual Boechera, were used to validate the candidates. Results Based on homologies with Arabidopsis, six genes were selected from a 454 cDNA library of Boechera: RPS18 (Ribosomal sub protein 18, Efalpha1 (Elongation factor 1 alpha, ACT 2 (Actin2, UBQ (polyubiquitin, PEX4 (Peroxisomal ubiquitin conjugating enzyme and At1g09770.1 (Arabidopsis thaliana cell division cycle 5. Total RNA was extracted from 17 different tissues, qRT-PCRs were performed, and raw Ct values were analyzed for primer efficiencies and gene ratios. The geNorm and normFinder applications were used for selecting the most stable genes among all tissues and specific tissue groups (ovule, anthers and vegetative tissues in both apomictic and sexual plants separately. Our results show that BoechRPS18, BoechEfα1, BoechACT2 and BoechUBQ were the most stable genes. Based on geNorm, the combinations of BoechRPS18 and BoechEfα1 or BoechUBQ and BoechEfα1 were the most stable in the apomictic plant, while BoechRPS18 and BoechACT2 or BoechUBQ and BoechACT2 performed best in the sexual plant. When subgroups of tissue samples were analyzed

  3. Segregation analysis of microsatellite (SSR) markers in sugarcane polyploids.

    Science.gov (United States)

    Lu, X; Zhou, H; Pan, Y-B; Chen, C Y; Zhu, J R; Chen, P H; Li, Y-R; Cai, Q; Chen, R K

    2015-01-01

    No information is available on segregation analysis of DNA markers involving both pollen and self-progeny. Therefore, we used capillary electrophoresis- and fluorescence-based DNA fingerprinting together with single pollen collection and polymerase chain reaction (PCR) to investigate simple sequence repeat (SSR) marker segregation among 964 single pollens and 288 self-progenies (S1) of sugarcane cultivar LCP 85-384. Twenty SSR DNA fragments (alleles) were amplified by five polymorphic SSR markers. Only one non-parental SSR allele was observed in 2392 PCRs. SSR allele inheritance was in accordance with Mendelian laws of segregation and independent assortment. Highly significant correlation coefficients were found between frequencies of observed and expected genotypes in pollen and S1 populations. Within the S1 population, the most frequent genotype of each SSR marker was the parental genotype of the same marker. The number of genotypes was higher in pollen than S1 population. PIC values of the five SSR markers were greater in pollen than S1 populations. Eleven of 20 SSR alleles (55%) were segregated in accordance with Mendelian segregation ratios expected from pollen and S1 populations of a 2n = 10x polyploid. Six of 20 SSR alleles were segregated in a 3:1 (presence:absence) ratio and were simplex markers. Four and one alleles were segregated in 77:4 and 143:1 ratios and considered duplex and triplex markers, respectively. Segregation ratios of remaining alleles were unexplainable. The results provide information about selection of crossing parents, estimation of seedling population optimal size, and promotion of efficient selection, which may be valuable for sugarcane breeders. PMID:26782486

  4. Coexistence and performance of diploid and polyploid Acacia senegal (L.) Willd

    DEFF Research Database (Denmark)

    Diallo, Adja Madjiguene

    populations within cytotypes revealed that the studied polyploid populations were more differentiated than diploid ones. The analysis of genetic relationships further suggest multiple origins of polyploid A. senegal and provide novel information for understanding the evolutionary history of the recently...... in all tested populations. In this study the growth rate of each tree could be estimated very precisely, because the sampled trees were part of a research trial, and the comparison between cytotypes in the progeny trial showed significantly higher growth rate of polyploids compared to diploid...... at this test site. A drought stress trial under controlled conditions (growth chamber) showed that diploid and tetraploids had similar growth rate when grown under well watered conditions, but tetraploids grew faster than diploids when subjected to drought stress. The findings suggest that presence...

  5. Transgressive phenotypes and generalist pollination in the floral evolution of Nicotiana polyploids.

    Science.gov (United States)

    McCarthy, Elizabeth W; Chase, Mark W; Knapp, Sandra; Litt, Amy; Leitch, Andrew R; Le Comber, Steven C

    2016-01-01

    Polyploidy is an important driving force in angiosperm evolution, and much research has focused on genetic, epigenetic and transcriptomic responses to allopolyploidy. Nicotiana is an excellent system in which to study allopolyploidy because half of the species are allotetraploids of different ages, allowing us to examine the trajectory of floral evolution over time. Here, we study the effects of allopolyploidy on floral morphology in Nicotiana, using corolla tube measurements and geometric morphometrics to quantify petal shape. We show that polyploid morphological divergence from the intermediate phenotype expected (based on progenitor morphology) increases with time for floral limb shape and tube length, and that most polyploids are distinct or transgressive in at least one trait. In addition, we show that polyploids tend to evolve shorter and wider corolla tubes, suggesting that allopolyploidy could provide an escape from specialist pollination via reversion to more generalist pollination strategies. PMID:27501400

  6. Genetic variability in apomictic mangosteen (Garcinia mangostana and its close relatives (Garcinia spp. based on ISSR markers

    Directory of Open Access Journals (Sweden)

    SOBIR

    2011-04-01

    Full Text Available Sobir, Poerwanto R, Santosa E, Sinaga S, Mansyah E (2011 Genetic variability in apomictic mangosteen (Garcinia mangostana and its close relatives (Garcinia spp. based on ISSR markers. Biodiversitas 12: 59-63. In order to reveal phylogenetic relationship of mangosteen and several close relatives (Garcinia spp., we employed seven ISSR dinucleotide primer systems on eleven close relatives of mangosteen and 28 mangosteen accessions from four islands in Indonesia (Sumatra, Java, Kalimantan and Lombok. ISSR analysis successfully amplified 43 bands on average 6.1 fragments for each primer system, and these all fragments were polymorphic. Seven close relatives of mangosteen were separated with mangosteen accessions at 0.22 level of dissimilarity, while other four including G. malaccensis, were clustered with mangosteen accessions, this results supported proposal that G. malaccensis was allopolyploid derivative of mangosteen. Clustering pattern among mangosteen accessions, however, not represented their origin, indicated that distribution of the accessions was not linked to their genetic properties.

  7. [Induction of polyploid in hairy roots of Nicotiana tabacum and its plant regeneration].

    Science.gov (United States)

    Hou, Lili; Shi, Heping; Yu, Wu; Tsang, Po Keung Eric; Chow, Cheuk Fai Stephen

    2014-04-01

    By genetic transformation with Agrobacterum rhizogenes and artificial chromosome doubling techniques, we studied the induction of hairy roots and their polyploidization, and subsequent plant regeneration and nicotine determination to enhance the content of nicotine in Nicotiana tabacum. The results show that hairy roots could be induced from the basal surface of leaf explants of N. tabacum 8 days after inoculation with Agrobacterium rhizogenes ATCC15834. The percentage of the rooting leaf explants was 100% 15 days after inoculation. The hairy roots could grow rapidly and autonomously on solid or liquid phytohormones-free MS medium. The transformation was confirmed by PCR amplification of rol gene of Ri plasmid and paper electrophoresis of opines from N. tabacum hairy roots. The highest rate of polyploidy induction, more than 64.71%, was obtained after treatment of hairy roots with 0.1% colchicine for 36 h. The optimum medium for plant regeneration from polyploid hairy roots was MS+2.0 mg/L 6-BA +0.2 mg/L NAA. Compared with the control diploid plants, the hairy roots-regenerated plants had weak apical dominance, more axillary buds and more narrow leaves; whereas the polyploid hairy root-regenerated plants had thicker stems, shorter internodes and the colour, width and thickness of leaves were significantly higher than that of the control. Observation of the number of chromosomes in their root tip cells reveals that the obtained polyploid regenerated plants were tetraploidy, with 96 (4n = 96) chromosomes. Pot-grown experiments showed compared to the control, the flowering was delayed by 21 days in diploid hairy roots-regenerated plants and polyploid hairy root-regenerated plants. GC-MS detection shows that the content of nicotine in polyploid plants was about 6.90 and 4.57 times the control and the diploid hairy roots-regenerated plants, respectively. PMID:25195248

  8. The involvement of human-nuc gene in polyploidization of K562 cell line.

    Science.gov (United States)

    Cavalloni, G; Danè, A; Piacibello, W; Bruno, S; Lamas, E; Bréchot, C; Aglietta, M

    2000-12-01

    During megakaryocyte differentiation, the immature megakaryocyte increases its ploidy to a 2(x) DNA content by a process called endomitosis. This leads to the formation of a giant cell, the mature megakaryocyte, which gives rise to platelets. We investigated the role of human-nuc (h-nuc), a gene involved in septum formation in karyokynesis in yeast, during megakaryocytic polyploidization. Nocodazole and 12-O-tetradecanoylphorbol-13-acetate (TPA) were used to induce megakaryocytic differentiation in K562 cell line. The ploidy distribution and CD41 expression of treated K562 cells were evaluated by flow cytometry. Using quantitative reverse transcriptase polymerase chain reaction (RT-PCR), we analyzed the h-nuc mRNA expression on treated K562 cells. Mature megakaryocyte-like polyploid cells were detected at day 5-7 of treatment with nocodazole. TPA also had a similar effect on K562 cells, but it was much weaker than that of nocodazole. The analysis of ploidy of nocodazole-treated K562 cells showed that nocodazole preferentially induced polyploidization of K562 cell line with a pronounced increase of the cells 8N at day 7 of culture. Expression of CD41, a differentiation-related phenotype, was significantly induced by TPA after 7 days of treatment, showing that functional maturation was mainly induced by TPA. In contrast, there was no significant increase in CD41 expression in nocodazole-treated K562 cells, suggesting that polyploidization and functional maturation are separately regulated during megakaryocytopoiesis. RT-PCR analysis indicated that h-nuc mRNA increased after 72 hours in the presence of nocodazole, preceding the induction of polyploidization. Our data indicate that h-nuc might play a role in polyploidization during megakaryocytic differentiation via inhibition of septum formation.

  9. ITS polymorphisms shed light on hybrid evolution in apomictic plants: a case study on the Ranunculus auricomus complex.

    Science.gov (United States)

    Hodač, Ladislav; Scheben, Armin Patrick; Hojsgaard, Diego; Paun, Ovidiu; Hörandl, Elvira

    2014-01-01

    The reconstruction of reticulate evolutionary histories in plants is still a major methodological challenge. Sequences of the ITS nrDNA are a popular marker to analyze hybrid relationships, but variation of this multicopy spacer region is affected by concerted evolution, high intraindividual polymorphism, and shifts in mode of reproduction. The relevance of changes in secondary structure is still under dispute. We aim to shed light on the extent of polymorphism within and between sexual species and their putative natural as well as synthetic hybrid derivatives in the Ranunculus auricomus complex to test morphology-based hypotheses of hybrid origin and parentage of taxa. We employed direct sequencing of ITS nrDNA from 68 individuals representing three sexuals, their synthetic hybrids and one sympatric natural apomict, as well as cloning of ITS copies in four representative individuals, RNA secondary structure analysis, and landmark geometric morphometric analysis on leaves. Phylogenetic network analyses indicate additivity of parental ITS variants in both synthetic and natural hybrids. The triploid synthetic hybrids are genetically much closer to their maternal progenitors, probably due to ploidy dosage effects, although exhibiting a paternal-like leaf morphology. The natural hybrids are genetically and morphologically closer to the putative paternal progenitor species. Secondary structures of ITS1-5.8S-ITS2 were rather conserved in all taxa. The observed similarities in ITS polymorphisms suggest that the natural apomict R. variabilis is an ancient hybrid of the diploid sexual species R. notabilis and the sexual species R. cassubicifolius. The additivity pattern shared by R. variabilis and the synthetic hybrids supports an evolutionary and biogeographical scenario that R. variabilis originated from ancient hybridization. Concerted evolution of ITS copies in R. variabilis is incomplete, probably due to a shift to asexual reproduction. Under the condition of

  10. ITS polymorphisms shed light on hybrid evolution in apomictic plants: a case study on the Ranunculus auricomus complex.

    Directory of Open Access Journals (Sweden)

    Ladislav Hodač

    Full Text Available The reconstruction of reticulate evolutionary histories in plants is still a major methodological challenge. Sequences of the ITS nrDNA are a popular marker to analyze hybrid relationships, but variation of this multicopy spacer region is affected by concerted evolution, high intraindividual polymorphism, and shifts in mode of reproduction. The relevance of changes in secondary structure is still under dispute. We aim to shed light on the extent of polymorphism within and between sexual species and their putative natural as well as synthetic hybrid derivatives in the Ranunculus auricomus complex to test morphology-based hypotheses of hybrid origin and parentage of taxa. We employed direct sequencing of ITS nrDNA from 68 individuals representing three sexuals, their synthetic hybrids and one sympatric natural apomict, as well as cloning of ITS copies in four representative individuals, RNA secondary structure analysis, and landmark geometric morphometric analysis on leaves. Phylogenetic network analyses indicate additivity of parental ITS variants in both synthetic and natural hybrids. The triploid synthetic hybrids are genetically much closer to their maternal progenitors, probably due to ploidy dosage effects, although exhibiting a paternal-like leaf morphology. The natural hybrids are genetically and morphologically closer to the putative paternal progenitor species. Secondary structures of ITS1-5.8S-ITS2 were rather conserved in all taxa. The observed similarities in ITS polymorphisms suggest that the natural apomict R. variabilis is an ancient hybrid of the diploid sexual species R. notabilis and the sexual species R. cassubicifolius. The additivity pattern shared by R. variabilis and the synthetic hybrids supports an evolutionary and biogeographical scenario that R. variabilis originated from ancient hybridization. Concerted evolution of ITS copies in R. variabilis is incomplete, probably due to a shift to asexual reproduction. Under the

  11. Synthetic polyploids of Tragopogon miscellus and T. mirus (Asteraceae): 60 Years after Ownbey's discovery.

    Science.gov (United States)

    Tate, Jennifer A; Symonds, V Vaughan; Doust, Andrew N; Buggs, Richard J A; Mavrodiev, Evgeny; Majure, Lucas C; Soltis, Pamela S; Soltis, Douglas E

    2009-05-01

    In plants, polyploidy has been a significant evolutionary force on both recent and ancient time scales. In 1950, Ownbey reported two newly formed Tragopogon allopolyploids in the northwestern United States. We have made the first synthetic lines of T. mirus and T. miscellus using T. dubius, T. porrifolius, and T. pratensis as parents and colchicine treatment of F(1) hybrids. We also produced allotetraploids between T. porrifolius and T. pratensis, which are not known from nature. We report on the crossability between the diploids, as well as the inflorescence morphology, pollen size, meiotic behavior, and fertility of the synthetic polyploids. Morphologically, the synthetics resemble the natural polyploids with short- and long-liguled forms of T. miscellus resulting when T. pratensis and T. dubius are reciprocally crossed. Synthetic T. mirus was also formed reciprocally, but without any obvious morphological differences resulting from the direction of the cross. Of the 27 original crosses that yielded 171 hybrid individuals, 18 of these lineages have persisted to produce 386 S(1) progeny; each of these lineages has produced S(2) seed that are viable. The successful generation of these synthetic polyploids offers the opportunity for detailed comparative studies of natural and synthetic polyploids within a nonmodel system. PMID:21628250

  12. Polyploid formation in cotton is not accompanied by rapid genomic changes.

    Science.gov (United States)

    Liu, B; Brubaker, C L; Mergeai, G; Cronn, R C; Wendel, J F

    2001-06-01

    Recent work has demonstrated that allopolyploid speciation in plants may be associated with non-Mendelian genomic changes in the early generations following polyploid synthesis. To address the question of whether rapid genomic changes also occur in allopolyploid cotton (Gossypium) species, amplified fragment length polymorphism (AFLP) analysis was performed to evaluate nine sets of newly synthesized allotetraploid and allohexaploid plants, their parents, and the selfed progeny from colchicine-doubled synthetics. Using both methylation-sensitive and methylation-insensitive enzymes, the extent of fragment additivity in newly combined genomes was ascertained for a total of approximately 22,000 genomic loci. Fragment additivity was observed in nearly all cases, with the few exceptions most likely reflecting parental heterozygosity or experimental error. In addition, genomic Southern analysis on six sets of synthetic allopolyploids probed with five retrotransposons also revealed complete additivity. Because no alterations were observed using methylation-sensitive isoschizomers, epigenetic changes following polyploid synthesis were also minimal. These indications of genomic additivity and epigenetic stasis during allopolyploid formation provide a contrast to recent evidence from several model plant allopolyploids, most notably wheat and Brassica, where rapid and unexplained genomic changes have been reported. In addition, the data contrast with evidence from repetitive DNAs in Gossypium, some of which are subject to non-Mendelian molecular evolutionary phenomena in extant polyploids. These contrasts indicate polyploid speciation in plants is accompanied by a diverse array of molecular evolutionary phenomena, which will vary among both genomic constituents and taxa. PMID:11444689

  13. Polyploid formation created unique avenues for response to selection in Gossypium (cotton).

    Science.gov (United States)

    Jiang, C; Wright, R J; El-Zik, K M; Paterson, A H

    1998-04-14

    A detailed restriction fragment length polymorphism map was used to determine the chromosomal locations and subgenomic distributions of quantitative trait loci (QTLs) segregating in a cross between cultivars of allotetraploid (AADD) Gossypium hirsutum ("Upland" cotton) and Gossypium barbadense ("Sea Island," "Pima," or "Egyptian" cotton) that differ markedly in the quality and quantity of seed epidermal fibers. Most QTLs influencing fiber quality and yield are located on the "D" subgenome, derived from an ancestor that does not produce spinnable fibers. D subgenome QTLs may partly account for the fact that domestication and breeding of tetraploid cottons has resulted in fiber yield and quality levels superior to those achieved by parallel improvement of "A" genome diploid cottons. The merger of two genomes with different evolutionary histories in a common nucleus appears to offer unique avenues for phenotypic response to selection. This may partly compensate for reduction in quantitative variation associated with polyploid formation and be one basis for the prominence of polyploids among extant angiosperms. These findings impel molecular dissection of the roles of divergent subgenomes in quantitative inheritance in many other polyploids and further exploration of both "synthetic" polyploids and exotic diploid genotypes for agriculturally useful variation.

  14. Studies on the Growth Habits and Characteristics of Two Polyploid Indica-Japonica Hybrid Rice with Powerful Heterosis

    Institute of Scientific and Technical Information of China (English)

    SONG Zhao-jian; DU Chao-qun; DAI Bing-cheng; CHEN Dong-ling; CHEN Jian-guo; CAI De-tian

    2007-01-01

    Based on a series of polyploid indica-japonica hybrid plant lines obtained from a new breeding strategy of using double predominance of wide cross and polyploidization to breed super rice, two polyploid indica-japonica hybrids, PSR073 and PSR120 were studied in their growth periods to show the powerful heterosis in a larger scale and to study the characteristics of polyploid indica-japonica hybrids more elaborately. The leaf age, tiller growth, flowering habits, and agronomic traits of them were observed to analyze their growth habits and characteristics. The results showed that the.agronomic traits of PSR073 and PSR 120, such as the plant height, panicle length, grain length, grain width, and 1000-grain weight, all acquired obvious predominance of polyploidy, and that the seed setting rate was more than 83%. No significant difference was observed between the two tetraploids and common diploids in the leaf age, tiller growth, and flowering habits. It was concluded that the characteristics of the two powerful heterosis polyploid hybrids were different from those of the polyploid rice reported earlier. Wide cross and polyploidization had no negative effects on their growth habits and characteristics; on the contrary these had powerful heterosis. This had provided theoretic and practical evidences for their application to agricultural production.

  15. Feasibility of physical map construction from fingerprinted bacterial artificial chromosome libraries of polyploid plant species

    Directory of Open Access Journals (Sweden)

    Doležel Jaroslav

    2010-02-01

    Full Text Available Abstract Background The presence of closely related genomes in polyploid species makes the assembly of total genomic sequence from shotgun sequence reads produced by the current sequencing platforms exceedingly difficult, if not impossible. Genomes of polyploid species could be sequenced following the ordered-clone sequencing approach employing contigs of bacterial artificial chromosome (BAC clones and BAC-based physical maps. Although BAC contigs can currently be constructed for virtually any diploid organism with the SNaPshot high-information-content-fingerprinting (HICF technology, it is currently unknown if this is also true for polyploid species. It is possible that BAC clones from orthologous regions of homoeologous chromosomes would share numerous restriction fragments and be therefore included into common contigs. Because of this and other concerns, physical mapping utilizing the SNaPshot HICF of BAC libraries of polyploid species has not been pursued and the possibility of doing so has not been assessed. The sole exception has been in common wheat, an allohexaploid in which it is possible to construct single-chromosome or single-chromosome-arm BAC libraries from DNA of flow-sorted chromosomes and bypass the obstacles created by polyploidy. Results The potential of the SNaPshot HICF technology for physical mapping of polyploid plants utilizing global BAC libraries was evaluated by assembling contigs of fingerprinted clones in an in silico merged BAC library composed of single-chromosome libraries of two wheat homoeologous chromosome arms, 3AS and 3DS, and complete chromosome 3B. Because the chromosome arm origin of each clone was known, it was possible to estimate the fidelity of contig assembly. On average 97.78% or more clones, depending on the library, were from a single chromosome arm. A large portion of the remaining clones was shown to be library contamination from other chromosomes, a feature that is unavoidable during the

  16. Cochicine-induced polyploidization depends on tubulin polymerization in c-metaphase cells

    OpenAIRE

    Caperta, A.; Delgado, M.; Ressurreição, F.; Meister, A.; Jones, R.N.; Viegas, W.; Houben, A.

    2006-01-01

    The microtubule cytoskeleton plays a crucial role in the cell cycle and in mitosis. Colchicine is a microtubule-depolymerizing agent that has long been used to induce chromosome individualization in cells arrested at metaphase and also in the induction of polyploid plants. Although attempts have been made to explain the processes and mechanisms underlying polyploidy induction, the role of the cytoskeleton still remains largely unknown. Through immunodetection of alpha-tub...

  17. Features micropropagation of apple gene Vf and the possibility of inducing polyploid meristems of in vitro

    Directory of Open Access Journals (Sweden)

    Valentina Djafarova

    2013-04-01

    Full Text Available The article summarizes the features of the two stages of micropropagation immune to scab of apple varieties. Introduction and optimization stages of micropropagation can replicate the variety in the form of buds and shoots (conglomerates. Tackling kidney for kolhitsinirovaniya allowed to identify the best options: adventitious buds the size of 3-4 mm and apical - up to 5 mm. On the basis of changes in ploidy meristems from kolhitsinirovaniya concludes the possibility of inducing mitotic polyploid

  18. Colchicine-induced polyploidization depends on tubulin polymerization in c-metaphase cells.

    Science.gov (United States)

    Caperta, A D; Delgado, M; Ressurreição, F; Meister, A; Jones, R N; Viegas, W; Houben, A

    2006-05-01

    The microtubule cytoskeleton plays a crucial role in the cell cycle and in mitosis. Colchicine is a microtubule-depolymerizing agent that has long been used to induce chromosome individualization in cells arrested at metaphase and also in the induction of polyploid plants. Although attempts have been made to explain the processes and mechanisms underlying polyploidy induction, the role of the cytoskeleton still remains largely unknown. Through immunodetection of alpha-tubulin, different concentrations (0.5 or 5 mM) of colchicine were found to produce opposite effects in the organization of the cytoskeleton in rye (Secale cereale L.). A low concentration (0.5 mM) induced depolymerization of the microtubular cytoskeleton in all phases of the cell cycle. In contrast, a high concentration (5 mM) was found to induce the polymerization of new tubulin-containing structures in c-metaphase cells. Furthermore, both treatments also showed contrasting effects in the induction of polyploid cells. Flow cytometric analysis and quantitative assessments of nucleolus-organizing regions revealed that only the high-concentration colchicine treatment was effective in the formation of polyploid cells. Our studies indicate that spindle disruption alone is insufficient for the induction of polyploid cells. The absence of any tubulin structures in plants treated with colchicine at the low concentration induced cell anomalies, such as the occurrence of nuclei with irregular shape and/or (additional) micronuclei, 12 h after recovery, pointing to a direct effect on cell viability. In contrast, the almost insignificant level of cell anomalies in the high-concentration treatment suggests that the presence of new tubulin-containing structures allows the reconstitution of 4C nuclei and their progression into the cell cycle. PMID:16520877

  19. Number of nucleoli in diploids and polyploids of the genus Achillea L.

    Directory of Open Access Journals (Sweden)

    Janina Dąbrowska

    2014-02-01

    Full Text Available Nucleoli were counted in 9228 interphase nuclei of the apical root meristem of 40 Achillea L. taxa (di-, tetra-. hexa- and octoploids. It was established that the distribution of nucleoli number in an interphase nucleus can be used as a rough practical indicator to distinguish between diploids and polyploids. The highest number of nucleoli (12 was found in an octoploid Achillea pannonica, but only in a small percentage of the nuclei (0.3% out of 283 nuclei.

  20. Akt1/PKB upregulation leads to vascular smooth muscle cell hypertrophy and polyploidization

    OpenAIRE

    Hixon, Mary L.; Muro-Cacho, Carlos; Wagner, Mark W.; Obejero-Paz, Carlos; Millie, Elise; Fujio, Yasushi; Kureishi, Yasuko; Hassold, Terry; Walsh, Kenneth; Gualberto, Antonio

    2000-01-01

    Vascular smooth muscle cells (VSMCs) at capacitance arteries of hypertensive individuals and animals undergo marked age- and blood pressure–dependent polyploidization and hypertrophy. We show here that VSMCs at capacitance arteries of rat models of hypertension display high levels of Akt1/PKB protein and activity. Gene transfer of Akt1 to VSMCs isolated from a normotensive rat strain was sufficient to abrogate the activity of the mitotic spindle cell–cycle checkpoint, promoting polyploidizati...

  1. Karyomorphometry on three polyploid species of Arum L. (Araceae, Aroideae)

    OpenAIRE

    Alessio Turco; Pietro Medagli; Antonella Albano; Saverio D'Emerico

    2014-01-01

    In this study three polyploid Arum Linnaeus, 1753 species from Southern Italy were chromosomally investigated. Arum italicum Miller, 1768 was found to have 2n = 84 chromosomes and a karyotype composed of numerous asymmetric chromosomes. Arum maculatum Linnaeus, 1753 and A. apulum (Carano) P. C. Boyce, 1993 were found to have 2n = 56 chromosomes. In the examined taxa some chromosome pairs were characterized by the presence of weakly coloured Feulgen-stained segments. The karyotype morphology o...

  2. Artificially induced polyploidization in Humulus lupulus L. and its effect on morphological and chemical traits.

    Science.gov (United States)

    Trojak-Goluch, Anna; Skomra, Urszula

    2013-12-01

    Chemically induced polyploids were obtained by the colchicine treatment of shoot tips of Humulus lupulus L. 'Sybilla'. Flow cytometry revealed that most of the treatments resulted in the production of tetraploids. The highest number of tetraploids was obtained when explants were immersed in 0.05% colchicine for 48 h. A field experiment was conducted to compare diploid and tetraploid plants and assess the effect of genome polyploidization on the morphological and chemical characteristics. Tetraploids showed significant differences in relation to diploids. They had thinner and shorter shoots. The influence of chromosome doubling was also reflected in the length, width and area of leaves. The length of female flowers in the tetraploids was significantly shorter than that observed in diploids. Tetraploids produced a diverse number of lupuline glands that were almost twice as large as those observed in diploids. The most distinct effect of genome polyploidization was a significant increase in the weight of cones and spindles. Contents of major chemical constituents of hop cones was little affected by ploidy level. Total essential oils were significantly lower than those in diploids. However there was a significant increase in the proportion of humulene, caryophyllene and farnesene, oils desired by the brewing industry. PMID:24399911

  3. Polyploid evolution and Pleistocene glacial cycles: A case study from the alpine primrose Primula marginata (Primulaceae

    Directory of Open Access Journals (Sweden)

    Casazza Gabriele

    2012-04-01

    Full Text Available Abstract Background Recent studies highlighted the role of Pleistocene climatic cycles in polyploid speciation and of southern Alpine refugia as reservoirs of diversity during glacial maxima. The polyploid Primula marginata, endemic to the southwestern Alps, includes both hexaploid and dodecaploid cytotypes that show no ecological or morphological differences. We used flow cytometry to determine variation and geographic distribution of cytotypes within and between populations and analyses of chloroplast (cp and nuclear ribosomal (nr DNA sequences from the Internal Transcribed Spacer (ITS region to infer the evolutionary history of the two cytotypes and the auto- vs. allopolyploid origin of dodecaploid populations. Results We did not detect any intermediate cytotypes or variation of ploidy levels within populations. Hexaploids occur in the western and dodecaploids in the eastern part of the distributional range, respectively. The cpDNA and nrDNA topologies are in conflict, for the former supports shared ancestry between P. marginata and P. latifolia, while the latter implies common origins between at least some ITS clones of P. marginata and P. allionii. Conclusions Our results suggest an initial episode of chloroplast capture involving ancestral lineages of P. latifolia and P. marginata, followed by polyploidization between P. marginata-like and P. allionii-like lineages in a southern refugium of the Maritime Alps. The higher proportion of ITS polymorphisms in dodecaploid than in hexaploid accessions of P. marginata and higher total nucleotide diversity of ITS clones in dodecaploid vs. hexaploid individuals sequences are congruent with the allopolyploid hypothesis of dodecaploid origin.

  4. The origin of the C-genome and cytoplasm of Avena polyploids.

    Science.gov (United States)

    Nikoloudakis, N; Katsiotis, A

    2008-07-01

    The contribution of C-genome diploid species to the evolution of polyploid oats was studied using C-genome ITS-specific primers. SCAR analysis among Avena accessions confirmed the presence of C-genome ITS1-5.8S-ITS2 sequences in the genome of AACC and AACCDD polyploids. In situ hybridization and screening of more than a thousand rRNA clones in Avena polyploid species containing the C-genome revealed substantial C-genome rRNA sequence elimination. C-genome clones sequenced and Maximum Likelihood Parsimony analysis revealed close proximity to Avena ventricosa ITS1-5.8S-ITS2 sequences, providing strong evidence of the latter's active role in the evolution of tetraploid and hexaploid oats. In addition, cloning and sequencing of the chloroplastic trnL intron among the most representative Avena species verified the maternal origin of A-genome for the AACC interspecific hybrid formation, which was the genetic bridge for the establishment of cultivated hexaploid oats.

  5. Activation of latent nucleolus organizers induced by experimental polyploidization in cells of hexaploid wheat Triticum aestivum L.

    Science.gov (United States)

    Lazareva, E M; Khoudoleeva, O A; Chentsov YuS; Polyakov VYu

    2000-01-01

    The effect of prolonged colchicine-induced polyploidization on activation of latent nucleolus-organizing regions (NOR) of chromosomes was studied in diploid meristematic cells and polyploid root cells of Triticum aestivum L. It has been shown that control diploid and tetraploid cells have maximal number of nucleoli equal to four, which corresponds to the number of nucleolar chromosomes (NC) with active (visualized by staining with AgNO3) NOR (two pairs of homologous chromosomes 1B and 6B). Treatment of wheat seedlings with colchicine for 30 h results in following changes in polyploid cells: (1) impregnation of NOR with silver is observed on homologues of either chromosomes 1A or 5D in all tetraploid metaphase plates (4n, 2x, 4c), which is indicative of the NOR activation on this chromosome in pre-mitotic polyploid interphase; (2) In tetraploid metaphase, NOR in all four homologues of activated chromosomes or in only two of them may be stained; (3) maximal number of nucleoli in tetraploid nuclei is increased till 12, which confirms activation of transcription of additional rRNA gene clusters in polyploids; (4) activation of the rRNA gene expression is induced by the cell polyploidization rather than by colchicine, since in the colchicine-treated diploid cells both maximal number of nucleoli and the number of metaphase chromosomes with active NOR is not changed as compared with control. The obtained data allow us to suggest that structural "separation" of NC in polyploid nuclei stimulates activation of latent NOR. PMID:11093578

  6. Gene expression regulation and lineage evolution: the North and South tale of the hybrid polyploid Squalius alburnoides complex

    Science.gov (United States)

    Pala, Irene; Schartl, Manfred; Brito, Miguel; Vacas, Joana Malta; Coelho, Maria Manuela

    2010-01-01

    The evolution of hybrid polyploid vertebrates, their viability and their perpetuation over evolutionary time have always been questions of great interest. However, little is known about the impact of hybridization and polyploidization on the regulatory networks that guarantee the appropriate quantitative and qualitative gene expression programme. The Squalius alburnoides complex of hybrid fish is an attractive system to address these questions, as it includes a wide variety of diploid and polyploid forms, and intricate systems of genetic exchange. Through the study of genome-specific allele expression of seven housekeeping and tissue-specific genes, we found that a gene copy silencing mechanism of dosage compensation exists throughout the distribution range of the complex. Here we show that the allele-specific patterns of silencing vary within the complex, according to the geographical origin and the type of genome involved in the hybridization process. In southern populations, triploids of S. alburnoides show an overall tendency for silencing the allele from the minority genome, while northern population polyploids exhibit preferential biallelic gene expression patterns, irrespective of genomic composition. The present findings further suggest that gene copy silencing and variable expression of specific allele combinations may be important processes in vertebrate polyploid evolution. PMID:20554543

  7. Involvement of Receptor Activator of Nuclear Factor-κB Ligand (RANKL)-induced Incomplete Cytokinesis in the Polyploidization of Osteoclasts.

    Science.gov (United States)

    Takegahara, Noriko; Kim, Hyunsoo; Mizuno, Hiroki; Sakaue-Sawano, Asako; Miyawaki, Atsushi; Tomura, Michio; Kanagawa, Osami; Ishii, Masaru; Choi, Yongwon

    2016-02-12

    Osteoclasts are specialized polyploid cells that resorb bone. Upon stimulation with receptor activator of nuclear factor-κB ligand (RANKL), myeloid precursors commit to becoming polyploid, largely via cell fusion. Polyploidization of osteoclasts is necessary for their bone-resorbing activity, but the mechanisms by which polyploidization is controlled remain to be determined. Here, we demonstrated that in addition to cell fusion, incomplete cytokinesis also plays a role in osteoclast polyploidization. In in vitro cultured osteoclasts derived from mice expressing the fluorescent ubiquitin-based cell cycle indicator (Fucci), RANKL induced polyploidy by incomplete cytokinesis as well as cell fusion. Polyploid cells generated by incomplete cytokinesis had the potential to subsequently undergo cell fusion. Nuclear polyploidy was also observed in osteoclasts in vivo, suggesting the involvement of incomplete cytokinesis in physiological polyploidization. Furthermore, RANKL-induced incomplete cytokinesis was reduced by inhibition of Akt, resulting in impaired multinucleated osteoclast formation. Taken together, these results reveal that RANKL-induced incomplete cytokinesis contributes to polyploidization of osteoclasts via Akt activation.

  8. Genetic compensation abilities of Aegilops speltoides chromosomes for homoeologous B-genome chromosomes of polyploid wheat in disomic S(B) chromosome substitution lines

    Science.gov (United States)

    The S genome of Aegilops speltoides is closely related to the B and G genomes of polyploid wheats. However, little work has been reported on the genetic relationships between the S-genome and B-genome chromosomes of polyploid wheat. Here we report the isolation of a set of disomic substitutions (DS)...

  9. In vitro colchicine-induced polyploid plantlet production and regeneration from leaf explants of the diploid pear (Pyrus communis L.) cultivar, 'Fertility'

    Science.gov (United States)

    Polyploid plantlets, including triploid, tetraploid and other polyploids, were induced from in vitro leaves of a European pear (Pyrus communis L.) cultivar 'Fertility' by a colchicine treatment. In vitro leaves were incubated in 0.4% colchicine solution for 24, 48 or 72 h, and transferred to an adv...

  10. HANDS: a tool for genome-wide discovery of subgenome-specific base-identity in polyploids.

    KAUST Repository

    Mithani, Aziz

    2013-09-24

    The analysis of polyploid genomes is problematic because homeologous subgenome sequences are closely related. This relatedness makes it difficult to assign individual sequences to the specific subgenome from which they are derived, and hinders the development of polyploid whole genome assemblies.We here present a next-generation sequencing (NGS)-based approach for assignment of subgenome-specific base-identity at sites containing homeolog-specific polymorphisms (HSPs): \\'HSP base Assignment using NGS data through Diploid Similarity\\' (HANDS). We show that HANDS correctly predicts subgenome-specific base-identity at >90% of assayed HSPs in the hexaploid bread wheat (Triticum aestivum) transcriptome, thus providing a substantial increase in accuracy versus previous methods for homeolog-specific base assignment.We conclude that HANDS enables rapid and accurate genome-wide discovery of homeolog-specific base-identity, a capability having multiple applications in polyploid genomics.

  11. Inference of haplotypic phase and missing genotypes in polyploid organisms and variable copy number genomic regions

    Directory of Open Access Journals (Sweden)

    Balding David J

    2008-12-01

    Full Text Available Abstract Background The power of haplotype-based methods for association studies, identification of regions under selection, and ancestral inference, is well-established for diploid organisms. For polyploids, however, the difficulty of determining phase has limited such approaches. Polyploidy is common in plants and is also observed in animals. Partial polyploidy is sometimes observed in humans (e.g. trisomy 21; Down's syndrome, and it arises more frequently in some human tissues. Local changes in ploidy, known as copy number variations (CNV, arise throughout the genome. Here we present a method, implemented in the software polyHap, for the inference of haplotype phase and missing observations from polyploid genotypes. PolyHap allows each individual to have a different ploidy, but ploidy cannot vary over the genomic region analysed. It employs a hidden Markov model (HMM and a sampling algorithm to infer haplotypes jointly in multiple individuals and to obtain a measure of uncertainty in its inferences. Results In the simulation study, we combine real haplotype data to create artificial diploid, triploid, and tetraploid genotypes, and use these to demonstrate that polyHap performs well, in terms of both switch error rate in recovering phase and imputation error rate for missing genotypes. To our knowledge, there is no comparable software for phasing a large, densely genotyped region of chromosome from triploids and tetraploids, while for diploids we found polyHap to be more accurate than fastPhase. We also compare the results of polyHap to SATlotyper on an experimentally haplotyped tetraploid dataset of 12 SNPs, and show that polyHap is more accurate. Conclusion With the availability of large SNP data in polyploids and CNV regions, we believe that polyHap, our proposed method for inferring haplotypic phase from genotype data, will be useful in enabling researchers analysing such data to exploit the power of haplotype-based analyses.

  12. Five nuclear loci resolve the polyploid history of switchgrass (Panicum virgatum L. and relatives.

    Directory of Open Access Journals (Sweden)

    Jimmy K Triplett

    Full Text Available Polyploidy poses challenges for phylogenetic reconstruction because of the need to identify and distinguish between homoeologous loci. This can be addressed by use of low copy nuclear markers. Panicum s.s. is a genus of about 100 species in the grass tribe Paniceae, subfamily Panicoideae, and is divided into five sections. Many of the species are known to be polyploids. The most well-known of the Panicum polyploids are switchgrass (Panicum virgatum and common or Proso millet (P. miliaceum. Switchgrass is in section Virgata, along with P. tricholaenoides, P. amarum, and P. amarulum, whereas P. miliaceum is in sect. Panicum. We have generated sequence data from five low copy nuclear loci and two chloroplast loci and have clarified the origin of P. virgatum. We find that all members of sects. Virgata and Urvilleana are the result of diversification after a single allopolyploidy event. The closest diploid relatives of switchgrass are in sect. Rudgeana, native to Central and South America. Within sections Virgata and Urvilleana, P. tricholaenoides is sister to the remaining species. Panicum racemosum and P. urvilleanum form a clade, which may be sister to P. chloroleucum. Panicum amarum, P. amarulum, and the lowland and upland ecotypes of P. virgatum together form a clade, within which relationships are complex. Hexaploid and octoploid plants are likely allopolyploids, with P. amarum and P. amarulum sharing genomes with P. virgatum. Octoploid P. virgatum plants are formed via hybridization between disparate tetraploids. We show that polyploidy precedes diversification in a complex set of polyploids; our data thus suggest that polyploidy could provide the raw material for diversification. In addition, we show two rounds of allopolyploidization in the ancestry of switchgrass, and identify additional species that may be part of its broader gene pool. This may be relevant for development of the crop for biofuels.

  13. Maternal inheritance in polyploid fish inferred from mitochondrial ATPase genes analysis

    Institute of Scientific and Technical Information of China (English)

    Jinpeng Yan; Xinhong Guo; Shaojun Liu; Jun Xiao; Zhen Liu; Yubao Chen; Yun Liu

    2009-01-01

    The sequences of the ATPase8/6 genes for the triploid, tetraploid and pentaploid hybrids as well as for their male parent blunt snout bream were determined. In order to examine mitochondrial maternal inheritance, the sequences were subjected to a comparative sequence analysis with the homologous sequences of red crucian carp, their female parent, and zebrafish as the outgroup. Base compo-sition and variation as well as the divergences based on nucleotide sequences and deduced amino acid sequences were calculated. Phy-logenetic trees were also constructed with maximum parsimony (MP), minimum evolution (ME), neighbor joining (NJ) and the unweighted pair group method with arithmetic mean (UPGMA) algorithms in MEGA 3.1. The results showed that most nucleotide sub-stitutions occurred at the third codon position of the two genes and thus represented synonymous mutations. The nucleotide sequence divergences of the ATPase8/6 genes ranged from 0.0% to 21.6% among ingroup samples (three types of polyploids and their parents), and 27.0-28.2% between their ingroup and the outgroup samples. All the polyploids were considerably closer in sequence relationship to the female parent red crucian carp (0.0-3.3%) compared to their male parent blunt snout bream (21.0-21.6%). The phylogenetic trees also showed a similar result. In conclusion, the mitochondrial ATPase8/6 genes of artificial polyploid fish stringently indicated maternal inheritance. Our results also suggested that the ATPase8/6 genes are valuable genetic markers to track genealogies and variations in the progenies of the hybrids.

  14. Interploid and intraploid hybridizations to produce polyploid Haskap (Lonicera caerulea var. emphyllocalyx) plants

    OpenAIRE

    Miyashita, Tomomi; Hoshino, Yoichiro

    2015-01-01

    We produced polyploid Haskap (Lonicera caerulea var. emphyllocalyx) plants by performing interploid and intraploid crosses of wild accessions. Embryo rescue in a tetraploid (4x) × diploid (2x) cross produced triploid plants; reciprocal 2x × 4x cross failed to produce viable seeds. Intraploidy crosses of 4x × 4x produced mostly tetraploids but also several hexaploid (6x) and octoploid (8x) plants. Using hexaploids obtained from this cross, we examined reciprocal 4x–6x crosses and found that bo...

  15. Haplotype inference from unphased SNP data in heterozygous polyploids based on SAT

    Directory of Open Access Journals (Sweden)

    Achenbach Ute

    2008-07-01

    Full Text Available Abstract Background Haplotype inference based on unphased SNP markers is an important task in population genetics. Although there are different approaches to the inference of haplotypes in diploid species, the existing software is not suitable for inferring haplotypes from unphased SNP data in polyploid species, such as the cultivated potato (Solanum tuberosum. Potato species are tetraploid and highly heterozygous. Results Here we present the software SATlotyper which is able to handle polyploid and polyallelic data. SATlo-typer uses the Boolean satisfiability problem to formulate Haplotype Inference by Pure Parsimony. The software excludes existing haplotype inferences, thus allowing for calculation of alternative inferences. As it is not known which of the multiple haplotype inferences are best supported by the given unphased data set, we use a bootstrapping procedure that allows for scoring of alternative inferences. Finally, by means of the bootstrapping scores, it is possible to optimise the phased genotypes belonging to a given haplotype inference. The program is evaluated with simulated and experimental SNP data generated for heterozygous tetraploid populations of potato. We show that, instead of taking the first haplotype inference reported by the program, we can significantly improve the quality of the final result by applying additional methods that include scoring of the alternative haplotype inferences and genotype optimisation. For a sub-population of nineteen individuals, the predicted results computed by SATlotyper were directly compared with results obtained by experimental haplotype inference via sequencing of cloned amplicons. Prediction and experiment gave similar results regarding the inferred haplotypes and phased genotypes. Conclusion Our results suggest that Haplotype Inference by Pure Parsimony can be solved efficiently by the SAT approach, even for data sets of unphased SNP from heterozygous polyploids. SATlotyper is

  16. Basic chromosome numbers and polyploid levels in some South African and Australian grasses (Poaceae

    Directory of Open Access Journals (Sweden)

    J. J. Spies

    1991-12-01

    Full Text Available Chromosome numbers of 46 specimens of grasses, involving 24 taxa from South Africa and Australia, have been determined during the present study. For the first time chromosome numbers are given for Eragrostis sarmentosa (Thunb. Trin. (n = 20. Panicum aequinerve Nees (n = 18,  Digitaria argyrograpta (Nees Stapf (n = 9 and D. maitlandii Stapf & C.E. Hubb. (n = 9. Additional polyploid levels are described for Diplachne fusca (L. Beauv. ex Roem. & Schult. (n = 10 and Digitaria diagonalis (Nees Stapf var.  diagonalis (n = 9.B-chromosomes were observed in several different specimens. The presence of B-chromosomes often results in abnormal chromosomal behaviour during meiosis.

  17. Sorting duplicated loci disentangles complexities of polyploid genomes masked by genotyping by sequencing

    DEFF Research Database (Denmark)

    Limborg, Morten; Seeb, Lisa W.; Seeb, J. E.

    2016-01-01

    Many plants and animals of polyploid origin are currently enjoying a genomics explosion enabled by modern sequencing and genotyping technologies. However, routine filtering of duplicated loci in most studies using genotyping by sequencing introduces an unacceptable, but often overlooked, bias when...... in a genome. Evidence shows that these duplications facilitate adaptation through one of two pathways: neo-functionalization or increased gene expression. Filtering duplicates removes distal ends of some chromosomes, and distal ends are especially known to harbour adaptively important genes. Thus, filtering...

  18. Halophilic archaea cultivated from surface sterilized middle-late eocene rock salt are polyploid.

    Directory of Open Access Journals (Sweden)

    Salla T Jaakkola

    Full Text Available Live bacteria and archaea have been isolated from several rock salt deposits of up to hundreds of millions of years of age from all around the world. A key factor affecting their longevity is the ability to keep their genomic DNA intact, for which efficient repair mechanisms are needed. Polyploid microbes are known to have an increased resistance towards mutations and DNA damage, and it has been suggested that microbes from deeply buried rock salt would carry several copies of their genomes. Here, cultivable halophilic microbes were isolated from a surface sterilized middle-late Eocene (38-41 million years ago rock salt sample, drilled from the depth of 800 m at Yunying salt mine, China. Eight unique isolates were obtained, which represented two haloarchaeal genera, Halobacterium and Halolamina. We used real-time PCR to show that our isolates are polyploid, with genome copy numbers of 11-14 genomes per cell in exponential growth phase. The ploidy level was slightly downregulated in stationary growth phase, but the cells still had an average genome copy number of 6-8. The polyploidy of halophilic archaea living in ancient rock salt might be a factor explaining how these organisms are able to overcome the challenge of prolonged survival during their entombment.

  19. Molecular Cytogenetics of Triticeae Polyploids: Lymegrass and Wheat x Lymegrass Hybrids

    International Nuclear Information System (INIS)

    The aim of this project was to develop molecular cytogenetic markers for identification and characterization of genomes of perennial polyploids in the tribe Triticeae (Poaceae), especially Leymus and related genera. These markers will enable taxonomic classification of this plant group, will lead to a better understanding of genetic resources for wheat breeding, can be used for verification of chromosome transfers into wheat crops and in triteymus breeding lines suitable for cultivation in cold climates. Two types of repetitive sequences have been obtained in this project: (A) dispersed retroelement-like sequences from the tetraploid Alaskan lymegrass species L. mollis and the octoploid Icelandic/European species L. arenarius, all of which are highly specific to the Nsgenome of Leymus and related genera, and (B) sub-heterochromatic satellite tandem repeats from the tetraploid American lymegrass species L. triticoides, sequences which are prevalent in North American lymegrass species but not detectable in European and Asiatic lymegrass. Both types of Ns specific sequences can be used for accurate identification of lymegrass chromosomes in natural polyploids and in breeding materials. (author)

  20. Meiotic behavior of two polyploid species of genus Pleurodema (Anura: Leiuperidae from central Argentina

    Directory of Open Access Journals (Sweden)

    Nancy E. Salas

    2014-06-01

    Full Text Available Polyploidy is an important evolutionary force but rare in vertebrates. However, in anurans, the genus Pleurodema has polyploid species, two of them tetraploid and one octoploid. The manner in which the chromosomes join in diakinesis can vary among species and, crucially, if they differ in their ploidy levels. In this work, we describe the meiotic configurations in two cryptic species from central Argentina, with different ploidy levels, Pleurodema kriegi (tetraploid and P. cordobae (octoploid. A total of 306 diakineses from 19 individuals were analyzed. In meiosis, P. kriegi form 22 bivalents, whereas P. cordobae exhibits variation in meiotic figures. We discuss the possible allo- and autopolyploid origin of these species, and we consider that the autopolyploid origin of P. cordobae from P. kriegi might be the most feasible.

  1. Quantification of ploidy in proteobacteria revealed the existence of monoploid, (mero-oligoploid and polyploid species.

    Directory of Open Access Journals (Sweden)

    Vito Pecoraro

    Full Text Available Bacteria are generally assumed to be monoploid (haploid. This assumption is mainly based on generalization of the results obtained with the most intensely studied model bacterium, Escherichia coli (a gamma-proteobacterium, which is monoploid during very slow growth. However, several species of proteobacteria are oligo- or polyploid, respectively. To get a better overview of the distribution of ploidy levels, genome copy numbers were quantified in four species of three different groups of proteobacteria. A recently developed Real Time PCR approach, which had been used to determine the ploidy levels of halophilic archaea, was optimized for the quantification of genome copy numbers of bacteria. Slow-growing (doubling time 103 minutes and fast-growing (doubling time 25 minutes E. coli cultures were used as a positive control. The copy numbers of the origin and terminus region of the chromosome were determined and the results were in excellent agreement with published data. The approach was also used to determine the ploidy levels of Caulobacter crescentus (an alpha-proteobacterium and Wolinella succinogenes (an epsilon-proteobacterium, both of which are monoploid. In contrast, Pseudomonas putida (a gamma-proteobacterium contains 20 genome copies and is thus polyploid. A survey of the proteobacteria with experimentally-determined genome copy numbers revealed that only three to four of 11 species are monoploid and thus monoploidy is not typical for proteobacteria. The ploidy level is not conserved within the groups of proteobacteria, and there are no obvious correlations between the ploidy levels with other parameters like genome size, optimal growth temperature or mode of life.

  2. Sequencing-based variant detection in the polyploid crop oilseed rape

    Science.gov (United States)

    2013-01-01

    Background The detection and exploitation of genetic variation underpins crop improvement. However, the polyploid nature of the genomes of many of our most important crops represents a barrier, particularly for the analysis of variation within genes. To overcome this, we aimed to develop methodologies based on amplicon sequencing that involve the incorporation of barcoded amplification tags (BATs) into PCR products. Results A protocol was developed to tag PCR products with 5’ 6-base oligonucleotide barcode extensions before pooling for sequencing library production using standard Illumina adapters. A computational method was developed for the de-convolution of products and the robust detection and scoring of sequence variants. Using this methodology, amplicons targeted to gene sequences were screened across a B. napus mapping population and the resulting allele scoring strings for 24 markers linkage mapped to the expected regions of the genome. Furthermore, using one-dimensional 8-fold pooling, 4608 lines of a B. napus mutation population were screened for induced mutations in a locus-specific amplicon (an orthologue of GL2.b) and mixed product of three co-amplified loci (orthologues of FAD2), identifying 10 and 41 mutants respectively. Conclusions The utilisation of barcode tags to de-convolute pooled PCR products in multiplexed, variation screening via Illumina sequencing provides a cost effective method for SNP genotyping and mutation detection and, potentially, markers for causative changes, even in polyploid species. Combining this approach with existing Illumina multiplexing workflows allows the analysis of thousands of lines cheaply and efficiently in a single sequencing run with minimal library production costs. PMID:23915099

  3. Increased phenotypic plasticity to climate may have boosted the invasion success of polyploid Centaurea stoebe.

    Directory of Open Access Journals (Sweden)

    Min A Hahn

    Full Text Available Phenotypic plasticity may allow organisms to cope with altered environmental conditions as e.g. after the introduction into a new range. In particular polyploid organisms, containing more than two sets of chromosomes, may show high levels of plasticity, which could in turn increase their environmental tolerance and invasiveness. Here, we studied the role of phenotypic plasticity in the invasion of Centaurea stoebe (Asteraceae, which in the native range in Europe occurs as diploids and tetraploids, whereas in the introduced range in North America so far only tetraploids have been found. In a common garden experiment at two sites in the native range, we grew half-sibs of the three geo-cytotypes (native European diploids, European tetraploids and invasive North American tetraploids from a representative sample of 27 populations. We measured the level and the adaptive significance of phenotypic plasticity in eco-physiological and life-history traits in response to the contrasting climatic conditions at the two study sites as well as three different soil conditions in pots, simulating the most crucial abiotic differences between the native and introduced range. European tetraploids showed increased levels of phenotypic plasticity as compared to diploids in response to the different climatic conditions in traits associated with rapid growth and fast phenological development. Moreover, we found evidence for adaptive plasticity in these traits, which suggests that increased plasticity may have contributed to the invasion success of tetraploid C. stoebe by providing an advantage under the novel climatic conditions. However, in invasive tetraploids phenotypic plasticity was similar to that of native tetraploids, indicating no evolution of increased plasticity during invasions. Our findings provide the first empirical support for increased phenotypic plasticity associated with polyploids, which may contribute to their success as invasive species in novel

  4. The pachytene checkpoint and its relationship to evolutionary patterns of polyploidization and hybrid sterility.

    Science.gov (United States)

    Li, X C; Barringer, B C; Barbash, D A

    2009-01-01

    Sterility is a commonly observed phenotype in interspecific hybrids. Sterility may result from chromosomal or genic incompatibilities, and much progress has been made toward understanding the genetic basis of hybrid sterility in various taxa. The underlying mechanisms causing hybrid sterility, however, are less well known. The pachytene checkpoint is a meiotic surveillance system that many organisms use to detect aberrant meiotic products, in order to prevent the production of defective gametes. We suggest that activation of the pachytene checkpoint may be an important mechanism contributing to two types of hybrid sterility. First, the pachytene checkpoint may form the mechanistic basis of some gene-based hybrid sterility phenotypes. Second, the pachytene checkpoint may be an important mechanism that mediates chromosomal-based hybrid sterility phenotypes involving gametes with non-haploid (either non-reduced or aneuploid) chromosome sets. Studies in several species suggest that the strength of the pachytene checkpoint is sexually dimorphic, observations that warrant future investigation into whether such variation may contribute to differences in patterns of sterility between male and female interspecific hybrids. In addition, plants seem to lack the pachytene checkpoint, which correlates with increased production of unreduced gametes and a higher incidence of polyploid species in plants versus animals. Although the pachytene checkpoint occurs in many animals and in fungi, at least some of the genes that execute the pachytene checkpoint are different among organisms. This finding suggests that the penetrance of the pachytene checkpoint, and even its presence or absence can evolve rapidly. The surprising degree of evolutionary flexibility in this meiotic surveillance system may contribute to the observed variation in patterns of hybrid sterility and in rates of polyploidization.

  5. Genetic basis and breeding application of clonal diversity and dual reproduction modes in polyploid Carassius auratus gibelio

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A unisexual species is generally associated with polyploidy, and reproduced by a unisexual reproduction mode, such as gyno- genesis, hybridogenesis or parthenogenesis. Compared with other unisexual and polyploid species, gibel carp (Carassius au- ratus gibelio) has a higher ploidy level of hexaploid. It has undergone several successive rounds of genome polyploidy, and experienced an additional, more recent genome duplication event. More significantly, the dual reproduction modes, including gynogenesis and sexual reproduction, have been demonstrated to coexist in the polyploid gibel carp. This article reviews the genetic basis concerning polyploidy origin, clonal diversity and dual reproduction modes, and outlines the progress in new va- riety breeding and gene identification involved in the reproduction and early development. The data suggests that gibel carp are under an evolutionary trajectory of diploidization. As a novel evolutionary developmental (Evo-Devo) biology model, this work highlights future perspectives about the functional divergence of duplicated genes and the sexual origin of vertebrate animals.

  6. Study Progress of Gossypium Polyploidization%棉属多倍化研究进展

    Institute of Scientific and Technical Information of China (English)

    王坤波; 刘旭

    2013-01-01

      多倍化在许多植物的物种形成及其随后的进化过程中发挥了关键作用。棉花是一个大属,一些棉种的起源发生过多倍体化,部分二倍体种是染色体二倍化的多倍体,比克氏棉最典型,拟似棉最复杂,还有D基因组的旱地棉和B基因组的3个种。陆地棉等5个异源四倍体种是多倍体化典型,是由A与D基因组近似的祖先种经过杂交和染色体加倍的双二倍体。它们的D亚组供体亲本种,前人认同的是雷蒙德氏棉,然而近期荧光原位杂交和叶绿体基因组学研究,提出了雷蒙德氏棉可能不是陆地棉亲本种的观点。四倍体棉种形成的多倍体化过程有多种推论,较为共识的时期是中更新世,结合近期包括叶绿体在内的基因组学的研究支持中更新世或更后些时候。荧光原位杂交、包括叶绿体在内的基因组学将为棉花多倍化分析提供更多的证据。%Polypoidization plays a key role in plant speciations and their evolution, the genus Gossypium, as a good example. Gossypum is a big genus in crops. There might exist polyploidy processes in most cotton species and many diploid cotton specie are a kind of polyploid which kept diploid chromosomes but existed polploidization. Gossypium bickii is a typical one and G. gossypioides is very special in the genus. The polyploidy indued species include G. aridum and three ones of B genome. In Gossypium allotetraploid speies is a typically polyploid origination. G. raimondii was generally considered as the closest donor of allotraploid cotton D-subgenome s but was not taken so at least to the G. hirsutum D-subgenome verified with gDNA-FISH. The allotraploid cotton sepeciation took place perhaps in Mid-Pleistocene or a little later. Recent FISH studies on cotton contributed much to speciations, interspecific relationships, and evolutions in Gossypium. There will be great advantages of FISH and genomics including cp-genome in

  7. Increase of genetic variation in 'Blue Daisy' (Brachycome multifida) by in-vitro mutagenesis and polyploidization

    International Nuclear Information System (INIS)

    'Blue Daisy' was recently introduced from Australia and became a popular ornamental in Europe, but it lacks genetic variation and does not produce seeds under European environment conditions. Thus, the development of new cultivars is handicapped. 'Blue Daisy' is vegetatively propagated by cuttings. Techniques were developed to increase genetic variation by in-vitro mutation induction and polyploidization. For in-vitro propagation nodal segments with one pinnate leaf were placed on MS-medium containing 0.1 mg/l NAA and 2 mg/l BAP (medium 'a') or 2 mg/l IAA and 0.2 mg/l BAP (medium 'b') solidified by 0.6% Oxoid agar. 25 deg C and 16 h illumination (800 lux) resulted in highest propagation rates. After 4 weeks on medium 'b' large numbers of axillary shoots could be cut off and placed for rooting on 1/3 strength MS-medium supplemented with 2 mg/l IAA. Another 3 weeks later plantlets could be transferred into the greenhouse for further cultivation. The chromosome number of B. multifida is 2n=14. Polyploidy was obtained by placing in-vitro derived explants for about 3 weeks on solid MS-medium 'a' containing 0.1% colchicine. The resulting axillary buds were transferred for 3-5 months to medium 'b' for shoot development. After rooting and transfer into the greenhouse polyploidy was first determined by comparison of pollen grains from treated and untreated plants. For confirmation, the number of chromosomes was counted using the orcein-acetic squash method. Two different polyploid types were obtained: one more erect and one more hanging phenotype, both having enlarged leaves and flowers. X-ray doses of 10-50 Gy were applied to freshly cut nodal segments. The explants were placed on solid medium 'b' in petri dishes. Inhibition of shoot development was used as criterium of radiosensitivity. The described procedure of in-vitro propagation of Brachycome during 3 years did not give any somaclonal variant. The shoots developing after application of X-rays were rooted and all

  8. 二十一世纪水稻育种新战略%A New Strategy of Rice Breeding in the 21st Century Ⅱ.Searching a New Pathway of Rice Breeding by Utilization of Double Heterosis of Wide Cross and Polyploidization

    Institute of Scientific and Technical Information of China (English)

    蔡得田; 袁隆平; 卢兴桂

    2001-01-01

    pairing of partial homologeous chromosomes, can be used to prevent the pairing of partial homologeous chromosomes in intergenomes of allopolyploid and formation of multivalent, chromosomal bridge, lag chromosome. These will ensure for their progenies with high rate of seed set and good stability in utilization of selecting allopolyploid rice and apomictic rice. Recent progress in this experiment have provided a good results. Using apomictic lines as a parent to cross with O.satva ssp indica and japonica and cross between O.sativa ssp Asian and American cultivars had obtained some superier polyploid plant lines with powerful heterosis and high up to 85% seed set. It has provided a very good background to realize the new breeding strategy.%本文论述了远缘杂交和多倍体化结合利用基因组间和多倍体杂种优势,开创水稻育种新途径的策略。纵观水稻育种的历史,无论是常规杂交育种,还是杂交稻育种,其研究战略都是建立在有性生殖和二倍体基础上的,归根结底,都是利用栽培稻同一基因组(A基因组)内优良基因的重组以及从野生稻向栽培稻引入少数优良基因。从作物进化趋势看,水稻是二倍体,基因组小、DNA含量低、染色体小,增加基因组数,提高倍性水平,利用异源多倍体杂种优势将是水稻育种新途径。针对同源四倍体水稻结实率低的关键问题,可采取拉大亲缘关系距离、减少多价体形成,应用广亲和、无融合生殖基因等措施,从遗传机理上提高多倍体水稻结实率。按三步实施战略:一、选用极端类型籼粳稻、爪哇稻,诱导亚种间杂种多倍体;二、诱导亚洲栽培稻和非洲栽培稻以及非洲野生稻种间杂种多倍体;三、诱导AA基因组的栽培稻与其它不同基因组野生稻(BB、CC、BBCC、CCDD、DD、EE、FF、GG、HHJJ)的种间多倍体。在实施过程中发挥一些特殊基因材料

  9. Sexual polyploidization in red clover Poliploidização sexual em trevo vermelho

    Directory of Open Access Journals (Sweden)

    Carine Simioni

    2006-02-01

    Full Text Available Because sexual polyploidization broadens genetic basis and supply plant breeders with more variability for the selection process, it can be useful in red clover breeding. This paper reports results of three crossing cycles, starting from a parental generation of tetraploid red clover plants (female parent, and diploids from the Quiñiqueli cultivar, selected for production of more than 1% of giant pollen grains (male parent aiming to obtain tetraploid plants to be used in red clover breeding programs. Crosses in the next generations were performed by mutual cross-pollinations. Chromosome number chimerism and high pollen sterility were detected in F1, F2 and F3, but there was a trend towards increasing seed production and seed viability along the generations, probably due to successful competition between fertile and sterile gametes. The identification of fertile triploids, as well as their recurrent formation along the generations, indicates that triploid block is not complete in red clover, and that triploids may be successfully used as a bridge for the production of sexual polyploids.Porque a poliploidização sexual amplia a base genética e proporciona aos melhoristas maior variabilidade para o processo de seleção, ela pode ser uma ferramenta útil ao melhoramento de trevo vermelho. Com o objetivo de obter plantas tetraplóides que possam ser utilizadas em programas de melhoramento de trevo vermelho, este trabalho relata resultados de três ciclos de cruzamentos, partindo de uma população parental de plantas tetraplóides de trevo vermelho, como genitores femininos, e de diplóides da cultivar Quiñiqueli, selecionados para produção de mais de 1% de grãos de pólen gigantes, como genitores masculinos. Nas outras gerações, os cruzamentos foram realizados por polinizações cruzadas mútuas. Quimerismo para número cromossômico e alta esterilidade de pólen foram detectados em F1 , F2 e F3, mas houve uma tendência para aumento da

  10. Circadian rhythms of sense and antisense transcription in sugarcane, a highly polyploid crop.

    Directory of Open Access Journals (Sweden)

    Carlos Takeshi Hotta

    Full Text Available Commercial sugarcane (Saccharum hybrid is a highly polyploid and aneuploid grass that stores large amounts of sucrose in its stem. We have measured circadian rhythms of sense and antisense transcription in a commercial cultivar (RB855453 using a custom oligoarray with 14,521 probes that hybridize to sense transcripts (SS and 7,380 probes that hybridize to antisense transcripts (AS.We estimated that 32% of SS probes and 22% AS probes were rhythmic. This is a higher proportion of rhythmic probes than the usually found in similar experiments in other plant species. Orthologs and inparalogs of Arabidopsis thaliana, sugarcane, rice, maize and sorghum were grouped in ortholog clusters. When ortholog clusters were used to compare probes among different datasets, sugarcane also showed a higher proportion of rhythmic elements than the other species. Thus, it is possible that a higher proportion of transcripts are regulated by the sugarcane circadian clock. Thirty-six percent of the identified AS/SS pairs had significant correlated time courses and 64% had uncorrelated expression patterns. The clustering of transcripts with similar function, the anticipation of daily environmental changes and the temporal compartmentation of metabolic processes were some properties identified in the circadian sugarcane transcriptome. During the day, there was a dominance of transcripts associated with photosynthesis and carbohydrate metabolism, including sucrose and starch synthesis. During the night, there was dominance of transcripts associated with genetic processing, such as histone regulation and RNA polymerase, ribosome and protein synthesis. Finally, the circadian clock also regulated hormone signalling pathways: a large proportion of auxin and ABA signalling components were regulated by the circadian clock in an unusual biphasic distribution.

  11. Assignment of SNP allelic configuration in polyploids using competitive allele-specific PCR: application to citrus triploid progeny

    Science.gov (United States)

    Cuenca, José; Aleza, Pablo; Navarro, Luis; Ollitrault, Patrick

    2013-01-01

    Background Polyploidy is a major component of eukaryote evolution. Estimation of allele copy numbers for molecular markers has long been considered a challenge for polyploid species, while this process is essential for most genetic research. With the increasing availability and whole-genome coverage of single nucleotide polymorphism (SNP) markers, it is essential to implement a versatile SNP genotyping method to assign allelic configuration efficiently in polyploids. Scope This work evaluates the usefulness of the KASPar method, based on competitive allele-specific PCR, for the assignment of SNP allelic configuration. Citrus was chosen as a model because of its economic importance, the ongoing worldwide polyploidy manipulation projects for cultivar and rootstock breeding, and the increasing availability of SNP markers. Conclusions Fifteen SNP markers were successfully designed that produced clear allele signals that were in agreement with previous genotyping results at the diploid level. The analysis of DNA mixes between two haploid lines (Clementine and pummelo) at 13 different ratios revealed a very high correlation (average = 0·9796; s.d. = 0·0094) between the allele ratio and two parameters [θ angle = tan−1 (y/x) and y′ = y/(x + y)] derived from the two normalized allele signals (x and y) provided by KASPar. Separated cluster analysis and analysis of variance (ANOVA) from mixed DNA simulating triploid and tetraploid hybrids provided 99·71 % correct allelic configuration. Moreover, triploid populations arising from 2n gametes and interploid crosses were easily genotyped and provided useful genetic information. This work demonstrates that the KASPar SNP genotyping technique is an efficient way to assign heterozygous allelic configurations within polyploid populations. This method is accurate, simple and cost-effective. Moreover, it may be useful for quantitative studies, such as relative allele-specific expression analysis and bulk segregant analysis

  12. Convergent adaptation to a marginal habitat by homoploid hybrids and polyploid ecads in the seaweed genus Fucus.

    Science.gov (United States)

    Coyer, James A; Hoarau, Galice; Pearson, Gareth A; Serrão, Ester A; Stam, Wytze T; Olsen, Jeanine L

    2006-09-22

    Hybridization and polyploidy are two major sources of genetic variability that can lead to adaptation in new habitats. Most species of the brown algal genus Fucus are found along wave-swept rocky shores of the Northern Hemisphere, but some species have adapted to brackish and salt marsh habitats. Using five microsatellite loci and mtDNA RFLP, we characterize two populations of morphologically similar, muscoides-like Fucus inhabiting salt marshes in Iceland and Ireland. The Icelandic genotypes were consistent with Fucus vesiculosus x Fucus spiralis F1 hybrids with asymmetrical hybridization, whereas the Irish ones consisted primarily of polyploid F. vesiculosus. PMID:17148415

  13. Convergent adaptation to a marginal habitat by homoploid hybrids and polyploid ecads in the seaweed genus Fucus

    Science.gov (United States)

    Coyer, James A; Hoarau, Galice; Pearson, Gareth A; Serrão, Ester A; Stam, Wytze T; Olsen, Jeanine L

    2006-01-01

    Hybridization and polyploidy are two major sources of genetic variability that can lead to adaptation in new habitats. Most species of the brown algal genus Fucus are found along wave-swept rocky shores of the Northern Hemisphere, but some species have adapted to brackish and salt marsh habitats. Using five microsatellite loci and mtDNA RFLP, we characterize two populations of morphologically similar, muscoides-like Fucus inhabiting salt marshes in Iceland and Ireland. The Icelandic genotypes were consistent with Fucus vesiculosus×Fucus spiralis F1 hybrids with asymmetrical hybridization, whereas the Irish ones consisted primarily of polyploid F. vesiculosus. PMID:17148415

  14. 百里香多倍化诱导技术研究%Polyploidizing Induction Technique in Thyme

    Institute of Scientific and Technical Information of China (English)

    戴丽娜; 吕国华; 聂传胜; 贾晓鹰; 权俊萍

    2013-01-01

    以百里香(T.quinquecostatus)种子为材料,研究了秋水仙素不同浓度及处理时间对其种子苗多倍化变异的影响.结果表明:0.20%秋水仙索处理6h的诱变效果最佳,种子发芽率为14.00%,种子苗形态变异率为5.00%.诱导后形成的多倍化植株表现为叶片变宽变大、叶色变深、茎变粗且节距变大等形态特征.叶片显微观测表明多倍化植株的气孔显著增大,单位叶面积气孔数目减少.染色体计数表明,多倍化植株染色体多为四倍体(2n=4x=48),还有少数六倍体和非整倍体,同时存在混倍化现象.%The thyme seeds were treated with colchicines at different concentration and treatment time,and the characteristics of polyploidization mutation seedling were studied.The results showed that the best treatment condition was 0.20 % colchicines with 6 hours,the seed germination rate was 14.00%,morphological variation rate was 5.00%.The morphology of polyploidizing induction seedlings mainly manifested as the wider blade,darker leaf color,and thicker stem and longer stem node.Microscopic observation of polyploidization mutation seedling showed that the size of stomata increased and density of stomata decreased significantly.Chromosome counts proved that most of polyploidization mutation plants were tetraploid (2n =4x =48),with small amount of hexploid and aneuploid plants.Meanwhile,there existed the few mixoploids phenomena.

  15. Re-annotation of the physical map of Glycine max for polyploid-like regions by BAC end sequence driven whole genome shotgun read assembly

    Directory of Open Access Journals (Sweden)

    Shultz Jeffry

    2008-07-01

    Full Text Available Abstract Background Many of the world's most important food crops have either polyploid genomes or homeologous regions derived from segmental shuffling following polyploid formation. The soybean (Glycine max genome has been shown to be composed of approximately four thousand short interspersed homeologous regions with 1, 2 or 4 copies per haploid genome by RFLP analysis, microsatellite anchors to BACs and by contigs formed from BAC fingerprints. Despite these similar regions,, the genome has been sequenced by whole genome shotgun sequence (WGS. Here the aim was to use BAC end sequences (BES derived from three minimum tile paths (MTP to examine the extent and homogeneity of polyploid-like regions within contigs and the extent of correlation between the polyploid-like regions inferred from fingerprinting and the polyploid-like sequences inferred from WGS matches. Results Results show that when sequence divergence was 1–10%, the copy number of homeologous regions could be identified from sequence variation in WGS reads overlapping BES. Homeolog sequence variants (HSVs were single nucleotide polymorphisms (SNPs; 89% and single nucleotide indels (SNIs 10%. Larger indels were rare but present (1%. Simulations that had predicted fingerprints of homeologous regions could be separated when divergence exceeded 2% were shown to be false. We show that a 5–10% sequence divergence is necessary to separate homeologs by fingerprinting. BES compared to WGS traces showed polyploid-like regions with less than 1% sequence divergence exist at 2.3% of the locations assayed. Conclusion The use of HSVs like SNPs and SNIs to characterize BACs wil improve contig building methods. The implications for bioinformatic and functional annotation of polyploid and paleopolyploid genomes show that a combined approach of BAC fingerprint based physical maps, WGS sequence and HSV-based partitioning of BAC clones from homeologous regions to separate contigs will allow reliable de

  16. Genetic similarity of polyploids - A new version of the computer program POPDIST (ver. 1.2.0) considers intraspecific genetic differentiation

    DEFF Research Database (Denmark)

    Tomiuk, Jürgen; Guldbrandtsen, Bernt; Loeschcke, Volker

    2009-01-01

    For evolutionary studies of polyploid species estimates of the genetic identity between species with different degrees of ploidy are particularly required because gene counting in samples of polyploid individuals often cannot be done, e.g., in triploids the phenotype AB can be genotypically eithe...... identity calculated on the basis of gene frequencies for any degree of ploidy. The new extended version of POPDIST (version 1.2.0) provides the option of choosing either the maximum-likelihood estimator or the band-sharing measure...

  17. Two unisexual artificial polyploid clones constructed by genome addition of common carp (Cyprinus carp) and crucian carp (Carassius auratus)

    Institute of Scientific and Technical Information of China (English)

    吴清江; 叶玉珍; 董新红

    2003-01-01

    A polyploid hybrid fish with natural gynogenesis can prevent segregation and maintain their hybrid vigor in their progenies. Supposing the reproduction mode of induced polyploid fish being natural gynogenesis, allopolyploid hybrid between common carp and crucian carp into allopolyploid was performed. The purpose of this paper is to describe a lineage from sexual diploid carp transforming into allotriploid and allotetraploid unisexual clones by genome addition. The diploid hybrid between common carp and crucian carp reproduces an unreduced nucleus consisting of two parental genomes. This unreduced female pronucleus will fuse with male pronucleus and form allotriploid zygote after penetration of related species sperms. Allotriploid embryos grow normally, and part of female allotriploid can produce unreduced mature ova with three genomes. Mature ova of most allotriploid females are provided with natural gynogenetic trait and their nuclei do not fuse with any entrance sperm. All female offspring are produced by gynogenesis of allotriploid egg under activation of penetrating sperms. These offspring maintain morphological traits of their allotriploid maternal and form an allotetraploid unisexual clone by gynogenetic reproduction mode. However, female nuclei of rare allotriploid female can fuse with penetrating male pronuclei and result in the appearance of allotetraploid individuals by means of genome addition. All allotetraploid females can reproduce unreduced mature eggs containing four genomes. Therefore, mature eggs of allotetraploid maintain gynogenetic trait and allotetraploid unisexual clone is produced under activation of related species sperms.

  18. Induced Polyploid Breeding of Ailanthus altissima%臭椿多倍体诱变的初步研究

    Institute of Scientific and Technical Information of China (English)

    岳建芳

    2012-01-01

    By modified agar method,the induced polyploid breeding of Ailanthus altissima(Mill.) swingle was carried with adding 0.2% colchicine solution into 1.0% agar solution for 24 h,48 h,72 h,respectively,which induction rates were 61.90%,62.07%,46.88%.According to morphological characteristics of polyploid,the biology characteristics of induced mutation were significantly related with the control.%用改良琼脂法,即0.2%秋水仙碱加1.0%琼脂溶胶对臭椿[Ailanthus altissima(Mill.)swingle.]进行24 h,48 h,72 h多倍体诱变,诱变率分别是61.90%,62.07%,46.88%.依据多倍体幼苗形态特征发现多倍体后代臭椿的生物学特征与对照相比有显著差异。

  19. Analysis of Triticum boeoticum and Triticum urartu seed defensins: To the problem of the origin of polyploid wheat genomes.

    Science.gov (United States)

    Odintsova, Tatyana I; Korostyleva, Tatyana V; Odintsova, Margarita S; Pukhalsky, Vitaliy A; Grishin, Eugene V; Egorov, Tsezi A

    2008-06-01

    The origin of polyploid wheat genomes has been the subject of numerous studies and is the key problem in wheat phylogeny. Different diploid species have been supposed to donate genomes to tetraploid and hexaploid wheat species. To shed light on phylogenetic relationships between the presumable A genome donors and hexaploid wheat species we have applied a new approach: the comparison of defensins from diploid Triticum species, Triticum boeoticum Boiss. and Triticum urartu Thum. ex Gandil., with previously characterized Triticum kiharae defensins [T.I. Odintsova et al., Biochimie 89 (2007) 605-612]. Defensins were isolated by acidic extraction of seeds followed by three-step chromatographic separation. Isolated defensins were identified by molecular masses using MALDI-TOF mass spectrometry and N-terminal sequencing. For the first time, we have shown that T. urartu defensins are more similar to those of the hexaploid wheat than T. boeoticum defensins, although variation among samples collected in different regions of the world was revealed. Our results clearly demonstrate that T. urartu of the Asian origin contributed the A genome to polyploid wheat species.

  20. Evolution of polyploid triticum wheats under cultivation: the role of domestication, natural hybridization and allopolyploid speciation in their diversification.

    Science.gov (United States)

    Matsuoka, Yoshihiro

    2011-05-01

    The evolution of the polyploid Triticum wheats is distinctive in that domestication, natural hybridization and allopolyploid speciation have all had significant impacts on their diversification. In this review, I outline the phylogenetic relationships of cultivated wheats and their wild relatives and provide an overview of the recent progress and remaining issues in understanding the genetic and ecological factors that favored their evolution. An attempt is made to view the evolution of the polyploid Triticum wheats as a continuous process of diversification that was initiated by domestication of tetraploid emmer wheat and driven by various natural events ranging from interploidy introgression via hybridization to allopolyploid speciation of hexaploid common wheat, instead of viewing it as a group of discrete evolutionary processes that separately proceeded at the tetraploid and hexaploid levels. This standpoint underscores the important role of natural hybridization in the reticulate diversification of the tetraploid-hexaploid Triticum wheat complex and highlights critical, but underappreciated, issues that concern the allopolyploid speciation of common wheat.

  1. A novel nucleo-cytoplasmic hybrid clone formed via androgenesis in polyploid gibel carp

    Directory of Open Access Journals (Sweden)

    Zhou Li

    2011-03-01

    Full Text Available Abstract Background Unisexual vertebrates have been demonstrated to reproduce by gynogenesis, hybridogenesis, parthenogenesis, or kleptogenesis, however, it is uncertain how the reproduction mode contributes to the clonal diversity. Recently, polyploid gibel carp has been revealed to possess coexisting dual modes of unisexual gynogenesis and sexual reproduction and to have numerous various clones. Using sexual reproduction mating between clone D female and clone A male and subsequent 7 generation multiplying of unisexual gynogenesis, we have created a novel clone strain with more than several hundred millions of individuals. Here, we attempt to identify genetic background of the novel clone and to explore the significant implication for clonal diversity contribution. Methods Several nuclear genome markers and one cytoplasmic marker, the mitochondrial genome sequence, were used to identify the genetic organization of the randomly sampled individuals from different generations of the novel clone. Results Chromosome number, Cot-1 repetitive DNA banded karyotype, microsatellite patterns, AFLP profiles and transferrin alleles uniformly indicated that nuclear genome of the novel clone is identical to that of clone A, and significantly different from that of clone D. However, the cytoplasmic marker, its complete mtDNA genome sequence, is same to that of clone D, and different from that of clone A. Conclusions The present data indicate that the novel clone is a nucleo-cytoplasmic hybrid between the known clones A and D, because it originates from the offspring of gonochoristic sexual reproduction mating between clone D female and clone A male, and contains an entire nuclear genome from the paternal clone A and a mtDNA genome (cytoplasm from the maternal clone D. It is suggested to arise via androgenesis by a mechanism of ploidy doubling of clone A sperm in clone D ooplasm through inhibiting the first mitotic division. Significantly, the selected nucleo

  2. Novel functions for atypical E2Fs, E2F7 and E2F8, in polyploidization and liver cancer

    NARCIS (Netherlands)

    Pandit, Shusil Kumar

    2014-01-01

    Atypical E2F transcription factors, E2F7 and E2F8, function as transcriptional repressors of E2F target genes and are crucial for controlling the cell proliferation. In this thesis, we reveal that these two factors are crucial for liver cell polyploidization, embryonic development and prevention of

  3. Research Progress on Polyploid Induction in Garlic%大蒜多倍体诱导及其研究进展

    Institute of Scientific and Technical Information of China (English)

    温艳斌; 程智慧

    2012-01-01

    多倍体植物在新开放或相对不稳定的环境中具有更强的生存能力和更大的生理生化灵活性,比二倍体祖先或近缘种更能耐受恶劣环境,在营养繁殖和多年生植物中具有明显的优势.多倍体育种是近代作物育种常用方法之一.大蒜作为我国的优势园艺作物,其多倍体研究也取得了一定的成绩.本文综述了国内外大蒜染色体多倍化技术研究的最新进展,分析了大蒜多倍体研究中存在的问题,并展望了大蒜多倍体育种技术的发展前景.%It is the physiological and biochemical flexibility that enable polyploid plants to possess stronger tolerance and viability than the diploid progenitors or relative species in adverse enviroment, especially for the vegetatively propagated or perennial plants. Polyploid breeding is widely adopted in crop breeding strategies. Some achievements have been made in polyploid aspect for garlic ( Allium sativum L. ) known as the traditionally horticultural crop in China. This paper gives an overview of the new progress made in the methods of polyploidization at home and abroad, and analyzes the existing problems in polyploid garlic breeding. The development of garlic breeding technology for the years to come is also prospected.

  4. Conjunctival polyploid cells and donor-derived myofibroblasts in ocular GvHD.

    Science.gov (United States)

    Hallberg, D; Stenberg, K; Hanson, C; Stenevi, U; Brune, M

    2016-05-01

    After allogeneic hematopoietic stem cell transplantation (allo-SCT), ocular GvHD is a common complication, typical symptoms being dry eye syndrome with features of fibrosis. In this study, we have identified and quantified two cell types-myofibroblasts (MFB) and polyploid (PP) cells-in the conjunctival surface of allo-SCT patients (pts) and have explored their kinetics and association with local and systemic GvHD. Results are compared with control groups of (a) pretransplant samples from allo-SCT patients, (b) recipients of autologous transplantation (auto-SCT) and (c) healthy controls. Imprint cytologies were obtained by pressing the conjunctival surface with a sterile, non-abrasive cellulose acetate filter (Millipore). After retraction, typically a monolayer of the outermost cells of the epithelium were retrieved. MFB were identified by immunofluorescent (IF) staining for alpha-smooth muscle protein. PP cells were detected by aberrant chromosome content analyzed via X/Y-FISH (X/Y fluorescence in situ hybridization). In female pts with a male donor (MF group), donor genotype were identified by sex chromosome detection using FISH methodology. IF and FISH methods were applied in situ on the same filter, and amounts of MFB and PP cells are expressed as the percentage of all cells on the filter. In all, 70 samples from 46 pts were obtained 1-122 months after allo-SCT. The total MFB density (MFB(TOT)) was higher in allo-SCT pts compared with healthy individuals and auto-SCT pts and increased by time after transplantation (Pobserved. In the MF group (n=25), both MFB(XY) and MFB(XX) were detected on 28 of the 37 imprints (76%). In pts >36 months post transplant, on 11/12 imprints, a median of 9.4% (1.4-39%) MFB(XY) and 3.6% (0-11%) MFB(XX) was found. In one patient, 1.6% MFB(XY) were detected at 3 weeks post transplant. PP cells (6-24n), exclusively of recipient origin, were found to a median of 0.6% (0-37%). The PP cell density differed significantly (Pcells at 3

  5. 大花蕙兰多倍体的高效诱导%High Efficient Polyploid Induction of Cymbidium hybridium

    Institute of Scientific and Technical Information of China (English)

    季必霞; 陈达伟; 张晨晨; 闵笛; 黄文静; 王钰

    2011-01-01

    The shoots of Cymbidium hybridium were soaked in colchicine solutions at different concentrations and treatment times to induce doubling of body cell chromosome. Ploidy levels were identified by morphological and cytological traits. The results showed that the treated shoots of C. Hybridium with 0.05% colchicine for 24 h had a higher inducing rate which was up to 28. 2%. The external morphology, the number of chloroplast as well as the number and size of stomata were obviously different between the diploid and polyploid. The nucleus of pol-yploid cell was obviously bigger and the number of chromosome was increased.%以大花蕙兰‘红瀑布’无菌苗丛芽为材料、秋水仙素为诱变剂,采用不同的处理浓度、时间诱导大花蕙兰体细胞加倍.通过形态学和细胞学观察、统计等方法对其进行倍性鉴定.结果表明:秋水仙素浓度0.05%,处理时间24h的条件下,诱导率高达28.2%;多倍体苗外部形态、叶绿体数目、气孔数目和大小与二倍体差异大,加倍后的细胞核明显变大,染色体倍数增加.

  6. Heterochromatin patterns and ribosomal DNA loci distribution in diploid and polyploid Crotalaria species (Leguminosae, Papilionoideae), and inferences on karyotype evolution.

    Science.gov (United States)

    Mondin, Mateus; Aguiar-Perecin, Margarida L R

    2011-09-01

    Most Crotalaria species display a symmetric karyotype with 2n = 16, but 2n = 14 is found in Chrysocalycinae subsection Incanae and 2n = 32 in American species of the section Calycinae. Seven species of the sections Chrysocalycinae, Calycinae, and Crotalaria were analyzed for the identification of heterochromatin types with GC- and AT-specific fluorochromes and chromosomal location of ribosomal DNA loci using fluorescent in situ hybridization (FISH). A major 45S rDNA locus was observed on chromosome 1 in all the species, and a variable number of minor ones were revealed. Only one 5S rDNA locus was observed in the species investigated. Chromomycin A(3) (CMA) revealed CMA(+) bands colocalized with most rDNA loci, small bands unrelated to ribosomal DNA on two chromosome pairs in Crotalaria incana, and CMA(+) centromeric bands that were quenched by distamycin A were detected in species of Calycinae and Crotalaria sections. DAPI(+) bands were detected in C. incana. The results support the species relationships based on flower specialization and were useful for providing insight into mechanisms of karyotype evolution. The heterochromatin types revealed by fluorochromes suggest the occurrence of rearrangements in repetitive DNA families in these heterochromatic blocks during species diversification. This DNA sequence turnover and the variability in number/position of rDNA sites could be interpreted as resulting from unequal crossing over and (or) transposition events. The occurrence of only one 5S rDNA locus and the smaller chromosome size in the polyploids suggest that DNA sequence losses took place following polyploidization events.

  7. Heterochromatin patterns and ribosomal DNA loci distribution in diploid and polyploid Crotalaria species (Leguminosae, Papilionoideae), and inferences on karyotype evolution.

    Science.gov (United States)

    Mondin, Mateus; Aguiar-Perecin, Margarida L R

    2011-09-01

    Most Crotalaria species display a symmetric karyotype with 2n = 16, but 2n = 14 is found in Chrysocalycinae subsection Incanae and 2n = 32 in American species of the section Calycinae. Seven species of the sections Chrysocalycinae, Calycinae, and Crotalaria were analyzed for the identification of heterochromatin types with GC- and AT-specific fluorochromes and chromosomal location of ribosomal DNA loci using fluorescent in situ hybridization (FISH). A major 45S rDNA locus was observed on chromosome 1 in all the species, and a variable number of minor ones were revealed. Only one 5S rDNA locus was observed in the species investigated. Chromomycin A(3) (CMA) revealed CMA(+) bands colocalized with most rDNA loci, small bands unrelated to ribosomal DNA on two chromosome pairs in Crotalaria incana, and CMA(+) centromeric bands that were quenched by distamycin A were detected in species of Calycinae and Crotalaria sections. DAPI(+) bands were detected in C. incana. The results support the species relationships based on flower specialization and were useful for providing insight into mechanisms of karyotype evolution. The heterochromatin types revealed by fluorochromes suggest the occurrence of rearrangements in repetitive DNA families in these heterochromatic blocks during species diversification. This DNA sequence turnover and the variability in number/position of rDNA sites could be interpreted as resulting from unequal crossing over and (or) transposition events. The occurrence of only one 5S rDNA locus and the smaller chromosome size in the polyploids suggest that DNA sequence losses took place following polyploidization events. PMID:21864195

  8. Nonadaptive processes governing early stages of polyploid evolution: Insights from a primary contact zone of relict serpentine Knautia arvensis (Caprifoliaceae).

    Science.gov (United States)

    Hanzl, Martin; Kolář, Filip; Nováková, Dora; Suda, Jan

    2014-06-11

    • Premise of the study: Contact zones between polyploids and their diploid progenitors may provide important insights into the mechanisms of sympatric speciation and local adaptation. However, most published studies investigated secondary contact zones where the effects of genome duplication can be confounded by previous independent evolution of currently sympatric cytotypes. We compared genetically close diploid and autotetraploid serpentine cytotypes of Knautia arvensis (Caprifoliaceae) in a primary contact zone and evaluated the role of adaptive and nonadaptive processes for cytotype coexistence.• Methods: DNA flow cytometry was used to determine ploidy distribution at various spatial scales (from across the entire contact zone to microgeographic). Habitat preferences of diploids and polyploids were assessed by comparing vegetation composition of nearby ploidy-uniform sites and by recording plant species immediately surrounding both cytotypes in mixed-ploidy plots.• Key results: Tetraploids considerably outnumbered their diploid progenitors in the contact zone. Both cytotypes were segregated at all investigated spatial scales. This pattern was not driven by ecological shifts, because both diploids and tetraploids inhabited sites with nearly identical vegetation cover. Certain interploidy niche differentiation was indicated only at the smallest spatial scale; ecologically nonadaptive processes were most likely responsible for this difference.• Conclusions: We conclude that a shift in ecological preferences (i.e., the adaptive scenario) is not necessary for the establishment and evolutionary success of autopolyploid derivatives in primary contact zones. Spatial segregation that would support ploidy coexistence can also be achieved by ecologically nonadaptive processes, including the founder effect, limited dispersal ability, intense clonal growth, and triploid block. PMID:24920762

  9. CoCl2, a mimic of hypoxia, induces formation of polyploid giant cells with stem characteristics in colon cancer.

    Directory of Open Access Journals (Sweden)

    Laura M Lopez-Sánchez

    Full Text Available The induction of polyploidy is considered the reproductive end of cells, but there is evidence that polyploid giant cancer cells (PGCCs contribute to cell repopulation during tumor relapse. However, the role of these cells in the development, progression and response to therapy in colon cancer remains undefined. Therefore, the main objective of this study was to investigate the generation of PGCCs in colon cancer cells and identify mechanisms of formation. Treatment of HCT-116 and Caco-2 colon cancer cells with the hypoxia mimic CoCl2 induced the formation of cells with larger cell and nuclear size (PGCCs, while the cells with normal morphology were selectively eliminated. Cytometric analysis showed that CoCl2 treatment induced G2 cell cycle arrest and the generation of a polyploid cell subpopulation with increased cellular DNA content. Polyploidy of hypoxia-induced PGCCs was confirmed by FISH analysis. Furthermore, CoCl2 treatment effectively induced the stabilization of HIF-1α, the differential expression of a truncated form of p53 (p47 and decreased levels of cyclin D1, indicating molecular mechanisms associated with cell cycle arrest at G2. Generation of PGCCs also contributed to expansion of a cell subpopulation with cancer stem cells (CSCs characteristics, as indicated by colonosphere formation assays, and enhanced chemoresistance to 5-fluorouracil and oxaliplatin. In conclusion, the pharmacological induction of hypoxia in colon cancer cells causes the formation of PGCCs, the expansion of a cell subpopulation with CSC characteristics and chemoresistance. The molecular mechanisms involved, including the stabilization of HIF-1 α, the involvement of p53/p47 isoform and cell cycle arrest at G2, suggest novel targets to prevent tumor relapse and treatment failure in colon cancer.

  10. Epigenetic inheritance in apomictic dandelions

    NARCIS (Netherlands)

    Preite, V.

    2016-01-01

    Epigenetic variation, such as changes in DNA methylations, regulatory small RNAs (sRNAs) and chromatin modifications can be induced by environmental stress. There is increasing information that such induced epigenetic modifications can be transmitted to offspring, potentially mediating adaptive tran

  11. 朝鲜百合离体多倍体诱导%Polyploid induction of Lilium amabile in vit ro

    Institute of Scientific and Technical Information of China (English)

    刘洋; 杨利平

    2015-01-01

    避光条件下,用0.10%秋水仙素附加2.00%二甲亚砜诱变离体培养的朝鲜百合小鳞茎,利用组织培养的不定芽诱导技术获得了多倍体幼苗,并对其根尖染色体数目进行常规鉴定。结果表明:诱导48 h效果好,变异率达到50.00%。对照植株和得到的4个变异株系进行细胞学观察后发现,对照为二倍体(2n=2x=24),诱变出的4个变异株系细胞染色体数目分别由34~54条的不同比例构成,其中四倍体细胞染色体(2n=4x=48)占38.18%~76.47%,属于嵌合体。%Bulblets of Lilium amabile were treated by 0 .10% colchicine with 2 .00% dimethyl sulfoxide for addition in vitro without light ,and the polyploid seedlings were obtained by ad‐ventitious bud induction .For the observation of the chromosome number in polyploid ,the re‐sult of 48‐hour‐induction leaded to a variation rate of 50 .00% .From the cytological observa‐tion with a control group of diploid (2n=2x=24)of 4 mutative strains ,the chromosome num‐bers after induction were in the range of 34-54 with different proportion ,and 38 .18% -76 .47% of the inducted cells were tetraploid (2n=4x=48) ,and they were chimera .

  12. A next-generation sequencing method for overcoming the multiple gene copy problem in polyploid phylogenetics, applied to Poa grasses

    Directory of Open Access Journals (Sweden)

    Robin Charles

    2011-03-01

    Full Text Available Abstract Background Polyploidy is important from a phylogenetic perspective because of its immense past impact on evolution and its potential future impact on diversification, survival and adaptation, especially in plants. Molecular population genetics studies of polyploid organisms have been difficult because of problems in sequencing multiple-copy nuclear genes using Sanger sequencing. This paper describes a method for sequencing a barcoded mixture of targeted gene regions using next-generation sequencing methods to overcome these problems. Results Using 64 3-bp barcodes, we successfully sequenced three chloroplast and two nuclear gene regions (each of which contained two gene copies with up to two alleles per individual in a total of 60 individuals across 11 species of Australian Poa grasses. This method had high replicability, a low sequencing error rate (after appropriate quality control and a low rate of missing data. Eighty-eight percent of the 320 gene/individual combinations produced sequence reads, and >80% of individuals produced sufficient reads to detect all four possible nuclear alleles of the homeologous nuclear loci with 95% probability. We applied this method to a group of sympatric Australian alpine Poa species, which we discovered to share an allopolyploid ancestor with a group of American Poa species. All markers revealed extensive allele sharing among the Australian species and so we recommend that the current taxonomy be re-examined. We also detected hypermutation in the trnH-psbA marker, suggesting it should not be used as a land plant barcode region. Some markers indicated differentiation between Tasmanian and mainland samples. Significant positive spatial genetic structure was detected at Conclusions Our results demonstrate that 454 sequencing of barcoded amplicon mixtures can be used to reliably sample all alleles of homeologous loci in polyploid species and successfully investigate phylogenetic relationships among

  13. Chromosome mapping of Xenopus tropicalis using the G- and Ag-bands: tandem duplication and polyploidization of larvae heads.

    Science.gov (United States)

    Uehara, Mariko; Haramoto, Yoshikazu; Sekizaki, Hiroyuki; Takahashi, Shuji; Asashima, Makoto

    2002-10-01

    Developmental cytogenetic analyses of Xenopus tropicalis larvae from two origins were performed on stage 27-34 heads treated with colchicine. Standard G-band karyotyping using trypsin and chromosome mapping of 184 bands were examined. Although the main karyotype was 2n = 20, polyploidy (3n = 30 or 4n = 40) and aneuploidy were detected in each individual treated with colchicine, even those treated for only 1 h. The percentage of polyploid karyotypes was 10-20% across the total of measured metaphases. The mean mitotic index was 0.10. Chromosomal breaks and exchanges were detected at the secondary constriction of chromosomes 5 or 6. Ag-band detection showed clearly positive staining at the secondary constriction of chromosome 5, which corresponds to the nucleolar organizer region. Tandem duplication of negative G-bands at the secondary constriction of chromosome 6 and the short arm of chromosome 10 was suggested by this study. X. tropicalis thus provides a good model to study the mechanism and effects of chromosomal abnormalities, gene mapping and tissue specific gene expression in the developmental process. PMID:12392576

  14. A nuclear DNA perspective on delineating evolutionarily significant lineages in polyploids: the case of the endangered shortnose sturgeon (Acipenser brevirostrum)

    Science.gov (United States)

    King, Timothy L.; Henderson, Anne P.; Kynard, Boyd E.; Kieffer, Micah C.; Peterson, Douglas L.; Aunins, Aaron W.; Brown, Bonnie L.

    2014-01-01

    The shortnose sturgeon, Acipenser brevirostrum, oft considered a phylogenetic relic, is listed as an “endangered species threatened with extinction” in the US and “Vulnerable” on the IUCN Red List. Effective conservation of A. brevirostrum depends on understanding its diversity and evolutionary processes, yet challenges associated with the polyploid nature of its nuclear genome have heretofore limited population genetic analysis to maternally inherited haploid characters. We developed a suite of polysomic microsatellite DNA markers and characterized a sample of 561 shortnose sturgeon collected from major extant populations along the North American Atlantic coast. The 181 alleles observed at 11 loci were scored as binary loci and the data were subjected to multivariate ordination, Bayesian clustering, hierarchical partitioning of variance, and among-population distance metric tests. The methods uncovered moderately high levels of gene diversity suggesting population structuring across and within three metapopulations (Northeast, Mid-Atlantic, and Southeast) that encompass seven demographically discrete and evolutionarily distinct lineages. The predicted groups are consistent with previously described behavioral patterns, especially dispersal and migration, supporting the interpretation that A. brevirostrum exhibit adaptive differences based on watershed. Combined with results of prior genetic (mitochondrial DNA) and behavioral studies, the current work suggests that dispersal is an important factor in maintaining genetic diversity in A. brevirostrum and that the basic unit for conservation management is arguably the local population.

  15. A nuclear DNA perspective on delineating evolutionarily significant lineages in polyploids: the case of the endangered shortnose sturgeon (Acipenser brevirostrum.

    Directory of Open Access Journals (Sweden)

    Tim L King

    Full Text Available The shortnose sturgeon, Acipenser brevirostrum, oft considered a phylogenetic relic, is listed as an "endangered species threatened with extinction" in the US and "Vulnerable" on the IUCN Red List. Effective conservation of A. brevirostrum depends on understanding its diversity and evolutionary processes, yet challenges associated with the polyploid nature of its nuclear genome have heretofore limited population genetic analysis to maternally inherited haploid characters. We developed a suite of polysomic microsatellite DNA markers and characterized a sample of 561 shortnose sturgeon collected from major extant populations along the North American Atlantic coast. The 181 alleles observed at 11 loci were scored as binary loci and the data were subjected to multivariate ordination, Bayesian clustering, hierarchical partitioning of variance, and among-population distance metric tests. The methods uncovered moderately high levels of gene diversity suggesting population structuring across and within three metapopulations (Northeast, Mid-Atlantic, and Southeast that encompass seven demographically discrete and evolutionarily distinct lineages. The predicted groups are consistent with previously described behavioral patterns, especially dispersal and migration, supporting the interpretation that A. brevirostrum exhibit adaptive differences based on watershed. Combined with results of prior genetic (mitochondrial DNA and behavioral studies, the current work suggests that dispersal is an important factor in maintaining genetic diversity in A. brevirostrum and that the basic unit for conservation management is arguably the local population.

  16. 福建金线兰多倍体的诱导和倍性鉴定%Induction and Ploidy Identification of the Polyploid of Anoectochilus fornosanus

    Institute of Scientific and Technical Information of China (English)

    禹华芳

    2012-01-01

    [目的]对福建金线兰多倍体进行诱导和倍性鉴定.[方法]以福建金线兰为材料,以秋水仙素为诱变剂,分别用浸泡法和涂抹法处理福建金线兰试管苗不定芽,进行多倍体诱导,并在显微镜下观察鉴定其染色体的倍性.[结果]以浓度0.05%秋水仙素为诱变剂,用涂抹法处理72h的效果较佳,加倍率为35%;对多倍体材料进行染色体鉴定发现,二倍体染色体为2n =40条,四倍体为4n=80条.[结论]该方法可以培育福建金线兰多倍体,能提高其移栽成活率和亩产量.%[Objective] To induce the polyploid of Anoectochilus fornosanus and identify its ploidy. [Method] The adventitious buds of Anoec tochilus fornosanus were respectively soaked and coated with colchicine to induce the polyploid, and the ploidy of the chromosome was observed under microscope. [Result] The ploidy was 35% when the adventitious buds were coated with 0.05% colchicine for 72 h; the ploidy identification showed that there were 40 diploid chromosomes and 80 tetraploid chromosomes. [Conclusion] The metnod can cultivate the polyploid of Anoeclochllm fomosannsand, improve its survival rate and per mu yield of its transplants.

  17. Progress in Research on Polyploid Induction Technology of Miscanthus Anderss.%芒属植物多倍体诱导技术的研究进展

    Institute of Scientific and Technical Information of China (English)

    杨宇晨; 陈智勇; 蒋建雄; 刘清波; 易自力

    2013-01-01

    芒属植物是一种新兴的纤维素类生物质能源植物.为了提高芒属植物生物质产量和开发具有抗逆性的新品种,国内外广泛开展了关于其多倍体育种的研究.近年来,通过对其体外再生和诱变育种等方面进行研究,取得了一些重要成果.从芒属植物体外培养时外植体的选择,愈伤和丛生芽的诱导,多倍体诱导过程中秋水仙碱和氨磺灵的处理,倍性鉴定方法这几个方面对芒属植物多倍体诱导的相关研究做了综述,并对芒属植物多倍体育种的应用和发展前景提出了展望.%Miscanthus Anderss. is a new kind of lignocellulosic biomass for the production of biofuels. In order to improve the biomass production and resistance of Miscanthus Anderss., the polyploid induction of Miscanthus have been widely researching all over the world. In recent years, researchers have got some important achievements in the researches on plant regeneration in vitro and mutation breeding. From the choice of explant, the induction of callus and cluster buds, the treatment by colchicine or oryzalin during polyploid induction of Miscanthus and the method of ploidy determination, this paper is doing an overview of the results. A forecast of the future was given about the application and development of Miscanthus polyploid breeding.

  18. Preliminary Study on Polyploid Inducement of Cannabis sativa%大麻多倍体诱导的初步研究

    Institute of Scientific and Technical Information of China (English)

    田斌; 郭鸿彦; 杨明; 辛培尧

    2013-01-01

      In order to improve the medicinal value and other quality characters of Cannabis sativa, we used colchicine to induce its polyploid germplasms.The seeds of Cannabis sativa were treated with different concentrations of colchicine for various times .The acquired polyploidy was identified by the methods of morphology and cytology .The results showed that the better polyploid induce-ment effect could be obtained by treating the seeds with 0.20%(or 0.15%) colchicine for 24 h (or 36 h).The polyploid cells of Cannabis sativa were found obviously after treatment of colchicine , but the treated plants were still in chimeric status .%  利用秋水仙素对大麻进行多倍体种质的诱导,获得大麻多倍体种质,以期提高大麻的药效价值或改良其他品质性状。以大麻种子为材料,在不同浓度秋水仙素溶液中处理不同时间,并对所得材料的倍性利用进行形态及细胞学鉴定。结果表明,0.2%和0.15%的秋水仙碱分别处理24 h和36 h,可获得较理想的诱变效果,经秋水仙素处理后,大麻细胞发生了明显的加倍,但被诱导植株仍然处于嵌合状态。

  19. Underestimated diversity in one of the world’s best studied mountain ranges: The polyploid complex of Senecio carniolicus (Asteraceae) contains four species in the European Alps

    Science.gov (United States)

    GARCÍA, PEDRO ESCOBAR; HÜLBER, KARL; SONNLEITNER, MICHAELA; WINKLER, MANUELA; SAUKEL, JOHANNES; SCHNEEWEISS, GERALD M.; SCHÖNSWETTER, PETER

    2015-01-01

    Senecio carniolicus (Asteraceae) is an intricate polyploid complex distributed in the European Alps (di-, tetra- and hexaploids) and Carpathians (hexaploids only). Molecular genetic, ecological, and crossing data allowed four evolutionary groups within S. carniolicus to be identified. Here, we establish that these four groups (two vicariant diploid lineages, tetraploids and hexaploids) are also morphologically differentiated. As a consequence, we draw taxonomic conclusions by characterizing four species, including the more narrowly circumscribed S. carniolicus (lectotypified here), the taxonomically elevated S. insubricus comb. nov. (lectotypified here), and the two newly described species S. disjunctus and S. noricus. PMID:26190915

  20. STUDIES ON POLYPLOID INDUCTION BY COLCHICINE IN PINUS BUNGEANA%秋水仙素诱导白皮松多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    闫辉; 张利; 于淑惠; 左曼曼; 樊金会

    2012-01-01

    Cotyledon explants of mature embryos of Pinus bungeana tissue were culture, the use of colchine induced polyploid. Cotyledons were cultured for 10 days, with the quality of volume fraction of 0. 01%, 0. 03%, 0. 05% of colchicine immersion, respectively 6 h, 12 h, 24 h, observation oi cotyledon growth and bud differentiation status, identification of chromosome doubling in 20 days. Results indicated that: different concentrations of colchicine effectfed cotyledon growth effect. Concertrstian was higher, processing time was longer, the higher the death; colchicine treated shoci regeneration is slow, and snoot regeneration rale increased with the concentration decreased; colchicine treated cotyledons chromosomes nave doubled, but with colchicine concentration enhancement and treatment the extension of time, polyploid induction rate showed a downward trend. Data displayed quality score of 0. 03% for the combination of 12 h treated with colchicine, polyploid inJuction rate was highest, 40. 5%. The study on polyploid induction of Pinus bungeann system were initially established .%以白皮松成熟胚的子叶作为外植体进行组织培养,利用秋水仙素诱导多倍体.将子叶预培养10 d后,用质量体积分数为0.01%、0.03%、0.05%的秋水仙素分别浸泡6h、12h、24h,观察子叶生长状态及芽分化状况,20 d后鉴定染色体加倍情况.结果表明:不同浓度的秋水仙素均对子叶生长状态产生影响,浓度越高、处理时间越长,死亡率越高;秋水仙素处理过的子叶芽再生缓慢,且芽再生率随浓度增高而降低;秋水仙素处理后的子叶染色体产生加倍,但随着秋水仙素浓度的提高和处理时间的延长,多倍体诱导率呈现出下降的趋势.数据显示质量分数为0.03%的秋水仙素处理12 h的组合,多倍体诱导率最高,为40.5%.本研究初步建立了白皮松多倍体诱导体系.

  1. Genome-wide DNA methylation profiling by modified reduced representation bisulfite sequencing in Brassica rapa suggests that epigenetic modifications play a key role in polyploid genome evolution.

    Science.gov (United States)

    Chen, Xun; Ge, Xianhong; Wang, Jing; Tan, Chen; King, Graham J; Liu, Kede

    2015-01-01

    Brassica rapa includes some of the most important vegetables worldwide as well as oilseed crops. The complete annotated genome sequence confirmed its paleohexaploid origins and provides opportunities for exploring the detailed process of polyploid genome evolution. We generated a genome-wide DNA methylation profile for B. rapa using a modified reduced representation bisulfite sequencing (RRBS) method. This sampling represented 2.24% of all CG loci (2.5 × 10(5)), 2.16% CHG (2.7 × 10(5)), and 1.68% CHH loci (1.05 × 10(5)) (where H = A, T, or C). Our sampling of DNA methylation in B. rapa indicated that 52.4% of CG sites were present as (5m)CG, with 31.8% of CHG and 8.3% of CHH. It was found that genic regions of single copy genes had significantly higher methylation compared to those of two or three copy genes. Differences in degree of genic DNA methylation were observed in a hierarchical relationship corresponding to the relative age of the three ancestral subgenomes, primarily accounted by single-copy genes. RNA-seq analysis revealed that overall the level of transcription was negatively correlated with mean gene methylation content and depended on copy number or was associated with the different subgenomes. These results provide new insights into the role epigenetic variation plays in polyploid genome evolution, and suggest an alternative mechanism for duplicate gene loss. PMID:26500672

  2. Genome-wide DNA Methylation Profiling by Modified Reduced Representation Bisulfite Sequencing in Brassica rapa Suggests that Epigenetic Modifications Play a Key Role in Polyploid Genome Evolution

    Directory of Open Access Journals (Sweden)

    Xun eChen

    2015-10-01

    Full Text Available Brassica rapa includes some of the most important vegetables worldwide as well as oilseed crops. The complete annotated genome sequence confirmed its paleohexaploid origins and provides opportunities for exploring the detailed process of polyploid genome evolution. We generated a genome-wide DNA methylation profile for B. rapa using a modified reduced representation bisulfite sequencing (RRBS method. This sampling represented 2.24% of all CG loci (2.5 x 105, 2.16% CHG (2.7 x 105 and 1.68% CHH loci (1.05 x 105 (where H = A, T or C. Our sampling of DNA methylation in B. rapa indicated that 52.4% of CG sites were present as 5mCG, with 31.8% of CHG and 8.3% of CHH. It was found that genic regions of single copy genes had significantly higher methylation compared to those of two or three copy genes. Differences in degree of genic DNA methylation were observed in a hierarchical relationship corresponding to the relative age of the three ancestral subgenomes, primarily accounted by single-copy genes. RNA-seq analysis revealed that overall the level of transcription was negatively correlated with mean gene methylation content and depended on copy number or associated with the different subgenomes. These results provide new insights into the role epigenetic variation plays in polyploid genome evolution, and suggest an alternative mechanism for duplicate gene loss.

  3. The genetic legacy of polyploid Bolivian Daphnia: the tropical Andes as a source for the North and South American D. pulicaria complex.

    Science.gov (United States)

    Mergeay, Joachim; Aguilera, Ximena; Declerck, Steven; Petrusek, Adam; Huyse, Tine; De Meester, Luc

    2008-04-01

    We investigated genetic variation in asexual polyploid members of the water flea Daphnia pulex complex from a set of 12 Bolivian high-altitude lakes. We used nuclear microsatellite markers to study genetic relationships among all encountered multilocus genotypes, and combined this with a phylogenetic approach using DNA sequence data of three mitochondrial genes. Analyses of mitochondrial gene sequence divergence showed the presence of three very distinct clades that likely represent cryptic undescribed species. Our phylogenetic results suggest that the Daphnia pulicaria group, a complex of predominantly North American species that has diversified rapidly since the Pleistocene, has its origin in South America, as specific tests of topology indicated that all three South American lineages are ancestral to the North American members of this species group. A comparison between variation of nuclear and mitochondrial markers revealed that closely related polyploid nuclear genotypes sometimes belonged to very divergent mitochondrial lineages, while distantly related nuclear genotypes often belonged to the same mitochondrial lineage. This discrepancy suggests that these South American water fleas originated through reciprocal hybridization between different endemic, sexually reproducing parental lineages. It is also likely that polyploidy of the investigated lineages resulted from this hybridization. Nevertheless, no putative diploid parental lineages were found in the studied region.

  4. Aneuploid progeny of the American oyster, Crassostrea virginica, produced by tetraploid × diploid crosses: another example of chromosome instability in polyploid oysters.

    Science.gov (United States)

    de Sousa, Joana Teixeira; Allen, Standish K; Baker, Haley; Matt, Joseph L

    2016-05-01

    The commercial production of triploids, and the creation of tetraploid broodstock to support it, has become an important technique in aquaculture of the eastern oyster, Crassostrea virginica. Tetraploids are produced by cytogenetic manipulation of embryos and have been shown to undergo chromosome loss (to become a mosaic) with unknown consequences for breeding. Our objective was to determine the extent of aneuploidy in triploid progeny produced from both mosaic and non-mosaic tetraploids. Six families of triploids were produced using a single diploid female and crossed with three mosaic and non-mosaic tetraploid male oysters. A second set of crosses was performed with the reciprocals. Chromosome counts of the resultant embryos were tallied at 2-4 cell stage and as 6-hour(h)-old embryos. A significant level of aneuploidy was observed in 6-h-old embryos. For crosses using tetraploid males, aneuploidy ranged from 53% to 77% of observed metaphases, compared to 36% in the diploid control. For crosses using tetraploid females, 51%-71% of metaphases were aneuploidy versus 53% in the diploid control. We conclude that somatic chromosome loss may be a regular feature of early development in triploids, and perhaps polyploid oysters in general. Other aspects of chromosome loss in polyploid oysters are also discussed. PMID:27070368

  5. Study on Induction of Polyploid Camphor with Colchicine%秋水仙素诱导香樟多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    邓文; 端木卜文; 吴沐秀; 余佳; 韩浩章

    2015-01-01

    Taking the germinated camphor seeds as test materials,using germinated seed soaking method, the effect of different concentration and processing time of colchicine on the polyploid induction of cam⁃phor were studied. The results showed that the highest polyploid induction rate happened when the germi⁃nated camphor seeds soaked 36~48h with 0.1%~0.2% of colchicine solution. The higher colchicine con⁃centration and the longer the processing time,the camphor seedling mortality was higher,obtaining 67 poly⁃ploids camphor seedlings.%以萌发的香樟种子为试材,采用种子浸渍法,研究了不同浓度秋水仙素、不同处理时间对香樟多倍体诱导的影响。结果表明:0.1%~0.2%的秋水仙素水溶液浸泡处理种子36~48h,其多倍体的诱导率最高,死亡率相对较低。秋水仙素浓度越高,处理时间越长,香樟幼苗死亡率越高,试验共获得香樟多倍体植株67株。

  6. Genetics, Morphology, Advertisement Calls, and Historical Records Distinguish Six New Polyploid Species of African Clawed Frog (Xenopus, Pipidae from West and Central Africa.

    Directory of Open Access Journals (Sweden)

    Ben J Evans

    Full Text Available African clawed frogs, genus Xenopus, are extraordinary among vertebrates in the diversity of their polyploid species and the high number of independent polyploidization events that occurred during their diversification. Here we update current understanding of the evolutionary history of this group and describe six new species from west and central sub-Saharan Africa, including four tetraploids and two dodecaploids. We provide information on molecular variation, morphology, karyotypes, vocalizations, and estimated geographic ranges, which support the distinctiveness of these new species. We resurrect Xenopus calcaratus from synonymy of Xenopus tropicalis and refer populations from Bioko Island and coastal Cameroon (near Mt. Cameroon to this species. To facilitate comparisons to the new species, we also provide comments on the type specimens, morphology, and distributions of X. epitropicalis, X. tropicalis, and X. fraseri. This includes significantly restricted application of the names X. fraseri and X. epitropicalis, the first of which we argue is known definitively only from type specimens and possibly one other specimen. Inferring the evolutionary histories of these new species allows refinement of species groups within Xenopus and leads to our recognition of two subgenera (Xenopus and Silurana and three species groups within the subgenus Xenopus (amieti, laevis, and muelleri species groups.

  7. Study on Polyploid Induction and Identification of Nervilia fordii%青天葵多倍体诱导、鉴别研究

    Institute of Scientific and Technical Information of China (English)

    林玉凤; 杜勤; 程凤丽; 王振华; 田军

    2015-01-01

    Objective To investigate the polyploid induction and identification of Nerviliae fordii for harvesting the polyploid plants. Methods The materials and methods for polyploid induction of Nerviliae fordii were screened separately by comparing the induction rates of rhizomes and bulbs under natural conditions and tissue culture environment, and by comparing soaking method with agar method. The effects of colchicine concentration ( 200, 300, 400, 300 mg/L), colchicine action time ( 7, 14, 21, 28 d), DMSO concentration ( 0, 10, 20, 40 mL/L) and KT concentration ( 0, 1.0, 2.0, 4.0 mg/L) on induction rate were observed by orthogonal design method. The polyploid induction in the treated plants was identified by morphology, cytology and chromosome methods. Results After the tissue culture rhizomes were treated with 300 mg/L colchicine, 10 mL/L DMSO, and 2.0 mg/L KT by agar method for 28 days, the polyploid induction rate arrived to 50%, showing better induction effect. The morphology of polyploid plants was characterized by giantism, and the leaf length, leaf width and plant height were respectively 152.17%, 158.67%and 60.90%of those of the diploid plants. The length, width and density of stoma of leaf epidermal cell as well as the number of chloroplast in the treated plants were 138.46%, 153.00%, 59.09% and 109.09% of those of the untreated plants. The results of chromosome identification showed that the amount of the tetraploid ( about 40) was 2 times of the diploid chromosome ( about 20) in the treated plants, proving that the achieved Nerviliae fordii was a tetraploid plant. Conclusion Polyploid plants of Nerviliae Fordii have been successfully obtained, which will supply evidence for improving species, richening seed-breeding resources, and selecting of improved seeds of Nerviliae fordii.%【目的】对青天葵进行多倍体诱导和鉴别研究,获得多倍体植株。【方法】通过比较自然和组培条件下根状茎和球茎的诱导率、浸泡法和

  8. 多倍化是杂草起源与演化的驱动力%Polyploidization, one of the driving forces for weed origin and evolution

    Institute of Scientific and Technical Information of China (English)

    李君; 强胜

    2012-01-01

    杂草及外来植物入侵给全球经济发展及生态环境都带来了严重危害,研究其起源与演化将有助于它们的管理与控制.多倍化是植物进化的主要驱动力量,然而多倍化在杂草起源与演化中的作用还停留在种类统计以及零碎的研究案例证据上.本文综述了植物多倍体基因组结构及基因表达的研究进展以及染色体加倍后的生态学效应.多倍化促进了基因组水平与表型水平的进化,影响物种或群体生存竞争能力和繁殖扩展能力,提高物种或群体生态适应性.这一遗传过程可能促使外来种在新的生境中的成功入侵进而转变为杂草,并提出重视开展对杂草及外来入侵植物的多倍化研究的设想.%Weeds and alien invasive plants have caused tremendously ecological and socio-economic damages and loses worldwide, therefore,it is important to study origin and evolution of weeds for their effective management. Polyploidy is believed to be the main driving force of plant evolution, however, its playing the role in weeds origin and evolution is poorly understood. In this paper we review the progresses on the polyploid genome structure and gene expression and the ecological consequences of chromosome doubling. The polyploidy promotes the evolution of genomic and phenotype, affects the species survival competition, reproduction and expansion capability, and improves the ecological adaptability. Polyploidization can drive the successful invasion of invasive alien species and consequently evolution into a weed in new habitats. In addition, it is proposed that the research works on invasive alien plants may focus on polyploidization function in weed evolution and alien plant invasion.

  9. Study on the Induction of Polyploid Bulb of Fritillaria Cirrhosa D. Don%卷叶贝母多倍体鳞茎诱导方法研究

    Institute of Scientific and Technical Information of China (English)

    王跃华; 胡胜铃; 代勇; 蒋婷婷; 付伟; 杨军

    2011-01-01

    [ Objective ] Rolyploid bulb of Fritillaria cirrhosa D. Don is introduced by tissue culture technique. [ Methods ] The compact callus cell mass of Fritillaria cirrhosa D. Don which are differentiation cultured beforehand are soaked in colchicine solution, and then cultured in the differential medium of MS + 6-BA 1.0 mg/L + NAA 0.3 mg/L. Polyploid bulb are obtained by induction differentiation culture. [ Result] Colchicine solution of 1.2 g/L is used to douse the compact callus cell mass of Fritillaria cirrhosa D. Don for 24 h. The highest inductivity of polyploid bulb was 83.3%. [ Conclusion] Chromosome number is 2n =4x =48 and the total alkaloids content is detected to be 0. 249%. It indicates that it is feasible to obtain high quality and high yield of Fritillaria cirrhosa D. Don polyploid bulb by tissue culture technique.%[目的]利用组织培养技术快速诱导生成卷叶贝母(Fritillaria cirrhosa D.Don)多倍体鳞茎.[方法]用一定浓度的秋水仙素溶液浸泡经预分化培养的卷叶贝母紧密愈伤组织团块,再经过诱导分化培养获得多倍体鳞茎.[结果]用浓度为1.2 g/L的秋水仙素溶液浸泡处理卷叶贝母紧密愈伤组织团块24 h后,接种在Ms+6-BA 1.0 mg/L+NAA 0.3 mg/L的分化培养基上培养,其多倍体鳞茎的诱导率最高为83.3%,细胞染色体数为2n=4x=48,总生物碱含量为0.249%.[结论]用组织培养技术获得优质高产卷叶贝母多倍体鳞茎的方法是可行的.

  10. Studies on Polyploid Induction of Caragana intermedia by Colchicine%秋水仙素诱导中间锦鸡儿多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    沈河溪; 梁国鲁; 韩素英; 齐力旺

    2011-01-01

    以中间锦鸡儿(caragana intermedia)种子为试验材料,通过秋水仙素浸泡种子的方法研究了不同浓度及作用时间下秋水仙素对其染色体加倍的诱导效果。结果表明,直接浸泡种子,以0.3%秋水仙素浸泡48h为最佳,诱变率为53.3%;种子经萌发12h后再处理,以0.15%秋水仙素浸泡36h诱变率最高,为73.3%。对变异株根尖进行染色体计数后发现,二倍体对照2n=2x=16,变异株2n=3x=24为三倍体,变异株2n=4x=32为四倍体,同时也发现存在嵌合体现象。%Caragana intermedia were treated with different concentrations of colchicine solution at different stages in order to figure out the best inducing method and obtain polyploids. The results indicated that the mutation rate of seeds was 53.3% with the treatment of 0.3% colchicines for 48 h, while for sprouting seeds immersed in 0.15% colchicines for 36 h, the mutation rate was 73.3%. Chromosome observation found that the chromosome number of mutated plants was 2n = 4x = 32 (tetraploid) and 2n = 3x = 24 (triploid), while that of the control plants was 2n = 2x = 16. The chimera was also found among treatment plants. A few polyploid seedlings were obtained in this study, this will provide the good base for Caragana polyploid breeding.

  11. Chromosome arm-specific BAC end sequences permit comparative analysis of homoeologous chromosomes and genomes of polyploid wheat

    Directory of Open Access Journals (Sweden)

    Sehgal Sunish K

    2012-05-01

    Full Text Available Abstract Background Bread wheat, one of the world’s staple food crops, has the largest, highly repetitive and polyploid genome among the cereal crops. The wheat genome holds the key to crop genetic improvement against challenges such as climate change, environmental degradation, and water scarcity. To unravel the complex wheat genome, the International Wheat Genome Sequencing Consortium (IWGSC is pursuing a chromosome- and chromosome arm-based approach to physical mapping and sequencing. Here we report on the use of a BAC library made from flow-sorted telosomic chromosome 3A short arm (t3AS for marker development and analysis of sequence composition and comparative evolution of homoeologous genomes of hexaploid wheat. Results The end-sequencing of 9,984 random BACs from a chromosome arm 3AS-specific library (TaaCsp3AShA generated 11,014,359 bp of high quality sequence from 17,591 BAC-ends with an average length of 626 bp. The sequence represents 3.2% of t3AS with an average DNA sequence read every 19 kb. Overall, 79% of the sequence consisted of repetitive elements, 1.38% as coding regions (estimated 2,850 genes and another 19% of unknown origin. Comparative sequence analysis suggested that 70-77% of the genes present in both 3A and 3B were syntenic with model species. Among the transposable elements, gypsy/sabrina (12.4% was the most abundant repeat and was significantly more frequent in 3A compared to homoeologous chromosome 3B. Twenty novel repetitive sequences were also identified using de novo repeat identification. BESs were screened to identify simple sequence repeats (SSR and transposable element junctions. A total of 1,057 SSRs were identified with a density of one per 10.4 kb, and 7,928 junctions between transposable elements (TE and other sequences were identified with a density of one per 1.39 kb. With the objective of enhancing the marker density of chromosome 3AS, oligonucleotide primers were successfully designed from

  12. Chromosomal characterization of the three subgenomes in the polyploids of Hordeum murinum L.: new insight into the evolution of this complex.

    Directory of Open Access Journals (Sweden)

    Ángeles Cuadrado

    Full Text Available Hordeum murinum L. is a species complex composed of related taxa, including the subspecies glaucum, murinum and leporinum. However, the phylogenetic relationships between the different taxa and their cytotypes, and the origin of the polyploid forms, remain points of controversy. The present work reports a comparative karyotype analysis of seven accessions of the H. murinum complex representing all subspecies and cytotypes. The karyotypes were determined by examining the distribution of the repetitive Triticeae DNA sequences pTa71, pTa794, pSc119.2, pAs1 and pHch950, the simple sequence repeats (SSRs (AG10, (AAC5, (AAG5, (ACT5, (ATC5, and (CCCTAAA3 via in situ hybridization. The chromosomes of the three subgenomes involved in the polyploids were identified. All tetraploids of all subspecies shared the same two subgenomes (thus suggesting them to in fact belong to the same taxon, the result of hybridization between two diploid ancestors. One of the subgenomes present in all tetraploids of all subspecies was found to be very similar (though not identical to the chromosome complement of the diploid glaucum. The hexaploid form of leporinum came about through a cross between a tetraploid and a third diploid form. Exclusively bivalent associations among homologous chromosomes were observed when analyzing pollen mother cells of tetraploid taxa. In conclusion, the present results identify all the individual chromosomes within the H. murinum complex, reveal its genome structure and phylogeny, and explain the appearance of the different cytotypes. Three cryptic species are proposed according to ploidy level that may deserve full taxonomic recognition.

  13. Comparative analysis and evolutionary significance of the HMG1 gene in crucian carp,blunt snout bream,and their polyploid progeny

    Institute of Scientific and Technical Information of China (English)

    Dong Liu; Zhen Liu; Shaojun Liu; Liangguo Liu; Cuiping You; Lin Chen; Huan Zhong; Yun Liu

    2009-01-01

    The full-length mRNA of the high mobility group protein 1 coding gene (HMG1) was obtained by RACE-PCR from red crucian carp (Carassius auratus red var.),blunt snout bream (Megalobrama amblycephala),and their triploid and tetraploid progeny.The sequence contained an open reading frame of 579 nucleotides coding for 193 amino acids.The nucleotide identity of HMG1 was higher between the tetraploid hybrid and the maternal red crucian carp (99%) than between the tetraploid hybrid and the paternal blunt snout bream (97%).The nucleotide identity between the triploid hybrids and each parent (95%) was lower than that between the parents (98%).The protein identity between the tetraploid hybrid and each parent (100%) was higher than that between the triploid hybrid and each parent (97%).Our results suggest that interspecific hybridization generates a shock to the HMG1 gene in triploid hybrids,causing divergence of nucleotides.The HMG1 protein of the tetraploid hybrids was consistent with that of its parents,which reduced the barrier of cross incompatibility between alleles,providing the basis for the bisexual fertile tetraploid hybrids forming a new polyploid species in nature.The secondary and tertiary structures of the HMG1 protein contain eight helices,three switches,two DNA-binding domains in the N-terminus,and a long acidic tail in the C-terminus.Together,these data suggest that the HMG1 protein plays a role of protein-DNA interactions,facilitating various DNA-dependent activities in the nucleus.We also investigated the phylogeny of fish,amphibian,reptilian,bird,and mammalian HMG1 proteins.Our results suggest that HMG1 is an ancestral protein that has been highly conserved.These data provide clues as to how interspecific hybridization may form polyploid hybrids.

  14. Induction of Zantedeschia hybrid ‘Parfait' polyploid and change of its biological characteristics%彩色马蹄莲品种‘Parfait’多倍体诱导及其生物学特征变化

    Institute of Scientific and Technical Information of China (English)

    刘晓静; 华小平; 陆波; 彭峰; 邓波; 郑玉红

    2014-01-01

    Taking in vitro multiple shoot clumps of Zantedeschia hybrid ‘ Parfait’ as experimental materials, colchicine and DMSO concentrations and their soaking time during polyploid induction process were analyzed, and differences in leaf indexes, stomatal characteristics, chlorophyll content and chromosome number between polyploid and diploid were compared, finally, the optimal induction condition was confirmed by regression analysis. The results show that with enhancing of colchicine mass-volume ratio and shortening of soaking time, survival rate of multiple shoot of different treatment groups increases gradually and is lower than that of the control, while polyploid induction rate decreases gradually and is significantly higher than that of the control. Comprehensively considering factors such as survival rate of multiple shoot and polyploid induction rate and according to regression analysis, the optimal induction condition of Z. hybrid ‘Parfait’ is soaking multiple shoot clumps in MS liquid medium containing mass-volume ratio 0. 20% colchicine and volume ratio 0. 10% DMSO for 24 h, its polyploid induction rate is up to 50. 02% . The comparison analysis results show that leaf length, leaf thickness and ratio of leaf length to leaf width of polyploid plants are 1. 23, 1. 19 and 2. 93 times to those of diploid plants, respectively. Length and width of guard cell and chloroplast number per stoma of polyploid plants are 1. 90, 1. 96 and 2. 03 times to those of diploid plants, respectively. Contents of chla and total chlorophyll of polyploid plants are 1. 28 and 1. 17 times to those of diploid plants, respectively. But leaf width and stomatal density of polyploid plants are smaller, which are only 42. 08% and 61. 55% of those of diploid plants, respectively. Except chlb content, there are significant differences in other biological characteristics between polyploid plants and diploid plants. The result of chromosome counting shows that polyploids obtained mostly are

  15. Study on Polyploid Induction and Primary Identification in Shuijing Grapes%水晶葡萄多倍体诱导及初步鉴定研究

    Institute of Scientific and Technical Information of China (English)

    李智; 陈瑞; 雷皓; 陈宗国; 张永福

    2014-01-01

    以水晶葡萄盆栽苗为试验材料,研究不同质量浓度的秋水仙碱,在不同处理时间下,运用套罩法进行染色体加倍诱导,确定最佳处理质量浓度和处理时间,并对诱导的变异植株与对照植株进行形态学、生理学、解剖学和细胞学鉴定。结果表明:质量浓度为8 mg/mL的秋水仙碱处理5 d效果最佳,处理后的植株为变异四倍体的可能性较大;经该处理后的植株在节间距、叶片厚度、SOD酶活性、气孔密度及大小、导管直径及长短、细胞大小等指标上均明显强于对照处理。%Potting Shuijing grapes were used as materials.The effects of colchicines treatment at different time and concentrations were studied on polyploid induction.The treated parts of the plants were shrouded by absorbent cotton to ensure the optimal treating time and concentration.Comparisons of configurations,physiology and biochemistry,anatomy,cytology identification were done between the variant plants and contrast plants.The results showed that the best induction rate was achieved at 8 mg/mL of colchicines treatment for 5 days.The treated plants showed the great possibility of polyploid and obviously stronger indications than water treatment plants in the distance between nodes,leaf thickness,SOD enzyme activity,stomatal density and size,tube diameter and length,and cell size.

  16. 东北红豆杉(Taxus cuspidata)多倍体诱变初探%Preliminary Study on Polyploid Induction of Northeast yew (Taxus cuspidata )

    Institute of Scientific and Technical Information of China (English)

    杨娜; 王哲; 赵晓明; 吴玉香

    2012-01-01

    Northeast yew (Taxus cuspidata) is a natural and valuable medicinal plant for cancer resistantance. This research focused on polyploid induction for Northeast yew to supplement natural source for this threatened plant. The diploid apical buds were induced under three treatments (4 d, 6 d and 8 d) by improved primary meristem method of 0. 2% colchicine semi-solid to obtain the best treatment time. Morphology identification was conducted between obtained mutants and diploid controls. The results showed that mutant rates of 6 d and 8 d were better than that of 4 d by morphology examination. Comparing with diploid controls, the growth rate of polyploid plants were slower and showed dark green, thicker, crimpled leaf and lower leaf index. Mutants have obvious polyploidy characteristics.%红豆杉(Taxus cuspidata)是一种天然珍稀抗癌药用植物,以东北红豆杉为材料,进行多倍体诱变研究,以期获得营养器官增大、药效成分提高的多倍体植株,改善因红豆杉资源有限造成紫杉醇稀缺的现状.采用改良初生分生组织处理法在0.2%秋水仙碱浓度下,不同处理时间(4d、6d、8 d)处理东北红豆杉茎尖顶芽,对其进行多倍体诱变,并对诱变结果进行统计分析.结果表明,东北红豆杉的最佳诱变时间为6d和8d,诱变效果较好.与对照组相比,试验组生长受阻,叶形指数变小,叶色浓绿,叶片变厚且皱缩卷曲,具有明显的多倍体特征.

  17. 秋水仙素诱导细叶百合多倍体研究%Colchicines-induced polyploid plants and identification in Lilium pumilum DC

    Institute of Scientific and Technical Information of China (English)

    杨英杰; 葛蓓孛; 魏倩; 高俊平; 洪波

    2013-01-01

    This work was aimed to obtain tetraploid Lilium pumilum DC with excellent ornamental traits and agronomic characters,and provide better cross parent for breeding of new Lilium variety. The seeds of Lilium pumilum DC (2n = 2x=24) were treated with different concentrations of colchicine solution at different hours in order to figure out a proper method and obtain polyploids. The results indicated that the most effective induction was obtained by 0.1 % colchicine treatment for 24 hours with 30 % mutation rate. By chromosome observation of root tip, the tetraploid plants were successfully obtained with the chromosome number In =4x = 48. The tetraploid plants showed obvious characteristics of low stoma density,large stoma,slow growth,thick and wide leaves and dark leaf color at the initial stage,but quick growth and large leaves at later stage. The results indicated that the polyploid plants were identified by phenotype, stomas and chromosome number observation.%为获得具有优良观赏性状和农艺性状的细叶百合四倍体植株,并为百合的新品种选育提供性状优良的杂交亲本,以细叶百合种子(2n=2x=24)为试验材料,通过秋水仙素浸泡种子的方法,研究了不同秋水仙素浓度和处理时间对细叶百合染色体加倍的诱导效果.结果表明:以0.1%秋水仙素处理24 h诱导效果最佳,变异率最高,达30%.经根尖染色体鉴定,四倍体植株染色体数目为2n=4x=48.四倍体植株气孔密度减少,气孔增大;前期生长势缓慢,叶片短缩增宽,叶色加深;后期生长健壮,叶片增大明显.通过对经秋水仙素诱导获得的变异植株形态、气孔的观察测定以及染色体倍性鉴定,成功获得了细叶百合的多倍体植株.

  18. D-subgenome bias of Xcm resistance genes in tetraploid Gossypium (cotton) suggests that polyploid formation has created novel avenues for evolution.

    Science.gov (United States)

    Wright, R J; Thaxton, P M; El-Zik, K M; Paterson, A H

    1998-08-01

    A detailed RFLP map was used to determine the chromosomal locations and subgenomic distributions of cotton (Gossypium) genes/QTLs that confer resistance to the bacterial blight pathogen, Xanthomonas campestris pv. malvacearum (Xcm). Genetic mapping generally corroborated classic predictions regarding the number and dosage effects of genes conferring Xcm resistance. One recessive allele (b6) was a noteworthy exception to the genetic dominance of most plant resistance alleles. This recessive allele appeared to uncover additional QTLs from both resistant and ostensibly susceptible genotypes, some of which corresponded in location to resistance (R)-genes effective against other Xcm races. One putatively "defeated" resistance allele (B3) reduced severity of Xcm damage by "virulent" races. Among the six resistance genes derived from tetraploid cottons, five (83%) mapped to D-subgenome chromosomes-if each subgenome were equally likely to evolve new R-gene alleles, this level of bias would occur in only about 1.6% of cases. Possible explanations of this bias include biogeographic factors, differences in evolutionary rates between subgenomes, gene conversion or other intergenomic exchanges that escaped detection by genetic mapping, or other factors. A significant D-subgenome bias of Xcm resistance genes may suggest that polyploid formation has offered novel avenues for phenotypic response to selection.

  19. QualitySNP: a pipeline for detecting single nucleotide polymorphisms and insertions/deletions in EST data from diploid and polyploid species

    Directory of Open Access Journals (Sweden)

    Voorrips Roeland E

    2006-10-01

    Full Text Available Abstract Background Single nucleotide polymorphisms (SNPs are important tools in studying complex genetic traits and genome evolution. Computational strategies for SNP discovery make use of the large number of sequences present in public databases (in most cases as expressed sequence tags (ESTs and are considered to be faster and more cost-effective than experimental procedures. A major challenge in computational SNP discovery is distinguishing allelic variation from sequence variation between paralogous sequences, in addition to recognizing sequencing errors. For the majority of the public EST sequences, trace or quality files are lacking which makes detection of reliable SNPs even more difficult because it has to rely on sequence comparisons only. Results We have developed a new algorithm to detect reliable SNPs and insertions/deletions (indels in EST data, both with and without quality files. Implemented in a pipeline called QualitySNP, it uses three filters for the identification of reliable SNPs. Filter 1 screens for all potential SNPs and identifies variation between or within genotypes. Filter 2 is the core filter that uses a haplotype-based strategy to detect reliable SNPs. Clusters with potential paralogs as well as false SNPs caused by sequencing errors are identified. Filter 3 screens SNPs by calculating a confidence score, based upon sequence redundancy and quality. Non-synonymous SNPs are subsequently identified by detecting open reading frames of consensus sequences (contigs with SNPs. The pipeline includes a data storage and retrieval system for haplotypes, SNPs and alignments. QualitySNP's versatility is demonstrated by the identification of SNPs in EST datasets from potato, chicken and humans. Conclusion QualitySNP is an efficient tool for SNP detection, storage and retrieval in diploid as well as polyploid species. It is available for running on Linux or UNIX systems. The program, test data, and user manual are available at

  20. Chromosome doubling in Paspalum notatum var. saure (cultivar Pensacola

    Directory of Open Access Journals (Sweden)

    Luis Weiler

    2015-04-01

    Full Text Available Paspalum notatum is one of the most important native grassland species of southern Brazil, and the main forage source for livestock. The native ecotypes are tetraploid and have apomictic reproduction, which prevents the registration and protection of plant varieties. However, the cultivated variety Paspalum notatum var. saurae (cultivar Pensacola is diploid and sexual. The objective of this study was to artificially produce polyploid cv. Pensacola plants, to be used as female parents in crosses with male tetraploid and apomictic parents. Seedlings and seeds were immersed in colchicine solutions for different periods. A tetraploid chromosome number was confirmed in three plants. The reproduction mode of the resulting polyploid plants will be assessed; if confirmed to be sexual, they can be used in crosses with native apomictic plants to breed new intraspecific hybrids.

  1. Combining SNP discovery from next-generation sequencing data with bulked segregant analysis (BSA to fine-map genes in polyploid wheat

    Directory of Open Access Journals (Sweden)

    Trick Martin

    2012-01-01

    Full Text Available Abstract Background Next generation sequencing (NGS technologies are providing new ways to accelerate fine-mapping and gene isolation in many species. To date, the majority of these efforts have focused on diploid organisms with readily available whole genome sequence information. In this study, as a proof of concept, we tested the use of NGS for SNP discovery in tetraploid wheat lines differing for the previously cloned grain protein content (GPC gene GPC-B1. Bulked segregant analysis (BSA was used to define a subset of putative SNPs within the candidate gene region, which were then used to fine-map GPC-B1. Results We used Illumina paired end technology to sequence mRNA (RNAseq from near isogenic lines differing across a ~30-cM interval including the GPC-B1 locus. After discriminating for SNPs between the two homoeologous wheat genomes and additional quality filtering, we identified inter-varietal SNPs in wheat unigenes between the parental lines. The relative frequency of these SNPs was examined by RNAseq in two bulked samples made up of homozygous recombinant lines differing for their GPC phenotype. SNPs that were enriched at least 3-fold in the corresponding pool (6.5% of all SNPs were further evaluated. Marker assays were designed for a subset of the enriched SNPs and mapped using DNA from individuals of each bulk. Thirty nine new SNP markers, corresponding to 67% of the validated SNPs, mapped across a 12.2-cM interval including GPC-B1. This translated to 1 SNP marker per 0.31 cM defining the GPC-B1 gene to within 13-18 genes in syntenic cereal genomes and to a 0.4 cM interval in wheat. Conclusions This study exemplifies the use of RNAseq for SNP discovery in polyploid species and supports the use of BSA as an effective way to target SNPs to specific genetic intervals to fine-map genes in unsequenced genomes.

  2. Morphological features of different polyploids for adaptation and molecular characterization of CC-NBS-LRR and LEA gene families in Agave L.

    Science.gov (United States)

    Tamayo-Ordóñez, M C; Rodriguez-Zapata, L C; Narváez-Zapata, J A; Tamayo-Ordóñez, Y J; Ayil-Gutiérrez, B A; Barredo-Pool, F; Sánchez-Teyer, L F

    2016-05-20

    Polyploidy has been widely described in many Agave L. species, but its influence on environmental response to stress is still unknown. With the objective of knowing the morphological adaptations and regulation responses of genes related to biotic (LEA) and abiotic (NBS-LRR) stress in species of Agave with different levels of ploidy, and how these factors contribute to major response of Agave against environmental stresses, we analyzed 16 morphological trials on five accessions of three species (Agave tequilana Weber, Agave angustifolia Haw. and Agave fourcroydes Lem.) with different ploidy levels (2n=2x=60 2n=3x=90, 2n=5x=150, 2n=6x=180) and evaluated the expression of NBS-LRR and LEA genes regulated by biotic and abiotic stress. It was possible to associate some morphological traits (spines, nuclei, and stomata) to ploidy level. The genetic characterization of stress-related genes NBS-LRR induced by pathogenic infection and LEA by heat or saline stresses indicated that amino acid sequence analysis in these genes showed more substitutions in higher ploidy level accessions of A. fourcroydes Lem. 'Sac Ki' (2n=5x=150) and A. angustifolia Haw. 'Chelem Ki' (2n=6x=180), and a higher LEA and NBS-LRR representativeness when compared to their diploid and triploid counterparts. In all studied Agave accessions expression of LEA and NBS-LRR genes was induced by saline or heat stresses or by infection with Erwinia carotovora, respectively. The transcriptional activation was also higher in A. angustifolia Haw. 'Chelem Ki' (2n=6x=180) and A. fourcroydes 'Sac Ki' (2n=5x=150) than in their diploid and triploid counterparts, which suggests higher adaptation to stress. Finally, the diploid accession A. tequilana Weber 'Azul' showed a differentiated genetic profile relative to other Agave accessions. The differences include similar or higher genetic representativeness and transcript accumulation of LEA and NBS-LRR genes than in polyploid (2n=5x=150 and 2n=6x=180) Agave accessions

  3. In vitro Polyploid Induction and Its Identification in Cymbidium sinense%墨兰多倍体的离体诱导和鉴定

    Institute of Scientific and Technical Information of China (English)

    王木桂; 曾瑞珍; 谢利; 高许花; 张志胜

    2011-01-01

    以墨兰'企剑白墨'的根状茎为材料,研究秋水仙素处理对墨兰根状茎生长和多倍体诱导的影响.结果表明,秋水仙素对根状茎有严重的毒害致死作用,在试验浓度和时间范围内,随着秋水仙素浓度的升高或处理时间的延长,根状茎存活率明显降低.秋水仙素能诱导'企剑白墨'根状茎的染色体加倍,但不同浓度和时间处理的染色体加倍效率不一样.只在0.01%×3天处理下诱导出四倍体,诱导率为11.11%,其余处理诱导出二、四混倍体,诱导率在0.00%~19.44%之间.四倍体根状茎比二倍体粗壮,顶端更圆,再生出的四倍体植株株型紧凑,叶片质地变硬,根明显增粗.%Investigations were carried out on the effects of colchicine treatment on growth and polyploid induction of rhizomes of Cymbidium sinense ‘QiJianBaiMo’. The results showed that colchicine treatment had severe toxic and lethal effects on the rhizomes, and in the range of concentration of colchicine and duration of treatment adopted, the higher the concentration of colchicine and the longer the duration of treatment were, the stronger the toxic and lethal effects were. Chromosome doubling was found in all treatments with colchicine, while, the efficiency depended on the concentration of colchicine and the duration of treatment. Tetraploids were obtained only in the treatment of 0.01%×3 d, with the induction rate being 11.11%. In other treatments, only mixoploids were produced with the induction rate between 0.00% and 19.44%. The tetraploid rhizome was rounder in growth tip and larger in diameter, and the regenerated tetraploid plant was more sturdy and compacted in appearance with harder leaves and thicker roots compared to the diploid one.

  4. 组织培养结合秋水仙素诱导滇杨多倍体的研究%Study on Polyploid Induction of Populus yunnanensis Dode by Tissue Culture Combined with Colchicine

    Institute of Scientific and Technical Information of China (English)

    陈杰; 周军; 孙正海; 唐军荣; 段安安; 王俊峰; 辛培尧

    2013-01-01

    Populus yunnanensis Dode was employed to induce polyploid by tissue Culture combined with colchicine in order to obtain new polyploid P. yunnanensis Dode. The result showed that the better combinations were 80 mg/L colchicine treated for 30 days or 90 mg/L colchicum treated for 20 ~ 30 days during tissue culture, and gotten the highest inducing rate was 18.6%. The morphological difference, chromosome number, and stomas size were also observed between normal and various P. yunnanensis. The morphological difference was very clearer between normal and variant P. yunnanensis. The chromosome number increased to 76, and the size of stomas increased in variant P. yunnanensis. The chlorophyll content in leaves was 1. 5 times higher in variant P. yunnanensis than that in normal plants.%利用组织培养结合秋水仙素对滇杨进行多倍体诱导,以期获得滇杨多倍体植株.结果表明:组织培养结合秋水仙素诱导滇杨产生多倍体的较优组合为秋水仙素浓度为80 mg/L下处理30 d或在90 mg/L下处理20~30 d,此时,多倍化诱导率最高可达18.6%.对滇杨多倍体植株与正常植株进行外部形态、染色体数目及单位叶面积内气孔数目的观察,发现多倍体植株与正常株形态差异明显,染色体数目增加为76条,叶表皮气孔变大,同时,叶片中叶绿素含量约为二倍体的1.5倍.

  5. 荧光原位杂交技术在植物多倍体起源与进化研究中的应用%Applications of Fluorescence in situ Hybridization (FISH/GISH) to Study the Origin and Evolution of Plant Polyploids

    Institute of Scientific and Technical Information of China (English)

    付文炎; 刘义飞; 黄宏文

    2014-01-01

    多倍化是植物物种形成与多样化的重要原动力。研究植物特别是一些重要经济作物和园艺植物多倍体的起源与进化,不仅对于揭示多倍体形成过程中性状变异的分子机制具有重要意义,而且可为植物遗传资源的保护与利用提供理论和技术支持。作为连接基因组序列片段到染色体组的桥梁,荧光原位杂交技术长期被广泛用来研究多倍体形成与进化过程中相关特异基因或序列的表达定位、外源染色体检测和鉴定、基因组结构变异等科学问题。因此,在简单介绍荧光原位杂交技术发展历史和植物多倍体主要类型的基础上,主要总结了荧光原位杂交技术在植物多倍体起源与进化相关研究上的应用。%Polyploidization is a driving force to the plant speciation and diversification. The researches about the origin and evolution of plant polyploids, in particular crop or horticultural plant polyploids can not only give insights of the molecular mechanism underlying trait variations, but also improve the conservation and utilization of valuable polyploid germplasm resources. The developing of lfuorescence in situ hybridization (FISH/GISH) technique recently provides a bridge between the sequences of a genome and the corresponding chromosomes. The uses of FISH and GISH can help to understand the processes of gene expressions, exotic chromosomal invasions and genomic structural variations related to polyploidy. Thus, the history of the developments of fluorescence in situ hybridization technique and the main types of plant polyploids were brielfy introduced. Furthermore, the recent progresses of the applications of FISH and GISH on the researches of the origin and evolution of plant polyploids were reviewed.

  6. Meiotic behavior of interspecific hybrids between artificially tetraploidized sexual Brachiaria ruziziensis and tetraploid apomictic B. brizantha (Poaceae Comportamento meiótico de híbridos interespecíficos entre tetraplóides artificiais de Brachiaria ruziziensis e tetraplóides apomíticos de B. brizantha (Poaceae

    Directory of Open Access Journals (Sweden)

    Mariana Ferrari Felismino

    2010-04-01

    Full Text Available The meiotic behavior of four interspecific promising hybrids was evaluated by conventional cytological methods. The female genitors were two artificially tetraploidized sexual accessions of B. ruziziensis (R41 and R44, 2n = 4χ = 36, which were crossed to an agronomically superior natural tetraploid apomictic genotype of B. brizantha (B140 - BRA003395. Three of them (HBGC313, HBGC 315, and HBGC324 were sexual and one (HBGC325 apomictic. Analyses of some cells in diakinesis revealed multivalent chromosome configurations, suggesting that genetic recombination and introgression of some genes could be present. The four hybrids had different types of meiotic abnormalities at various frequencies. Abnormalities related to irregular chromosome segregation due to polyploidy were common among these hybrids, and characterized by precocious chromosome migration to the poles, laggard chromosomes, both generating micronuclei in telophases and tetrads and, as a consequence, unbalanced gametes. One abnormality genotype-specific, related to spindle orientation (a putative divergent spindle mutation, was recorded for the first time in two of the hybrids, HBGC313 and HBGC325. The sexual hybrid HBGC324 had the lower rate of abnormalities, and it could be used as a female genitor in future crosses in the breeding program. The abnormalities present in these hybrids may impact fertility and affect seed production. Based on the results, HBGC324 is the single hybrid recommended to the breeding program. Hybrids must produce a good amount of viable seeds, besides good overall dry matter production and nutritive value, in order to be widely utilized and adopted in production systems. Due to pseudogamy, the desirable superior apomictic hybrids need viable pollen grains to fertilize the secondary nucleus of the embryo sac and thus ensure normal and vigorous endosperm development and plenty of seed set.O comportamento meiótico de quatro híbridos interespec

  7. 氮离子注入对蒙古黄芪多倍体诱导的影响%Effect of N + Implantation on the Inducement of Polyploid Astragalus membranaceus (Fisch.) Bge.var.mongholicus (Bge.) Hsiao

    Institute of Scientific and Technical Information of China (English)

    张利珍; 李前忠; 杨林源; 武成艳

    2011-01-01

    A new method of improving induction rate of polyploid through chemical induction combined with physical mutation were proposed by using the diploid Astragalus membranaceus ( Fisch. ) Bge. Var. Mongholicus (Bge. ) Hsiao seeds as the materials and N+ beam as the mutagenic agent. The results indicated that N + implantation showed significant biological effects. The effects of N + implantation combined with colchicine on inducing polyploidy of Astragalus were obvious, 44.4% doubling rate was obtained by being treated by the combination of N+ ion implantation dose 2.6 x 1016 N + /cm2 and colchicine concentration 100 mg · L-1 for 5 d. The best result of 46.2% was obtained by using the combination of N+ implantation dose 5.2 x 1016 N + /cm2 and colchicine concentration 100 mg · L-1 for 10 d. They were higher than the control group of maximum induction rate 13.9% of colchicine concentration 100 mg · L-l, treatment time 15 d. Cell chromosome identification results showed that the polyploid is tetraploid.%利用二倍体蒙古黄芪种子为材料,以低能氮离子束为诱变源,将化学诱导与物理诱变相结合,探索出一套高效的多倍体诱导新方法.研究结果表明:氮离子注入种子后表现出明显的生物学效应;氮离子注入与秋水仙素联合诱导黄芪多倍体的效果很明显.氮离子注入剂量为2.6×1016 N+/cm2,秋水仙素浓度为100 mg·L-1,培养5d诱导率最高为44.4%;氮离子注入剂量为5.2×1016 N+/cm2,秋水仙素浓度为150mg· L-1,培养10d的诱导率最高为46.2%;二者均高于对照组秋水仙素浓度为100mg·L-1培养15 d的最高诱导率13.9%.利用细胞染色体计数鉴定多倍体为四倍体.

  8. 咖啡因加热休克诱导皱纹盘鲍多倍体的研究%Induction of Polyploid in the Pacific Abalone by Caffeine-Heat Shock Treatments

    Institute of Scientific and Technical Information of China (English)

    毛连菊; 王子臣; 刘相全; 李雅娟; 高悦勉

    2000-01-01

    Polyploid of Pacific abalone, Haliotis discus hannai Ino, was induced by blocking Polar body I with caffeine-heat shock treatments. Fertilized eggs were treated with caffeine concentrations at: 2.5mmol/L, 5mmol/L and 10mmol/L; heat shock temperatures at 24℃, 26℃, 28℃, lasting for 10min to 30min, total 5 periods of time,beginning at 10min post-pertilization. Both fertilizing and incubating at 21℃ sea water.The results of studies showed that the effective procedure for inducing triploid appeared to be 5mmol/L and 10mmol/L Caffeine concentration, heat shock tempera- ture 26℃, duration 10min to 15min, all beginning at 10min after insemination. The percentage of triploid was 64.6%~77.8%, Comprehensive efficiency index of polyploid induction was 0.57~0.61. Under the condition of 5mmol/L caffeine conce- ntration and the temperature 26℃ for 30 min duration at 10min post-fertilization, 2.8%~3.6% tetraploid embryos could be produced.%报道了用咖啡因加热休克抑制受精卵的第一极体的释放诱导皱纹盘鲍(Haliotis discus hannai Ino)多倍体的研究结果。皱纹盘鲍的卵在21℃海水中受精,受精后10分钟开始处理,药物浓度分别为2.5mmol/L、5mmol/L、10mmol/L,热休克温度分别为24℃、26℃、28℃,处理的持续时间为10分钟至30分钟,共分5个时间段。结果表明,药物浓度5mmol/L和10mmol/L,处理温度26℃,处理持续时间10~15分钟,其三倍体诱导率可达66.4%~77.8%,综合评价指数为0.57~0.61。在5mmol/L,26℃条件下,处理持续时间30分钟可以产生2.8%~3.6%的四倍体胚胎。

  9. Chromosome doubling in Paspalum notatum var. saure (cultivar Pensacola)

    OpenAIRE

    Luis Weiler; Karine Cristina Krycki; Divanilde Guerra; Carine Simioni; Miguel Dall’Agnol

    2015-01-01

    Paspalum notatum is one of the most important native grassland species of southern Brazil, and the main forage source for livestock. The native ecotypes are tetraploid and have apomictic reproduction, which prevents the registration and protection of plant varieties. However, the cultivated variety Paspalum notatum var. saurae (cultivar Pensacola) is diploid and sexual. The objective of this study was to artificially produce polyploid cv. Pensacola plants, to be used as female parent...

  10. Effect of Polyploidization of Pear( Pyrus communis L.)on Shoot Regeneration Ability from in vitro Leaf Explants%梨多倍体化对离体叶片不定梢再生能力的影响

    Institute of Scientific and Technical Information of China (English)

    孙清荣; 孙洪雁; 辛力; 李慧峰; 刘庆忠

    2012-01-01

    以源于二倍体梨品种Fertility(Pyrus communis L.)通过秋水仙碱离体诱变体细胞染色体加倍获得的不同同源多倍体无性系为试材,以离体叶片为外植体,观察研究了不同倍性无性系叶片的不定梢再生能力.结果表明,多倍体的不定梢再生率显著低于二倍体的再生率.不同多倍体无性系的不定梢再生能力也存在显著差异.三倍体无性系3x-3和四倍体无性系4x-4不能诱导产生不定梢.表明器官发生能力下降或植物细胞全能性的丧失与细胞染色体多倍体化有关.%Shoot regeneration ability from in vitro leaf explants of different ploidy clones which were derived from the same diploid cultivar of pear ( Pyrus communis L. ) by colchicine treatment was examined. The regeneration rates of Neopolyploids were significantly lower than that of diploid control. Regeneration rates among different neopolyploid clones were significantly different. Triploid '3x-3' and tetraploid '4x-4' failed to regenerate. These results revealed that the decrease of regeneration ability or loss of totipotency was related to the polyploidization.

  11. 多倍体啤酒酵母URA3基因的失活与恢复%Inactivation and Recovery of URA3 Gene of Polyploid Brewer's Yeast

    Institute of Scientific and Technical Information of China (English)

    许海艳; 赵丽彬; 董健; 肖冬光

    2014-01-01

    Polyploid brewer's yeast strain S6 was used as the starting strain to construct uracil auxotrophic strain S6-△U through gene homologous recombination, which could be used as a genetic marker. Then uracil auxotrophic strain S6-△U was restored to original strain and named strain S6'. The growth of strain S6, strain S6-△U and strain S6' was compared and the results suggested that the mutation of URA3 gene would not re-duce the growth of the strain. Accordingly, a method for rapid preparation of auxotrophic brewer's strains had been established in this study.%以多倍体啤酒酵母菌株S6作为出发菌株,利用同源重组的方法构建了尿嘧啶营养缺陷型啤酒酵母菌株S6-△U,使之用于遗传标记,并把缺陷型菌株恢复成原营养型S6'。同时对出发菌株S6,缺陷型菌株S6-△U和恢复后的菌株S6'的生长状况进行比较。结果表明,URA 3点突变并没有弱化菌株的生长状况。从而建立一种快速获得缺陷型啤酒酵母菌株的方法。

  12. 丰都车前的细胞学研究,兼论它的多倍体起源%Cytological studies of Plantago erosa var.fengdouensis,with special reference to its polyploid origin

    Institute of Scientific and Technical Information of China (English)

    王恒昌; 孟爱平; 李建强; 王勇; 陶勇

    2004-01-01

    Cytological studies including mitosis and meiosis of Plantago erosa var. fengdouensis, an endangered plant native to the Three-Gorge Reservoir Area of China,have been investigated. It may be an allotetraploid.The karyotype can be formulated as 2n=4x=24= 12m(2sat)+12sm(2sat), belonging to 2A type. Extreme environmental impetus especially the seasonal flooding may play a principal role in the polyploid formation of it. Chromosome number of P. asiatica is reconfirmed,and P. asiatica is a hexaploid. This study will supply a cytological evidence for the further genetics conservation research of Plantago erosa var.fengdouensis.%对长江三峡库区特有濒危植物丰都车前(Plantago erosa var.fengdouensis)进行了细胞学研究,包括有丝分裂和减数分裂两方面.丰都车前可能为一异源四倍体.其核型公式为2n=4x=24=12m(2sat)+12sm(2sat),属于2A型.极端的环境压力尤其是季节性的水淹可能是此四倍体物种形成的主要原因.对同属内的另一物种车前(P.asiatica)进行了比较观察,确证车前为六倍体.该实验为丰都车前的保育遗传学研究提供了细胞学证据.

  13. Poliploidização em berinjela (Solanum melongena L.: II - Observações em plantas resultantes de tratamentos com colquicina Polyploidization in egg-plant (Solanum melongena L.: II - Observation in plants resulting from colchicine treatments

    Directory of Open Access Journals (Sweden)

    Dixier M. Medina

    1972-01-01

    Full Text Available As observações de diversos caracteres morfológicos em plantas de berinjela (Solatium melongena L. provenientes de tratamentos com colquicina levaram à separação de razoável número de possíveis poliplóides. O número de cromossomos determinado em células-mães de pólen revelou a existência de plantas tetraplóides e plantas quiméricas, além das normais diplóides. Numa amostra representando os diferentes tratamentos, encontrou-se uma associação quase perfeita entre a natureza tetraplóide ou quimérica da planta e a irregularidade do tamanho do pólen; tal associação não foi encontrada quando se analisou a quantidade de pólen vazio. Os frutos tetraplóides obtidos produziram sementes maiores e em número bem menor que os diplóides de pesos equivalentes.The observations on several morphological characteristics made on plants derived from treatments of seed with colchicine in the egg-plant (Solatium melongena L. led to separation of a reasonable number of possible polyploids. Chromosome number determined in P.M.C. indicated the existence of tetraploid plants, chimeric plants at level 24-48 and at level 48-96 beside the diploid normal ones. In a certain number of plants representing the different treatments, it was found an almost perfect association between tetraploidy and chimeric condition of the plants at one side and irregular size of the pollen at the other side; such an association was not found when the amount of empty pollen was analysed. The tetraploid fruits produced low number of seeds which were not uniform in size but were larger and in general heavier than the diploid ones.

  14. Establishment of an in vitro system for regeneration and polyploid induction of Miscanthus floridulus%五节芒离体再生与多倍体诱导技术体系的建立

    Institute of Scientific and Technical Information of China (English)

    周玥玥; 陈智勇; 黄丽芳; 邓果特; 蒋建雄; 易自力

    2012-01-01

    以五节芒(Miscanthus floridulus)幼穗为外植体,建立了五节芒的离体再生体系:幼穗的最佳愈伤诱导培养基为MS+4.0mg/L 2,4-D+0.1mg/L 6-BA,最佳分化培养基为MS+2.0mg/L 6-BA,最佳生根培养基为MS+1.0mg/L IAA+0.1mg/L IBA+1.0mg/L CCC.比较不同浓度秋水仙碱溶液对五节芒愈伤组织诱变的效果,结果显示,以1000mg/L秋水仙碱处理愈伤组织72h,诱导率可达12.48%,形态特征、DNA含量和染色体核型分析表明,诱导获得的再生植株为五节芒四倍体.%The immature inflorescence of Miscanthus floridulus were used as explants to establish the regeneration system in vitro. The results indicate that the best medium for callus induction was MS medium with 4.0 mg/L 2,4-D, 0.1 mg/L 6-BA, for bud differentiation was MS medium with 2.0 mg/L 6-BA and for plantlets rooting was MS medium withl.O mg/L IAA, 0.1 mg/L IBA and 1.0 mg/L CCC. The effects of different concentrations of colchicine on polyploid induction were investigated in vitro. The results indicate that the induction rate of polyploidy in the treatment with 1 000 mg/L colchicine solution for 72 h reached 12.48%. The morphological characteristic, nuclear DNA contents and chromosome karyotype of the regenerated plantlets showed the inducted plantlets were tetraploid.

  15. Chromosome numbers, characterization of chromosomal pairing during meiosis, origin and natural propagation in polyploid cytotypes (4x, 5x and 6x) of Agrimonia eupatoria L. (Rosaceae) in northwest Himalayas (India).

    Science.gov (United States)

    Kumar, Puneet; Rana, Pawan K; Himshikha; Singhal, Vijay Kumar; Gupta, R C

    2014-07-01

    Despite the presence of intraspecific polyploidy (2x, 4x, 5x and 6x) in Agrimonia eupatoria, origin of these cytotypes has never been addressed adequately. The aim of the present study was to record the original chromosome counts and characterize chromosomal pairing during meiosis and microsporogenesis in the 5x cytotype, and discussing the hypothesis regarding the possible origin of polyploid cytotypes (4x, 5x and 6x) in the species. The geographical distribution pattern of cytotypes in the Indian Himalayas and elsewhere has also been analyzed. The present meiotic analysis revealed three chromosomes counts, the tetraploid (2n = 4x = 56), the pentaploid (2n = 5x = 70) and the hexaploid (2n = 6x = 84) cytotypes based on x = 14. Meiotic course was perfectly normal in the 4x and 6x cytotypes resulting into high pollen fertility (94-100 %). Meiotic course in the imbalanced 5x cytotype has been found to be irregular characterized by the presence of high frequency of univalents at diakinesis and metaphase-I. Abnormal meiotic course contributed towards high pollen sterility (74-88 %). Even the apparently fertile/stained pollen grains were of irregular shape and of heterogeneous sizes. Meiotic behaviour of the 5x cytotype is like typical of allopolyploid. Individuals of 5x cytotype did not produce seeds and propagate vegetatively (root suckers) while 4x and 6x cytotypes exploited sexual (seeds) as well as vegetative means for propagation. Chromosomal pairing in pentaploid cytotype is like typical of an allopolyploid and we assume that it might have originated owing to natural inter-cytotype hybridization between 4x and 6x cytotypes in a mixed population. Analysis of geographical distribution pattern of cytotypes shows that Indian Himalayas represent the most cytotype-diverse region for A. eupatoria with the existence of all the four cytotypes (2x, 4x, 5x, 6x). This shows the dynamic nature of the species at chromosomal level in this part of the world.

  16. N+注入对蒙古黄芪多倍体生化指标的影响%Effects of N+ Implantation on Biochemical Indexes of Induced Polyploid Astragalus membranaceus

    Institute of Scientific and Technical Information of China (English)

    张利珍; 李前忠; 杨林源; 武成艳

    2011-01-01

    为了研究N+注入对蒙古黄芪多倍体生化指标的影响,采用培养基中添加秋水仙素的方法诱导多倍体,测定不同剂量N+注入的情况下,不同诱导时间内分化出的不定芽及二倍体和四倍体植株叶片的生化指标变化情况.结果表明:未注入组丙二醛(malonaldehyde,MDA)的含量,以及过氧化物酶( peroxidase,POD)、过氧化氢酶(catalase,CAT)和超氧化物歧化酶(superoxide dismutase,SOD)的活性,随诱导时间的延长而增高,蛋白质含量随诱导时间的延长而降低,蛋白质含量与MDA含量呈负相关;注入组的生化指标在诱导时间内都有一定的波动,但总体趋势与未注入组一致;四倍体与二倍体相比较,四倍体的MDA含量及POD、CAT和SOD的活性都高于二倍体,而蛋白质含量却低于二倍体.说明离子束注入能使种子产生大量自由基,自由基的增加可导致MDA的产生,从而破坏蛋白质的合成,同时,N+注入又可诱发新的修复机制;四倍体植株受伤害程度更大,但四倍体植株的自我保护能力高于二倍体植株,即四倍体植株的抗逆性较二倍体增强.%To study effects of N+ implantation on biochemical indexes of polyploid Astragalus membranaceus, colchicine was added into medium to induce polyploidy. By measuring the biochemical indexes of adventitious buds at different induction times and leaves from tetraploid and diploid plants, data showed that malondialdehyde (MDA) content, and peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) activities were positively correlated with induction time, but protein content was negatively correlated with induction time in control group. The biochemical indexes of treated group showed fluctuations during induction. MDA content and POD, CAT, SOD activities in tetraploids were higher than in diploids, while protein content in tetraploids was lower than in diploids. These data indicated that abundant free radicals were produced by N

  17. 秋水仙素对蚕豆胚根生长的影响及多倍体诱导效应分析%Influence of colchicine on radicle growth of Vicia faba and the polyploid inductive effect

    Institute of Scientific and Technical Information of China (English)

    闫秋洁; 杨琼

    2012-01-01

    In order to test the optimum induction combination(time and concentration), and analyse the inductive effects of colchicine induced the radicle polyploid in Vicia faba. The radicle cells were treated with the colchicine of five concentrations (0.025%,0. 050%,0.100%,0.150% ,0. 200%,respectively) combining various culture time (12,24, 48,60 h,respectively). And the radicle cell were treated with distilled water simultaneously,which were taken as the control. The optimum induction combination induced by colchicine was confirmed by significant difference of the root tip inductivity and the radicle expanding ratio. And the chromosome number of radicle cells and stoma number of seedling were detected to identify the induction effect. The radicle amount and seeding height were analized subsequently. The optimum inductive condition was 48 h combining colchicine concentration of 0.100%. There were significant differences in stoma number between inducted time and inducted concentration, however, the radicle number and height of V. faba seedling showed significant difference in inductive concentration but no significant difference in culture time.%筛选秋水仙素诱导蚕豆胚根多倍体的最适诱导处理组合并分析其诱导效应.以秋水仙素5个浓度 (0.025%、0.050%、0.100%、0.150%、0.200%)和4个诱导时间(12、24、48、60 h)正交组合(蒸馏水处理为对照)分别处理蚕豆胚根.以根尖诱导率和胚根膨大率的显著性差异确定蚕豆胚根多倍体的最适诱导处理组合,并以胚根细胞染色体数目和幼叶气孔数目的变化对诱导效果进行鉴定,分析其幼苗期的胚根数目和幼苗长度.结果表明:秋水仙素最适诱导时间为48 h和浓度为0.100%;气孔数量在诱导时间和诱导浓度之间均有显著差异,但幼苗期的胚根数量和幼苗长度在不同的诱导时间之间无显著差异,诱导浓度之间差异显著.

  18. Studies on Anther Development of 4x Sexual Polyploidization Male Sterile Lines in Non-heading Chinese Cabbage%有性多倍化白菜四倍体雄性不育花药发育的解剖学研究

    Institute of Scientific and Technical Information of China (English)

    钟程; 田鑫; 张蜀宁; 张文华

    2012-01-01

    [目的]对有性多倍化雄性不育系花药的败育时期和方式进行研究,为雄性不育基础研究提供理论依据.[方法]以同源四倍体白菜为母本,以秋水仙素诱导筛选出含2n配子较高的二倍体为父本杂交获得四倍体不育系及其保持系为材料,采用常规石蜡切片法对其花药进行解剖学研究,观察其花药的败育时期.[结果]退化的雄蕊可分为4种类型,均败育于孢原细胞分化期,始终处在孢原细胞期,无绒毡层与花粉母细胞的分化,不形成药室,属孢子体败育型.[结论]有性多倍化白菜四倍体雄性不育的4种类型都是孢子体败育型.%[Objective]Cytological investigation on microsporogenesis of male sterility of sexual polyploidizationmale sterile lines in non-heading Chinese cabbage were studied to provide theoretical basis for the male sterility. [Method]Anther anatomical structure and development were observed using a light microscope through paraffin slices on the production of Ax CMS by sexual polyploidization and its maintainer line in Chinese cabbage. Abortion stage of 4x CMS was observed. [Jiesult] There were four types in the degraded stamens. The abortion of stamen occurred at the stage of archesporial cell differentiation,at which there was no differentiation of fibrous layer,tapetum and microspore mother cell. It belonged to non-sporange cytoplasmic male sterility. [Conclusion]Four types of the 4x sexual polyploidization CMS lines in non-heading Chinese cabbage were sporophyte abortion.

  19. Use of next-generation sequencing in genomic studies of polyploid crops:cotton as an example%高通量测序技术在多倍体作物基因组学研究中的应用(英文)

    Institute of Scientific and Technical Information of China (English)

    朱乾浩; 丹尼·卢埃林; 印·威尔逊

    2014-01-01

    Next-generation sequencing ( NGS ) technologies provide enormous power and new potential to access the complex polyploid genomes and transcriptomes of major crops , including cotton . This article summarises the applications of NGS in cotton genomic studies , including genome sequencing and resequencing , transcriptomic analysis , small RNA sequencing and miRNA identification , and identification of single nucleotide polymorphisms . NGS has rapidly accelerated genomic studies in cotton and will further expand our understanding of the evolution and polyploidisation of cotton at the species level as well as our understanding of the biology of the development of the unique seed trichomes that characterise the commercial textile fibres produced by some members of the Gossypium genus . Realisation of substantial impacts on applied cotton genetics and breeding will largely depend on the formulation of novel applications of NGS and the development of handy bioinformatic tools for dealing with and interpretation of the vast amounts of data generated by this technology .%高通量测序或第二代测序( next-generation sequencing , NGS)技术已被广泛地应用于动植物基因组学研究并对其产生了深刻影响.该文总结了NGS在棉花基因组测序、转录组分析、微小RNA和单核苷酸多态性鉴定等方面的应用研究进展,并对NGS在棉花基因组学和遗传育种中的应用前景作了展望.NGS在棉花中的应用对其他多倍体作物的类似研究具有参考和指导意义,但其更广泛和有效的应用有赖于简便、高效生物信息学方法的开发和利用.

  20. 高通量测序技术在多倍体作物基因组学研究中的应用(英文)%Use of next-generation sequencing in genomic studies of polyploid crops:cotton as an example

    Institute of Scientific and Technical Information of China (English)

    朱乾浩; 丹尼·卢埃林; 印·威尔逊

    2014-01-01

    Next-generation sequencing ( NGS ) technologies provide enormous power and new potential to access the complex polyploid genomes and transcriptomes of major crops , including cotton . This article summarises the applications of NGS in cotton genomic studies , including genome sequencing and resequencing , transcriptomic analysis , small RNA sequencing and miRNA identification , and identification of single nucleotide polymorphisms . NGS has rapidly accelerated genomic studies in cotton and will further expand our understanding of the evolution and polyploidisation of cotton at the species level as well as our understanding of the biology of the development of the unique seed trichomes that characterise the commercial textile fibres produced by some members of the Gossypium genus . Realisation of substantial impacts on applied cotton genetics and breeding will largely depend on the formulation of novel applications of NGS and the development of handy bioinformatic tools for dealing with and interpretation of the vast amounts of data generated by this technology .%高通量测序或第二代测序( next-generation sequencing , NGS)技术已被广泛地应用于动植物基因组学研究并对其产生了深刻影响.该文总结了NGS在棉花基因组测序、转录组分析、微小RNA和单核苷酸多态性鉴定等方面的应用研究进展,并对NGS在棉花基因组学和遗传育种中的应用前景作了展望.NGS在棉花中的应用对其他多倍体作物的类似研究具有参考和指导意义,但其更广泛和有效的应用有赖于简便、高效生物信息学方法的开发和利用.

  1. Self-sterility in the hexaploid Handroanthus serratifolius (Bignoniaceae, the national flower of Brazil

    Directory of Open Access Journals (Sweden)

    Mariana Ferreira Alves

    2013-12-01

    Full Text Available Polyploidization is common among angiosperms and might induce typically allogamous plants to become autogamous (self-compatible, relying on sexual self-fertilization or apomictic (achieving asexual reproduction through seeds. This work aimed to determine whether neopolyploidy leads to the breakdown of the self-incompatibility system in the hexaploid non-apomictic species Handroanthus serratifolius (Vahl S. Grose, through analyses of its floral biology, pollination biology and breeding system. Although anthesis lasted for three days, increasing the overall floral display, receptivity decreased as of the second day. Centridini and Euglossini bees were the main pollinators, and low nectar availability (1.95 ± 1.91 µl/flower might have obliged them to visit multiple flowers. We observed low reproductive efficacy. That might be explained by self-sterility and by the great number of flowers per individual, which could increase the frequency of geitonogamy. Ovule penetration by the pollen tubes in self-pollinated pistils with posterior abscission indicated late-acting self-incompatibility in H. serratifolius, as observed in other diploid Bignoniaceae species, although inbreeding depression cannot be excluded. The self-sterility found in the monoembryonic, hexaploid individuals studied here contrasts with the results for other neopolyploid Handroanthus and Anemopaegma species, which are often autogamous and apomictic. Our results suggest that neopolyploidy is not the main factor leading to self-fertility in Handroanthus.

  2. Polyploid induction of Allium ascalonicum L. by colchicine

    OpenAIRE

    SUMINAH; SUTARNO; AHMAD DWI SETYAWAN

    2002-01-01

    The low production rate of shallot (Allium ascalonicum L.) in Indonesia could be caused by rarely excellent cultivars. Colchicine was one of the mutation agents frequently used in plant breeding in order to get polyploidy of cultivars. The aim of this research was to find out the differentiation of morphometric evidences and ploidy of shallot chromosomes induced by colchicines 1%. Preparation was made by squash method and stained by acetocarmine. The results indicated that the amount, length ...

  3. Induction Of Polyploid Mutant In Linum Usitatissimum L. By Cytomixis

    OpenAIRE

    Alka; M.Y.K. Ansari,; Towseef Mohsin Bhat; Sana Choudhary; Rumana Aslam

    2012-01-01

    Anti-mitotic agents such as colchicine have been used to induce polyploidy in various plants. Here we examined the effects of the combined treatment of 5 kR Gy + 0.10% SA on polyploidy induction in Linum usitatissimum. The phenomenon of chromatin transfer (cytomixis) among the proximate pollen mother cells (PMCs) in this species seems to be directly under genetic control and causes various meiotic abnormalities. Chromatin transfer also resulted in the formation of coenocytes, aneuploid, polyp...

  4. [Induction and identification of polyploid of Astragalus membranaceus var. mongholicus].

    Science.gov (United States)

    Wu, Yuxiang; Gao, Jianping; Zhao, Xiaoming

    2003-05-01

    In this article, improved agar painting method, with semi-solid of 0.2% colchicine and 0.1% agar, was adopted to treat apical buds of Astragalus membranaceus var. mongholicus (Bge.) Hsiao seedlings. Obtained plants were proved to be tetraploids by identification of biological characteristics and chromosome numbers. PMID:14535010

  5. Captive breeding programs based on family groups in polyploid sturgeons.

    Science.gov (United States)

    Boscari, Elisa; Pujolar, Jose Martin; Dupanloup, Isabelle; Corradin, Riccardo; Congiu, Leonardo

    2014-01-01

    In species with long life cycles and discontinuous availability of individuals to reproduction, implementing a long-term captive breeding program can be difficult or impossible. In such cases, managing diversity among familiar groups instead of individuals could become a suitable approach to avoid inbreeding and increase the possibility to accomplish a breeding scheme. This is the case of several sturgeon species including the Adriatic sturgeon, whose recovery depends on the management of a few captive stocks directly descended from the same group of wild parents. In the present study, relatedness among 445 potential breeders was inferred with a novel software for pedigree reconstruction in tetraploids ("BreedingSturgeons"). This information was used to plan a breeding scheme considering familiar groups as breeding units and identifying mating priorities. A two-step strategy is proposed: a short-term breeding program, relying on the 13 remaining F0 individuals of certain wild origin; and a long-term plan based on F1 families. Simulations to evaluate the loss of alleles in the F2 generation under different pairing strategies and assess the number of individuals to breed, costs and logistical aquaculture constraints were performed. The strategy proposed is transferable to the several other tetraploid sturgeon species on the brink of extinction.

  6. Segregation analysis of microsatellite (SSR) markers in sugarcane polyploids

    Science.gov (United States)

    Although the microsatellite (SSR) DNA markers have been extensively used in sugarcane breeding research, little is known about its inheritance mechanism. To address this problem, a high throughput molecular genotyping experiment was conducted on 964 single pollen grains and a 288-self progeny S1 map...

  7. Interspecific hybridization and polyploidization as tools in ornamental plant breeding

    OpenAIRE

    Tuyl, van, J.M.; Kim, K. B.

    2003-01-01

    Interspecific hybridisation and polyploidy are recognized as the most impor-tant sources of evolution and domestication of flowering plants. In ornamental plant breeding these phenomena go hand in hand and can be observed in the breeding his-tory of many ornamental crops (Rosa, Chrysanthemum, Gladiolus, Alstroemeria, Lil-ium, orchids etc). With lily as model crop techniques developed for overcoming pre- and post-fertilisation barriers are reviewed. For overcoming F1-sterility mitotic and meio...

  8. Interspecific hybridization and polyploidization as tools in ornamental plant breeding

    NARCIS (Netherlands)

    Tuyl, van J.M.; Kim, K.B.

    2003-01-01

    Interspecific hybridisation and polyploidy are recognized as the most impor-tant sources of evolution and domestication of flowering plants. In ornamental plant breeding these phenomena go hand in hand and can be observed in the breeding his-tory of many ornamental crops (Rosa, Chrysanthemum, Gladio

  9. Mechanisms of sexual polyploidization and inheritance in triploid citrus populations

    OpenAIRE

    CUENCA IBÁÑEZ, JOSÉ

    2013-01-01

    Citrus is the main fruit crop in the world and Spain is the 6th producer and the major exporter for the fresh fruit market. Seedlessness is one of the most important fruit quality traits for this market since consumers do not accept seedy fruits. Recovery of triploid hybrids has become an important breeding strategy to develop new seedless citrus varieties and several of them have been already released from citrus breeding programs worldwide. Despite the undisputable importance of polyploidy ...

  10. The obligate human pathogen, Neisseria gonorrhoeae, is polyploid.

    OpenAIRE

    Tobiason, Deborah M.; H Steven Seifert

    2006-01-01

    We show using several methodologies that the Gram-negative, diplococcal-bacterium Neisseria gonorrhoeae has more than one complete genome copy per cell. Gene dosage measurements demonstrated that only a single replication initiation event per chromosome occurs per round of cell division, and that there is a single origin of replication. The region containing the origin does not encode any genes previously associated with bacterial origins of replication. Quantitative PCR results showed that t...

  11. The obligate human pathogen, Neisseria gonorrhoeae, is polyploid.

    Directory of Open Access Journals (Sweden)

    Deborah M Tobiason

    2006-06-01

    Full Text Available We show using several methodologies that the Gram-negative, diplococcal-bacterium Neisseria gonorrhoeae has more than one complete genome copy per cell. Gene dosage measurements demonstrated that only a single replication initiation event per chromosome occurs per round of cell division, and that there is a single origin of replication. The region containing the origin does not encode any genes previously associated with bacterial origins of replication. Quantitative PCR results showed that there are on average three genome copies per coccal cell unit. These findings allow a model for gonococcal DNA replication and cell division to be proposed, in which a minimum of two chromosomal copies exist per coccal unit within a monococcal or diplococcal cell, and these chromosomes replicate in unison to produce four chromosomal copies during cell division. Immune evasion via antigenic variation is an important mechanism that allows these organisms to continually infect a high risk population of people. We propose that polyploidy may be necessary for the high frequency gene conversion system that mediates pilin antigenic variation and the propagation of N. gonorrhoeae within its human hosts.

  12. Ploidy-Dependent Unreductional Meiotic Cell Division in Polyploid Wheat

    Science.gov (United States)

    Meiosis includes one round of DNA replication and two successive nuclear divisions, i.e. meiosis I (reductional) and meiosis II (equational). This specialized cell division reduces chromosomes in half and generates haploid gametes in sexual reproduction of eukaryotes. It ensures faithful transmiss...

  13. The epigenetic footprint of poleward range-expanding plants in apomictic dandelions

    NARCIS (Netherlands)

    Preite, V.; Snoek, L.B.; Oplaat, C.; Biere, A.; Putten, van der W.H.; Verhoeven, K.J.F.

    2015-01-01

    Epigenetic modifications, such as DNA methylation variation, can generate heritable phenotypic variation independent of the underlying genetic code. However, epigenetic variation in natural plant populations is poorly documented and little understood. Here, we test if northward range expansion of ob

  14. Heritable gene expression differences between apomictic clone members in Taraxacum officinale

    NARCIS (Netherlands)

    Ferreira de Carvalho, Julie; Oplaat, Carla; Pappas, Nikolaos; Derks, Martijn; Ridder, de Dick; Verhoeven, Koen J.F.

    2016-01-01

    Background: Asexual reproduction has the potential to enhance deleterious mutation accumulation and to constrain adaptive evolution. One source of mutations that can be especially relevant in recent asexuals is activity of transposable elements (TEs), which may have experienced selection for high

  15. Sexual and apomictic reproduction in Hieracium sub genus Pilosella are closely interrelated developmental pathways

    NARCIS (Netherlands)

    Tucker, M.R.; Araujo, A.C.G.; Paech, N.A.; Hecht, V.; Schmidt, E.D.L.; Rossel, J.B.; Vries, de S.C.; Koltunow, A.M.

    2003-01-01

    Seed formation in flowering plants requires meiosis of the megaspore mother cell (MMC) inside the ovule, selection of a megaspore that undergoes mitosis to form an embryo sad, and double fertilization to initiate embryo and endosperm formation. During apomixis, or asexual seed formation, in Hieraciu

  16. 从ATPase8-6基因研究杂交多倍体鱼线粒体母性遗传%Evidence for maternal inheritance of mitochondrial DNA in polyploid fish of crosses by ATPase8 and ATPase6 genes

    Institute of Scientific and Technical Information of China (English)

    郭新红; 刘少军; 刘筠

    2004-01-01

    were silent mutations. Phylogenetic trees showing three clusters were constructed with the ATPase8 and ATPase6 gene sequence data for all samples. The first cluster contained triploid common carp and diploid common carp; the second cluster contained triploid crucian carp and diploid Japanese crucian carp;and the third cluster contained allotetraploid fish and diploid red crucian carp. This finding indicated that mitochondrial ATPase8 and ATPase6 genes of the artificial polyploid fish including the allotetraploid fish, triploid crucian carp, and triploid common carp were inherited maternally. It was noticeable that after eleven generations from F1 to F1 hybrids, the F11 allotetraploid fish still kept the high homology to the female parent red crucian carp in the ATPase8 and ATPase6genes. The high homology of F11 tetraploid to the female parent red crucian carp also indicated that the F11 allotetraploid fish possessed the stable inheritable characteristic. The analysis and elucidation of the variation of the ATPase8 and ATPase6 DNA in different cyprinids proved that ATPase8 and ATPase6 genes were the useful genetic markers to monitor the variations in the progeny of the crosses [Acta Zoologica Sinica 50 (3): 408 - 413, 2004].

  17. Sexual and apomictic plant reproduction in the genomics era: exploring the mechanisms potentially useful in crop plants.

    Science.gov (United States)

    Dwivedi, Sangam L; Perotti, Enrico; Upadhyaya, Hari D; Ortiz, Rodomiro

    2010-12-01

    Arabidopsis, Mimulus and tomato have emerged as model plants in researching genetic and molecular basis of differences in mating systems. Variations in floral traits and loss of self-incompatibility have been associated with mating system differences in crops. Genomics research has advanced considerably, both in model and crop plants, which may provide opportunities to modify breeding systems as evidenced in Arabidopsis and tomato. Mating system, however, not recombination per se, has greater effect on the level of polymorphism. Generating targeted recombination remains one of the most important factors for crop genetic enhancement. Asexual reproduction through seeds or apomixis, by producing maternal clones, presents a tremendous potential for agriculture. Although believed to be under simple genetic control, recent research has revealed that apomixis results as a consequence of the deregulation of the timing of sexual events rather than being the product of specific apomixis genes. Further, forward genetic studies in Arabidopsis have permitted the isolation of novel genes reported to control meiosis I and II entry. Mutations in these genes trigger the production of unreduced or apomeiotic megagametes and are an important step toward understanding and engineering apomixis.

  18. Evolution and Origins of Polyploid Sonchus (Subgenus Sonchus) and the Woody Sonchus Alliance

    OpenAIRE

    Yao, Li

    2010-01-01

    The Sonchinae is the most widely distributed subtribe in the tribe Cichorieae, with a discontinuous, almost cosmopolitan, and very peculiar phytogeographic distribution. In particular, genus Sonchus subgenus Sonchus, appears to be responsible for the origin of several island endemics both in the Pacific Ocean (Dendroseris, Thamnoseris, Actites, Kirkianella and Embergeria ) and the Atlantic Ocean (woody Sonchus alliance in the Macaronesian Islands). So polyploidy Sonchus and their relative Pac...

  19. Genome Sizes in Hepatica Mill: (Ranunculaceae Show a Loss of DNA, Not a Gain, in Polyploids

    Directory of Open Access Journals (Sweden)

    B. J. M. Zonneveld

    2010-01-01

    , and a possible pentaploid. The somatic nuclear DNA contents (2C-value, as measured by flow cytometry with propidium iodide, were shown to range from 33 to 80 pg. The Asiatic and American species, often considered subspecies of H. nobilis, could be clearly distinguished from European H. nobilis. DNA content confirmed the close relationships in the Asiatic species, and these are here considered as subspecies of H. asiatica. Parents for the allotetraploid species could be suggested based on their nuclear DNA content. Contrary to the increase in genome size suggested earlier for Hepatica, a significant (6%–14% loss of nuclear DNA in the natural allopolyploids was found.

  20. Sample size for collecting germplasms – a polyploid model with mixed mating system

    Indian Academy of Sciences (India)

    R L Sapra; Prem Narain; S V S Chauhan; S K Lal; B B Singh

    2003-03-01

    The present paper discusses a general expression for determining the minimum sample size (plants) for a given number of seeds or vice versa for capturing multiple allelic diversity. The model considers sampling from a large 2 k-ploid population under a broad range of mating systems. Numerous expressions/results developed for germplasm collection/regeneration for diploid populations by earlier workers can be directly deduced from our general expression by assigning appropriate values of the corresponding parameters. A seed factor which influences the plant sample size has also been isolated to aid the collectors in selecting the appropriate combination of number of plants and seeds per plant. When genotypic multiplicity of seeds is taken into consideration, a sample size of even less than 172 plants can conserve diversity of 20 alleles from 50,000 polymorphic loci with a very large probability of conservation (0.9999) in most of the cases.

  1. 杜仲多倍体的诱导%POLYPLOID INDUCEMENT OF Eucommia ulmoides

    Institute of Scientific and Technical Information of China (English)

    毕春侠; 张存旭; 郭军战; 耿增超

    1999-01-01

    用20 Gy、40 Gy、50 Gy、60 Gy、70 Gy 60Co射线辐照处理萌动的杜仲种子,通过幼苗成株率及外部形态变异状况分析,60 Gy辅射处理变异率高;用0.05%、0.1%、0.2%的秋水仙素处理幼苗生长点,结果表明0.1%秋水仙素诱导变异率较高.

  2. Chromosomal and morphological studies of diploid and polyploid cytotypes of Stevia rebaudiana (Bertoni Bertoni (Eupatorieae, Asteraceae

    Directory of Open Access Journals (Sweden)

    Vanessa M. de Oliveira

    2004-01-01

    Full Text Available In this study, we examined the chromosome number and some morphological features of strains of Stevia rebaudiana. The chromosomes were analyzed during mitosis and diakinesis, and the tetrad normality and pollen viability were also assessed. In addition, stomata and pollen were measured and some plant features were studied morphometrically. All of the strains had 2n = 22, except for two, which had 2n = 33 and 2n = 44. Pairing at diakinesis was n = 11II for all of the diploid strains, whereas the triploid and tetraploid strains had n = 11III and n = 11IV, respectively. Triploid and tetraploid plants had a lower tetrad normality rate than the diploids. All of the strains had inviable pollen. Thus, the higher the ploidy number, the greater the size of the pollen and the stomata, and the lower their number per unit area. The triploid strain produced the shortest plants and the lowest number of inflorescences, whereas the tetraploid strain had the largest leaves. Analysis of variance revealed highly significant differences among the strains, with a positive correlation between the level of ploidy and all of the morphological features examined.

  3. Genomic and polyploid evolution in genus Avena as revealed by RFLPs of repeated DNA sequences.

    Science.gov (United States)

    Morikawa, Toshinobu; Nishihara, Miho

    2009-06-01

    Phylogenetic relationships and genome affinities were investigated by utilizing all the biological Avena species consisting of 11 diploid species (15 accessions), 8 tetraploid species (9 accessions) and 4 hexaploid species (5 accessions). Genomic DNA regions of As120a, avenin, and globulin were amplified by PCR. A total of 130 polymorphic fragments were detected out of 156 fragments generated by digesting the PCR-amplified fragments with 11 restriction enzymes. The number of fragments generated by PCR-amplification followed by digestion with restriction enzymes was almost the same as those among the three repeated DNA sequences. A high level of genetic distance was detected between A. damascena (Ad) and A. canariensis (Ac) genomes, which reflected their different morphology and reproductive isolation. The A. longiglumis (Al) and A. prostrata (Ap) genomes were closely related to the As genome group. The AB genome species formed a cluster with the AsAs genome artificial autotetraploid and the As genome diploids indicating near-autotetraploid origin. The A. macrostachya is an outbreeding autotetraploid closely related with the C genome diploid and the AC genome tetraploid species. The differences of genetic distances estimated from the repeated DNA sequence divergence among the Avena species were consistent with genome divergences and it was possible to compare the genetic intra- and inter-ploidy relationships produced by RFLPs. These results suggested that the PCR-mediated analysis of repeated DNA polymorphism can be used as a tool to examine genomic relationships of polyploidy species.

  4. Developing Association Mapping in Polyploid Perennial Biofuel Grasses: Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Buckler, Edward S; Casler, Michael D; Cherney, Jerome H

    2012-01-20

    This project had six objectives, four of which have been completed: 1) Association panels of diverse populations and linkage populations for switchgrass and reed canarygrass (~1,000 clones each) were assembled and planted in two sites (Ithaca, NY and Arlington, WI); 2) Key biofeedstock characteristics were evaluated in these panels for three field seasons; 3) High density SNP markers were developed in switchgrass; and 4) Switchgrass association panels and linkage populations were genotyped. The remaining two original objectives will be met in the next year, as the analyses are completed and papers published: 5) Switchgrass population structure and germplasm diversity will be evaluated; and 6) Association mapping will be established and marker based breeding values estimated in switchgrass. We also completed a study of the chromosome-number variation found in switchgrass.

  5. Modified Method of Metaphase Plates Obtaining for Polyploid Fish Genera Carassius and Cobitis Karyotyping (Actinopterygii, Cypriniformes

    Directory of Open Access Journals (Sweden)

    Pukhtayevych P. P.

    2014-08-01

    Full Text Available Ото- браны и апробированы современные методики получения метафазных пластинок соматических клеток рыб, дающих наибольший эффект при исследовании полиплоидных видов. На основании эмпирических данных в отношении представителей родов Carassius и Cobitis рекомендуется ме- тодика с использованием CoCl2 и колхицина. В статье приведено подробное описание модифи- цированной методики и полученные в результате её применения метафазные пластинки Carassius auratus Linnaeus, 1758, Carassius carassius Linnaeus, 1758 и триплоидной формы Cobitis taenia Linnaeus, 1758.

  6. Genome composition of triploid lily cultivars derived from sexual polyploidization of Longiflorum x Asiatic hybrids (Lilium)

    NARCIS (Netherlands)

    Shujun Zhou,; Ramanna, M.S.; Visser, R.G.F.; Tuyl, van J.M.

    2008-01-01

    About 19 cultivars, which had originated from backcrosses between F1 LA (Longiflorum × Asiatic) hybrids (2n = 2x = 24) as female parents and Asiatic cultivars as male parents (2n = 2x = 24), were analyzed with genomic in situ hybridization. 17 of them were triploid (2n = 3x = 36), and two aneuploid

  7. Evidence of Allopolyploidy in Urochloa humidicola Based on Cytological Analysis and Genetic Linkage Mapping.

    Science.gov (United States)

    Vigna, Bianca B Z; Santos, Jean C S; Jungmann, Leticia; do Valle, Cacilda B; Mollinari, Marcelo; Pastina, Maria M; Pagliarini, Maria Suely; Garcia, Antonio A F; Souza, Anete P

    2016-01-01

    The African species Urochloa humidicola (Rendle) Morrone & Zuloaga (syn. Brachiaria humidicola (Rendle) Schweick.) is an important perennial forage grass found throughout the tropics. This species is polyploid, ranging from tetra to nonaploid, and apomictic, which makes genetic studies challenging; therefore, the number of currently available genetic resources is limited. The genomic architecture and evolution of U. humidicola and the molecular markers linked to apomixis were investigated in a full-sib F1 population obtained by crossing the sexual accession H031 and the apomictic cultivar U. humidicola cv. BRS Tupi, both of which are hexaploid. A simple sequence repeat (SSR)-based linkage map was constructed for the species from 102 polymorphic and specific SSR markers based on simplex and double-simplex markers. The map consisted of 49 linkage groups (LGs) and had a total length of 1702.82 cM, with 89 microsatellite loci and an average map density of 10.6 cM. Eight homology groups (HGs) were formed, comprising 22 LGs, and the other LGs remained ungrouped. The locus that controls apospory (apo-locus) was mapped in LG02 and was located 19.4 cM from the locus Bh027.c.D2. In the cytological analyses of some hybrids, bi- to hexavalents at diakinesis were observed, as well as two nucleoli in some meiocytes, smaller chromosomes with preferential allocation within the first metaphase plate and asynchronous chromosome migration to the poles during anaphase. The linkage map and the meiocyte analyses confirm previous reports of hybridization and suggest an allopolyploid origin of the hexaploid U. humidicola. This is the first linkage map of an Urochloa species, and it will be useful for future quantitative trait locus (QTL) analysis after saturation of the map and for genome assembly and evolutionary studies in Urochloa spp. Moreover, the results of the apomixis mapping are consistent with previous reports and confirm the need for additional studies to search for a co

  8. Abnormal meiosis in tetraploid genotypes of Brachiaria brizantha (Poaceae) induced by colchicine: its implications for breeding.

    Science.gov (United States)

    Mendes-Bonato, A B; Ferrari Felismino, M; Souza Kaneshima, A M; Pessim, C; Calisto, V; Suely Pagliarini, M; Borges do Valle, C

    2009-01-01

    Meiotic behavior was analyzed in 6 progenies from 3 artificially induced tetraploid (2n = 4x = 36) sexual genotypes (C31, C41, and C48) of the normally apomictic Brachiaria brizantha (Hochst. ex A. Rich.) Stapf., syn. Urochloa brizantha (Hochst. ex A. Rich.) R. Webster. These are key plants to allow intraspecific hybridization of this important forage species, widely used for pastures in the tropics. The percentage of abnormal cells among the plants ranged from 39.8% to 63.2%. In the single plant derived from C48, only the common meiotic abnormalities typical of polyploids were observed, while in plants derived from C31 and C41, a distinct behavior was found. In the majority of cells of those plants, the chromosomes remained scattered in the cytoplasm in the first division, without forming a metaphase plate. This abnormality blocked chromosome movements at anaphase I. Several micronuclei of various sizes were formed and, after the occurrence of an irregular first cytokinesis, the meiocytes progressed normally to the second division, generating polyads with unbalanced microspores. Pollen viability was not correlated with meiotic abnormalities. The importance of these findings to the Brachiaria breeding program is discussed. The sexual progeny of C48 seems most suitable as female parents to be used in intra- and interspecific hybridization. PMID:19433904

  9. The Behavior of Chromosomes During Parthenogenetic Oogenesis in Marmorkrebs Procambarus fallax f. virginalis.

    Science.gov (United States)

    Kato, Miku; Hiruta, Chizue; Tochinai, Shin

    2016-08-01

    Parthenogenetic oogenesis varies among and even within species. Based on cytological mechanisms, it can largely be divided into apomixis (ameiotic parthenogenesis) producing genetically identical progeny, and automixis (meiotic parthenogenesis) producing genetically non-identical progeny. Polyploidy is common in parthenogenetic species, although the association between parthenogenesis and polyploidy throughout evolution is poorly understood. Marmorkrebs, or the marbled crayfish, was first identified as a parthenogenetic decapod and was tentatively named as Procambarus fallax f. virginalis. Previous studies revealed that Marmorkrebs is triploid and produces genetically identical offspring, suggesting that apomixis occurs during parthenogenetic oogenesis. However, the behavior of chromosomes during the process of oogenesis is still not well characterized. In this study, we observed parthenogenetic oogenesis around the time of ovulation in P. fallax f. virginalis by histology and immunohistochemistry. During oogenesis, the chromosomes were separated into two groups and behaved independently from each other, and one complete division corresponding to mitosis (the second meiosis-like division) was observed. This suggests that parthenogenetic oogenesis in Marmorkrebs exhibits gonomery, a phenomenon commonly found in apomictic parthenogenesis in polyploid animals. PMID:27498802

  10. The evolution of meiotic sex and its alternatives

    Science.gov (United States)

    Mirzaghaderi, Ghader

    2016-01-01

    Meiosis is an ancestral, highly conserved process in eukaryotic life cycles, and for all eukaryotes the shared component of sexual reproduction. The benefits and functions of meiosis, however, are still under discussion, especially considering the costs of meiotic sex. To get a novel view on this old problem, we filter out the most conserved elements of meiosis itself by reviewing the various modifications and alterations of modes of reproduction. Our rationale is that the indispensable steps of meiosis for viability of offspring would be maintained by strong selection, while dispensable steps would be variable. We review evolutionary origin and processes in normal meiosis, restitutional meiosis, polyploidization and the alterations of meiosis in forms of uniparental reproduction (apomixis, apomictic parthenogenesis, automixis, selfing) with a focus on plants and animals. This overview suggests that homologue pairing, double-strand break formation and homologous recombinational repair at prophase I are the least dispensable elements, and they are more likely optimized for repair of oxidative DNA damage rather than for recombination. Segregation, ploidy reduction and also a biparental genome contribution can be skipped for many generations. The evidence supports the theory that the primary function of meiosis is DNA restoration rather than recombination. PMID:27605505

  11. Separate Location of Parental Chromosomes in Squashed Metaphases of Hybrid between Hordeum vulgare L. and Four Polyploid, Alien Species

    DEFF Research Database (Denmark)

    Jensen, J.; Linde-Laursen, Ib

    1984-01-01

    In 38 squashed, somatic metaphases of four hybrids between diploid Hordeum vulgare and two tetra-and two hexaploid alien species, each of the H. vulgare chromosomes was identifed, and differentiated from the chromosomes of the other parental species, by its Giemsa C-banding pattern. The H. vulgare...

  12. The Use and Limits of AFLP Data in the Taxonomy of Polyploid Wild Potato Species in Solanum Series Conicibaccata

    Science.gov (United States)

    Solanum sect. Petota (tuber-bearing wild and cultivated potatoes) are a group of approximately 190 wild species distributed throughout the Americas from the southwestern United States south to Argentina, Chile, and Uruguay. Solanum series Conicibaccata are a group of approximately 40 species within ...

  13. Parallel expression evolution of oxidative stress-related genes in fiber from wild and domesticated diploid and polyploid cotton (Gossypium

    Directory of Open Access Journals (Sweden)

    Mittler Ron

    2009-08-01

    Full Text Available Abstract Background Reactive oxygen species (ROS play a prominent role in signal transduction and cellular homeostasis in plants. However, imbalances between generation and elimination of ROS can give rise to oxidative stress in growing cells. Because ROS are important to cell growth, ROS modulation could be responsive to natural or human-mediated selection pressure in plants. To study the evolution of oxidative stress related genes in a single plant cell, we conducted comparative expression profiling analyses of the elongated seed trichomes ("fibers" of cotton (Gossypium, using a phylogenetic approach. Results We measured expression changes during diploid progenitor species divergence, allopolyploid formation and parallel domestication of diploid and allopolyploid species, using a microarray platform that interrogates 42,429 unigenes. The distribution of differentially expressed genes in progenitor diploid species revealed significant up-regulation of ROS scavenging and potential signaling processes in domesticated G. arboreum. Similarly, in two independently domesticated allopolyploid species (G. barbadense and G. hirsutum antioxidant genes were substantially up-regulated in comparison to antecedent wild forms. In contrast, analyses of three wild allopolyploid species indicate that genomic merger and ancient allopolyploid formation had no significant influences on regulation of ROS related genes. Remarkably, many of the ROS-related processes diagnosed as possible targets of selection were shared among diploid and allopolyploid cultigens, but involved different sets of antioxidant genes. Conclusion Our data suggests that parallel human selection for enhanced fiber growth in several geographically widely dispersed species of domesticated cotton resulted in similar and overlapping metabolic transformations of the manner in which cellular redox levels have become modulated.

  14. Dynamic formation of asexual diploid and polyploid lineages: multilocus analysis of Cobitis reveals the mechanisms maintaining the diversity of clones.

    Directory of Open Access Journals (Sweden)

    Karel Janko

    Full Text Available Given the hybrid genomic constitutions and increased ploidy of many asexual animals, the identification of processes governing the origin and maintenance of clonal diversity provides useful information about the evolutionary consequences of interspecific hybridization, asexuality and polyploidy. In order to understand the processes driving observed diversity of biotypes and clones in the Cobitis taenia hybrid complex, we performed fine-scale genetic analysis of Central European hybrid zone between two sexual species using microsatellite genotyping and mtDNA sequencing. We found that the hybrid zone is populated by an assemblage of clonally (gynogenetically reproducing di-, tri- and tetraploid hybrid lineages and that successful clones, which are able of spatial expansion, recruit from two ploidy levels, i.e. diploid and triploid. We further compared the distribution of observed estimates of clonal ages to theoretical distributions simulated under various assumptions and showed that new clones are most likely continuously recruited from ancestral populations. This suggests that the clonal diversity is maintained by dynamic equilibrium between origination and extinction of clonal lineages. On the other hand, an interclonal selection is implied by nonrandom spatial distribution of individual clones with respect to the coexisting sexual species. Importantly, there was no evidence for sexually reproducing hybrids or clonally reproducing non-hybrid forms. Together with previous successful laboratory synthesis of clonal Cobitis hybrids, our data thus provide the most compelling evidence that 1 the origin of asexuality is causally linked to interspecific hybridization; 2 successful establishment of clones is not restricted to one specific ploidy level and 3 the initiation of clonality and polyploidy may be dynamic and continuous in asexual complexes.

  15. primary Report on Polyploid Induction of Raspberry Seed%树莓多倍体诱导试验初报

    Institute of Scientific and Technical Information of China (English)

    陈双建; 郜敏; 温福喜; 刘志新

    2011-01-01

    With various dosages of colchicines raspberry seeds were soaked for different durations in the test. The result showed that soaking with 0.3% colchicines for forty-eight hours, the mutagenic ratio could reach 20%.%用不同剂量的秋水仙碱对刚刚萌发的树莓种子进行不同时间的浸泡,结果表明,用0.3%的秋水仙碱浸泡48 h,效果最好,诱变率可达20%.

  16. A Bayesian Approach for Discriminating Among Alternative Inheritance Hypotheses in Plant Polyploids: The Allotetraploid Origin of Genus Borderea (Dioscoreaceae)

    OpenAIRE

    CATALÁN, PILAR; Segarra-Moragues, José Gabriel; Palop-Esteban, Marisa; Moreno, Carlos; González-Candelas, Fernando

    2006-01-01

    Polyploidy is a common phenomenon occurring in a vast number of land plants. Investigations of patterns of inheritance and the origins of plants (i.e., autopolyploidy vs. allopolyploidy) usually involve cytogenetic and molecular studies of chromosome pairing, chromosome mapping, and marker segregation analysis through experimental crosses and progeny tests. Such studies are missing for most wild species, for which artificial crosses are difficult, not feasible, or unaffordable. We report here...

  17. Among-population variation in tolerance to larval herbivory by Anthocharis cardamines in the polyploid herb Cardamine pratensis.

    Directory of Open Access Journals (Sweden)

    Malin A E König

    Full Text Available Plants have two principal defense mechanisms to decrease fitness losses to herbivory: tolerance, the ability to compensate fitness after damage, and resistance, the ability to avoid damage. Variation in intensity of herbivory among populations should result in variation in plant defense levels if tolerance and resistance are associated with costs. Yet little is known about how levels of tolerance are related to resistance and attack intensity in the field, and about the costs of tolerance. In this study, we used information about tolerance and resistance against larval herbivory by the butterfly Anthocharis cardamines under controlled conditions together with information about damage in the field for a large set of populations of the perennial plant Cardamine pratensis. Plant tolerance was estimated in a common garden experiment where plants were subjected to a combination of larval herbivory and clipping. We found no evidence of that the proportion of damage that was caused by larval feeding vs. clipping influenced plant responses. Damage treatments had a negative effect on the three measured fitness components and also resulted in an earlier flowering in the year after the attack. Tolerance was related to attack intensity in the population of origin, i.e. plants from populations with higher attack intensity were more likely to flower in the year following damage. However, we found no evidence of a relationship between tolerance and resistance. These results indicate that herbivory drives the evolution for increased tolerance, and that changes in tolerance are not linked to changes in resistance. We suggest that the simultaneous study of tolerance, attack intensity in the field and resistance constitutes a powerful tool to understand how plant strategies to avoid negative effects of herbivore damage evolve.

  18. The impact of Ty3-gypsy group LTR retrotransposons Fatima on B-genome specificity of polyploid wheats

    Directory of Open Access Journals (Sweden)

    Huneau Cecile

    2011-06-01

    Full Text Available Abstract Background Transposable elements (TEs are a rapidly evolving fraction of the eukaryotic genomes and the main contributors to genome plasticity and divergence. Recently, occupation of the A- and D-genomes of allopolyploid wheat by specific TE families was demonstrated. Here, we investigated the impact of the well-represented family of gypsy LTR-retrotransposons, Fatima, on B-genome divergence of allopolyploid wheat using the fluorescent in situ hybridisation (FISH method and phylogenetic analysis. Results FISH analysis of a BAC clone (BAC_2383A24 initially screened with Spelt1 repeats demonstrated its predominant localisation to chromosomes of the B-genome and its putative diploid progenitor Aegilops speltoides in hexaploid (genomic formula, BBAADD and tetraploid (genomic formula, BBAA wheats as well as their diploid progenitors. Analysis of the complete BAC_2383A24 nucleotide sequence (113 605 bp demonstrated that it contains 55.6% TEs, 0.9% subtelomeric tandem repeats (Spelt1, and five genes. LTR retrotransposons are predominant, representing 50.7% of the total nucleotide sequence. Three elements of the gypsy LTR retrotransposon family Fatima make up 47.2% of all the LTR retrotransposons in this BAC. In situ hybridisation of the Fatima_2383A24-3 subclone suggests that individual representatives of the Fatima family contribute to the majority of the B-genome specific FISH pattern for BAC_2383A24. Phylogenetic analysis of various Fatima elements available from databases in combination with the data on their insertion dates demonstrated that the Fatima elements fall into several groups. One of these groups, containing Fatima_2383A24-3, is more specific to the B-genome and proliferated around 0.5-2.5 MYA, prior to allopolyploid wheat formation. Conclusion The B-genome specificity of the gypsy-like Fatima, as determined by FISH, is explained to a great degree by the appearance of a genome-specific element within this family for Ae. speltoides. Moreover, its proliferation mainly occurred in this diploid species before it entered into allopolyploidy. Most likely, this scenario of emergence and proliferation of the genome-specific variants of retroelements, mainly in the diploid species, is characteristic of the evolution of all three genomes of hexaploid wheat.

  19. Use of 2n gametes for the production of sexual polyploids from sterile Oriental x Asiatic hybrids of lilies (Lilium)

    NARCIS (Netherlands)

    Barba Gonzalez, R.; Lokker, A.C.; Lim Ki-Byung,; Ramanna, M.S.; Tuyl, van J.M.

    2004-01-01

    Sixteen Oriental and 12 Asiatic cultivars were crossed in 158 different combinations. A total of 708 F1 hybrids were obtained from 86 of the different combinations of 15 Oriental and 11 Asiatic cultivars. Because the Lilium cultivars (2n=2x=24) used for the production of these hybrids belong to two

  20. Patterns of chloroplast DNA polymorphism in the endangered polyploid Centaurea borjae (Asteraceae): Implications for preserving genetic diversity

    Institute of Scientific and Technical Information of China (English)

    Lua LOPEZ; Rodolfo BARREIRO

    2013-01-01

    A previous study with amplified fragment length polymorphism (AFLP) fingerprints found no evidence of genetic impoverishment in the endangered Centaurea borjae and recommended that four management units (MUs) should be designated.Nevertheless,the high ploidy (6x) of this narrow endemic plant suggested that these conclusions should be validated by independent evidence derived from non-nuclear markers.Here,the variable trnT-F region of the plastid genome was sequenced to obtain this new evidence and to provide an historical background for the current genetic structure.Plastid sequences revealed little genetic variation; calling into question the previous conclusion that C.borjae does not undergo genetic impoverishment.By contrast,the conclusion that gene flow must be low was reinforced by the strong genetic differentiation detected among populations using plastid sequences (global FST =0.419).The spatial arrangement of haplotypes and diversity indicate that the populations currently located at the center of the species range are probable sites of long-persistence whereas the remaining sites may have derived from a latter colonization.From a conservation perspective,four populations contributed most to the allelic richness of the plastid genome of the species and should be given priority.Combined with previous AFLP results,these new data recommended that five,instead of four,MUs should be established.Altogether,our study highlights the benefits of combining markers with different modes of inheritance to design accurate conservation guidelines and to obtain clues on the evolutionary processes behind the present-day genetic structures.

  1. 76 FR 13597 - Availability of an Environmental Assessment and Finding of No Significant Impact for a Biological...

    Science.gov (United States)

    2011-03-14

    ...; ] DEPARTMENT OF AGRICULTURE Animal and Plant Health Inspection Service Availability of an Environmental Assessment and Finding of No Significant Impact for a Biological Control Agent for Hawkweeds AGENCY: Animal... subterminalis, into the continental United States as a biological control agent to reduce the severity...

  2. Evidence of Allopolyploidy in Urochloa humidicola Based on Cytological Analysis and Genetic Linkage Mapping.

    Science.gov (United States)

    Vigna, Bianca B Z; Santos, Jean C S; Jungmann, Leticia; do Valle, Cacilda B; Mollinari, Marcelo; Pastina, Maria M; Pagliarini, Maria Suely; Garcia, Antonio A F; Souza, Anete P

    2016-01-01

    The African species Urochloa humidicola (Rendle) Morrone & Zuloaga (syn. Brachiaria humidicola (Rendle) Schweick.) is an important perennial forage grass found throughout the tropics. This species is polyploid, ranging from tetra to nonaploid, and apomictic, which makes genetic studies challenging; therefore, the number of currently available genetic resources is limited. The genomic architecture and evolution of U. humidicola and the molecular markers linked to apomixis were investigated in a full-sib F1 population obtained by crossing the sexual accession H031 and the apomictic cultivar U. humidicola cv. BRS Tupi, both of which are hexaploid. A simple sequence repeat (SSR)-based linkage map was constructed for the species from 102 polymorphic and specific SSR markers based on simplex and double-simplex markers. The map consisted of 49 linkage groups (LGs) and had a total length of 1702.82 cM, with 89 microsatellite loci and an average map density of 10.6 cM. Eight homology groups (HGs) were formed, comprising 22 LGs, and the other LGs remained ungrouped. The locus that controls apospory (apo-locus) was mapped in LG02 and was located 19.4 cM from the locus Bh027.c.D2. In the cytological analyses of some hybrids, bi- to hexavalents at diakinesis were observed, as well as two nucleoli in some meiocytes, smaller chromosomes with preferential allocation within the first metaphase plate and asynchronous chromosome migration to the poles during anaphase. The linkage map and the meiocyte analyses confirm previous reports of hybridization and suggest an allopolyploid origin of the hexaploid U. humidicola. This is the first linkage map of an Urochloa species, and it will be useful for future quantitative trait locus (QTL) analysis after saturation of the map and for genome assembly and evolutionary studies in Urochloa spp. Moreover, the results of the apomixis mapping are consistent with previous reports and confirm the need for additional studies to search for a co

  3. Meiotic behaviour in three interspecific three-way hybrids between Brachiaria ruziziensis and B. brizantha (Poaceae: Paniceae)

    Indian Academy of Sciences (India)

    Eleniza De Victor Adamowski; Maria Suely Pagliarini; Cacilda Borges Do Valle

    2008-04-01

    The meiotic behaviour of three three-way interspecific promising hybrids (H17, H27, and H34) was evaluated. These hybrids resulted from the crosses between B. ruziziensis × B. brizantha and crossed to another B. brizantha. Two half-sib hybrids (H27 and H34) presented an aneuploid chromosome number ($2n = 4x = 33$), whereas hybrid H17 was a tetraploid ($2n = 4x = 36$), as expected. Chromosome paired predominantly as multivalents suggesting that genetic recombination and introgression of specific target genes from B. brizantha into B. ruziziensis can be expected. Arrangement of parental genomes in distinct metaphase plates was observed in H27 and H34, which have different male genitors. Hybrids H17 and H34 have the same male genitor, but did not display this abnormality. In H17, abnormalities were more frequent from anaphase II, when many laggard chromosomes appeared, suggesting that each genome presented a different genetic control for meiotic phase timing. Despite the phylogenetic proximity among these two species, these three hybrids presented a high frequency of meiotic abnormalities, mainly those related to irregular chromosome segregation typical of polyploids, H34, 69.1%; H27, 56.1% and H17, 44.9%. From the accumulated results obtained through cytological studies in Brachiaria hybrids, it is evident that cytogenetical analysis is of prime importance in determining which genotypes can continue in the process of cultivar development and which can be successfully used in the breeding. Hybrids with high frequency of meiotic abnormalities can seriously compromise seed production, a key trait in assuring adoption of a new apomictic cultivar of Brachiaria for pasture formation.

  4. Implications of hybridisation and cytotypic differentiation in speciation assessed by AFLP and plastid haplotypes - a case study of Potentilla alpicola La Soie

    Directory of Open Access Journals (Sweden)

    Paule Juraj

    2012-08-01

    Full Text Available Abstract Background Hybridisation is presumed to be an important mechanism in plant speciation and a creative evolutionary force often accompanied by polyploidisation and in some cases by apomixis. The Potentilla collina group constitutes a particularly suitable model system to study these phenomena as it is morphologically extensively variable, exclusively polyploid and expresses apomixis. In the present study, the alpine taxon Potentilla alpicola has been chosen in order to study its presumed hybrid origin, identify underlying evolutionary processes and infer the discreteness or taxonomic value of hybrid forms. Results Combined analysis of AFLP, cpDNA sequences and ploidy level variation revealed a hybrid origin of the P. alpicola populations from South Tyrol (Italy resulting from crosses between P. pusilla and two cytotypes of P. argentea. Hybrids were locally sympatric with at least one of the parental forms. Three lineages of different evolutionary origin comprising two ploidy levels were identified within P. alpicola. The lineages differed in parentage and the complexity of the evolutionary process. A geographically wide-spread lineage thus contrasted with locally distributed lineages of different origins. Populations of P. collina studied in addition, have been regarded rather as recent derivatives of the hexaploid P. argentea. The observation of clones within both P. alpicola and P. collina suggested a possible apomictic mode of reproduction. Conclusions Different hybridisation scenarios taking place on geographically small scales resulted in viable progeny presumably stabilised by apomixis. The case study of P. alpicola supports that these processes played a significant role in the creation of polymorphism in the genus Potentilla. However, multiple origin of hybrids and backcrossing are considered to produce a variety of evolutionary spontaneous forms existing aside of reproductively stabilised, established lineages.

  5. The transmission and reproduetive characters of apomictic monosomic addition lines of Beta vulgaris L.%甜菜无融合生殖单体附加系的繁殖传递特性

    Institute of Scientific and Technical Information of China (English)

    郭德栋; 刘丽萍; 康传红; 李海英; 韩晓云; 唐艳; 王桂芝

    2001-01-01

    由栽培甜菜(Beta vulgaris L.)和白花甜菜(B.croolliflora Zoss.)杂交分离荻得的甜菜无融合生殖单体附加系具有高频率近100%传递的特性.经过四代传递分析,平均传递率达95%以上,表现为稳定传递.在其传递后代中,分离出BⅢ后代(VV+1C+V,2n=28)、二倍体(2n=18)非整倍体(2n=29,2n=20)等.无融合生殖单体附加系后代结实株数、结实率、单株种粒产量与其二倍体姊妹相比皆明显下降,说明它们的繁殖特性受到破坏,表现出雌配子体突变特征.本文对高频传递和分离产生各种类型的原因及意义进行了讨论.

  6. Histologia da embriogênese somática induzida em embriões de sementes maduras de Urochloa brizantha apomítica Histology of somatic embryogenesis induced in embryos of mature seeds of the apomictic Urochloa brizantha

    Directory of Open Access Journals (Sweden)

    Sandra Janeth Lenis-Manzano

    2010-05-01

    Full Text Available O objetivo deste trabalho foi descrever o processo de embriogênese somática em Urochloa brizantha cv. Marandu (Syn. Brachiaria brizantha cv. Marandu e fornecer subsídios para o aprimoramento dos métodos de cultura de tecidos e transformação genética. Calos embriogênicos foram obtidos por indução em embriões isolados de sementes maduras, e cultivados in vitro, em meio de cultura que continha ácido 2,4-diclorofenoxiacético, 6-benzilaminopurina e caseína hidrolisada. Plântulas foram regeneradas a partir dos calos embriogênicos, na presença de ácido naftalenoacético e cinetina. Esse processo foi descrito morfologicamente por observações em microscopia de luz de secções seriadas semifinas de tecidos fixados, ao longo do processo de regeneração, em FAA [formaldeído (40%: ácido acético glacial: etanol (50%, a 5:5:90 v/v/v]. Os embriões das sementes de U. brizantha cv. Marandu não têm epiblasto e são classificados como do tipo panicoide. Nas condições estabelecidas de cultura in vitro, calos embriogênicos e embriões somáticos de U. brizantha cv. Marandu, desenvolvem-se a partir de células meristemáticas do escutelo.The objective of this work was to describe the process of somatic embryogenesis in Urochloa brizantha cv. Marandu (Syn. Brachiaria brizantha cv. Marandu and to provide support for the improvement of tissue culture and genetic transformation methods. Embryogenic calli were obtained by induction in embryos isolated from mature seeds, and cultivated in vitro in culture medium containing 2,4-dichlorophenoxyacetic acid, 6-benzylaminopurine and hydrolyzed casein. Plantlets were regenerated from the embryogenic calli in the presence of naphthaleneacetic acid and kinetin. This process was described by morphological observations of serial semithin sections of tissues fixed along the regeneration process in FAA (40% formaldehyde: acetic acid: 50% ethanol, at 5:5:90 v/v/v, using light microscopy. Seed embryos of U. brizantha cv. Marandu do not have epiblast and are classified as Panicum-type. Under in vitro culture conditions, embryogenic calli and somatic embryos of U. brizantha cv. Marandu develop from meristematic cells of the scutellum.

  7. Genotype by Environment (G x E) Modeling of the Variable Initiation of Parthenocarpy sensu stricto in Musa: Elucidation of the Environmental Components of Variable Expressivity of Parthenocarpy in a Facultative Apomictic Musa acuminata Subspecies Microcarpa Model System

    OpenAIRE

    Shaibu, A. A.; Okoro, P; Ude, G.; Olukolu, B. A.; Ingelbrecht, I; Tenkouano, A; Ogburia, M. N.; Moonan, F; Dimkpa, C.

    2013-01-01

    To better understand the genome by environment (G x E) interactions that need to be accommodated in order to better predict hybrid performance for a high breeding value vegetative parthenocarpy trait sensu stricto. An analysis of the possible environmental signals contributing to the variability of a vegetative parthenocarpy trait sensu stricto via the genome x environment initiation of a genetic lesion that temporally, developmentally and systematically results in abortion of a parthenocarpi...

  8. Interspecific hybridization, polyploidization, and backcross of Brassica oleracea var. alboglabra with B. rapa var. purpurea morphologically recapitulate the evolution of Brassica vegetables

    OpenAIRE

    Xiaohui Zhang; Tongjin Liu; Xixiang Li; Mengmeng Duan; Jinglei Wang; Yang Qiu; Haiping Wang; Jiangping Song; Di Shen

    2016-01-01

    Brassica oleracea and B. rapa are two important vegetable crops. Both are composed of dozens of subspecies encompassing hundreds of varieties and cultivars. Synthetic B. napus with these two plants has been used extensively as a research model for the investigation of allopolyploid evolution. However, the mechanism underlying the explosive evolution of hundreds of varieties of B. oleracea and B. rapa within a short period is poorly understood. In the present study, interspecific hybridization...

  9. RAPD analysis on the genome evolution of polyploids in Brassica%芸薹属多倍体植物基因组进化的RAPD分析

    Institute of Scientific and Technical Information of China (English)

    刘爱华; 王建波; 朱英国

    2003-01-01

    多倍化是促进高等植物发生进化的重要力量。为了更清楚地了解多倍体在形成之后其基因组是如何进化的,利用38个随机引物对芸薹属Brassica L.禹氏三角(U'Triangle)中的多倍体物种及其祖先二倍体物种进行了研究。根据扩增出的273条带计算了遗传距离,并用UPGMA法进行了聚类分析。结果发现,二倍体物种B. Campestris (AA)与B. Oleracea (CC)的亲缘关系比与B. Nigra (BB)的要近;异源多倍体B. Napus (AACC)比起其二倍体祖先之一B. Campestris(AA)与另一个祖先种B. Oleracea(CC)的关系更近,异源多倍体B. Juncea (AABB)和B. Carinata(BBCC)都只与其二倍体祖先种之一B. Nigra (BB)的关系更为接近。结合统计分析的结果表明,比较而言,异源多倍体B. Napus (AACC)形成后其祖先基因组A和C变化不大;B. Juncea(AABB)和B. Carinata (BBCC)形成后各自都是其一个祖先基因组,即B基因组变化较小,其余的基因组变化较大.

  10. 紫锥菊多倍体诱导与鉴定%Induction and Identification of the Polyploid Seedlings of Echinacea purpurea

    Institute of Scientific and Technical Information of China (English)

    肖艳; 鲍美华; 彭菲; 李艳辉

    2009-01-01

    本实验以紫锥菊愈伤组织上刚分化出的不定芽为材料,用不同浓度秋水仙素溶液对其进行诱导,确定最佳处理浓度和处理时间,并对诱导的多倍体与二倍体进行形态、显微、染色体及过氧化氢酶(CAT)活性的比较鉴定.结果表明:0.025%秋水仙素浓度处理24h的诱导效果最好,诱导率达42.85%;多倍体植株叶片肥厚、根粗壮,气孔面积极显著地大于二倍体植株,染色体数从24~28条不等,CAT平均酶活性是二倍体的2.1倍.

  11. Ecological differentiation, lack of hybrids involving diploids, and asymmetric gene flow between polyploids in narrow contact zones of Senecio carniolicus (syn. Jacobaea carniolica, Asteraceae).

    Science.gov (United States)

    Hülber, Karl; Sonnleitner, Michaela; Suda, Jan; Krejčíková, Jana; Schönswetter, Peter; Schneeweiss, Gerald M; Winkler, Manuela

    2015-03-01

    Areas of immediate contact of different cytotypes offer a unique opportunity to study evolutionary dynamics within heteroploid species and to assess isolation mechanisms governing coexistence of cytotypes of different ploidy. The degree of reproductive isolation of cytotypes, that is, the frequency of heteroploid crosses and subsequent formation of viable and (partly) fertile hybrids, plays a crucial role for the long-term integrity of lineages in contact zones. Here, we assessed fine-scale distribution, spatial clustering, and ecological niches as well as patterns of gene flow in parental and hybrid cytotypes in zones of immediate contact of di-, tetra-, and hexaploid Senecio carniolicus (Asteraceae) in the Eastern Alps. Cytotypes were spatially separated also at the investigated microscale; the strongest spatial separation was observed for the fully interfertile tetra- and hexaploids. The three main cytotypes showed highly significant niche differences, which were, however, weaker than across their entire distribution ranges in the Eastern Alps. Individuals with intermediate ploidy levels were found neither in the diploid/tetraploid nor in the diploid/hexaploid contact zones indicating strong reproductive barriers. In contrast, pentaploid individuals were frequent in the tetraploid/hexaploid contact zone, albeit limited to a narrow strip in the immediate contact zone of their parental cytotypes. AFLP fingerprinting data revealed introgressive gene flow mediated by pentaploid hybrids from tetra- to hexaploid individuals, but not vice versa. The ecological niche of pentaploids differed significantly from that of tetraploids but not from hexaploids. PMID:25859328

  12. 秋水仙素诱导甘菊多倍体研究%POLYPLOID OF Dendranthema lavandulifolium INDUCED BY COLCHICINES

    Institute of Scientific and Technical Information of China (English)

    莫官站; 张启翔; 潘会堂; 孙明

    2010-01-01

    以甘菊种子为试验材料,研究了不同秋水仙素浓度和处理时间对甘菊多倍体诱导的影响.结果表明:500mg/L的秋水仙素水溶液浸渍种子12h,变异率为23% ,达到了极显著差异.根尖染色体压片检查表明,四倍体染色体数为2n=4x=36,并且获得了同源四倍体甘菊1株(2n=4x=36).四倍体植株表现出叶片下表皮气孔保卫细胞变大,叶绿体数变多,叶片变小,花径变大,舌状花数目减少,管状花数目增多.

  13. The Progress of Polyploids Induced in vitro via Colchicine%秋水仙素离体诱导多倍体研究进展

    Institute of Scientific and Technical Information of China (English)

    周慧文; 冯斗; 严华兵

    2015-01-01

    本文总结了近十年来秋水仙素离体诱导植物多倍体的研究进展,对影响诱导效率的因素如外植体类型、处理方法及其他因素进行了综述,并探讨了倍性嵌合体的分离方法、同源多倍化效应及其分子机理研究.该综述旨在为植物多倍体育种研究提供参考.

  14. Methods of Polyploid Induction of Cymbidium with Colchicine%秋水仙素诱导兰属'素心黄'多倍体的方法研究

    Institute of Scientific and Technical Information of China (English)

    邓樱; 周晔; 陈继敏

    2008-01-01

    采用继代培养法和侧芽萌动培养法比较秋水仙素诱导'素心黄'多倍体的效果.结果表明,继代培养法加倍效果较好,其诱导率为16.7%;细胞学鉴定表明,该方法诱导培育的植株具有多倍体表型特征,其体细胞染色体数2n=80,未见嵌合现象,而对照2n=40.

  15. 秋水仙素诱导新疆一枝蒿多倍体%Polyploid Induction of Artemisia rupestris L. by Colchicine

    Institute of Scientific and Technical Information of China (English)

    唐晓义; 王晓军; 郝秀英; 刘敏; 康喜亮; 波拉提; 徐琴

    2008-01-01

    以茎段浸泡法和培养基培养法诱导新疆一枝蒿多倍体的结果表明,茎段浸泡法的诱导效果比较好,其中以0.2%秋水仙素浸泡茎段1 d的处理效果最好,多倍体诱导率达27.3%.

  16. 秋水仙碱诱导枣多倍体的研究%Studies on Polyploid Induction of Chinese Jujube with Colchicine

    Institute of Scientific and Technical Information of China (English)

    蒋洪恩; 刘孟军

    2004-01-01

    以冬枣、临猗梨枣和辣椒枣一年生嫁接苗为试材,以秋水仙碱为诱变剂诱导多倍体.结果表明:临猗梨枣诱变率最高可达50%,最佳组合为0.15%秋水仙碱处理茎尖18 h;冬枣和辣椒枣的诱变率最高可达43.3%,最佳处理组合分别为0.1%/30 h和0.15%/18 h.变异材料的细胞染色体数(2 n=4 x=44)和单细胞DNA含量均为二倍体对照的2倍,在辣椒枣中还出现了染色体数为2 n=2 x+2=26及DNA含量为八倍体的细胞.四倍体变异材料均表现出叶长、叶宽、叶面积增大,叶形指数减小,节间长度变短等特征.另外,还表现出叶片气孔保卫细胞增大,叶绿体增多,花粉粒增大,畸形花粉增多,四孔沟花粉出现及花粉粒育性降低等.

  17. 秋水仙素诱导石斛多倍体的初步研究%PRIMARY STUDY ON POLYPLOID OF Dendrobium HYBRID INDUCED BY COLCHICINES

    Institute of Scientific and Technical Information of China (English)

    张莹; 王雁; 李振坚

    2009-01-01

    本试验以秋水仙素为诱导剂,对石斛杂交种Dendrobium utopia‘Messenger'× Den.whiterabbit ‘Sakurahime'的二倍体试管苗进行了多倍体诱导、细胞学观察及染色体鉴定等研究.结果表明,当秋水仙素浓度为0.4~0.6mg/L时石斛的诱导率较高,最高时可达62.2%.变异植株的叶片变短变厚,假鳞茎明显增粗.在显微镜下观察到变异株的气孔长度和宽度约增加21.44%和28.30%,保卫细胞的长度和宽度约增加30.88%和24.98%.

  18. 滇北球花报春多倍体诱导及核型分析%Polyploid Induction and Karyomorphological Studies of Primula denticulata ssp.sinodenticulata

    Institute of Scientific and Technical Information of China (English)

    张超; 李枝林; 李佳; 张婷; 蒋亚莲; 李涵

    2011-01-01

    Tetraploids were induced from in vitro plantlets of diploid Primula denticulata ssp.sinodenticulata by dipping shoot tips in colchicine solutions at different concentrations and treating durations.The results showed:the best condation was treatment with 0.6% colchicines for 72 h,and the induction rate was 54 %.Mutation buds were screened by morphological appraisal.Tetraploid of P.denticulata ssp.sinodenticulata was characterized by darker leaf color, thicker leaves,larger stoma and less stomatal numbers in unit area.Cytological identification and karyomorphological studies indicated that the number of metaphase chromosomes were formulated to be 2n= 2x= 4m+16sm+2st for P.denticulata ssp.sinodenticulata,tetraploids were formulated to be 2n = 4x= 8m + 32sm+ 4st, their karyotypes are all 3A.Tetraploids P.denticulata ssp.sinodenticulata were successfully induced.%以滇北球花报春(Primula denticulata ssp.sinodenticulata)为供试材料,在离体条件下,采用秋水仙素对其丛生芽进行诱导,比较不同浓度、不同处理时间秋水仙素诱导多倍体的效果.结果表明:以0.6%的秋水仙素处理72 h诱导效果最佳,诱导率达54%.经形态学观察发现,变异材料叶色变深,叶片质感变厚;气孔面积增大,单位面积气孔数目减少;染色体计数及核型分析显示,滇北球花报春的二倍体核型为2n=2x=4m+16sm+2st,四倍体核型为2n=4x=8m+32sm+4st,均属3A核型,并成功获得了滇北球花报春的四倍体植株.

  19. Polyploid Induction of Viola yedoensis by Colchicine%秋水仙碱诱导紫花地丁多倍体

    Institute of Scientific and Technical Information of China (English)

    张楠楠; 孙晓梅

    2007-01-01

    用不同浓度的秋水仙素溶液不同时间处理紫花地丁种子和幼苗,结果发现,种子处理中以0.8%浓度处理10 h效果最佳,诱变率达到46.7%.幼苗处理中以0.2%处理16 h和0.8%处理8 h效果最好,诱变率达到80%.诱变后产生的多倍体植株与二倍体植株相比,具有茎增粗、叶片加厚且叶色浓绿、染色体数目加倍等特点.

  20. The Preliminary Study of Tulip Sexual Polyploidization Induced by Colchicines%秋水仙素诱导郁金香有性多倍化研究

    Institute of Scientific and Technical Information of China (English)

    赵雁; 刘武林; 郑思乡; 肖亚琼

    2006-01-01

    通过采用不同浓度(0.005%、0.01%和0.02%)的秋水仙素对郁金香6个品种(纯金,法国之光,王朝,比万昝特,利奥维茨,紫旗)的花器官进行处理,观察其形态及花粉粒大小的变化,以确定最佳的处理浓度.研究表明:郁金香对秋水仙素十分敏感,用0.01%的秋水仙素处理纯金,死亡率为100%.秋水仙素处理后花梗缩短变粗,其中法国之光的花梗长度明显缩短,为15.5 cm,缩短了41.3%.对法国之光、比万昝特和利奥维茨三个品种而言,有效诱变浓度在0.01%~0.02%之间,其中用0.01%秋水仙素诱导比万昝特,变异率高达83.3%.太高的浓度导致郁金香死亡而太低的浓度则不产生变异.

  1. 秋水仙素诱导紫珠多倍体育种研究%Study on Colchicines Induced Polyploid Breeding of Callicarpa bodinieri

    Institute of Scientific and Technical Information of China (English)

    童俊; 陈法志

    2012-01-01

    The tetraploid Callicarpa bodinieri Levl. was induced by treating the seeds and shoot tip meristem with colchicine. The effects of concentration and treatment time of colchicine were studied; and the ploidy level was identified by morphological trait, cytological and flow cytometry techniques. The results showed that treating the shoot tip meristems with 6 mg/mL colchicine for 48 h has the best efficient with the mutation rate up to 40.83%. The tetraploid plant differed from the diploid morphologically and cytologicallly; it was with larger leaves, larger stomata and more chloroplast in stomata guard cell. The ornamental value of C. bodinieri was greatly improved as the flower diameter was increased by 37.26%; and the fruit diameter was increased by 33.11%.%试验采用秋水仙素处理紫珠的种子和幼苗茎尖生长点以诱导四倍体紫珠植株,并对秋水仙素的诱导时间和浓度进行了探讨,对诱导对象采用流式细胞分析仪鉴定和形态观察等方法进行了倍性鉴定.结果表明,秋水仙素成功地诱导出了四倍体紫珠植株,其中以6 mg/mL的秋水仙素对幼苗茎尖生长点处理48 h的效果较好,其形态变异率最高可达40.83%.四倍体紫珠植株较二倍体紫珠植株的形态有一定差异,表现为叶片普遍变大,气孔器保卫细胞较二倍体明显增大,叶绿体数目明显增多.同时,花径和果径平均增大37.26%和33.11%,观赏效果更加突出.

  2. STUDY ON INDUCTION OF POLYPLOID Dendranthema nankingense WITH COLCHICINE%秋水仙素诱导菊花脑多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    陈发棣; 蒋甲福; 房伟民

    2002-01-01

    利用秋水仙素对菊花脑进行浸种诱导多倍体,比较了不同处理浓度和时间的效果.结果表明,0.5/L浓度处理48h可以获得较好的效果,植株形态变异率为83.1%;1 0g/L、2.0g/L浓度处理12h以上变异率虽然升高,但由于生长抑制严重,后期死亡率明显升高;诱变株结实率和种子发芽率明显低于对照.对4个形态变异株进行了叶片气孔保卫细胞大小、叶绿粒数测定和根尖细胞染色体观察,鉴定出四倍体菊花脑1株(2n=36),嵌合体1株.

  3. 秋水仙素诱导桉树多倍体的初步研究%Preliminary Study on Colchicine Inducing Eucalyptus Polyploid

    Institute of Scientific and Technical Information of China (English)

    胡洲鹤; 覃子海; 蔡玲

    2004-01-01

    以组织培养的桉树(Eucalypts)丛生芽和单芽为材料,研究秋水仙素在不同浓度、不同处理时间下对染色体的诱变效果.以正常芽丛作对照,经诱导的芽丛茎粗壮且短,叶片肥厚增长,形态扭曲,颜色变深;同时变异细胞体积增大,染色体条数增多.秋水仙素诱导丛生芽多倍体的效果比用单芽好.随着秋水仙素浓度和处理时间提高,丛生芽变异率会增加,由于对芽丛刺激较大,死亡率也会增加,用0.5%秋水仙素对桉树丛生芽处理96 h是比较适宜的.

  4. Study of Gerbera jamesonii Inducing Polyploid Plants with Colchicine%用秋水仙碱诱导非洲菊多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    王晓红; 谭晓风

    2005-01-01

    用秋水仙碱处理离体的非洲菊愈伤组织与丛生芽,研究了4种不同浓度的秋水仙碱对非洲菊芽增殖和染色体加倍的影响.结果表明:以0.05%的秋水仙碱溶液处理12 h效果较好,变异率达38.46%;叶片表皮细胞的气孔数量减少、体积增大以及植株叶大根粗等外部形态特征均可作为鉴别非洲菊多倍体的间接证据.

  5. 水稻籼粳杂种多倍体的研究%Studies on somatic chimaera in polyploid of indica×japonica hybrids induced by colchicine

    Institute of Scientific and Technical Information of China (English)

    刘幼琪; 刘信民; 陈建国; 陈冬玲; 蔡得田

    2002-01-01

    以秋水仙碱诱导的水稻籼粳杂种多倍体植株中,部分植株的体细胞呈现具有整倍体和非整倍体染色体数细胞嵌合现象,其中四倍体细胞最高可占35.3 %,其余均为染色体数低于48条的各种细胞.与二倍体植株相比,这些植株的叶表皮气孔增大,气孔数减少,花粉粒直径增大都是十分显著的,与多倍体植株无明显区别.并对这类植株根尖体细胞中存在具各种染色体数目细胞嵌合现象可能的原因进行了分析.

  6. 秋水仙素诱导非洲凤仙多倍体的研究%Polyploid Induction in Impatiens walleriana Using Colchicine

    Institute of Scientific and Technical Information of China (English)

    孔红; 王宝增; 马建军; 姚虹

    2015-01-01

    以非洲凤仙扦插苗为试材,采用不同浓度(0.2%和0.5%)秋水仙素溶液,在不同处理时间(48 h和72 h)下诱导非洲凤仙扦插苗,通过其形态观察及染色体计数进行倍性鉴定.结果表明:秋水仙素诱导非洲凤仙得到了四倍体,在0.5%浓度,48h条件下诱导效果最好.二倍体非洲凤仙染色体数目为2n=2x=16,诱导的同源四倍体染色体数目为2n=4x=32.四倍体与二倍体在形态学和细胞学上具有明显的差异.

  7. Study on Garlic Root Tip Polyploid Induced by Colchicine%秋水仙素诱导大蒜根尖多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    武延生

    2012-01-01

    以秋水仙素0、0.1、0.2、0.5、1.0、2.0 g/L 6个浓度梯度,分别处理大蒜根尖12、24、36、48和60 h,研究不同浓度的秋水仙素及不同处理时间对诱导大蒜根尖产生多倍体的效果.结果表明:在0.5 g/L处理浓度下,从24~48 h,大蒜根尖的膨大率均在82%以上,综合效果较好.

  8. Studies on Polyploid Induction of Tomato with Colchicine%秋水仙碱诱导番茄多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    陈圣栋; 杨建平; 曹德航; 王清华; 吴玉辉; 马宁; 李凯

    2007-01-01

    以巨宝金冠和毛粉802的种子和幼苗为试材,以秋水仙碱为诱变剂诱导多倍体.结果表明:处理番茄种子,以秋水仙碱浓度0.4%处理12 h效果最好,巨宝金冠和毛粉802的诱导率分别为26.7%和30%;处理番茄幼苗,以秋水仙碱浓度为0.03%处理8 h效果最好,巨宝金冠和毛粉802的诱导率分别为46.7%和50%.变异材料的细胞染色体(2n=4x=48)为2倍体材料的二倍.此外,四倍体变异材料均表现出叶长、叶宽、叶面积增大,叶形指数减少等特征.

  9. Identification of Colchicines-induced Polyploid Plants in Two Species of Impatiens balsamina%两种凤仙花多倍体的诱导

    Institute of Scientific and Technical Information of China (English)

    杜晓华; 孙涌栋; 袁少寒; 李倩青; 巩振辉

    2011-01-01

    以凤仙花和茶花凤仙为试材,研究秋水仙素处理质量分数和时间对2种试材的多倍体诱变效应,通过植株形态特征、气孔数量及大小、染色体数目的观察进行倍性鉴定.结果表明,用w=0.5%的秋水仙素处理72~96 h的植株材料变异率较高,其中以0.5%秋水仙素处理96 h凤仙花的变异率最高,达29%.染色体压片检查表明,四倍体染色体数为2n=4x=28,二倍体对照为2n= 2x= 14.四倍体叶片长、宽、厚均增大,气孔密度减小,气孔保卫细胞增大,花径增加、花瓣增多,单朵花观赏价值显著提高.%The effects of colchicine concentration and treatment time duration on the chromosome doubling of the seedlings in two species of Impatiens balsamina have been conducted in this study, and the ploidy level was identified by morphological trait, stoma size and chromosome number. The results showed that treated two species of J. Balsamina with 0. 5% colchicine for 72 - 96 h led to a high mutation rate, and the highest mutation rate (up to 29%) was achieved in the I. Balsamina by treatment of 0. 5% colchicine for 96 h. Two tested species of I. Balsamina have obtained a number of tet-raploidy plants. The chromosome number of mutated plants was 2n = 4x=28, while that of the control plants was 2n=2x=14. The tetraploid plants exhibited some morphological and cytological variations , including larger and thicker leaves, darker leaf color, larger stomata and fewer stomata per unit area. The ornamental value of single flower had also been greatly improved by increasing of flower diameter and petals number.

  10. A Technical Reseach on Induction of Flax Polyploid by Colchicine%秋水仙碱诱导亚麻四倍体的技术研究

    Institute of Scientific and Technical Information of China (English)

    郭永霞; 王丽艳; 孙强; 潘翠翠; 殷奎德

    2013-01-01

    The mature seed of flax ShuangYa-7 as material, induction of flax polyploidy was conducted through flax seeds immersion of colchicines followed by sterile culture. Namely, the disinfected seeds were applied to induce the polyploidy after germination in perti dish, the polyploidy were induced by the treatment of colchicines. The results showed that the aberration rate of flax seeds is 40. 7% while the seeds after germination in water for 36 h were treated with 0. 075% concentration of colchicines for 24 h. Through observation of the external morphology, the stem of tetra-ploid is stronger than that of diploid, the leaf of tetraploid is thicker than that of diploid and the color of tetraploid is darker than that of diploid, the surface of tetraploid is rougher than that of diploid, the root of tetraploid is stronger than that of diploid and root number of branches are less than that of diploid.%以双亚7号成熟种子为材料,利用秋水仙碱浸泡亚麻种子后进行无菌培养来诱导多倍体.方法是将种子消毒后在培养皿中萌动处理后,利用秋水仙碱处理来诱导多倍体.结果表明:种子在水中萌动时间为36 h,秋水仙碱溶液处理浓度为0.075%,处理时间为24 h,变异率为40.7%.通过对外部形态的观察发现四倍体的茎比二倍体的粗壮,叶片较二倍体厚,颜色较二倍体稍深,表面较二倍体略显粗糙,通过生根后对根的观察发现四倍体的根较二倍体的粗壮,根条数比二倍体的要少.

  11. Polyploid Induction of Buddleja asiatica Lour. by Colchicine%秋水仙素诱导七里香多倍体

    Institute of Scientific and Technical Information of China (English)

    陈高; 孙卫邦

    2006-01-01

    以不同浓度(0.02%、0.04%、0.08%、0.16%)秋水仙素溶液与二甲基亚砜和丙草胺的体积混合比为2000:10:l的溶液诱导七里香种子萌发苗1~3d的结果表明,所有处理均得到七里香多倍体,其中以秋水仙素浓度为0.08%的混合液处理3 d的诱导效果最好,多倍体诱导率达36.7%.

  12. 秋水仙素诱导西瓜多倍体的研究%Study on Colchicines Induced Polyploid Plants and Identification of Citrullus lanatus

    Institute of Scientific and Technical Information of China (English)

    施先锋; 彭金光; 王宏太; 李煜华; 曾红霞; 张安华; 杨皓琼

    2010-01-01

    研究了不同浓度秋水仙素处理对3个西瓜品系幼苗染色体加倍的诱导效应,通过形态观察、染色体计数以及流式细胞仪等方法进行了倍性鉴定.结果表明.秋水仙素诱导3个西瓜品系均得到了四倍体,0.3%的秋水仙素处理幼苗的变异率较高,其中以0.3%秋水仙素处理黄小玉母本的变异率最高,迭15.1%.四倍体表现出叶片长、宽、厚均增大,花瓣大小和果皮厚度均较二倍体明显增加.根尖染色体压片检查表明,四倍体染色体教为2n=4x=44,二倍体对照为2n=2x=22.流式细胞仪检测结果表明,诱导不仅产生四倍体,还有嵌合体.

  13. Polyploid Induction of Lycopersicum Esculentum Mill. Var. Vulgate with Colchicine%秋水仙素诱导普通番茄多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    乔永刚; 宋秀英

    2008-01-01

    以普通番茄的三个品种为诱变材料,用0.2%秋水仙素溶液进行多倍体诱变.研究秋水仙素诱变对不同品种番茄的诱导效果以及变异株的形态学与细胞学变化.结果显示3个普通番茄品种均获得了四倍体材料.

  14. Advances in Fruit Polyploid Breeding with Colchicine%秋水仙素在果树多倍体育种中的研究进展

    Institute of Scientific and Technical Information of China (English)

    刘璐璐; 柴明良

    2006-01-01

    对秋水仙素在果树多倍体育种中的应用进行了概述.主要包括利用秋水仙素诱变已经获得多倍体的果树种类及其品种;诱变浓度及诱变特点;诱导多倍体的途径及倍性鉴定方法,并指出了目前所存在的问题与研究动向.

  15. Colchicines to Induce polyploid on Moringa oleifera in Tissue Culture%秋水仙素对离体培养辣木多倍体的诱导

    Institute of Scientific and Technical Information of China (English)

    张洁; 何林; 王力超; 梁国鲁

    2007-01-01

    以印度辣木栽培品种PKM(Moringa oleifera PKM-1)一年生植株茎尖为外植体,采用秋水仙素结合组织培养技术诱导多倍体的方法,研究了秋水仙素浓度及处理时间对诱导染色体倍性变异的影响,以及不同外源植物生长调节剂浓度对茎段培养的增殖影响,结果表明:辣木芽初代培养的最适培养基为MS+6-BA2.0mg/L+NAA0.2mg/L,不定芽增殖的最佳培养基为MS+6-BA0.6mg/L,增殖系数为3.57,用0.1%秋水仙素处理24h左右,可诱导获得四倍体再生植株.

  16. 大花香石竹多倍体育种研究%Polyploid Breeding Studying of Standard Carnation (Dianthus caryophyllus L.)

    Institute of Scientific and Technical Information of China (English)

    莫锡君; 桂敏; 瞿素萍; 熊丽; 杨明

    2005-01-01

    对102个大花香石竹品种的染色体倍性进行鉴定,二倍体、三倍体和四倍体品种分别占77%、6%和17%,当前生产上的主栽品种马斯特、达拉斯和卡曼(具有大花苞性状)都是二倍体品种,71%的四倍体品种为花边复色类型.初步认为部分香石竹四倍体栽培品种是远缘杂交的后代.通过用秋水仙碱处理香石竹品种马斯特的试管苗,获得两株四倍体植株,其花蕾直径增大,而节间变短.

  17. TALEN mediated targeted mutagenesis of the caffeic acid O-methyltransferase in highly polyploid sugarcane improves cell wall composition for production of bioethanol.

    Science.gov (United States)

    Jung, Je Hyeong; Altpeter, Fredy

    2016-09-01

    Sugarcane (Saccharum spp. hybrids) is a prime crop for commercial biofuel production. Advanced conversion technology utilizes both, sucrose accumulating in sugarcane stems as well as cell wall bound sugars for commercial ethanol production. Reduction of lignin content significantly improves the conversion of lignocellulosic biomass into ethanol. Conventional mutagenesis is not expected to confer reduction in lignin content in sugarcane due to its high polyploidy (x = 10-13) and functional redundancy among homo(eo)logs. Here we deploy transcription activator-like effector nuclease (TALEN) to induce mutations in a highly conserved region of the caffeic acid O-methyltransferase (COMT) of sugarcane. Capillary electrophoresis (CE) was validated by pyrosequencing as reliable and inexpensive high throughput method for identification and quantitative characterization of TALEN mediated mutations. Targeted COMT mutations were identified by CE in up to 74 % of the lines. In different events 8-99 % of the wild type COMT were converted to mutant COMT as revealed by pyrosequencing. Mutation frequencies among mutant lines were positively correlated to lignin reduction. Events with a mutation frequency of 99 % displayed a 29-32 % reduction of the lignin content compared to non-transgenic controls along with significantly reduced S subunit content and elevated hemicellulose content. CE analysis displayed similar peak patterns between primary COMT mutants and their vegetative progenies suggesting that TALEN mediated mutations were faithfully transmitted to vegetative progenies. This is the first report on genome editing in sugarcane. The findings demonstrate that targeted mutagenesis can improve cell wall characteristics for production of lignocellulosic ethanol in crops with highly complex genomes. PMID:27306903

  18. 沙田柚多倍体基因组AFLP分析%Genome Analysis of Nature and Artificial Polyploids by AFLP in Citrus grandis.cv.Shatianyou

    Institute of Scientific and Technical Information of China (English)

    何波; 汪卫星; 向素琼; 刘秀芳; 李晓林; 郭启高; 梁国鲁

    2009-01-01

    沙田柚性状优良却多核,通过多倍体选育获得无核或少核品种具有很高的价值.本研究运用AFLP技术分析沙田柚多倍体基因组的变化,以期为多倍化选育优良品种提供一定的理论依据.结果表明,多倍体沙田柚基因组存在大量片段的丢失,也有许多新的酶切位点出现,变异率在21 %~29 %之间.其中多个位点同时发生了相同变异,暗示着多倍体基因组的进化并不是一个随机事件,而这些变异与哪些表观遗传变异直接相关,还有待深入研究.

  19. Interspecific hybridization, polyploidization, and backcross of Brassica oleracea var. alboglabra with B. rapa var. purpurea morphologically recapitulate the evolution of Brassica vegetables.

    Science.gov (United States)

    Zhang, Xiaohui; Liu, Tongjin; Li, Xixiang; Duan, Mengmeng; Wang, Jinglei; Qiu, Yang; Wang, Haiping; Song, Jiangping; Shen, Di

    2016-01-01

    Brassica oleracea and B. rapa are two important vegetable crops. Both are composed of dozens of subspecies encompassing hundreds of varieties and cultivars. Synthetic B. napus with these two plants has been used extensively as a research model for the investigation of allopolyploid evolution. However, the mechanism underlying the explosive evolution of hundreds of varieties of B. oleracea and B. rapa within a short period is poorly understood. In the present study, interspecific hybridization between B. oleracea var. alboglabra and B. rapa var. purpurea was performed. The backcross progeny displayed extensive morphological variation, including some individuals that phenocopied subspecies other than their progenitors. Numerous interesting novel phenotypes and mutants were identified among the backcross progeny. The chromosomal recombination between the A and C genomes and the chromosomal asymmetric segregation were revealed using Simple Sequence Repeats (SSR) markers. These findings provide direct evidence in support of the hypothesis that interspecific hybridization and backcrossing have played roles in the evolution of the vast variety of vegetables among these species and suggest that combination of interspecific hybridization and backcrossing may facilitate the development of new mutants and novel phenotypes for both basic research and the breeding of new vegetable crops. PMID:26727246

  20. QualitySNP: a pipeline for detecting single nucleotide polymorphisms and insertions/deletions in EST data from diploid and polyploid species

    NARCIS (Netherlands)

    Tang, J.; Vosman, B.; Voorrips, R.E.; Linden, van der C.G.; Leunissen, J.A.M.

    2006-01-01

    Background - Single nucleotide polymorphisms (SNPs) are important tools in studying complex genetic traits and genome evolution. Computational strategies for SNP discovery make use of the large number of sequences present in public databases (in most cases as expressed sequence tags (ESTs)) and are

  1. Study on Polyploid Induction of Hyperaccumulator Plant—Phytolacca acinosa Roxb.%超富集植物商陆多倍体诱导研究

    Institute of Scientific and Technical Information of China (English)

    张丽珍; 杨冬业; 刘杰; 曾惠玲

    2014-01-01

    以商陆为试材,对商陆幼苗进行秋水仙素诱导多倍体试验.结果表明:0.2%秋水仙素诱变48 h效果最好,与对照相比,变异株茎粗壮,叶宽、叶厚较对照分别增加40.15%和33.25%;气孔纵横径较对照分别增加30.25%和60.82%,气孔密度增加150%;压片法对变异植株和对照植株的根尖有丝分裂分别进行染色体鉴定,证明变异株为多倍体.

  2. Colchicines Induced Polyploid Plants of Muscari armeniacum%秋水仙素诱导葡萄风信子多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    贾美丽; 王飞; 贾爱平; 郑丽娜

    2011-01-01

    在离体培养条件下,比较了秋水仙素不同质量分数、不同处理时间诱导亚美尼亚葡萄风信子体细胞染色体加倍的效果.利用秋水仙素混配和浸泡法对亚美尼亚葡萄风信子的染色体进行加倍诱导,采用染色体常规压片法鉴定染色体数目.结果表明,浸泡法以秋水仙素质量分数为0.05%,时间为15 h的变异率最高,达到45.6%;混培法以秋水仙素质量分数为0.05%,时间为15 d的变异率最高,为21.1%.经秋水仙素诱导的变异株与正常二倍体植株比较,诱变植株叶片变厚变宽,叶色变深,鳞茎变大,气孔显著增大而单位面积气孔数减少,对诱变植株进行细胞学观察后发现,对照二倍体植株2n=2x=18,变异株2n=4x=36,为四倍体,另外还发现嵌合体的存在.%The effect of colchicine concentration on chromosome reduplication of Muscari armeniacum was compared and time duration under the condition of vitro cultivation. The chromosome reduplication of Muscari armeniacum was induced with mixed and soaked colchicine, and chromosome number were identified by conventional chromosome pellet. For the treatment of soaked colchicines, the best induction effect was obtained under the condition of concentration 0.05 % and time duration 15 h, induction rate reached to 45.6%. For the mixed colchicines, the highest induction rate was 21. i% under the condition of concentration 0.05% and time duration 15 d. Compared with the normal diploid plants and the colchicines-induced plants, the colchicines-induced plants had thicker and larger leaves,darker leaf color, larger bulbs, larger stomata and fewer stomata number per unit area. Cytological observation confirmed that chromosome number of tetraploids was 2n = 4x =36, however, chromosome number of diploids was 2n=2x =18, and a few mosaic were found.

  3. Microsatellite DNA marker inheritance indicates preferential pairing between two highly homologous genomes in polyploid and hemisexual dogroses, Rosa L. sect. Caninae DC

    NARCIS (Netherlands)

    Nybom, H.; Esselink, D.; Werlemarkt, G.; Vosman, B.J.

    2004-01-01

    According to previous cytological evidence, the hemisexual dog-rose species, Rosa sect. Caninae, transmit only seven chromosomes (derived from seven bivalents) through their pollen grains, whereas egg cells contain 21, 28 or 35 chromosomes (derived from seven bivalents and 14, 21 or 28 univalents) d

  4. Colchicines Induced Polyploid Plants and Identification in Welsh Onion%秋水仙素诱导大葱多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    董飞; 陈运起; 刘世琦; 高莉敏; 王传增; 陈伟

    2011-01-01

    The welsh onion seeds were treated with colchicines at different concentration and treatment time duration,and the ploidy level was identified by morphological trait,chromosome number and flow cytometry techniques.The results showed that the best effect was obtained by the treatment of 0.8% colchicines with 48 hours.The mutated plants we got were vitreous seedlings,they could not survive after transplanting.By tissue culture we obtained tetraploids.The choromosome number of tetraploids was 2n = 4x = 32,the plants showed the general characteristics of tetraploids,such as darker leaf color,larger stomata,fewer stomata per unit area.Comparing the plant height and welsh onion stalk length,there were remarkable difference between tetraploids and the control.%以章丘大葱种子为材料,研究了秋水仙素处理浓度和时间对大葱体细胞染色体加倍的效果,并利用形态观察,根尖细胞染色体计数及流式细胞仪等方法进行倍性鉴定。结果表明,0.8%秋水仙素处理48 h的诱变效果最佳。诱变植株存在明显"玻璃化"现象,生根困难,移栽后不能成活。通过组织培养去"玻璃化",获得正常生长的四倍体植株。四倍体植株的细胞染色体数2n=4x=32,植株多倍体形态特征明显,植株生长健壮,叶色浓绿,叶面气孔变大,气孔密度减少;株高、葱白长度等与二倍体植株相比极显著增加。

  5. Giemsa C-banding in two polyploid, South American Hordeum species, H. tetraploidum and H. lechleri, and their aneuploid hybrids with H. vulgare

    DEFF Research Database (Denmark)

    Linde-Laursen, Ib; Bothmer, R. von

    1986-01-01

    American taxa of the same sections suggest a rather close relationship and support that the biological basis for their classification with different sections is questionable. C-banding patterns identified the chromosomes of parental genomes in interspecific hybrids between the two species and H. vulgare....... The hybrids were stably aneuploid. Both had lost and acquired H. vulgare chromosomes. Thus, somatic elimination of chromosomes was combined with multiplication of chromosomes. The observations of stably aneuploid hybrids have implications for the exploitation of alien germplasm. The activity of non-H. vulgare...

  6. Variation among hexaploid Paspalum dilatum Poir. regenerants from tissue culture.

    Science.gov (United States)

    The common biotype of Paspalum dilatatum, called paspalum in Australia and dallisgrass in the U.S.A., is a pentaploid obligate apomict and efforts to improve the grass have not been successful because of its asexual reproduction and irregular meiosis. An apomictic hexaploid biotype, known as Urugua...

  7. AGRONOMIC PERFORMANCE OF DALLISGRASS TISSUE CULTURE REGENERANTS

    Science.gov (United States)

    Common dallisgrass, Paspalum dilatatum, is a pentaploid obligate apomict and efforts to improve this important forage grass have not been successful because of its asexual reproduction and irregular meiosis. An apomictic hexaploid biotype, known as Uruguayan dallisgrass, is a new source of genetic v...

  8. Identification of apomixis in the Kentucky bluegrass (Poa pratensis L. using auxin test

    Directory of Open Access Journals (Sweden)

    Janetta Niemann

    2012-08-01

    Full Text Available The effect of auxin treatment on the formation of apomictic – endospermless grains in Poa pratensis was investigated in the study. Four Polish cultivars: Skiz, Eska 46, Alicja, Ani as well as six breeding lines: POB 13, SK-W-33, SKW-15, SKW-35A, SK-W-35A and SK-W-35B were tested by embryological methods to reveal the reproduction pathway in greenhouse and field conditions. The obtained results showed that four genotypes, i.e. Alicja, Ani, Eska 46 and SK-W-35B are facultative apomictic and the other have formed seeds only on the apomictic way. In facultative apomicts it was found that in many cases both endospermless ovules containing embryo sacs with embryos or embryo sacs with well developed endosperm were formed. In the case of apomictic genotypes only endospermless seeds were observed.

  9. Apomixis does not affect visitation to flowers of Melastomataceae, but pollen sterility does.

    Science.gov (United States)

    Maia, F R; Varassin, I G; Goldenberg, R

    2016-01-01

    Apomixis is an asexual seed reproduction mechanism thorough which embryos are originated from material tissues inside the ovules, without precedent fertilisation. It allows plants to colonise new habitats, even in places where flower visitors are scarce or where plants are isolate. Apomixis seems to be related to pollen sterility and, in species with flowers that offer pollen as a reward for pollinators, the amount or quality of the pollen offered by these species may influence the amount of the visits and specific composition of the visitors. In order to test this hypothesis, we studied breeding systems of 16 species of Melastomataceae and their flower visitors, evaluating composition and abundance of the visits to apomictic and sexual species. Apomictic plants with no viable pollen or with pollen with low viability did not receive visits from pollinators, and consequently probably produce strictly apomictic fruits. On the other hand, apomictic and sexual plants with high pollen viability do receive visits; in this case, apomictic plants may produce fruits and seeds through both sexual and apomictic methods. The species composition of insects visiting Melastomataceae with high pollen viability was similar, regardless of whether the plants were apomictic or not. It seems that pollen viability levels are important to determine visits to the flowers irrespective of breeding system. PMID:26152277

  10. Apomixis does not affect visitation to flowers of Melastomataceae, but pollen sterility does.

    Science.gov (United States)

    Maia, F R; Varassin, I G; Goldenberg, R

    2016-01-01

    Apomixis is an asexual seed reproduction mechanism thorough which embryos are originated from material tissues inside the ovules, without precedent fertilisation. It allows plants to colonise new habitats, even in places where flower visitors are scarce or where plants are isolate. Apomixis seems to be related to pollen sterility and, in species with flowers that offer pollen as a reward for pollinators, the amount or quality of the pollen offered by these species may influence the amount of the visits and specific composition of the visitors. In order to test this hypothesis, we studied breeding systems of 16 species of Melastomataceae and their flower visitors, evaluating composition and abundance of the visits to apomictic and sexual species. Apomictic plants with no viable pollen or with pollen with low viability did not receive visits from pollinators, and consequently probably produce strictly apomictic fruits. On the other hand, apomictic and sexual plants with high pollen viability do receive visits; in this case, apomictic plants may produce fruits and seeds through both sexual and apomictic methods. The species composition of insects visiting Melastomataceae with high pollen viability was similar, regardless of whether the plants were apomictic or not. It seems that pollen viability levels are important to determine visits to the flowers irrespective of breeding system.

  11. Distribution and origin of chromosomal races in the freshwater planarian Dugesia polychroa (Turbellaria : Tricladida)

    NARCIS (Netherlands)

    Beukeboom, Leo W.; Weinzierl, Rolf P.; Reed, Kent M.; Michiels, Nico K.

    1996-01-01

    We present a karyotypic survey of the European freshwater planarian Dugesia polychroa, detailing frequencies of diploid and polyploid forms from 35 localities in seven countries. In this hermaphroditic species, diploids reproduce sexually and polyploids by pseudogamous parthenogenesis. Previous labo

  12. ニセアカシアの試験管内コルヒチン処理による倍数体の作出

    OpenAIRE

    鄒, 徳本; 玉泉, 幸一郎; 矢幡, 久

    1994-01-01

    In the polyploidization of chromosome by colchicine treatment on seedlings, there was various difficult points. Namely, the ratio of the polyploidization is generally very low and the inducement of polyploid is localized into only a few joints. And so, we tested the use of tissue culture technique to overcome all difficulties in relation to induce of polyploid. The tetraploid plantlets of Niseakasia (Robinia Pseudoacacia L.) were induced effectively by culture of callus originated from seedli...

  13. Apomixie, sexualité et amélioration des graminées tropicales

    Directory of Open Access Journals (Sweden)

    Gobbe, J.

    1983-01-01

    Full Text Available Apomixis, sexuality and improvement of tropical grasses. Gametophytic apomixis together with sexuality can be used for the improvement of tropical grasses. Apomixis is researched for providing an easy spreading of cultivars. Apomictic and sexual species are found in the genus Brachiaria ; hybridizations are carried out between a tetraploid, colchicine induced form of the sexual species B. ruziziensis Germain et Evrard, and natural tetraploid apomicts, B. brizantha Stapf. and B. decumbens (Hochst Stapf.

  14. 秋水仙素诱导蒙古黄芪多倍体的研究%Study on Induction of Polyploid Astragalus membranaceus(Fisch.) Bge.var.mongholicus(Bge.) Hsiao with Colchicines

    Institute of Scientific and Technical Information of China (English)

    张利珍; 李前忠

    2010-01-01

    以黄芪种子和带子叶的上胚为处理对象,用在培养基里添加不同浓度秋水仙素的方法,研究了秋水仙素不同浓度、不同处理时间对黄芪多倍体诱导的影响.结果表明,两种处理对象的诱导效果受秋水仙素浓度和处理时间两方面的影响.以成熟种子为处理对象,各种秋水仙素浓度和处理时间组合均可诱导出多倍体植株,但以秋水仙素浓度100mg/L,处理时间14d的组合加倍率最高,达13.3%;以带子叶的上胚为处理对象,从秋水仙素浓度50mg/L,处理时间7d开始有较低的加倍率,以秋水仙素浓度100mg/L处理时间7d的加倍效果最好,为10.9%.细胞染色体鉴定结果为:四倍体染色体数为2n=4x=32;而二倍体的染色体数为2n=2x=16.

  15. Study on Polyploid Induction of Lilium lancifolium in Vitro with Colchicine Treatment%秋水仙素诱变离体卷丹多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    陈艾; 杨利平; 谭艳; 彭春涛; 唐彪

    2014-01-01

    用0.15%秋水仙素附加2.00%二甲基亚砜诱变离体培养的卷丹小鳞茎,遮光条件下摇床诱导,用组织培养结合不定芽诱导技术获得了多倍体苗,并对多倍体染色体数目进行鉴定.结果显示,诱导96h效果最好,变异率达到54.29%.细胞学观察发现,对照为三倍体、非整倍体和极少数单倍体细胞组成的嵌合体,诱变出的4棵变异株细胞分别为染色体数目由53 ~72条的不同比例构成,属于典型的非整倍的异倍型嵌合体.诱变株与对照植株间幼苗叶形指数、气孔密度及气孔大小等特征差异比较明显.

  16. 紫薇多倍体的诱导、鉴定及内多倍性研究%Induction, Ploidy Determination and Endopolyploidy of Polyploid in Lagerstroemia indicaL

    Institute of Scientific and Technical Information of China (English)

    宋新红; 丰震; 谷衍川; 张鑫鑫; 王长宪; 张林

    2012-01-01

    以紫薇子叶期幼苗为试验材料,采用不同秋水仙素浓度和时间组合处理其生长点,成功获得四倍体(2n=4x=96)和六倍体(2n=6x=144)。诱变株与二倍体对照植株形态差异明显,植株矮小粗壮,叶片变皱、粗糙,增厚,气孔密度减小,气孔保卫细胞(一对,下同)长、宽分别增大65.79%和45.01%,保卫细胞内叶绿体数量增加80.25%,且颗粒增大。四倍体花粉粒直径增大59.07%,花瓣长宽略有增加,但花序长和花朵数反而减少。人工诱导四倍体和普通二倍体茎尖都有内多倍化现象,并且前者内多倍化水平低于后者。%Tetraploid (2n=4x= 96) and hexaploid (2n= 6x= 144) plants were successfully induced from seedling of Lagerstroernia indica L. by processing shoot apical meristem with colchicine. The results indicated that the variants, which were characterized by stunted but stout plant, wrinkled and thicker leaves, less stoma frequency, larger(length rised by 65.79 % and width, 45.01%) guard cells (a pair, the same as below), more larger(rised by 80.25%) chloroplasts in each pair of guard cells, were significantly different from the diploid plants in morphology. Tetraploid plant got markedly larger (rised by 59. 07%) pollen grains, slightly larger petals, longer inflorescence but less flowers than diploid plants. Endopolyploidy was observed in both induced tetraploid plant and diploid plant, and endopolyploidy degree of the former was lower than that of the latter.

  17. 秋水仙素对四季桔多倍体的诱导效应%A preliminary study on induction of polyploids in fortunella calamondin with colchicines

    Institute of Scientific and Technical Information of China (English)

    郑君强; 罗筱玉; 方小燕

    2005-01-01

    以四季桔(Fortunella calamondin)种子为外植体,研究了秋水仙素对多倍体诱导的影响,结果表明:将种子用秋水仙素溶液浸渍比直接接种在含秋水仙素的培养基上,诱导多倍体的效果更好,用0.2%秋水仙素溶液浸渍种子12.75h,诱导率最高,达14.4%;在含0.2%秋水仙素的培养基上培养50d,诱导率为9.8%;变异植株叶片变大,茎变粗,有少量植株出现三出复叶突变;变异植株的气孔明显大于二倍体植株,气孔密度降低.

  18. 组织培养与秋水仙碱诱导相结合培育植物多倍体的应用(综述)%A Review of in vitro Induction of Polyploid Plants with Colchicine

    Institute of Scientific and Technical Information of China (English)

    谭德冠; 庄南生; 黄华孙

    2005-01-01

    本文概述组织培养与秋水仙碱诱导相结合培育植物多倍体的优点、诱导方法、最佳药液处理浓度与处理时间组合的选择及诱导材料的选取,并展望其应用前景.

  19. 秋水仙素诱导抗枯1号香蕉多倍体试验%In vitro polyploid induction of banana Kangku 1 using colchicine

    Institute of Scientific and Technical Information of China (English)

    谭平; 唐晓华; 劳世辉; 魏岳荣; 洪林

    2012-01-01

    This study aimed to obtain polyploidy banana by chemical introduction in order to provide new banana breeding germplasm resources. [Method]In this research, the embryogenic cell suspension (ECS) of banana Kangku 1 was treated with colchicine at different concentrations and induction times. The corresponding results were recorded and analyzed. [ Result ]The results showed that some types of chromosome natural variation occurred at the ECS subculture stage. During this occurrence, the variation proportion reached up to 11.76%. On the other hand, the chromosome variation of treated regenerated seedlings was at a higher rate of 76.92% ~100.00% while accompanying with a small amount of chimera regeneration plants. Considering the numbers of regenerated seedlings and the variation proportion, the best effect could be obtained after treating the ECS with 0.1% colchicine for 12 hours. Three hexaploid banana plants and large number of aneuploid variation plants were successfully identified from the regenerated seedlings. [ Conclusion ]The natural variation of banana was produced during the subculture of Kangku 1 ECS, and the efficiency of polyploidy induction increased. The best treatment amongst all the ones tested was treating the ECS with 0.1% colchicine concentration for 12 hours.%[目的]通过多倍体诱导途径为香蕉育种提供新型种质资源.[方法]以抗枯1号香蕉胚性细胞悬浮系(ECS)为材料,利用秋水仙素进行多倍体诱导,探讨在秋水仙素不同浓度、不同处理时间条件下多倍体的获得情况.[结果]在未采用秋水仙素处理的条件下,抗枯1号香蕉ECS在继代培养过程中存在一定比例的染色体数目自然变异,变异率为11.76%;而秋水仙素处理后再生苗的染色体数目变异率介于76.92%~100.00%,且有少量的嵌合体再生植株;不同浓度秋水仙素及处理时间获得的再生苗数及其变异率不同,其中以0.1%秋水仙素处理12h的效果较好,共获得3株六倍体植株,且能得到大量非整倍体变异.[结论]通过秋水仙素诱导香蕉ECS获得再生加倍值株是可行的.

  20. 苦参种子催芽及秋水仙素诱导多倍体研究%Study on Germination Accelerating-technology on Sophora(Sophora flavescens Ait.) Seeds and Polyploid Induction by Colchicine

    Institute of Scientific and Technical Information of China (English)

    李桂双; 何莎; 白成科

    2009-01-01

    采用浓硫酸浸种、热水浸泡和种皮破损等方法来提高苦参(Sophora flavescens Ait.)种子的萌发率,并用秋水仙素处理已萌发苦参种子,通过根尖压片观察细胞染色体加倍情况.结果表明,苦参种子发芽率随浓硫酸浸种时间的延长先增加后降低,其中浸种90 min的效果最好,种子的发芽率高达83%,不采用任何处理的对照发芽率仅有13%;70℃热水处理提高种子发芽率,随着处理时间延长,发芽率逐渐降低;种皮破损也能显著提高苦参的种子发芽率;根尖压片观察细胞染色体的结果表明,秋水仙素能够诱导苦参根尖四倍体细胞的产生,当处理浓度相同时,多倍体细胞率随着处理时间的延长呈先增加后降低的趋势,诱变植株率却一直明显增加,其中处理0.2%+72 h时,根尖多倍体细胞率最高为59.5%,处理0.2%+108 h时,诱变植株率高达68%,0.1%+48 h的根尖多细胞率和诱变植株率均最低,分别为18.5%和8%.同时部分个体出现了混倍体细胞现象,其中四倍体细胞出现几率高于八倍体细胞.

  1. Study on polyploid induction of Pleione maculate Lindl.with colchicine%秋水仙素诱导秋花独蒜兰多倍化的研究

    Institute of Scientific and Technical Information of China (English)

    成倩; 唐娅梅; 张伟; 胡晓丽; 魏兴强; 纳海燕

    2010-01-01

    以秋花独蒜兰(Pleione maculata Lindl.)拟原球茎为材料,研究不同浓度及时间条件下,对秋水仙素诱导秋花独蒜兰多倍化的诱变效果.实验结果表明:秋水仙素浓度为0.2%、处理时间为60 h时,诱导结果最佳,变异率为25.64%;细胞学鉴定表明,该方法诱导培育的植株具有多倍体表型特征,其体细胞染色体数多为2n=76~80条,而对照2n=38~40条.

  2. 秋水仙素诱导川贝母(Fritillaria cirrhosa D.Don)愈伤组织多倍体的研究%Induction of Polyploid from Colchicine-Treated Fritillaria cirrhosa D.Don Callus

    Institute of Scientific and Technical Information of China (English)

    王强; 兰利琼; 傅华龙

    2002-01-01

    应用组织培养技术对川贝母(Fritillaria cirrhosa D.Don)进行多倍体诱导.结果表明:组织培养条件下,将川贝母愈伤组织在培养基中添加一定浓度的秋水仙素处理一段时间,或者经一定浓度的秋水仙素浸泡一段时间后再培养,均可诱发川贝母多倍体的产生,但以前者效果较好,在秋水仙素浓度为1 000 mg/L,处理5 d的条件下,诱导率最高达70%.细胞染色体鉴定结果为:四倍体染色体数为2n=4x=48,而二倍体的染色体数为2n=2x=24.

  3. 秋水仙素处理柴胡诱导多倍体形成的形态学研究%Colchicine Polyploid Induction Morphological Study on the Formation of Bupleurum

    Institute of Scientific and Technical Information of China (English)

    庄云; 马尧; 陈映

    2013-01-01

    采用分生组织细胞内的染色体加倍方法,对柴胡种芽和幼苗生长点进行诱导突变,以确定秋水仙素的最佳处理比较和处理时间,并对突变植株进行植物学观察,结果表明,浓度为0.3%的秋水仙素处理24 h,柴胡幼苗的突变率较高,相对死亡率较低. 诱变植株形态上,处理植株幼苗的前期真叶生长明显受抑制,变异的幼苗不仅第1对真叶出现较迟,株高都显著低于对照株,叶片也较对照厚,但其主茎却较对照株粗壮,其主茎的节间也缩短.%The chromosome doubling in meristem cells that was applied bupleurum buds and seedlings growth point induced mutation was used to study the best treatment and processing time, and mutant was observed in botany. The results showed that bupleurum treated with the concentration of 0. 3% for 24 h had the higher seedlings mutation rate and lower mortality rate. Mutation in plant morphology, seedlings of early leaf growth was restrained, variation of seedling not only the first pair of true leaf appears later, plant height were significantly lower than those in the control lines, blade was more thick than confrol, but its main stem was thickset than control,its main stem internodes shorten.

  4. 秋水仙素诱导三种紫薇多倍体的研究%Colchicines Induced Polyploid Plants and Their Identification in Three Species of Lagerstroemia indica

    Institute of Scientific and Technical Information of China (English)

    童俊; 叶要妹; 冯彪; 袁玮

    2009-01-01

    研究了秋水仙素处理浓度和时间对3种紫薇幼苗染色体加倍的诱导效应,通过染色体计数、流式细胞仪以及形态观察等方法进行了倍性鉴定.结果表明:秋水仙素诱导3种紫薇均得到了四倍体,0.5%~0.8%的秋水仙素处理紫薇和银薇48~96 h的变异率较高,其中以0.5%秋水仙素处理紫薇72 h的变异率最高,达54.17%.根尖染色体压片检查表明,四倍体染色体数为2n=4x=96,二倍体对照为2n=2x:48.四倍体表现出叶片长、宽、厚均增大,气孔密度减小,气孔保卫细胞增大,保卫细胞内叶绿体数增加,花粉粒直径增大,花径、花瓣长、花瓣基部爪长均较二倍体明显增加,单朵花观赏价值大大提高.

  5. Study on the Polyploid Induction of Melastoma dodecandrum Lour. by Using Colchicine%利用秋水仙素诱导地菍多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    胡松梅; 蒋道松; 龚泽修

    2008-01-01

    [目的]探索利用秋水仙素诱导地蒸多倍体的可行性.[方法]以秋水仙素作为诱变剂,对地菍无菌试管苗丛芽进行多倍体诱导,研究秋水仙素浓度、处理方法和处理时间对地菍组培苗丛芽诱导效果的影响.经纯化和鉴定后,分析地菍多倍体的外部形态和叶片气孔特征.[结果]采用混培法用0.1%秋水仙素对地菍处理14 d的诱导率达28%,明显优于浸泡法.秋水仙素浓度对地菍染色体的加倍率影响显著.采用不定芽技术切取变异株顶芽继代5次后,可得到纯合四倍体地菍植株,染色体数目为2n=56.与正常二倍体相比,四倍体地菍植株表现出多倍体巨大型特征.[结论]采用混培法用0.1%秋水仙素处理地菍试管苗丛芽21 d,可获得最好的诱导效果.

  6. Polyploid Induced from Wild Lilium sulphureum with Colchicine in Guizhou%秋水仙素诱导贵州野生淡黄花百合的多倍体

    Institute of Scientific and Technical Information of China (English)

    钟程; 田鑫; 刘伦沛; 李性苑; 杨芩

    2015-01-01

    以贵州野生淡黄花百合为材料,通过不同浓度及时间的秋水仙素浸泡处理芽诱导多倍体,进行无菌培养.结果表明:以0.15%秋水仙素处理48 h的诱导效果最佳,四倍体诱导率达16.67%,四倍体植株叶面皱缩,部分扭曲,根系粗壮,根尖染色体加倍.

  7. 秋水仙素对黑麦有丝分裂及多倍体诱导的影响%EFFECTS OF COLCHICINE ON MITOSIS AND POLYPLOID-INDUCTION IN RYE

    Institute of Scientific and Technical Information of China (English)

    陈于和; 秦素平; 林小虎; 董超华; 东方阳

    2006-01-01

    本文研究了秋水仙素在不同浓度(0.01%、0.05%、0.10%、0.15%、0.20%)和不同处理时间(12、24、36、48、60和72h)对黑麦根尖细胞染色体、中期分裂指数、细胞加倍指数的影响.结果表明,秋水仙素处理使黑麦根尖细胞内染色体数目发生了变化,观察到的细胞内染色体数有14、28及56条不等;0.15%的秋水仙素处理24h,细胞的中期分裂指数最大,达到0.202%,同浓度秋水仙素处理36h,细胞加倍指数最高,达到0.096%.

  8. Studies on Polyploid Induction in Anthurium andraeanum Using Oryzalin,Trifluralin and Colchicine%氨磺灵、氟乐灵和秋水仙素诱导安祖花多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    储丽红; 彭佳佳; 王钊; 赵凯; 袁素霞; 明军; 刘春

    2014-01-01

    采用氨磺灵、氟乐灵和秋水仙素对‘Dakota’安祖花组培苗进行浸泡处理,诱导多倍体产生.结果表明,15 mg·L-1氨磺灵处理7d,死亡率为14.58%,诱导率达48.72%; 100 mg· L-1氟乐灵处理5d,死亡率为16.67%,诱导率达71.79%; 0.5%秋水仙素处理5d,死亡率为31.11%,诱导率达62.96%.

  9. Effects of Multi-Factor on Efficiency of Polyploid Induction with Colchicine%多因素对秋水仙素诱导多倍体效率的影响

    Institute of Scientific and Technical Information of China (English)

    常青云; 朱莉思; 曹鑫; 刘本翠; 张志毅

    2007-01-01

    [目的]明确各因素对秋水仙素诱导效率的影响.[方法]通过正交试验,研究秋水仙素浓度、紫外线辐射单次时长及频数、温降单次时长及频数对秋水仙素诱导刺槐多倍体效率的影响.[结果]紫外辐射时长对秋水仙素诱导效率的影响最显著,80 s时膨大率最高,其次是浓度.各浓度组间膨大率呈周期性变化,随浓度增加整体略有上升.辐射频数和温降频数对膨大率的影响较小,分别以2、1次最好.温降时长以5 min最佳.不同辐射时长和不同辐射时间点的诱导效果有明显差异.单纯的紫外辐射不能诱导根尖膨大细胞加倍,不能降低秋水仙素的最低有效诱导浓度.单次剂量2 min出现抑制效果,4 min出现明显的生长抑制,8 min生长停止.[结论]最优组合是0.3%秋水仙素,辐射40 s共2次,温度骤降5 min共1次.

  10. 秋水仙素诱导维多利亚葡萄试管苗多倍体研究%Study on colchicine inducing of polyploid on in-vitro plantlets of Victoria

    Institute of Scientific and Technical Information of China (English)

    吴红; 刘争; 贾书果; 常永义

    2012-01-01

    本实验采用0.05%、0.1%的秋水仙素溶液对维多利亚葡萄试管苗单芽茎段进行24 h、48 h浸泡处理来诱导发生多倍体.对诱变四倍体和二倍体进行染色体、保卫细胞叶绿体等进行比较.结果表明:0.1%的秋水仙素处理24 h对诱导葡萄发生多倍体效果最好.加倍率从M1代的40.9%提高到M9代的75.8%.根尖染色体压片检查表明,四倍体染色体数为2n=4x=76,二倍体对照为2n=2x=38.四倍体植株叶片表现气孔密度减小,气孔保卫细胞增大,保卫细胞内叶绿体数增加.

  11. Study on polyploid induction of blueberry in vitro with colchicine treatment%秋水仙素诱导离体培养越橘多倍体研究

    Institute of Scientific and Technical Information of China (English)

    李晓艳; 张志东; 李亚东; 吴林; 刘海广

    2010-01-01

    试验研究了秋水仙素不同处理方法、浓度和时间对美登、达柔和埃利奥特3个越橘品种试管苗的诱变效果,并采用根尖压片方法和流式细胞仪对诱变材料倍性进行检测.结果表明,采用药剂培养基法处理效果不如茎段浸渍法.经秋水仙素处理的所有品种都发生不同程度的变异,其中达柔用0.1%秋水仙素浸渍24 h的处理效果最好,变异率达到22.6%,诱变株系为嵌合体.流式细胞仪测定DNA含量方法与根尖压片方法检测结果一致.

  12. Analysis on the Influences of Colchicine on the Growth of Allium sativum and Its Polyploid Induction Effect%秋水仙素对大蒜生长的影响及多倍体诱导效应分析

    Institute of Scientific and Technical Information of China (English)

    谢晓玲; 邓自发

    2009-01-01

    [目的]探讨诱导大蒜染色体加倍的有效方法.[方法]以秋水仙素为诱变剂,比较不同浓度和不同时间处理对大蒜的多倍体诱导效应.[结果]经秋水仙素处理过的植株,在相同浓度下,随着秋水仙素处理时间的延长,株高降低,细胞有丝分裂指数减小,染色体加倍率升高.在相同的处理时间内,随着秋水仙素浓度的升高,株高降低,细胞有丝分裂指数明显减小,染色体加倍率显著升高.当秋水仙素浓度为0.05%,处理6 d时,染色体加倍率达到最高,为28.67%.随着浓度的增加和处理时间的延长,植株的死亡率逐渐上升,气孔面积也呈上升趋势.[结论]该研究为丰富大蒜种质资源和加速高产优质大蒜的育种进程奠定了基础.

  13. Study on Polyploid Induction of Welsh Onion Callus by Colchicines%秋水仙碱处理大葱愈伤组织诱导多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    高莉敏; 宗红; 陈运起; 高秀云; 董飞

    2010-01-01

    试验采用秋水仙碱加入培养基和秋水仙碱溶液浸泡处理大蒜愈伤组织,经染色体数目鉴定表明,这两种方法都能有效地诱导四倍体细胞.加入培养基法在诱导率和操作上都优于液体浸泡法.其中以在培养基中加入0.08%秋水仙碱,处理4 d的诱导效果较好,加倍率达26.0%.

  14. Seeds Germination and Polyploid Induction by the Colchicine of Lychnis fulgens Fisch.%剪秋罗种子催芽及秋水仙碱诱导多倍体研究

    Institute of Scientific and Technical Information of China (English)

    肖宁; 李旦; 武永明; 曹芹; 夏昶; 张金凤

    2012-01-01

    In order to solve the problem of low germination rate in Lychnis fulgens seeds, influence on germinative force and germination rate in seed of Lychnis fulgens between stored and new seeds, different planting substrate and different concentrations of gibberellic acid (GA3) pretreatment were compared. The result showed one year of stored seeds were better than when new seeds on seed indicators, then the seed may have a newborn sleep characteristics. Using 150 mg/L of GA3 pretreated the stored seeds for 24 h sown in petri dishes could get the highest germinative force of 76.33% and the highest germination rate of 85.33% . Germinated seeds were treated by different concentration of colchicine (0.05%, 0.10%, 0.20%) and different treating time (12 h, 24 h, 36 h, 48 h) to induce polyploidy. And morphologic, stoma and cytologio comparison between treated plants and CK were studied. The survival rate was generally low after colchicine treatment. Variative plants were obtained under each colchicine concentration and concentration of 0.10% was the optimal induction concentration with the higher mutagenic rate and lower death rate. Varieties plants showed differences on morphologic, stoma and cytological analysis to control plants. One polyploidy was obtained after identification. This study opened up a new way for breeding new cultivar of Lychnis fulg%为了解决剪秋罗种子发芽率不高的问题,以剪秋罗种子为试验材料,比较种子新旧、播种基质以及不同浓度赤霉素(GA3)对剪秋罗种子发芽势和发芽率的影响,并在此基础上利用不同浓度秋水仙碱和不同时间处理剪秋罗萌动种子诱导多倍体.通过形态鉴定、气孔鉴定以及细胞学鉴定变异植株.结果表明:存放1年的剪秋罗种子发芽指标均优于当年新种子,当年种子可能具有初生休眠特性.以150 mg/L的GA3预处理存放1年的剪秋罗种子24 h并播种于培养皿中能获得最高的发芽势(76.33%)和最高的发芽率(85.33%).经过秋水仙碱处理的种子普遍存活率低,但每个处理浓度下都获得了变异植株,秋水仙碱浓度0.1%为筛选出的最适诱导浓度.变异植株表现出了与对照植株在形态上、气孔分析上和细胞学检测上的差异.经鉴定,初选出1株多倍体.研究为培育剪秋罗多倍体新品种探索出了一条新的育种途径.

  15. Comparison of baicalin in skullcap polyploid determined by MEKC and HPLC methods%MEKC法和HPLC法测定黄芩多倍体中黄芩苷含量的研究

    Institute of Scientific and Technical Information of China (English)

    高山林; 刘蓁; 朱丹妮

    2003-01-01

    目的采用MEKC和HPLC法对黄芩多倍体进行了黄芩苷含量的测定,为大量样品的检测提供可靠的方法.方法对MEKC法和HPLC进行方法学考察的基础上,测定了黄芩中黄芩苷的含量,并进行数据的比较和相关性分析.结果两种方法的测定结果基本一致,其中采用HPLC法测定的结果偏高1%~3%,但两种方法测定的数据之间差异并无显著性,且相关系数较高.结论两种方法均可以应用于黄芩苷含量测定,但是MEKC法分析样品速度快、时间短、试剂费用低廉,如果仪器条件许可,MEKC法更适合于大量黄芩样品的测定.

  16. Studies on Chromosome Karyotype and Polyploid Induction of Vegetable Jute%叶用黄麻染色体核型分析和多倍体诱导研究

    Institute of Scientific and Technical Information of China (English)

    周庆红; 曾勇军; 范淑英; 邓启刚; 袁亮

    2013-01-01

    采用常规压片法可获得分散良好,形态清晰的黄麻有丝分裂中期染色体.对其进行核型分析后表明,黄麻的染色体数目为2n=14;全组染色体的总长度为21.36 μm,平均长度3.05 μm;臂比均介于1~1.7,其染色体均属于中着丝粒染色体,且第四对染色体具有一对随体,核型公式为2n=2x=14=12m+ 2m(SAT).此外,经不同浓度秋水仙素溶液浸泡后的黄麻种子,其萌发的时间会随溶液浓度的增加而延后,常规压片后可观察到清晰的同源三倍体、四倍体和六倍体.%The well-spread and clear mitotic metaphase chromosomes of jute were obtained.The karyotype analysis showed that jute was diploid (2n =2x =14).The total length of jute' s chromosome was 21.36 μm and the average length was 3.05 μm.The arm ratios were all between 1 ~ 1.7,meaning that their chromosomes belonged to the centromere of chromosomes,and the fourth pair of chromosomes had a pair of accompanying bodies.The karyotype formula was 2n =2x =14 =12m + 2m (SAT).In addition,the germination time of the jute seeds soaked with different concentrations of colchicine solution,would be delayed with the concentration increased.The autotetraploid and hexaploid of the jute could be observed when treated with 0.1% colchicine solution.

  17. Partial self-incompatibility in the polyploid endemic species Scalesia affinis (Asteraceae) from the Galápagos: remnants of a self-incompatibility system?

    DEFF Research Database (Denmark)

    Nielsen, Lene Rostgaard; Siegismund, Hans Redlef; Philipp, Marianne

    2003-01-01

    Galápapos, kolonisering, pollinator adfærd, frøsætning, Scalesia, sporofytisk selv-inkompatibilitet, Xylocopa darwini......Galápapos, kolonisering, pollinator adfærd, frøsætning, Scalesia, sporofytisk selv-inkompatibilitet, Xylocopa darwini...

  18. Studies on Polyploid Induction of Different Varieties of the Colored Zantedeschia Hybrid%彩色马蹄莲不同品种多倍体诱导研究初探

    Institute of Scientific and Technical Information of China (English)

    杨辉; 缑辉; 周涤; 都婷; 吴红芝

    2014-01-01

    以15个彩色马蹄莲栽培品种的无菌苗为材料,接种至筛选出的最适丛生芽诱导培养基MS+0.1 mg/LNAA+1.5mg/L6-BA中,分别比较了它们丛生芽诱导分化能力和秋水仙素诱导无性多倍体产生的差异以及各品种多倍体与二倍体早期形态学的差异.结果表明:彩色马蹄莲无性多倍体的成功诱导与点状丛生芽块的形成密切相关,‘ Treasure’,‘Pot of gold’,‘Liberty’,‘Black Magic’,‘Gold Finger'5个品种成功获得多倍体,丛生芽的增殖系数分别为3.7,4.7,5.6,4.3,5.2,秋水仙素处理后多倍体的变异率分别表现为16%,22%,28%,20%,25%;5个品种多倍体幼苗的叶长分别为二倍体的123.9%,119.8%,107.9%,108.8,142.9%,叶宽分别为二倍体的207.5%,189.5%,171.7%,173.3%和157.1%.

  19. Obtaining Polyploids and Genome Analysis of Tetraploids by GISH in Citrus grandis cv. Shatianyou%沙田柚多倍体的获得与基因组原位杂交(GISH)分析

    Institute of Scientific and Technical Information of China (English)

    向素琼; 梁国鲁; 李晓林; 汪卫星; 郭启高; 何桥; 陈瑶

    2008-01-01

    [目的]沙田柚是中国特有的柚类名优品种,但种子多,一般100粒左右.为创新三倍体无核品种积累育种材料,本研究通过实生筛选获得不同倍性沙田柚新种质,同时运用基因组原位杂交(GISH)技术分析天然与人工四倍体新种质的染色体组组成.[方法]随机采集沙田柚自然授粉果实,萌发种子检测其染色体数目获得倍性变异植株;以2x母株gDNA为探针,同获得的4x植株中期染色体杂交进行GISH分析.[结果]从6 000粒沙田柚种子中共获得三倍体5株,四倍体9株;对沙田柚天然与人工四倍体新种质的基因组原位杂交(GISH)分析表明,天然四倍体中有7株为异源四倍体,2株为同源四倍体,秋水仙碱诱导获得的人工四倍体4株均为同源四倍体;初步观察显示;与二倍体相比,四倍体植株生长缓慢,树冠较小,枝短而密生,叶片浓绿,宽度变宽,叶形指数减小,叶片厚度增加明显.[结论]多倍体单胚柚新种质的获得为进一步选育无核品种奠定了基础,同时GISH分析证实了沙田柚雌性未减数配子的存在.

  20. Polyploid Induction of Saussurea involucrata an Endangered Chinese Medicinal Herb%濒危药用植物天山雪莲多倍体植株的化学诱导

    Institute of Scientific and Technical Information of China (English)

    赵红艳; 江丽丽; 马淼

    2012-01-01

    以叶片诱导的愈伤组织为材料,用秋水仙素溶液浸泡法和秋水仙素加入培养基法分别进行诱导.实验结果表明,秋水仙素加入培养基法要好于秋水仙素溶液浸泡法,具体表现为:用秋水仙素加入培养基法诱导出的愈伤组织褐化死亡率低,分化率高,四倍体细胞平均比例高.而在处理浓度与时间的选择中,以高浓度的秋水仙素与短时间处理组合较好.秋水仙素的浓度为600 mg/L处理3d效果最佳,四倍体细胞比例达41.5%.%Callus induction from leaf explant was disposed in two methods; immersion in colchicine solution; adding the colchicine in the medium. The result showed that when operated the callus by the method of adding the colchicine in the medium, the browning rate and mortality were low, the differentiation rate was high, and the proportion of tetraploid cell was high, which was better than the method of immersion in colchicine. Meanwhile, the treatment combination of high concentrations of colchicine and short time was the best. 41. 5% tetraploid cell proportion was got when added 600 mg/L colchicine in medium and continuous cultured 3 days.

  1. Study of Colchicines to Induce Polyploid on Onion in Tissue Culture%秋水仙素结合组织培养技术诱导大葱多倍体的研究

    Institute of Scientific and Technical Information of China (English)

    张数鑫; 谢芝馨; 于元杰; 张玉喜; 程立

    2005-01-01

    该文研究了秋水仙素不同浓度不同时间处理大葱愈伤组织的诱导效果,发现随着处理时间和浓度的增加,愈伤组织死亡率增加,多倍体细胞诱导率在一定范围内随处理时间和浓度增加升高,但浓度超过一定量诱导率则相反.以0.06%的秋水仙素处理72h多倍体细胞诱导率最佳,且不对愈伤组织产生严重伤害.获得的变异材料与正常二倍体相比,其叶片变粗,生长迟缓,气孔器变大,经鉴定为多倍体.

  2. 甜菜无融合生殖单体附加系M14的小孢子发生与雄配子体发育的观察%THE OBSERVATION OF MICROSPOROGENESIS AND THE DEVELOPMENT OF MALE GAMETOPHYTES IN THE MONOSOMIC ADDITION LINES OF APOMICTIC BEET M14

    Institute of Scientific and Technical Information of China (English)

    申业; 申家恒; 郭德栋; 方晓华

    2003-01-01

    利用常规石蜡制片技术,对甜菜无融合生殖单体附加系M14品系(Beta vulgaris L.)小孢子发生、雄配子体发育进行了研究.结果表明:1.小孢子母细胞减数分裂过程中的胞质分裂为同时型,四分孢子为四面体形.2.单核小孢子经两次有丝分裂,产生营养细胞和两个精子,成熟的花粉粒为三细胞型.单核小孢子第一次有丝分裂后,80%的花粉败育,可育花粉只有20%.3.花药壁由五至六层结构组成,表皮,药室内壁,2至3层中层,绒毡层为分泌型.4.同一朵花中,在前期,雄蕊的发育早于雌蕊的发育,在后期,当花粉成熟时,雌配子体也达到成熟.提供了花蕾的大小与雌、雄蕊发育的相关数据.

  3. Dynamics of Callose Deposition in Cell Walls during Megasporogenesis in the Apomictic Monosomic Addition Line M14 of Beta corolliflora of Sugar Beet%甜菜无融合生殖单体附加系M14大孢子发生期间细胞壁胼胝质的变化

    Institute of Scientific and Technical Information of China (English)

    申业; 申家恒; 郭德栋; 方晓华; 刘丽萍

    2006-01-01

    应用脱色苯胺蓝诱导荧光法观察了甜菜单体附加系M14(Beta vulgaris L.,VV+1C、2n=18+1)正常有性生殖与二倍体孢子生殖时,大孢子发生期间细胞壁内胼胝质的变化.结果表明,韭型(Allium odorum-type)胚囊大孢子发生时,自大孢子母细胞的珠孔端细胞壁内出现胼胝质荧光,并逐渐扩展到整个细胞壁,中期Ⅰ至末期Ⅰ细胞壁呈现胼胝质荧光.二分体时,珠孔端大孢子细胞壁内胼胝质荧光消失,二分体之间的横壁以及合点端功能大孢子的侧壁上荧光明显.二倍体功能大孢子的合点端细胞壁内的胼胝质荧光消失.单核胚囊形成后,其细胞壁内无胼胝质荧光,而退化的大孢子细胞壁胼胝质荧光显著.蝶须型(Antennaria-type)胚囊大孢子发生时,大孢子母细胞、二倍体功能大孢子的细胞壁均无胼胝质荧光.蓼型(Polygonum-type)胚囊大孢子母细胞减数分裂时,其珠孔端细胞壁出现胼胝质荧光,并逐渐扩展到整个细胞壁.二分体、三分体、四分体时期,胼胝质荧光主要存在于大孢子之间的横壁上,侧壁内胼胝质荧光较弱.退化的大孢子细胞壁胼胝质荧光明显,功能大孢子细胞壁上缺少胼胝质荧光.此外,还讨论了大孢子母细胞减数分裂与细胞壁内沉积胼胝质之间的相关性.

  4. Megasporogenesis and Development of Female Gametophyte in the Apomictic Monosomic Addition Line M14 of Beta corolliflora in Sugar Beet%甜菜无融合生殖单体附加系M14雌配子体的发生与发育

    Institute of Scientific and Technical Information of China (English)

    申业; 申家恒; 郭德栋; 方晓华; 刘丽萍

    2006-01-01

    利用常规石蜡制片法,对甜菜单体附加系M14(Beta vulgaris L.VV+1C、 2n=18+1)雌配子体的发生与发育进行了研究,结果表明:二倍体孢子生殖雌配子体为韭型(Allium odorum-type)和蝶须型(Antennaria-type),有性生殖雌配子体为蓼型(Polygonum-type).韭型和蝶须型的大孢子母细胞发育成为二倍体雌配子体,蓼型大孢子母细胞形成单倍体的雌配子体.在二倍体孢子生殖雌配子体发育过程中,出现发育迟缓,胚囊败育等情况,正常发育的雌配子体只有25%.讨论了二倍体孢子生殖雌配子体发生与发育特点.

  5. シロイヌナズナに対する倍数化処理の減数分裂期染色体に及ぼす影響に関する研究

    OpenAIRE

    岩元, 明敏; IWAMOTO, Akitoshi(Department of Biology, Tokyo Gakugei University); 杉山, 宗隆; Sugiyama, Munetaka; 安積, 良隆; Azumi, Yoshitaka

    2008-01-01

    We observed chromosome behavior during meiosis of Arabidopsis thaliana justafter polyploidization. Two strains of A. thaliana, Columbia (Col) and Landsberg erecta(Ler), were treated with colchicine to induce polyploid lines, and the treated generationswere analyzed. Flow cytometric analysis revealed that a tetraploid line was obtained fromthe treated Col and an octoploid line from the treated Ler. Meiotic chromosomes of pollenmother cells of these polyploid lines were visualized by DAPI stain...

  6. Microsporogenesis in Brachiaria bovonei (Chiov. Robyns and B. subulifolia (Mez Clayton (Poaceae Microsporogênese em Brachiaria bovonei (Chiov. Robyns e B. subulifolia (Mez Clayton (Poaceae

    Directory of Open Access Journals (Sweden)

    Claudicéia Risso-Pascotto

    2009-10-01

    Full Text Available Some African species of Brachiaria have been introduced into the Americas and became the most important forage for pastures in the tropics. New cultivars can be obtained either from direct selections from the natural existing variability in the germplasm collections or from interspecific hybridizations. Polyploidy is predominant in the genus Brachiaria and correlated with apomixis which complicates hybridization. The objective of cytological studies underway on the Brachiaria germplasm collection at Embrapa Beef Cattle is to determine the chromosome number and meiotic behavior of accessions. For the breeding of Brachiaria species, compatible sexual and apomictic accessions need to be identified. Microsporogenesis was evaluated in two accessions of Brachiaria bovonei (BO01 and BO05 and one accession of B. subulifolia (SU01. BO01 is pentaploid (2n = 5x = 45, BO05 is tetraploid (2n = 4x = 36, and SU01 is hexaploid (2n = 6x = 54, derived from x = 9. Meiotic abnormalities typical of polyploids, characterized by precocious chromosome migration to the poles in metaphases, laggard chromosomes in anaphases, and micronuclei in telophases and tetrads, were recorded in high frequency in all the accessions generating unbalanced gametes. Both accessions of B. bovonei presented chromosome stickiness. The results are discussed in the view of the Brachiaria breeding program objectives.Algumas espécies africanas de Brachiaria foram introduzidas nas Américas e tornaram-se importantes pastagens nos trópicos. Novas cultivares podem ser obtidas por seleção direta da variabilidade genética existente na coleção de germoplasma ou por hibridização interespecífica. Poliploidia é predominante no gênero Brachiaria e correlacionada com apomixia, o que complica a hibridização. O objetivo dos estudos citogenéticos na coleção de germoplasma de Brachiaria da Embrapa Gado de Corte é determinar o número de cromossomos e o comportamento meiótico dos acessos. A

  7. Evolution of the apomixis transmitting chromosome in Pennisetum

    Directory of Open Access Journals (Sweden)

    Yamada-Akiyama Hitomi

    2011-10-01

    Full Text Available Abstract Background Apomixis is an intriguing trait in plants that results in maternal clones through seed reproduction. Apomixis is an elusive, but potentially revolutionary, trait for plant breeding and hybrid seed production. Recent studies arguing that apomicts are not evolutionary dead ends have generated further interest in the evolution of asexual flowering plants. Results In the present study, we investigate karyotypic variation in a single chromosome responsible for transmitting apomixis, the Apospory-Specific Genomic Region carrier chromosome, in relation to species phylogeny in the genera Pennisetum and Cenchrus. A 1 kb region from the 3' end of the ndhF gene and a 900 bp region from trnL-F were sequenced from 12 apomictic and eight sexual species in the genus Pennisetum and allied genus Cenchrus. An 800 bp region from the Apospory-Specific Genomic Region also was sequenced from the 12 apomicts. Molecular cytological analysis was conducted in sixteen Pennisetum and two Cenchrus species. Our results indicate that the Apospory-Specific Genomic Region is shared by all apomictic species while it is absent from all sexual species or cytotypes. Contrary to our previous observations in Pennisetum squamulatum and Cenchrus ciliaris, retrotransposon sequences of the Opie-2-like family were not closely associated with the Apospory-Specific Genomic Region in all apomictic species, suggesting that they may have been accumulated after the Apospory-Specific Genomic Region originated. Conclusions Given that phylogenetic analysis merged Cenchrus and newly investigated Pennisetum species into a single clade containing a terminal cluster of Cenchrus apomicts, the presumed monophyletic origin of Cenchrus is supported. The Apospory-Specific Genomic Region likely preceded speciation in Cenchrus and its lateral transfer through hybridization and subsequent chromosome repatterning may have contributed to further speciation in the two genera.

  8. Quantification of Allele Dosage in tetraploid Roses

    NARCIS (Netherlands)

    Vukosavljev, M.; Guardo, Di M.; Weg, van de W.E.; Arens, P.; Smulders, M.J.M.

    2012-01-01

    Many important crops (wheat, potato, strawberry, rose, etc.) are polyploid. This complicates genetic analyses, as the same locus can be present on multiple homologous or homoeologous chromosomes. SSR markers are suitable for mapping in segregating populations of polyploids as they are multi-allelic,

  9. Polyploidy can Confer Superiority to West African Acacia senegal (L.) Willd. Trees

    Science.gov (United States)

    Diallo, Adja M.; Nielsen, Lene R.; Kjær, Erik D.; Petersen, Karen K.; Ræbild, Anders

    2016-01-01

    Polyploidy is a common phenomenon in the evolution of angiosperms. It has been suggested that polyploids manage harsh environments better than their diploid relatives but empirical data supporting this hypothesis are scarce, especially for trees. Using microsatellite markers and flow cytometry, we examine the frequency of polyploids and diploids in a progeny trial testing four different populations of Acacia senegal, a species native to sub-Saharan regions of Africa. We compare growth between cytotypes and test whether polyploid seedlings grow better than diploids. Our results show that polyploids coexist with diploids in highly variable proportions among populations in Senegal. Acacia senegal genotypes were predominantly diploid and tetraploid, but triploid, pentaploid, hexaploid, and octaploid forms were also found. We find that polyploids show faster growth than diploids under our test conditions: in an 18 years old field trial, polyploid superiority was estimated to be 17% in trunk diameter and 9% in height while in a growth chamber experiment, polyploids grew 28% taller, but only after being exposed to drought stress. The results suggest that polyploid A. senegal can have an adaptive advantage in some regions of Africa. PMID:27379120

  10. Apomixis is not prevalent in subnival to nival plants of the European Alps

    OpenAIRE

    Hörandl, Elvira; Dobeš , Christoph; Suda, Jan; Vít, Petr; Urfus, Tomáš; Temsch, Eva M.; Cosendai, Anne-Caroline; Wagner, Johanna; Ladinig, Ursula

    2011-01-01

    Background and Aims High alpine environments are characterized by short growing seasons, stochastic climatic conditions and fluctuating pollinator visits. These conditions are rather unfavourable for sexual reproduction of flowering plants. Apomixis, asexual reproduction via seed, provides reproductive assurance without the need of pollinators and potentially accelerates seed development. Therefore, apomixis is expected to provide selective advantages in high-alpine biota. Indeed, apomictic s...

  11. The genetic control of apomixis: asexual seed formation.

    Science.gov (United States)

    Hand, Melanie L; Koltunow, Anna M G

    2014-06-01

    Apomixis (asexual seed formation) is the result of a plant gaining the ability to bypass the most fundamental aspects of sexual reproduction: meiosis and fertilization. Without the need for male fertilization, the resulting seed germinates a plant that develops as a maternal clone. This dramatic shift in reproductive process has been documented in many flowering plant species, although no major seed crops have been shown to be capable of apomixis. The ability to generate maternal clones and therefore rapidly fix desirable genotypes in crop species could accelerate agricultural breeding strategies. The potential of apomixis as a next-generation breeding technology has contributed to increasing interest in the mechanisms controlling apomixis. In this review, we discuss the progress made toward understanding the genetic and molecular control of apomixis. Research is currently focused on two fronts. One aims to identify and characterize genes causing apomixis in apomictic species that have been developed as model species. The other aims to engineer or switch the sexual seed formation pathway in non-apomictic species, to one that mimics apomixis. Here we describe the major apomictic mechanisms and update knowledge concerning the loci that control them, in addition to presenting candidate genes that may be used as tools for switching the sexual pathway to an apomictic mode of reproduction in crops.

  12. Plant Breeding: Surprisingly, Less Sex Is Better.

    Science.gov (United States)

    van Dijk, Peter J; Rigola, Diana; Schauer, Stephen E

    2016-02-01

    Introduction of apomixis, asexual reproduction through seeds, into crop species has the potential to dramatically transform plant breeding. A new study demonstrates that traits can be stably transferred between generations in newly produced apomictic lines, and heralds a breeding revolution needed to increase food production for the growing planet.

  13. Maintenance of genetic variation in automictic root-knot nematodes

    NARCIS (Netherlands)

    Van Der Beek, J. G. ( Hans); Punacker, Laas P.

    2008-01-01

    Differences in amplified fragment length polymorphisms (AFLP) between isolates and between mono-female lines of facultative automictic Meloidogyne hapla race A and obligate apomictic M incognita were determined to test the hypothesis that inverted meiosis occurs. DNA of the parthenogenetic nematode

  14. Capricious, or tied to history’s apron strings? Floristic regions in north-west European brambles (Rubus subgenus Rubus, Rosaceae)

    NARCIS (Netherlands)

    Haveman, R.; Bijlsma, R.J.; Ronde, de I.; Schaminee, J.H.J.

    2016-01-01

    Aim To classify and describe distributional patterns in apomictic Rubus subgenus
    Rubus in north-west Europe and to characterize the major regions by
    statistically derived character species.
    Location North-western Europe, in particular Ireland, the United Kingdom,
    the Netherlands, Den

  15. Genetic tests of ancient asexuality in Root Knot Nematodes reveal recent hybrid origins

    Directory of Open Access Journals (Sweden)

    Lunt David H

    2008-07-01

    Full Text Available Abstract Background The existence of "ancient asexuals", taxa that have persisted for long periods of evolutionary history without sexual recombination, is both controversial and important for our understanding of the evolution and maintenance of sexual reproduction. A lack of sex has consequences not only for the ecology of the asexual organism but also for its genome. Several genetic signatures are predicted from long-term asexual (apomictic reproduction including (i large "allelic" sequence divergence (ii lack of phylogenetic clustering of "alleles" within morphological species and (iii decay and loss of genes specific to meiosis and sexual reproduction. These genetic signatures can be hard to assess since it is difficult to demonstrate the allelic nature of very divergent sequences, divergence levels may be complicated by processes such as inter-specific hybridization, and genes may have secondary roles unrelated to sexual reproduction. Apomictic species of Meloidogyne root knot nematodes have been suggested previously to be ancient asexuals. Their relatives reproduce by meiotic parthenogenesis or facultative sexuality, which in combination with the abundance of nematode genomic sequence data, makes them a powerful system in which to study the consequences of reproductive mode on genomic divergence. Results Here, sequences from nuclear protein-coding genes are used to demonstrate that the first two predictions of ancient asexuality are found within the apomictic root knot nematodes. Alleles are more divergent in the apomictic taxa than in those species exhibiting recombination and do not group phylogenetically according to recognized species. In contrast some nuclear alleles, and mtDNA, are almost identical across species. Sequencing of Major Sperm Protein, a gamete-specific gene, from both meiotic and ameiotic species reveals no increase in evolutionary rate nor change in substitution pattern in the apomictic taxa, indicating that the locus

  16. Apomixis in plant reproduction: a novel perspective on an old dilemma.

    Science.gov (United States)

    Barcaccia, Gianni; Albertini, Emidio

    2013-09-01

    Seed is one of the key factors of crop productivity. Therefore, a comprehension of the mechanisms underlying seed formation in cultivated plants is crucial for the quantitative and qualitative progress of agricultural production. In angiosperms, two pathways of reproduction through seed exist: sexual or amphimictic, and asexual or apomictic; the former is largely exploited by seed companies for breeding new varieties, whereas the latter is receiving continuously increasing attention from both scientific and industrial sectors in basic research projects. If apomixis is engineered into sexual crops in a controlled manner, its impact on agriculture will be broad and profound. In fact, apomixis will allow clonal seed production and thus enable efficient and consistent yields of high-quality seeds, fruits, and vegetables at lower costs. The development of apomixis technology is expected to have a revolutionary impact on agricultural and food production by reducing cost and breeding time, and avoiding the complications that are typical of sexual reproduction (e.g., incompatibility barriers) and vegetative propagation (e.g., viral transfer). However, the development of apomixis technology in agriculture requires a deeper knowledge of the mechanisms that regulate reproductive development in plants. This knowledge is a necessary prerequisite to understanding the genetic control of the apomictic process and its deviations from the sexual process. Our molecular understanding of apomixis will be greatly advanced when genes that are specifically or differentially expressed during embryo and embryo sac formation are discovered. In our review, we report the main findings on this subject by examining two approaches: i) analysis of the apomictic process in natural apomictic species to search for genes controlling apomixis and ii) analysis of gene mutations resembling apomixis or its components in species that normally reproduce sexually. In fact, our opinion is that a novel

  17. Polyploidy in the Arabidopsis genus.

    Science.gov (United States)

    Bomblies, Kirsten; Madlung, Andreas

    2014-06-01

    Whole genome duplication (WGD), which gives rise to polyploids, is a unique type of mutation that duplicates all the genetic material in a genome. WGD provides an evolutionary opportunity by generating abundant genetic "raw material," and has been implicated in diversification, speciation, adaptive radiation, and invasiveness, and has also played an important role in crop breeding. However, WGD at least initially challenges basic biological functions by increasing cell size, altering relationships between cell volume and DNA content, and doubling the number of homologous chromosome copies that must be sorted during cell division. Newly polyploid lineages often have extensive changes in gene regulation, genome structure, and may suffer meiotic or mitotic chromosome mis-segregation. The abundance of species that persist in nature as polyploids shows that these problems are surmountable and/or that advantages of WGD might outweigh drawbacks. The molecularly especially tractable Arabidopsis genus has several ancient polyploidy events in its history and contains several independent more recent polyploids. This genus can thus provide important insights into molecular aspects of polyploid formation, establishment, and genome evolution. The ability to integrate ecological and evolutionary questions with molecular and genetic understanding makes comparative analyses in this genus particularly attractive and holds promise for advancing our general understanding of polyploid biology. Here, we highlight some of the findings from Arabidopsis that have given us insights into the origin and evolution of polyploids. PMID:24788061

  18. Dalsze studia cyto-embriologiczne di-, tetra- i oktoploidaluych form Trifolium [Further cyto-embryological studies on di, tetra- and octoploid forms of Trifolium

    Directory of Open Access Journals (Sweden)

    K. Bijok

    2015-06-01

    Full Text Available In the course of this study no significant differences in the length of pollen-tubes of ecological types collected from natural stations (Trifolium pratense L. var. spontaneum Willk., T. hybridum L. and T. repens L, were found as compared with their polyploid forms obtained in the experimental way. Disorders in fertilization, decay of unfertilized embryo sacs, and degeneration of embroys were observed more frequently on a percentage basis in the polyploid forms. Embryo and endosperm development were similar in the initial species and in the experimentally obtained polyploids.

  19. Single copy nuclear gene analysis of polyploidy in wild potatoes (Solanum section Petota

    Directory of Open Access Journals (Sweden)

    Cai Danying

    2012-05-01

    Full Text Available Abstract Background Recent genomic studies have drastically altered our knowledge of polyploid evolution. Wild potatoes (Solanum section Petota are a highly diverse and economically important group of about 100 species widely distributed throughout the Americas. Thirty-six percent of the species in section Petota are polyploid or with diploid and polyploid cytotypes. However, the group is poorly understood at the genomic level and the series is ideal to study polyploid evolution. Two separate studies using the nuclear orthologs GBSSI and nitrate reductase confirmed prior hypotheses of polyploid origins in potato and have shown new origins not proposed before. These studies have been limited, however, by the use of few accessions per polyploid species and by low taxonomic resolution, providing clade-specific, but not species-specific origins within clades. The purpose of the present study is to use six nuclear orthologs, within 54 accessions of 11 polyploid species, 34 accessions of 29 diploid species of section Petota representing their putative progenitors, and two outgroups, to see if phenomena typical of other polyploid groups occur within wild potatoes, to include multiple origins, loss of alleles, or gain of new alleles. Results Our results increase resolution within clades, giving better ideas of diploid progenitors, and show unexpected complexity of allele sharing within clades. While some species have little diversity among accessions and concur with the GBSSI and nitrate reductase results, such as S. agrimonifolium, S. colombianum, S. hjertingii, and S. moscopanum, the results give much better resolution of species-specific progenitors. Seven other species, however, show variant patterns of allele distributions suggesting multiple origins and allele loss. Complex three-genome origins are supported for S. hougasii, and S. schenckii, and one of the ten accessions of S. stoloniferum. A very unexpected shared presence of alleles occurs

  20. 秋水仙素对草莓离体叶片再生和多倍体诱导的影响%Effects of colchicine on regeneration and polyploid induction from leaf in vitro of strawberry(Fragaria×ananassa)

    Institute of Scientific and Technical Information of China (English)

    张计育; 李国平; 乔玉山; 王萌; 李金凤; 章镇

    2009-01-01

    以草莓(Fragaria×ananassa Duch.)栽培品种'雪蜜'(2n=8X=56)的离体叶片为外植体,研究了不同浓度秋水仙素对愈伤组织诱导率、不定芽再生率以及多倍体植株诱导的影响,并采用流式细胞仪对多倍体植株的倍性进行鉴定.结果显示,用质量体积分数0.1%、0.3%、0.5%和0.7%的秋水仙素浸泡2、4和6 d,草莓离体叶片均能诱导出愈伤组织和不定芽,但随秋水仙素浓度的提高和处理时间的延长,愈伤组织诱导率和不定芽再生率均显著下降.用不同浓度秋水仙素处理均能产生多倍体植株,倍性为9X、10X、11X、12X、14X和16X;随秋水仙素浓度的提高,多倍体诱导率呈现先上升后下降的变化趋势.用质量体积分数0.3%秋水仙素浸泡处理4 d是最佳的草莓离体叶片诱导方法,不定芽再生率达到40.5%,多倍体诱导率为100.0%,并且诱导产生出16X的植株.

  1. Species-genomic relationships among the tribasic diploid and polyploid Carthamus taxa based on physical mapping of active and inactive 18S-5.8S-26S and 5S ribosomal RNA gene families, and the two tandemly repeated DNA sequences.

    Science.gov (United States)

    Agrawal, Renuka; Tsujimoto, Hisashi; Tandon, Rajesh; Rao, Satyawada Rama; Raina, Soom Nath

    2013-05-25

    In the genus Carthamus (2n=20, 22, 24, 44, 64; x=10, 11, 12), most of the homologues within and between the chromosome complements are difficult to be identified. In the present work, we used fluorescent in situ hybridisation (FISH) to determine the chromosome distribution of the two rRNA gene families, and the two isolated repeated DNA sequences in the 14 Carthamus taxa. The distinctive variability in the distribution, number and signal intensity of hybridisation sites for 18S-26S and 5S rDNA loci could generally distinguish the 14 Carthamus taxa. Active 18S-26S rDNA sites were generally associated with NOR loci on the nucleolar chromosomes. The two A genome taxa, C. glaucus ssp. anatolicus and C. boissieri with 2n=20, and the two botanical varieties of B genome C. tinctorius (2n=24) had diagnostic FISH patterns. The present results support the origin of C. tinctorius from C. palaestinus. FISH patterns of C. arborescens vis-à-vis the other taxa indicate a clear division of Carthamus taxa into two distinct lineages. Comparative distribution and intensity pattern of 18S-26S rDNA sites could distinguish each of the tetraploid and hexaploid taxa. The present results indicate that C. boissieri (2n=20) is one of the genome donors for C. lanatus and C. lanatus ssp. lanatus (2n=44), and C. lanatus is one of the progenitors for the hexaploid (2n=64) taxa. The association of pCtKpnI-2 repeated sequence with rRNA gene cluster (orphon) in 2-10 nucleolar and non-nucleolar chromosomes and the consistent occurrence of pCtKpnI-1 repeated sequence at the subtelomeric region in all the taxa analysed indicate some functional role of these sequences.

  2. Induction and identification of polyploids in Cattleya intermedia Lindl. (orchidaceae by in vitro techniques Indução e identificação de poliploides em Cattleya intermedia Lindl. (orchidaceae através de técnicas in vitro

    Directory of Open Access Journals (Sweden)

    Paulo Artur Konzen Xavier de Mello e Silva

    2000-03-01

    Full Text Available The effect of colchicine on the protocorm-like bodies of Cattleya intermedia L. (Orchidaceae cultured in vitro was studied. Different concentrations of the drug (0.00, 0.05, 0.10 and 0.20% as well as two times of culture (4 or 8 days were tested to determine the best treatment for the induction of tetraploid plants. Of the 3 colchicine levels applied, 0.05 and 0.10% of drug treatments appeared to be effective on the production of mixoploids and tetraploids and could be further used in breeding programs. The suitability of stomatal area and stomata density as criteria for the distinction between diploids and tetraploids was also tested. The results suggested that tetraploid plants could be identified with a fair amount of certainty when the screening was based on the density of stomata.No presente trabalho, foi estudado o efeito da colchicina em corpos semelhantes a protocormos de Cattleya intermedia L. (Orchidaceae. Diferentes concentrações da droga (0,00; 0,05; 0,10 e 0,20%, bem como diferentes tempos de cultura (4 ou 8 dias foram testados para determinar o melhor tratamento para a indução de plantas tetraplóides. Dos três níveis de colchicina aplicados, os tratamentos com 0,05 e 0,10% da droga parecem ser mais efetivos na produção de mixoplóides e tetraplóides, sendo que tais tratamentos podem ser utilizados em programas de melhoramento. Como critério para distinção entre diplóides e tetraplóides, foram realizadas medidas de área de estômatos e densidade de estômatos das folhas. Os resultados sugerem que as plantas tetraplóides podem ser identificadas com elevado grau de certeza quando a seleção é realizada com base na densidade de estômatos.

  3. Yeast Interacting Proteins Database: YCL029C, YER016W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available rotubules and kinetochore, involved in sister chromatid separation; essential in polyploid cells but not in ...le-associated protein, component of the interface between microtubules and kinetochore, involved in sister chromatid separation

  4. Allozyme variability in sexual and parthenogenetic freshwater planarians : Evidence for polyphyletic origin of parthenogenetic lineages through hybridization with coexisting sexuals

    NARCIS (Netherlands)

    Pongratz, Norbert; Sharbel, Timothy F.; Beukeboom, Leo W.; Michiels, Nico K.

    1998-01-01

    In Dugesia polychroa, a hermaphroditic planarian, diploid sexual and polyploid pseudogamous parthenogenetic forms exist in separate populations and in sympatry. Parthenogens produce viable, haploid sperm that are exchanged between two individuals during copulation and trigger sperm-dependent parthen

  5. Genetic instability in nerve sheath cell tumors

    DEFF Research Database (Denmark)

    Rogatto, Silvia Regina; Casartelli, Cacilda; Rainho, Claudia Aparecida;

    1995-01-01

    by the presence of polyploid cells with inconsistent abnormalities, endoreduplications and telomeric associations resulting in dicentric chromosomes. It is probable that these cytogenetic abnormalities represent some kind of evolutionary advantage for the in vitro progression of nerve sheath tumors....

  6. Involvement of Disperse Repetitive Sequences in Wheat/Rye Genome Adjustment

    OpenAIRE

    Manuela Silva; Miguel Bento; Diana Tomás; Wanda Viegas

    2012-01-01

    The union of different genomes in the same nucleus frequently results in hybrid genotypes with improved genome plasticity related to both genome remodeling events and changes in gene expression. Most modern cereal crops are polyploid species. Triticale, synthesized by the cross between wheat and rye, constitutes an excellent model to study polyploidization functional implications. We intend to attain a deeper knowledge of dispersed repetitive sequence involvement in parental genome reshuffle ...

  7. Cytogenetics of a parthenogenetic Arctic species of Micropsectra (Diptera, Chironomidae

    Directory of Open Access Journals (Sweden)

    David Porter

    2011-11-01

    Full Text Available Micropsectra sedna (Oliver, 1976 is a parthenogenetic midge from the Canadian Arctic. The parthenogenetic mechanism is apomictic thelytoky, with a restitutional division during oogenesis, as found in other parthenogenetic Chironomidae. It is triploid, with two similar chromosome sets, and the third is relatively dissimilar, pairing little with the diploid set. Two karyotypes were observed: a single individual with eight polytene elements in the salivary glands (3n=12, considered standard, while the majority of larvae showed only seven polytene chromosomes (3n=11. Hybrid speciation is considered likely, although chromosomal recombination following the origin of thelytoky has played some part in karyotype evolution. A single morphologically distinct larva was also found, which might be the donor of the haploid chromosome set. The apomictic restitutional system is compared to that of the other, independently derived, parthenogenetic Chironomids to assess the extent of similarity between species.

  8. Exogenous steroid hormones stimulate full development of autonomous endosperm in Arabidopsis thaliana

    OpenAIRE

    Joanna Rojek; Łukasz Pawełko; Małgorzata Kapusta; Aleksandra Naczk; Jerzy Bohdanowicz

    2015-01-01

    Most flowering plants, including important crops, require double fertilization to form an embryo and endosperm, which nourishes it. Independence from fertilization is a feature of apomictic plants that produce seeds, from which the plants that are clones of the mother plant arise. The phenomenon of apomixis occurs in some sexual plants under specific circumstances. Since the launch of a fertilization-independent mechanism is considered a useful tool for plant breeding, there have been efforts...

  9. Involvement of facultative apomixis in inheritance of EPSPS gene amplification in glyphosate-resistant Amaranthus palmeri.

    Science.gov (United States)

    Ribeiro, Daniela N; Pan, Zhiqiang; Duke, Stephen O; Nandula, Vijay K; Baldwin, Brian S; Shaw, David R; Dayan, Franck E

    2014-01-01

    The inheritance of glyphosate resistance in two Amaranthus palmeri populations (R1 and R2) was examined in reciprocal crosses (RC) and second reciprocal crosses (2RC) between glyphosate-resistant (R) and -susceptible (S) parents of this dioecious species. R populations and Female-R × Male-S crosses contain higher 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene copy numbers than the S population. EPSPS expression, EPSPS enzyme activity, EPSPS protein quantity, and level of resistance to glyphosate correlated positively with genomic EPSPS relative copy number. Transfer of resistance was more influenced by the female than the male parent in spite of the fact that the multiple copies of EPSPS are amplified in the nuclear genome. This led us to hypothesize that this perplexing pattern of inheritance may result from apomictic seed production in A. palmeri. We confirmed that reproductively isolated R and S female plants produced seeds, indicating that A. palmeri can produce seeds both sexually and apomictically (facultative apomixis). This apomictic trait accounts for the low copy number inheritance in the Female-S × Male-R offsprings. Apomixis may also enhance the stability of the glyphosate resistance trait in the R populations in the absence of reproductive partners.

  10. Apomixis Allows the Transgenerational Fixation of Phenotypes in Hybrid Plants.

    Science.gov (United States)

    Sailer, Christian; Schmid, Bernhard; Grossniklaus, Ueli

    2016-02-01

    The introduction of apomixis-asexual reproduction through seeds-into crop plants is considered the holy grail of agriculture, as it would provide a mechanism to maintain agriculturally important phenotypes [1, 2]. Apomicts produce clonal offspring, such that apomixis could be used to transgenerationally fix any genotype, including that of F1 hybrids, which are used in agriculture due to their superior vigor and yield [3-9]. However, traits (phenotypes) do not only result from a complex combination of genetic and environmental variation but can also be influenced by epigenetic variation, which can be transgenerationally heritable in plants [10-15]. Hence, it is far from clear whether genetic fixation by apomixis suffices to fix the agriculturally relevant phenotypes of F1 hybrids, in particular because hybridization was recently shown to induce epigenetic changes [16, 17]. Here, we show that the phenotypes of Hieracium pilosella hybrids can be fixed across generations by apomixis. Using a natural apomict, we created 11 hybrid genotypes (lines). In these and a parental line, we analyzed 20 phenotypic traits that are related to plant growth and reproduction. Of the 20 traits, 18 (90%) were stably inherited over two apomictic generations, grown at the same time in a randomized design, in 11 of the 12 lines. Although one hybrid line showed phenotypic instability, our results provide a fundamental proof of principle, demonstrating that apomixis can indeed be used in plant breeding and seed production to fix complex, quantitative phenotypes across generations.

  11. Tratamento de mandioca pela colchicina: II. formas poliplóides obtidas

    Directory of Open Access Journals (Sweden)

    E. A. Graner

    1942-02-01

    Full Text Available The methods used in obtaining polyploid cassava (Manihot utilissima Pohl by colchicine treatment were described in detail. Two solutions of colchicine were tried, one at 0.5% and other at 1.0%, both giving identical results in producing many altered plants. The chromosome number of the altered plants was determined and [a correlation between chromosome duplication and increase of the major diameter of stomata was found. Size of stomata in cassava serves to identify poliploids individuals if the plant produced by treatment is not a chimera, a very frequent event in producing polyploid cassava by colchicine. It was emphasized that the plants obtained by treatment were a type of chimera, with the aerial part polyploid and the subterranean base diploid. The development of polyploid individuals obtained from the polyploid aerial part of the treated was analyzed. A comparison between the tetraploid and the diploid control plants was made, the octoploid plant being too slow in development. There are many groups of polivalents in the first meiotic metaphase of the autopoly-ploid individuals obtained. By an analysis of the polen grains it was assumed that the diploid plant may be a structural hybrid. The production of the tetraploid plants was computed preliminarly, other detailed experiments involving spacing being necessary for estimating the commercial production,, since the diploid produces more branched plants than the tetraploid ones.

  12. Molecular characterization of vernalization loci VRN1 in wild and cultivated wheats

    Directory of Open Access Journals (Sweden)

    Golovnina Kseniya A

    2010-08-01

    Full Text Available Abstract Background Variability of the VRN1 promoter region of the unique collection of spring polyploid and wild diploid wheat species together with diploid goatgrasses (donor of B and D genomes of polyploid wheats were investigated. Accessions of wild diploid (T. boeoticum, T. urartu and tetraploid (T. araraticum, T. timopheevii species were studied for the first time. Results Sequence analysis indicated great variability in the region from -62 to -221 nucleotide positions of the VRN1 promoter region. Different indels were found within this region in spring wheats. It was shown that VRN1 promoter region of B and G genome can also contain damages such as the insertion of the transposable element. Some transcription factor recognition sites including hybrid C/G-box for TaFDL2 protein known as the VRN1 gene upregulator were predicted inside the variable region. It was shown that deletions leading to promoter damage occurred in diploid and polyploid species independently. DNA transposon insertions first occurred in polyploid species. At the same time, the duplication of the promoter region was observed in A genomes of polyploid species. Conclusions We can conclude that supposed molecular mechanism of the VRN1 gene activating in cultivated diploid wheat species T. monococcum is common also for wild T. boeoticum and was inherited by T. monococcum. The spring polyploids are not related in their origin to spring diploids. The spring T. urartu and goatgrass accessions have another mechanism of flowering activation that is not connected with indels in VRN1 promoter region. All obtained data may be useful for detailed insight into origin of spring wheat forms in evolution and domestication process.

  13. The genus Rubus in South Africa. I. Chromosome numbers and geographical distribution of species

    Directory of Open Access Journals (Sweden)

    J. J. Spies

    1984-12-01

    Full Text Available The geographical distribution of 14 of the Rubus species in South Africa is presented. Chromosome numbers of nine of the species were determined: six for the first time, one is confirmed and additional polyploid levels are described for the other two species. It is demonstrated that the South African species of the subgenus Idaeobatus contain less diploid specimens and more polyploid specimens than their extra-African counterparts. This phenomenon could be attributed to hybridization between the subgenera Eubatus and  Idaeobatus.

  14. Comparative Transmission Genetics of Introgressed Chromatin in Gossypium Species

    Institute of Scientific and Technical Information of China (English)

    WAGHMARE Vijay N; RONG Jun-kang; ROGERS Carl J; BOWERS John E; PATERSON Andrew H

    2008-01-01

    @@ Wild relatives and un-adapted germplasm of crop species harbors several adaptive traits.Introgression of genes for economic and adaptive traits brings in novel genetic variation into the gene pools of many crops including cotton.We compared patterns of introgression into polyploid Gossypium hirsuture from its sister G.tomentosum,and from G.barbadense representing a different clade tracing to the same polyploidization.Advanced-generation populations,resulting from recurrent backcrossing to G.hirsutum,show a paucity of G.tomentosum alleles and severe deficiencies of homozygotes.

  15. 普通小麦7B染色体两类低拷贝专化DNA序列的特性%Characterization of Two Groups of Low-copy and Specific DNA Sequences Isolated from Chromosome 7B of Common Wheat

    Institute of Scientific and Technical Information of China (English)

    刘振兰; 董玉柱; 刘宝

    2002-01-01

    Recent work revealed that, in the genomes of polyploid wheat, there exists a class of low-copy and chromosome-specific sequences that are labile upon polyploid formation. This class of sequences was proposed to play a critical role in the stabilization and establishment of nascent plant polyploids as new species. To further study this issue, five wheat chromosome 7B-specific sequences, isolated from common wheat (Triticum aestivum L.) by chromosome microdissection, were characterized. The sequences were studied by genomic Southern hybridizations on a collection of polyploid wheats and their diploid progenitors. Four sequences hybridized to all polyploid species, but at the diploid level to only species closely related to the B-genome of polyploid wheat. This indicates that these sequences originated with the divergence of the diploid species, and was then vertically transmitted to polyploids. One sequence hybridized to all species at both the diploid and polyploid levels, suggesting its elimination after the polyploid wheat formation. The hybridization of this sequence to two synthetic polyploid wheats indicated that sequence elimination is a rapid event and probably related to methylation status of the sequence. Based on the above results, we suggest that selective changes of low-copy sequences occur rapidly after polyploid formation, which may contribute to the differentiation of chromosomes in newly formed allopolyploid wheats.%研究表明, 多倍体小麦基因组中存在一类低拷贝、染色体专化的DNA序列, 其在多倍体形成时常表现出不稳定性.这类序列被认为在异源多倍体的建立和稳定中起着关键作用.为进一步研究这一问题, 对通过染色体显微切割从普通小麦( Triticum aestivum L.)中分离的5个7B染色体专化DNA序列的特性进行了研究.以这些序列为探针对大量的多倍体小麦和它们的二倍体祖先物种进行了Southern杂交分析.结果表明, 这些序列可

  16. Breeding tropical forages

    Directory of Open Access Journals (Sweden)

    L Jank

    2011-01-01

    Full Text Available Brazil has the largest commercial beef cattle herd and is the main beef exporter in the world. Cultivated pastures arethe basis for the Brazilian beef production, and occupy an area of 101.4 million hectares. However, very few forage cultivars arecommercially available, and the majority of these are of apomictic reproduction, thus genetically homogeneous. Tropical foragebreeding is at its infancy, but much investment and efforts have been applied in the last three decades and some new cultivars havebeen released. In this paper, origin of different species, modes of reproduction, breeding programs and targets are discussed andthe resulting new cultivars released are presented.

  17. Hieracium sinoaestivum (Asteraceae, a new species from North China

    Directory of Open Access Journals (Sweden)

    Alexander Sennikov

    2014-06-01

    Full Text Available Hieracium sinoaestivum Sennikov sp. nov. is described as new to science and illustrated. This presumably apomictic species is solely known from two old collections made in a single locality in the Shanxi Province of China. It belongs to the hybridogenous group H. sect. Aestiva (H. sect. Prenanthoidea × H. sect. Umbellata and is most similar to H. veresczaginii from southern Siberia. The new species occurs at low altitudes in the forest belt of Lülian Mts. and belongs to taiga forest elements.

  18. Bats and bees are pollinating Parkia biglobosa in the Gambia

    DEFF Research Database (Denmark)

    Lassen, Kristin Marie; Ræbild, Anders; Hansen, Henrik;

    2012-01-01

    A pollination experiment was conducted with Parkia biglobosa (Fabaceae) in The Gambia. P. biglobosa is integrated in the farming systems and produces fruit pulp and seeds used in cooking. The species is bat-pollinated, and in areas with few bats the main pollinators are assumed to be honey bees...... in significantly less aborted seeds. The treatment which excluded all flower visitors developed no mature pods, indicating that P. biglobosa was not autonomous autogamous, apomictic, or parthenocarpic, while the treatment with confined honey bees showed that geitonogamy is possible. Sugar content of fruit pulp...... beekeeping in the vicinity of P. biglobosa as a way to increase yield....

  19. Cassava in South America, Brazil's contribution and the lesson to be learned from India.

    Science.gov (United States)

    Nassar, Nagib M A

    2006-11-30

    South America is responsible for about half of the cassava world production. In the 1970's productivity of the crop on the continent was about 15 ton/ha, and dropped continuously until reaching 12 ton/ha in 2004. India's productivity of cassava increased from 10 ton/ha in the 1970's to 28 ton/ha in 2004. Brazil contributed significantly to improving cassava crops through the Instituto Agronômico de Campinas in the 1960's and 1970's. The Universidade de Brasília released high-protein content hybrids, apomictic clones and explored the potential of indigenous landraces.

  20. Biased Gene Fractionation and Dominant Gene Expression among the Subgenomes of Brassica rapa

    NARCIS (Netherlands)

    Cheng, F.; Wu, J.; Fang, L.; Sun, S.; Liu, B.; Lin, K.; Bonnema, A.B.; Wang, Xiaowu

    2012-01-01

    Polyploidization, both ancient and recent, is frequent among plants. A ‘‘two-step theory’’ was proposed to explain the meso-triplication of the Brassica ‘‘A’’ genome: Brassica rapa. By accurately partitioning of this genome, we observed that genes in the less fractioned subgenome (LF) were dominantl

  1. Effect of 17 beta-oestradiol on growth curves and flow cytometric DNA distribution of two human breast carcinomas grown in nude mice

    DEFF Research Database (Denmark)

    Brünner, N; Spang-Thomsen, M; Vindeløv, L;

    1983-01-01

    distribution could be demonstrated following the treatment. The results indicate that the oestradiol-induced cell kill could be explained to some extent by the induction of polyploid cells, which eventually die. Since the cell cycle changes monitored by FCM in the receptor-positive breast carcinoma appeared...

  2. Elucidation of intergenomic recombination and chromosome translocation: meiotic evidence from interspecific hybrids of Lilium through GISH analysis

    NARCIS (Netherlands)

    Xie, S.L.; Ramanna, M.S.; Visser, R.G.F.; Arens, P.; Tuyl, van J.M.

    2013-01-01

    Intergenomic exchange has been found to be a normal phenomenon in sexual polyploids. In order to distinguish whether such exchanges are derived from intergenomic recombination or translocation, 13 genotypes of an interspecific hybrid, which were previously used as parents to generate sexual polyploi

  3. BAC-pool 454-sequencing: A rapid and efficient approach to sequence complex tetraploid cotton genomes

    Science.gov (United States)

    New and emerging next generation sequencing technologies have been promising in reducing sequencing costs, but not significantly for complex polyploid plant genomes such as cotton. Large and highly repetitive genome of G. hirsutum (~2.5GB) is less amenable and cost-intensive with traditional BAC-by...

  4. Balancing selection contributed to domestication of autopolyploid sugarcane (Saccharum officinarum L.)

    Science.gov (United States)

    Sugarcane is a source of plant sugar and a promising biofuel feedstock. The genetic basis of sugar yield and its components remain unresolved despite numerous genetic linkage and association mapping studies because of its complex polyploid genome. Genome-wide scans to identify genes or regions in th...

  5. Genetic diversity in diploid vs. tetraploid Rorippa amphibia (Brassicaceae)

    NARCIS (Netherlands)

    P.C. Luttikhuizen; M. Stift; P. Kuperus; P.H. van Tienderen

    2007-01-01

    The frequency of polyploidy increases with latitude in the Northern Hemisphere, especially in deglaciated, recently colonized areas. The cause or causes of this pattern are largely unknown, but a greater genetic diversity of individual polyploid plants due to a doubled genome and/or a hybrid origin

  6. Development and integration of an SSR-based molecular identity database into sugarcane breeding program

    Science.gov (United States)

    Sugarcane breeding is very difficult and it takes 12 to 14 years to develop a new cultivar for commercial production. This is because sugarcane varieties are highly polyploid, inter-specific hybrids with 100 to 130 chromosomes that may vary across geographical areas. Other obstacles/constraints incl...

  7. Expression profiling reveals functionally redundant multiple-copy genes related to zinc, iron and cadmium responses in Brassica rapa

    NARCIS (Netherlands)

    Li, J.; Liu, B.; Cheng, F.; Wang, X.; Aarts, M.G.M.; Wu, J.

    2014-01-01

    Genes underlying environmental adaptability tend to be over-retained in polyploid plant species. Zinc deficiency (ZnD) and iron deficiency (FeD), excess Zn (ZnE) and cadmium exposure (CdE) are major environmental problems for crop cultivation, but little is known about the differential expression of

  8. On the road to diploidization? Homoeolog loss in independently formed populations of the allopolyploid Tragopogon miscellus (Asteraceae

    Directory of Open Access Journals (Sweden)

    Soltis Pamela S

    2009-06-01

    Full Text Available Abstract Background Polyploidy (whole-genome duplication is an important speciation mechanism, particularly in plants. Gene loss, silencing, and the formation of novel gene complexes are some of the consequences that the new polyploid genome may experience. Despite the recurrent nature of polyploidy, little is known about the genomic outcome of independent polyploidization events. Here, we analyze the fate of genes duplicated by polyploidy (homoeologs in multiple individuals from ten natural populations of Tragopogon miscellus (Asteraceae, all of which formed independently from T. dubius and T. pratensis less than 80 years ago. Results Of the 13 loci analyzed in 84 T. miscellus individuals, 11 showed loss of at least one parental homoeolog in the young allopolyploids. Two loci were retained in duplicate for all polyploid individuals included in this study. Nearly half (48% of the individuals examined lost a homoeolog of at least one locus, with several individuals showing loss at more than one locus. Patterns of loss were stochastic among individuals from the independently formed populations, except that the T. dubius copy was lost twice as often as T. pratensis. Conclusion This study represents the most extensive survey of the fate of genes duplicated by allopolyploidy in individuals from natural populations. Our results indicate that the road to genome downsizing and ultimate genetic diploidization may occur quickly through homoeolog loss, but with some genes consistently maintained as duplicates. Other genes consistently show evidence of homoeolog loss, suggesting repetitive aspects to polyploid genome evolution.

  9. Plants with double genomes might have had a better chance to survive the Cretaceous-Tertiary extinction event.

    Science.gov (United States)

    Fawcett, Jeffrey A; Maere, Steven; Van de Peer, Yves

    2009-04-01

    Most flowering plants have been shown to be ancient polyploids that have undergone one or more whole genome duplications early in their evolution. Furthermore, many different plant lineages seem to have experienced an additional, more recent genome duplication. Starting from paralogous genes lying in duplicated segments or identified in large expressed sequence tag collections, we dated these youngest duplication events through penalized likelihood phylogenetic tree inference. We show that a majority of these independent genome duplications are clustered in time and seem to coincide with the Cretaceous-Tertiary (KT) boundary. The KT extinction event is the most recent mass extinction caused by one or more catastrophic events such as a massive asteroid impact and/or increased volcanic activity. These events are believed to have generated global wildfires and dust clouds that cut off sunlight during long periods of time resulting in the extinction of approximately 60% of plant species, as well as a majority of animals, including dinosaurs. Recent studies suggest that polyploid species can have a higher adaptability and increased tolerance to different environmental conditions. We propose that polyploidization may have contributed to the survival and propagation of several plant lineages during or following the KT extinction event. Due to advantages such as altered gene expression leading to hybrid vigor and an increased set of genes and alleles available for selection, polyploid plants might have been better able to adapt to the drastically changed environment 65 million years ago. PMID:19325131

  10. Meiotic analysis and FISH with rDNA and rice BAC probes of the Thai KPS 01-01-25 sugarcane cultivar

    NARCIS (Netherlands)

    Thumjamras, Sarut; Iamtham, Siriluck; Prammanee, Siripatr; Jong, de Hans

    2016-01-01

    The interspecific sugarcane hybrid “KPS 01-01-25” is one of Thailand’s most successful cultivars, but its genetics and genomic constitution are greatly complicated due to the highly polyploid nature of this crop. Here we analyzed the crop’s karyotype, studied chromosome pairing at meiosis I and p

  11. CRISPR–Cas system enables fast and simple genome editing of industrial Saccharomyces cerevisiae strains

    DEFF Research Database (Denmark)

    Stovicek, Vratislav; Borodina, Irina; Förster, Jochen

    2015-01-01

    , their genetic manipulation is challenging, as they are usually diploid or polyploid. Therefore, there is a need to develop more efficient genetic engineering tools. We applied a CRISPR–Cas9 system for genome editing of different industrial strains, and show simultaneous disruption of two alleles of a gene...

  12. Allelic divergence and cultivar-specific SSR alleles revealed by capillary electrophoresis using fluorescence-labeled SSR markers in sugarcane

    Science.gov (United States)

    Though sugarcane cultivars (Saccharum spp. hybrids) are complex aneu-polyploid hybrids, genetic evaluation and tracking of clone- or cultivar-specific alleles become possible due to capillary electrophoregrams (CE) using fluorescence-labeled SSR primer pairs. Twenty-four sugarcane cultivars, 12 each...

  13. Analysis of Duplicate Genes in Soybean

    Institute of Scientific and Technical Information of China (English)

    C.M. Cai; K.J. Van; M.Y. Kim; S.H. Lee

    2007-01-01

    @@ Gene duplication is a major determinant of the size and gene complement of eukaryotic genomes (Lockton and Gaut, 2005). There are a number of different ways in which duplicate genes can arise (Sankoff, 2001), but the most spectacular method of gene duplication may be whole genome duplication via polyploidization.

  14. The Significance of Polyploidy for Bulbous Ornamentals: A Molecular Cytogenetic Assessment

    NARCIS (Netherlands)

    Ramanna, M.S.; Marasek Ciolakowska, A.R.; Xie, S.L.; Khan, N.; Arens, P.; Tuyl, van J.M.

    2012-01-01

    Most of the bulbous crops, viz., Crocus, Narcissus, Tulipa, Alstroemeria and Lilium that are commercially important, share certain common characteristics. The present day cultivars are all derived from hybrids between distantly related species, and in almost all cases spontaneous polyploidization ha

  15. Combined array-comparative genomic hybridization and single-nucleotide polymorphism-loss of heterozygosity analysis reveals complex changes and multiple forms of chromosomal instability in colorectal cancers

    DEFF Research Database (Denmark)

    Gaasenbeek, Michelle; Howarth, Kimberley; Rowan, Andrew J;

    2006-01-01

    Cancers with chromosomal instability (CIN) are held to be aneuploid/polyploid with multiple large-scale gains/deletions, but the processes underlying CIN are unclear and different types of CIN might exist. We investigated colorectal cancer cell lines using array-comparative genomic hybridization ...

  16. Colchicine-and Oryzalin-Induced Polyploidy in Hedychium muluense R.M. Smith

    Science.gov (United States)

    The genus Hedychium, which belongs to the Gingiberaceae family, consists of about 80 species with increasing popularity as ornamentals. H. muluense is an epiphytic tropical that bears small but pretty flowers. Induced polyploidization in plants can be used for different purposes, including increasin...

  17. Chromosome studies on African plants. 11. The tribe Andropogoneae (Poaceae: Panicoideae

    Directory of Open Access Journals (Sweden)

    J. J. Spies

    1994-12-01

    Full Text Available Representative specimens of various species of the genera  Andropogon L.,  Cymbopogon Spreng.,  Elionurus Kunth ex Willd.,  Hyparrhenia Foum. and  Hyperthelia Clayton were cytogenetically studied. All specimens had a secondary basic chromosome number of ten. Polyploidy, either as alloploidy or segmental alloploidy. was frequent. The taxa studied represent mature polyploid complexes.  

  18. Developing improved durum wheat germplasm by altering the cytoplasmic genome

    Science.gov (United States)

    In eukaryotic organisms, nuclear and cytoplasmic genomes interact to drive cellular functions. These genomes have co-evolved to form specific nuclear-cytoplasmic interactions that are essential to the origin, success, and evolution of diploid and polyploid species. Hundreds of genetic diseases in h...

  19. Evolutionary origins and dynamics of octoploid strawberry subgenomes revealed by dense targeted capture linkage maps.

    Science.gov (United States)

    Tennessen, Jacob A; Govindarajulu, Rajanikanth; Ashman, Tia-Lynn; Liston, Aaron

    2014-12-04

    Whole-genome duplications are radical evolutionary events that have driven speciation and adaptation in many taxa. Higher-order polyploids have complex histories often including interspecific hybridization and dynamic genomic changes. This chromosomal reshuffling is poorly understood for most polyploid species, despite their evolutionary and agricultural importance, due to the challenge of distinguishing homologous sequences from each other. Here, we use dense linkage maps generated with targeted sequence capture to improve the diploid strawberry (Fragaria vesca) reference genome and to disentangle the subgenomes of the wild octoploid progenitors of cultivated strawberry, Fragaria virginiana and Fragaria chiloensis. Our novel approach, POLiMAPS (Phylogenetics Of Linkage-Map-Anchored Polyploid Subgenomes), leverages sequence reads to associate informative interhomeolog phylogenetic markers with linkage groups and reference genome positions. In contrast to a widely accepted model, we find that one of the four subgenomes originates with the diploid cytoplasm donor F. vesca, one with the diploid Fragaria iinumae, and two with an unknown ancestor close to F. iinumae. Extensive unidirectional introgression has converted F. iinumae-like subgenomes to be more F. vesca-like, but never the reverse, due either to homoploid hybridization in the F. iinumae-like diploid ancestors or else strong selection spreading F. vesca-like sequence among subgenomes through homeologous exchange. In addition, divergence between homeologous chromosomes has been substantially augmented by interchromosomal rearrangements. Our phylogenetic approach reveals novel aspects of the complicated web of genetic exchanges that occur during polyploid evolution and suggests a path forward for unraveling other agriculturally and ecologically important polyploid genomes.

  20. Bringing together evolution on serpentine and polyploidy: spatiotemporal history of the diploid-tetraploid complex of Knautia arvensis (Dipsacaceae.

    Directory of Open Access Journals (Sweden)

    Filip Kolář

    Full Text Available Polyploidization is one of the leading forces in the evolution of land plants, providing opportunities for instant speciation and rapid gain of evolutionary novelties. Highly selective conditions of serpentine environments act as an important evolutionary trigger that can be involved in various speciation processes. Whereas the significance of both edaphic speciation on serpentine and polyploidy is widely acknowledged in plant evolution, the links between polyploid evolution and serpentine differentiation have not yet been examined. To fill this gap, we investigated the evolutionary history of the perennial herb Knautia arvensis (Dipsacaceae, a diploid-tetraploid complex that exhibits an intriguing pattern of eco-geographic differentiation. Using plastid DNA sequencing and AFLP genotyping of 336 previously cytotyped individuals from 40 populations from central Europe, we unravelled the patterns of genetic variation among the cytotypes and the edaphic types. Diploids showed the highest levels of genetic differentiation, likely as a result of long term persistence of several lineages in ecologically distinct refugia and/or independent immigration. Recurrent polyploidization, recorded in one serpentine island, seems to have opened new possibilities for the local serpentine genotype. Unlike diploids, the serpentine tetraploids were able to escape from the serpentine refugium and spread further; this was also attributable to hybridization with the neighbouring non-serpentine tetraploid lineages. The spatiotemporal history of K. arvensis allows tracing the interplay of polyploid evolution and ecological divergence on serpentine, resulting in a complex evolutionary pattern. Isolated serpentine outcrops can act as evolutionary capacitors, preserving distinct karyological and genetic diversity. The serpentine lineages, however, may not represent evolutionary 'dead-ends' but rather dynamic systems with a potential to further influence the surrounding

  1. Rare diploid females coexist with rare males: a novel finding in triploid parthenogenetic populations in the psyllid Cacopsylla myrtilli (W. Wagner, 1947) (Hemiptera, Psylloidea) in northern Europe.

    Science.gov (United States)

    Nokkala, C; Kuznetsova, V G; Nokkala, S

    2015-10-01

    Using a cytological approach, diploid females were found coexisting with rare males in triploid apomictic parthenogenetic populations of the psyllid Cacopsylla myrtilli (W. Wagner, 1947) in Norway, Sweden, Finland and northwest Russia. Diploid females were easily distinguished from triploid apomictic females by the presence of 13 chiasmate bivalents instead of 39 univalent chromosomes at metaphase I. Abundance equaled that of males, but the proportion of males and diploid females was significantly greater in high altitude compared with low altitude populations. Males mated with females but showed no mating preference for diploid females. Lack of genuine bisexual reproduction owing to either asynaptic meiosis in males, or rarity of males with normal meiosis, suggests that diploids are produced in every generation by parthenogenetic females as reversals from triploidy, with their production being enhanced by environmental factor(s) associated with high altitude. This is further supported by the observation that within a population the COI haplotype found in rare males was the same as that in parthenogenetic triploid females. Thus, in northern Europe parthenogenesis in C. myrtilli is obligate, geographic parthenogenesis. Bisexual populations of C. myrtilli should be looked for in Central and Southern Europe. From the evolutionary point of view, the presence of males and diploid females with normal meiosis in parthenogenetic populations could be significant as they exhibit the potential to re-evolve either a new sexual species of parthenogenetic ancestry or a new parthenogenetic species by contagious parthenogenesis.

  2. Variation in chromosome number in the seedling progeny of a somaclone of Paspalum dilatatum

    Institute of Scientific and Technical Information of China (English)

    ZHUJM; LJDAVIES; 等

    1994-01-01

    The somaclone,C39,derived by tissue culture from the obligate apomict Paspalum dilatatum cv Raki(2n=50),had 50 chromosomes and a karyotype apparently identical to Raki.SC2 seedlings of C39 showed a high degree of phenotypic variation which was often associated with increased chromosome numbers,but some of the variant seedlings were karyotypically indistinguishable from Raki or C39.Plants with increased chromosome numbers exhibited a high degree of intraplant chromosome variation(aneusomaty).In one of the SC2 seedlings,the chromosome number of root tip cells varied from 58 to 82 and in several other seedlings the range was more than 10.The results suggested that the ability to form seed apomictically was much reduced in C39 and that this plant showed some capacity for sexual reproduction and the resulting seedlings,with a chromosome number of about 70,were genetically unstable.Of 11 SC2 seedlings examined cytologically,6 did not produce any viable seed.Seedlings grown from seed of the remaining 5 plants showed that aneusomaty persisted in the SC3 generation.SC3 seedlings which were phenotypically similar to their maternal parent showed a similar range of chromosome numbers to that parent.Some of the SC3 seedlings exhibited an even wider range of chromosome numbers(e.g.56-136),and these plants were all dwarfs.

  3. Panax ginseng natural populations: their past, current state and perspec-tives

    Institute of Scientific and Technical Information of China (English)

    Yuri N ZHURAVLEV; Olga G KOREN; Galina D REUNOVA; Tamara I MUZAROK; Tatiyana Yu GORPENCHENKO; Irina L KATS; Yuliya A KHROLENKO

    2008-01-01

    Aim:The mating system of Panax ginseng, genetics and ontogenetic structure of its natural populations of Primorye (Russia) were investigated. Methods: Genetic diversity was assessed using allozyme and the fluorescently based au-tomated amplified fragment length polymorphism (AFLP) and simple sequence repeats (SSR) markers. Results: Total genetic diversity at species level is low with allozyme assay (0.023), and high with AFLP (0.255) and SSR (0.259) meth-ods. It is observed within populations according to allozyme (>99%), AFLP (>85%), and SSR (>73%) assays. The indices of genetic variability distribution point out the re-colonization of the Sikhote-Alin by ginseng plants from southern refuges during the warming period in the early Holocene. The capability of gin-seng plants to cross- and self-pollinate was shown and the assumption that Panax ginseng is a facultative apomictic plant was confirmed. The reproductive system of ginseng possesses high plasticity and stability of the fertilization process that help the species to survive in stress conditions. Disturbances caused by external or internal factors can be reduced due to the morphogenetic potential of ginseng ovule or apomictic embryo development. Analysis of life stages structure of gin-seng populations demonstrates that all of them are not full-constituents because some life stages are absent or occur rarely. Conclusion: In all 3 populations, virgin and young generative individuals are predominant. This means that popu-lations studied are viable and the reintroduction of natural ginseng population is possible yet.

  4. Análisis de la producción y frecuencia de microsporas no reducidas en diploides de Turnera sidoides (Turneraceae Analysis of the production and frequency of unreduced microspores in diploids of Turnera sidoides (Turneraceae

    Directory of Open Access Journals (Sweden)

    Andrea F. Panseri

    2008-07-01

    Full Text Available Turnera sidoides es un complejo poliploide (x= 7 de hierbas rizomatosas, perennes y distilas, que incluye cinco subespecies. Debido a la alta frecuencia de poliploides en el complejo, los estudios que se llevan a cabo actualmente están orientados a la comprensión de los mecanismos involucrados en el origen y establecimiento de los mismos a fin de proveer evidencias sobre los patrones evolutivos que operan en T. sidoides. En este trabajo se investiga la producción y frecuencia de microsporas no reducidas en plantas diploides provenientes de nueve poblaciones naturales pertenecientes a cuatro subespecies de T. sidoides, mediante el análisis del rango de variación del tamaño del polen y de la constitución de las esporadas. Los resultados obtenidos mostraron que casi todas las poblaciones estudiadas producen microsporas 2x y 4x, tanto en las flores brevistilas como en las longistilas. Asimismo, el análisis realizado aportó evidencias que sustentan la poliploidización sexual como uno de los mecanismos involucrados en el origen de los poliploides dentro del complejo. Se discute, además, el papel del polen no reducido en el establecimiento y la persistencia de los poliploides formados de novo en las poblaciones diploides de la especie.Turnera sidoides is a polyploid complex (x= 7 of dystilous perennial rhizomatous herbs that includes five subspecies. Owing to the high frequency of polyploids within the complex, ongoing studies in T. sidoides are focused on the understanding of the mechanisms involved in the origin and the establishment of polyploids in order to provide evidences of the evolutionary patterns in T. sidoides. In this report we investigate the occurrence and frequency of unreduced microspores in diploid plants from nine natural populations of four subspecies of T. sidoides by analyzing the range of variation of pollen volume and the constitution of the sporads. The results obtained showed that almost all the populations studied

  5. Conservation of the microstructure of genome segments in Brassica napus and its diploid relatives.

    Science.gov (United States)

    Rana, Debashis; van den Boogaart, Tom; O'Neill, Carmel M; Hynes, Llewelyn; Bent, Elisabeth; Macpherson, Lee; Park, Jee Young; Lim, Yong Pyo; Bancroft, Ian

    2004-12-01

    The cultivated Brassica species are the group of crops most closely related to Arabidopsis thaliana (Arabidopsis). They represent models for the application in crops of genomic information gained in Arabidopsis and provide an opportunity for the investigation of polyploid genome formation and evolution. The scientific literature contains contradictory evidence for the dynamics of the evolution of polyploid genomes. We aimed at overcoming the inherent complexity of Brassica genomes and clarify the effects of polyploidy on the evolution of genome microstructure in specific segments of the genome. To do this, we have constructed bacterial artificial chromosome (BAC) libraries from genomic DNA of B. rapa subspecies trilocularis (JBr) and B. napus var Tapidor (JBnB) to supplement an existing BAC library from B. oleracea. These allowed us to analyse both recent polyploidization (under 10,000 years in B. napus) and more ancient polyploidization events (ca. 20 Myr for B. rapa and B. oleracea relative to Arabidopsis), with an analysis of the events occurring on an intermediate time scale (over the ca. 4 Myr since the divergence of the B. rapa and B. oleracea lineages). Using the Arabidopsis genome sequence and clones from the JBr library, we have analysed aspects of gene conservation and microsynteny between six regions of the genome of B. rapa with the homoeologous regions of the genomes of B. oleracea and Arabidopsis. Extensive divergence of gene content was observed between the B. rapa paralogous segments and their homoeologous segments within the genome of Arabidopsis. A pattern of interspersed gene loss was identified that is similar, but not identical, to that observed in B. oleracea. The conserved genes show highly conserved collinearity with their orthologues across genomes, but a small number of species-specific rearrangements were identified. Thus the evolution of genome microstructure is an ongoing process. Brassica napus is a recently formed polyploid resulting

  6. Study on Floral and Pollen Characters of Tetraploid Rice

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-xin; CHEN Jian-guo; CHEN Dong-ling; SONG Zhao-jian; DAI Bing-cheng; CAI De-tian

    2009-01-01

    Polyploidization is the evolution trend of many crops, and the yield increased obviously after polyploidization. The polyploidization of rice often brings "gigas" of both vegetative organs and seeds. Howevere, in rice breeding, it is required for restoring lines to have not only big anthers but also abundant pollens. People often doubt that the enlargement of the floral organ may just be enlargement of cell size in polyploid rice. So, it is of significance to study characteristics of floral organs and pollens of several tetraploid rice varieties or lines. Floral organ and pollen characteristics of Sg99012 and HN2026 were studied comparatively by stages and different ploidy levels, with the materials 9311, HD9802S, and PA64S as the control. The results showed that chromosome doubling had much more influence on floral characteristics of every lines than seeding by stages, and the tetraploids of every lines displayed "gigas". In correlation analysis, spikelet length, spikelet width, and anther length had significant correlation; spikelet width and anther width had significant correlation, too. Both seeding by stages and chromosome doubling made the correlations of characters between every floral organ changed to some extent. Seeding by stages had little effect on pollen diameter and fertility of HN2026-4X and Sg99012-4X. But chromosome doubling increased pollen size of every lines remarkably, and also increased the pollen quantity of PMeS (polyploid meiosis stability) restoring line HN2026-4X and gene map restoring line 9311-4X remarkably, whereas only had little effect on that of sterile lines. Moreover, chromosome doubling changed pollen fertility and made the number of fertility pollen of 9311 reduced significantly, but the pollen fertility of HN2026 (PMeS restoring line) and PA64S (sterile line) almost had no change after chromosome doubling. The results showed that tetraploid restoring lines had advantage of abundant and big size pollens, and tetraploid sterile

  7. Nucleotide diversity maps reveal variation in diversity among wheat genomes and chromosomes

    Directory of Open Access Journals (Sweden)

    McGuire Patrick E

    2010-12-01

    Full Text Available Abstract Background A genome-wide assessment of nucleotide diversity in a polyploid species must minimize the inclusion of homoeologous sequences into diversity estimates and reliably allocate individual haplotypes into their respective genomes. The same requirements complicate the development and deployment of single nucleotide polymorphism (SNP markers in polyploid species. We report here a strategy that satisfies these requirements and deploy it in the sequencing of genes in cultivated hexaploid wheat (Triticum aestivum, genomes AABBDD and wild tetraploid wheat (Triticum turgidum ssp. dicoccoides, genomes AABB from the putative site of wheat domestication in Turkey. Data are used to assess the distribution of diversity among and within wheat genomes and to develop a panel of SNP markers for polyploid wheat. Results Nucleotide diversity was estimated in 2114 wheat genes and was similar between the A and B genomes and reduced in the D genome. Within a genome, diversity was diminished on some chromosomes. Low diversity was always accompanied by an excess of rare alleles. A total of 5,471 SNPs was discovered in 1791 wheat genes. Totals of 1,271, 1,218, and 2,203 SNPs were discovered in 488, 463, and 641 genes of wheat putative diploid ancestors, T. urartu, Aegilops speltoides, and Ae. tauschii, respectively. A public database containing genome-specific primers, SNPs, and other information was constructed. A total of 987 genes with nucleotide diversity estimated in one or more of the wheat genomes was placed on an Ae. tauschii genetic map, and the map was superimposed on wheat deletion-bin maps. The agreement between the maps was assessed. Conclusions In a young polyploid, exemplified by T. aestivum, ancestral species are the primary source of genetic diversity. Low effective recombination due to self-pollination and a genetic mechanism precluding homoeologous chromosome pairing during polyploid meiosis can lead to the loss of diversity from large

  8. Polyploidy in aspen alters plant physiology and drought sensitivity

    Science.gov (United States)

    Greer, B.; Still, C. J.; Brooks, J. R.; Meinzer, F. C.

    2015-12-01

    Polyploids of quaking aspen (Populus tremuloides) may be better suited to dry climatic conditions than diploids. However, the expression of diploid and polyploid functional traits, including water use efficiency, an important component of drought avoidance and tolerance, are not well understood in quaking aspen. In this study diploid and triploid aspen clones' leaf, ramet, and stand functional traits were measured near the Rocky Mountain Biological Laboratory in Gothic, Colorado. The physiology of diploid and triploid aspen, including leaf size, chlorophyll content, stomatal size and density and stomatal conductance, as well as growth rates and carbon isotope discrimination in response to climate (measured in tree rings), were found to be significantly different between ploidy levels. These findings demonstrate different sensitivities of diploid and triploid clones to drought related climate stressors which may impact strategies for aspen forest management and conservation.

  9. Karyomegalic interstitial nephritis and DNA damage-induced polyploidy in Fan1 nuclease-defective knock-in mice.

    Science.gov (United States)

    Lachaud, Christophe; Slean, Meghan; Marchesi, Francesco; Lock, Claire; Odell, Edward; Castor, Dennis; Toth, Rachel; Rouse, John

    2016-03-15

    The Fan1 endonuclease is required for repair of DNA interstrand cross-links (ICLs). Mutations in human Fan1 cause karyomegalic interstitial nephritis (KIN), but it is unclear whether defective ICL repair is responsible or whether Fan1 nuclease activity is relevant. We show that Fan1 nuclease-defective (Fan1(nd/nd)) mice develop a mild form of KIN. The karyomegalic nuclei from Fan1(nd/nd) kidneys are polyploid, and fibroblasts from Fan1(nd/nd) mice become polyploid upon ICL induction, suggesting that defective ICL repair causes karyomegaly. Thus, Fan1 nuclease activity promotes ICL repair in a manner that controls ploidy, a role that we show is not shared by the Fanconi anemia pathway or the Slx4-Slx1 nuclease also involved in ICL repair.

  10. Homoeologs: What Are They and How Do We Infer Them?

    Science.gov (United States)

    Glover, Natasha M; Redestig, Henning; Dessimoz, Christophe

    2016-07-01

    The evolutionary history of nearly all flowering plants includes a polyploidization event. Homologous genes resulting from allopolyploidy are commonly referred to as 'homoeologs', although this term has not always been used precisely or consistently in the literature. With several allopolyploid genome sequencing projects under way, there is a pressing need for computational methods for homoeology inference. Here we review the definition of homoeology in historical and modern contexts and propose a precise and testable definition highlighting the connection between homoeologs and orthologs. In the second part, we survey experimental and computational methods of homoeolog inference, considering the strengths and limitations of each approach. Establishing a precise and evolutionarily meaningful definition of homoeology is essential for understanding the evolutionary consequences of polyploidization.

  11. Male sterility in plants. Induction, isolation and utilization

    International Nuclear Information System (INIS)

    Both induced and spontaneously arising male sterility mutants exist in a number of important plant species. These mutants are somewhat unique in that they effect procedures for breeding improved varieties. They allow for the possibility of easily obtaining large numbers of hybrids, population breeding systems and the production of hybrid varieties. These mutants are normally classified as cytoplasmic mutants or chromosomal mutants, the latter also being referred to as nuclear or genic mutants. Specific examples of these types of sterility are examined in relation to the breeding system of the species and their potential use for varietal development. Male sterility in diploid and polyploid species is compared, with reference to gene duplication in polyploids. The mechanism of male sterility is examined in the various species at the anatomical and biochemical levels. Methods of isolating male sterility mutants are compared and a specific example is outlined for hexaploid wheat. Future use of male sterility mutants for improving varieties of various crops is examined. (author)

  12. Polyploidy Induction of Pteroceltis tatarinowii Maxim

    Institute of Scientific and Technical Information of China (English)

    Lin ZHANG; Feng WANG; Zhongkui SUN; Cuicui ZHU; Rongwei CHEN

    2015-01-01

    3%Objective] This study was conducted to obtain tetraploid Pteroceltis tatari-nowi Maxim. with excel ent ornamental traits. [Method] The stem apex growing points of Pteroceltis tatarinowi Maxim. were treated with different concentrations of colchicine solution for different hours to figure out a proper method and obtain poly-ploids. [Result] The most effective induction was obtained by treatment with 0.6%-0.8% colchicine for 72 h with 34.2% mutation rate. Flow cytometry and chromosome observation of the stem apex growing point of P. tatarinowi Maxim. proved that the tetraploid plants were successful y obtained with chromosome number 2n=4x=36. [Conclusion] The result not only fil s the blank of polyploid breeding of P. tatarinowi , but also provides an effective way to broaden the methods of cultivation of fast-growing, high-quality, disease-resilience, new varieties of Pteroceltis.

  13. Genome size variation in the genus Avena.

    Science.gov (United States)

    Yan, Honghai; Martin, Sara L; Bekele, Wubishet A; Latta, Robert G; Diederichsen, Axel; Peng, Yuanying; Tinker, Nicholas A

    2016-03-01

    Genome size is an indicator of evolutionary distance and a metric for genome characterization. Here, we report accurate estimates of genome size in 99 accessions from 26 species of Avena. We demonstrate that the average genome size of C genome diploid species (2C = 10.26 pg) is 15% larger than that of A genome species (2C = 8.95 pg), and that this difference likely accounts for a progression of size among tetraploid species, where AB genome configuration had similar genome sizes (average 2C = 25.74 pg). Genome size was mostly consistent within species and in general agreement with current information about evolutionary distance among species. Results also suggest that most of the polyploid species in Avena have experienced genome downsizing in relation to their diploid progenitors. Genome size measurements could provide additional quality control for species identification in germplasm collections, especially in cases where diploid and polyploid species have similar morphology.

  14. Genetically based location from triploid populations and gene ontology of a 3.3-mb genome region linked to alternaria brown spot resistance in citrus reveal clusters of resistance genes

    OpenAIRE

    José Cuenca; Pablo Aleza; Antonio Vicent; Dominique Brunel; Patrick Ollitrault; Luis Navarro

    2013-01-01

    Genetic analysis of phenotypical traits and marker-trait association in polyploid species is generally considered as a challenge. In the present work, different approaches were combined taking advantage of the particular genetic structures of 2n gametes resulting from second division restitution (SDR) to map a genome region linked to Alternaria brown spot (ABS) resistance in triploid citrus progeny. ABS in citrus is a serious disease caused by the tangerine pathotype of the fungus Alternaria ...

  15. Genome evolution in alpine oat-like grasses through homoploid hybridization and polyploidy

    Science.gov (United States)

    Winterfeld, Grit; Wölk, Alexandra; Röser, Martin

    2016-01-01

    Hybridization and polyploidization can radically impact genome organization from sequence level to chromosome structure. As a result, often in response to environmental change and species isolation, the development of novel traits can arise and will tend to result in the formation of homoploid or polyploid hybrid species. In this study we focus on evidence of hybridization and polyploidization by ascertaining the species parentage of the endemic alpine Helictotrichon parlatorei group. This group comprises five taxa; the diploids H. parlatorei, Helictotrichon setaceum subsp. setaceum and subsp. petzense, their putative hybrid Helictotrichon ×krischae and the hexaploid Helictotrichon sempervirens. For molecular analyses, cloned nuclear Topoisomerase VI genes of H. sempervirens and H. ×krischae were sequenced and compared with sequences of the diploids to estimate the evolutionary history in this group. In addition, detailed chromosome studies were carried out including fluorescence in situ hybridization (FISH) with 5S and 45S ribosomal and satellite DNA probes, and fluorochrome staining with chromomycin and DAPI. Two distinct types of Topoisomerase VI sequences were identified. One of them (SET) occurs in both subspecies of H. setaceum, the other (PAR) in H. parlatorei. Both types were found in H. ×krischae and H. sempervirens. Karyotypes of H. parlatorei and H. setaceum could be distinguished by chromosomes with a clearly differentiated banding pattern of ribosomal DNAs. Both patterns occurred in the hybrid H. ×krischae. Hexaploid H. sempervirens shares karyotype features with diploid H. parlatorei, but lacks the expected chromosome characteristics of H. setaceum, possibly an example of beginning diploidization after polyploidization. The geographic origin of the putative parental species and their hybrids and the possible biogeographical spread through the Alps are discussed. PMID:27255513

  16. Parallel changes in mate-attracting calls and female preferences in autotriploid tree frogs

    OpenAIRE

    Tucker, Mitch A.; Gerhardt, H. C.

    2011-01-01

    For polyploid species to persist, they must be reproductively isolated from their diploid parental species, which coexist at the same time and place at least initially. In a complex of biparentally reproducing tetraploid and diploid tree frogs in North America, selective phonotaxis—mediated by differences in the pulse-repetition (pulse rate) of their mate-attracting vocalizations—ensures assortative mating. We show that artificially produced autotriploid females of the diploid species (Hyla c...

  17. CLASSICAL AND MOLECULAR CYTOGENETIC STUDIES FOR BREEDING AND SELECTION OF TULIPS

    OpenAIRE

    Aurel Popescu; Anca Nicoleta Sutan

    2012-01-01

    Due to their extreme popularity as fresh cut flowers and garden plants, and being used extensively for landscaping, tulips undergone a continuous process of selective breeding. For almost nine decades, classical cytogenetic studies, mainly the chromosome counts, have been an important part in the breeding programme for polyploid tulips. The efficiency of breeding is greatly aided by a thorough knowledge of the occurrence of polyploidy in the plant material. While the traditional cytogenetic ...

  18. Investigation on Evolutionary Relationships of the Subgenomes in Interspecific Triploid Cotton via Meiotic FISH

    Institute of Scientific and Technical Information of China (English)

    ZOU Mei-juan; PENG Ren-hai; WANG Kun-bo; WANG Chtm-ying; SONG Guo-li; LIU Fang; LI Shao-hui; ZHANG Xiang-di; WANG Yu-hong

    2008-01-01

    @@ We report in this paper primary studies on interspecific species of cotton vis GISH (genomic in situ hybridization).We use interspecific triploid hybrids (F1 from hybridization of allotetraploid cultivated species with diploid A,D,or C genome species) and two cultivated tetraploids to study the chromosome paring during meiosis of pollen mother cellls (PMCs) and to estimate the consequences on synapsis between these three subgenomes after synthetic polyploid formation.

  19. Progress in Understanding and Sequencing the Genome of Brassica rapa

    OpenAIRE

    Hong, Chang Pyo; Kwon, Soo-Jin; Kim, Jung Sun; Yang, Tae-Jin; Park, Beom-Seok; Lim, Yong Pyo

    2008-01-01

    Brassica rapa, which is closely related to Arabidopsis thaliana, is an important crop and a model plant for studying genome evolution via polyploidization. We report the current understanding of the genome structure of B. rapa and efforts for the whole-genome sequencing of the species. The tribe Brassicaceae, which comprises ca. 240 species, descended from a common hexaploid ancestor with a basic genome similar to that of Arabidopsis. Chromosome rearrangements, including fusions and/or fissio...

  20. A sequence-based genetic linkage map as a reference for Brassica rapa pseudochromosome assembly

    OpenAIRE

    Cheng Feng; Wang Qian; Liao Yongcui; Deng Jie; Wang Hui(Wendy); Liu Bo; Sun Silong; Wang Yan; Wang Xiaowu; Wu Jian

    2011-01-01

    Abstract Background Brassica rapa is an economically important crop and a model plant for studies concerning polyploidization and the evolution of extreme morphology. The multinational B. rapa Genome Sequencing Project (BrGSP) was launched in 2003. In 2008, next generation sequencing technology was used to sequence the B. rapa genome. Several maps concerning B. rapa pseudochromosome assembly have been published but their coverage of the genome is incomplete, anchoring approximately 73.6% of t...

  1. [Induction and identification of autotetraploid plant of Platycodon grandiflorum].

    Science.gov (United States)

    Gao, Shanlin; Shu, Luan

    2002-07-01

    The methods and technique of inducing polyploid plants of Platycodon grandiflorum were done. Many autotetraploid plant lines were induced by colchicine in vitro successfully. The identification of main agronomic characteristics of these clonal lines was conduced in the fields. The results showed the giant type occurred in tetraploid plants comparing with that in diploid plants. It may show prospective way in developing new varieties with high yield and high content of useful compounds. PMID:12599753

  2. Genetic response of Paspalum plicatulum to genome duplication.

    Science.gov (United States)

    Weihmüller, Emilse; Beltrán, Celina; Sartor, María; Espinoza, Francisco; Spampinato, Claudia; Pessino, Silvina

    2014-06-01

    Paspalum plicatulum is a perennial rhizomatous grass with natural diploid and polyploid cytotypes. In this study, we investigated the occurrence of sequence polymorphisms arising immediately after genome autoduplication in this species. Two mixoploid plants (4C and 7D) were previously obtained through colchicine treatment of seeds generated by open pollination of a diploid plant (H14-2x). Diploid and tetraploid sectors from both mixoploids were dissected to generate two ploidy series (4C-2x/4C-4x and 7D-2x/7D-4x). Molecular fingerprints were generated from the maternal plant H14-2x, both ploidy series (4C-2x/4C-4x and 7D-2x/7D-4x), and a tetraploid plant (C1) produced by selfing 7D-4x. Our results indicate that immediately after polyploidization P. plicatulum suffers genetic rearrangements affecting ~28-38 % of the genome. Band gain and loss were equally prevalent at a statistically significant level. At least 5.62 % of the genome experimented recurrent genetic variation in a non-random basis with a confidence of 94.88 %. A significant proportion of novel bands (36 out of 195; 18.4 %) was detected in the C1 tetraploid plant. Half of these bands were not amplified in either H14-2x or 7D-4x, while the remainders were present in H14-2x but absent in 7D-4x. Our results indicate the occurrence of a considerable number of genetic changes in P. plicatulum immediately after polyploidization, some of which were recurrently detected in different independent events. Moreover, we confirmed that after polyploidization, lost ancestral alleles were spontaneously recovered in further generations, a phenomenon previously reported by other research groups. PMID:24858395

  3. The effect of the drug colchicine on the early life of fish

    OpenAIRE

    Aluko, P.O.

    1993-01-01

    The alkaloid drug colchicine is a mitotic inhibitor. The results of this study show that colchicine influence the normal functioning of the mitotic process in Sarotherodon galilaeus, S. melanotheron and the hybrid S. galilaeus, X S. melanotheron leading to the production of unusual chromosomal events such as anaphase bridges, laggards and polyploid cells. These unusual events could have serious genetic implications in the area of variability of the chromosome number. The use of colchicine als...

  4. Tissue culture and generation of autotetraploid plants of Sophora flavescens Aiton

    OpenAIRE

    Kun-Hua, Wei; Shan-Lin, Gao; He-Ping, Huang

    2010-01-01

    Background: Sophora flavescens Aiton is an important medicinal plant in China. Early in vitro researches of S. flavescens were focused on callus induction and cell suspension culture, only a few were concerned with in vitro multiplication. Objective: To establish and optimize the rapid propagation technology of S. flavescens and to generate and characterize polyploid plants of S. flavescens. Materials and Methods: The different concentrations of 6-benzylaminopurine (BAP), indole-3-acetic acid (IA...

  5. The report of my death was an exaggeration: A review for researchers using microsatellites in the 21st century 1

    OpenAIRE

    Hodel, Richard G. J.; Segovia-Salcedo, M. Claudia; Landis, Jacob B.; Crowl, Andrew A.; Sun, Miao; Liu, Xiaoxian; Gitzendanner, Matthew A.; Douglas, Norman A.; Germain-Aubrey, Charlotte C.; Chen, Shichao; Soltis, Douglas E.; Pamela S Soltis

    2016-01-01

    Microsatellites, or simple sequence repeats (SSRs), have long played a major role in genetic studies due to their typically high polymorphism. They have diverse applications, including genome mapping, forensics, ascertaining parentage, population and conservation genetics, identification of the parentage of polyploids, and phylogeography. We compare SSRs and newer methods, such as genotyping by sequencing (GBS) and restriction site associated DNA sequencing (RAD-Seq), and offer recommendation...

  6. Polyploidy in haloarchaea: advantages for growth and survival

    OpenAIRE

    JörgSoppa

    2014-01-01

    The investigated haloarchaeal species, Halobacterium salinarum, Haloferax mediterranei, and H. volcanii, have all been shown to be polyploid. They contain several replicons that have independent copy number regulation, and most have a higher copy number during exponential growth phase than in stationary phase. The possible evolutionary advantages of polyploidy for haloarchaea, most of which have experimental support for at least one species, are discussed. These advantages include a low mutat...

  7. An expressed sequence tag (EST) library from developing fruits of an Hawaiian endemic mint (Stenogyne rugosa, Lamiaceae): characterization and microsatellite markers

    OpenAIRE

    Leebens-Mack James H; Oppenheimer David G; Yoo Mi-Jeong; Grey Paris; Scheen Anne-Cathrine; Lindqvist Charlotte; Soltis Douglas E; Soltis Pamela S; Albert Victor A

    2006-01-01

    Background The endemic Hawaiian mints represent a major island radiation that likely originated from hybridization between two North American polyploid lineages. In contrast with the extensive morphological and ecological diversity among taxa, ribosomal DNA sequence variation has been found to be remarkably low. In the past few years, expressed sequence tag (EST) projects on plant species have generated a vast amount of publicly available sequence data that can be mined for...

  8. Down-regulation of stathmin expression is required for megakaryocyte maturation and platelet production

    OpenAIRE

    Iancu-Rubin, Camelia; Gajzer, David; Tripodi, Joseph; Najfeld, Vesna; Gordon, Ronald E; Hoffman, Ronald; Atweh, George F.

    2011-01-01

    The final stages of of megakaryocyte (MK) maturation involve a series of steps, including polyploidization and proplatelet formation. Although these processes are highly dependent on dynamic changes in the microtubule (MT) cytoskeleton, the mechanisms responsible for regulation of MTs in MKs remain poorly defined. Stathmin is a highly conserved MT-regulatory protein that has been suggested to play a role in MK differentiation of human leukemic cell lines. However, previous studies defining th...

  9. Rapid Concerted Evolution of Nuclear Ribosomal DNA in Two Tragopogon Allopolyploids of Recent and Recurrent Origin

    OpenAIRE

    Kovarik, A; Pires, J. C.; Leitch, A. R.; Lim, K. Y.; Sherwood, A M; Matyasek, R.; Rocca, J.; Soltis, D. E.; Soltis, P S

    2005-01-01

    We investigated concerted evolution of rRNA genes in multiple populations of Tragopogon mirus and T. miscellus, two allotetraploids that formed recurrently within the last 80 years following the introduction of three diploids (T. dubius, T. pratensis, and T. porrifolius) from Europe to North America. Using the earliest herbarium specimens of the allotetraploids (1949 and 1953) to represent the genomic condition near the time of polyploidization, we found that the parental rDNA repeats were in...

  10. High-Resolution Radiation Hybrid Map of Wheat Chromosome 1D

    OpenAIRE

    Kalavacharla, Venu; Hossain, Khwaja; Gu, Yong; Riera-Lizarazu, Oscar; Vales, M. Isabel; Bhamidimarri, Suresh; Gonzalez-Hernandez, Jose L.; Maan, Shivcharan S; Kianian, Shahryar F

    2006-01-01

    Physical mapping methods that do not rely on meiotic recombination are necessary for complex polyploid genomes such as wheat (Triticum aestivum L.). This need is due to the uneven distribution of recombination and significant variation in genetic to physical distance ratios. One method that has proven valuable in a number of nonplant and plant systems is radiation hybrid (RH) mapping. This work presents, for the first time, a high-resolution radiation hybrid map of wheat chromosome 1D (D geno...

  11. Hybridization of powdery mildew strains gives rise to pathogens on novel agricultural crop species

    OpenAIRE

    Menardo, Fabrizio; Praz, Coraline R; Wyder, Stefan; Ben-David, Roi; Bourras, Salim; Matsumae, Hiromi; McNally, Kaitlin E.; Parlange, Francis; Riba, Andrea; Roffler, Stefan; Schaefer, Luisa K; Shimizu, Kentaro K; Valenti, Luca; Zbinden, Helen; Wicker, Thomas

    2016-01-01

    Throughout the history of agriculture, many new crop species (polyploids or artificial hybrids) have been introduced to diversify products or to increase yield. However, little is known about how these new crops influence the evolution of new pathogens and diseases. Triticale is an artificial hybrid of wheat and rye, and it was resistant to the fungal pathogen powdery mildew (Blumeria graminis) until 2001 (refs. 1,2,3). We sequenced and compared the genomes of 46 powdery mildew isolates cover...

  12. High-Throughput Sequencing and Mutagenesis to Accelerate the Domestication of Microlaena stipoides as a New Food Crop

    OpenAIRE

    Shapter, Frances M.; Michael Cross; Gary Ablett; Sylvia Malory; Chivers, Ian H.; King, Graham J.; Henry, Robert J.

    2013-01-01

    Global food demand, climatic variability and reduced land availability are driving the need for domestication of new crop species. The accelerated domestication of a rice-like Australian dryland polyploid grass, Microlaena stipoides (Poaceae), was targeted using chemical mutagenesis in conjunction with high throughput sequencing of genes for key domestication traits. While M. stipoides has previously been identified as having potential as a new grain crop for human consumption, only a limited...

  13. [Karyotypes of the stem eelworms from wild-growing plants].

    Science.gov (United States)

    Barabashova, V N

    1979-01-01

    Unlike the stem eelworms of cultivated plants, which have n = 12, the stem eelworms of wild plants (Picris sp., Taraxacum officinale, Hieracium pratense, H. pilosella, Cirsium setosum and Falcaria vulgaris) possess high chromosomal numbers (from n = 19 in the first to n = 28 in the latter). Due to this the stem eelworms of wild plants must be separated from the collective species Ditylenchus dipsaci. Apparently these forms of stem eelworms are distinct species polyploid in their origin.

  14. Food Conditioning Affects Expression of Insect Resistance in Diploid Willows (Salix spp.)

    OpenAIRE

    Christer Björkman; Karin Eklund; Anna Lehrman; Stenberg, Johan A

    2013-01-01

    The high energy quota and versatility of use make willows (Salix spp.) attractive as bioenergy crops. Insect defoliation constitutes a threat to the profitability of willow growers. Hitherto, the breeding for resistance against the main insect pests has been hampered by the fact that all known resistant willow clones are polyploids, and existing molecular breeding tools work most effectively for diploids. Here, we firstly report diploid willows highly resistant to the main insect defoliator, ...

  15. Diversity and relationships of Crocus sativus and its relatives analysed by inter-retroelement amplified polymorphism (IRAP)

    OpenAIRE

    Alsayied, Nouf Fakieh; Fernández, José Antonio; Schwarzacher, Trude; Heslop-Harrison, J.S.

    2015-01-01

    Background and Aims: Saffron (Crocus sativus) is a sterile triploid (2n = 3x = 24) cultivated species, of unknown origin from other diploid and polyploid species in the genus Crocus (Iridaceae). Species in the genus have high morphological diversity, with no clear phylogenetic patterns below the level of section Crocus series Crocus. Using DNA markers, this study aimed to examine the diversity and relationships within and between species of Crocus series Crocus.

  16. Estimating genetic variability in horticultural crop species at different stages of domestication

    OpenAIRE

    Persson, Helena

    2001-01-01

    Domestication may be viewed as an evolutionary process, involving mechanisms like muta- tion, selection, genetic drift, hybridization and polyploidization, and in the end resulting in individuals with traits profitable for man. The advent of modern plant breeding has acceler- ated the domestication of plants considerably. Plant breeding is essentially a selection of plant material based on the existence of genetic variation. Genetic variation within species has been assessed by many methods a...

  17. Manipulation of Karyotype in Caenorhabditis elegans Reveals Multiple Inputs Driving Pairwise Chromosome Synapsis During Meiosis.

    Science.gov (United States)

    Roelens, Baptiste; Schvarzstein, Mara; Villeneuve, Anne M

    2015-12-01

    Meiotic chromosome segregation requires pairwise association between homologs, stabilized by the synaptonemal complex (SC). Here, we investigate factors contributing to pairwise synapsis by investigating meiosis in polyploid worms. We devised a strategy, based on transient inhibition of cohesin function, to generate polyploid derivatives of virtually any Caenorhabditis elegans strain. We exploited this strategy to investigate the contribution of recombination to pairwise synapsis in tetraploid and triploid worms. In otherwise wild-type polyploids, chromosomes first sort into homolog groups, then multipartner interactions mature into exclusive pairwise associations. Pairwise synapsis associations still form in recombination-deficient tetraploids, confirming a propensity for synapsis to occur in a strictly pairwise manner. However, the transition from multipartner to pairwise association was perturbed in recombination-deficient triploids, implying a role for recombination in promoting this transition when three partners compete for synapsis. To evaluate the basis of synapsis partner preference, we generated polyploid worms heterozygous for normal sequence and rearranged chromosomes sharing the same pairing center (PC). Tetraploid worms had no detectable preference for identical partners, indicating that PC-adjacent homology drives partner choice in this context. In contrast, triploid worms exhibited a clear preference for identical partners, indicating that homology outside the PC region can influence partner choice. Together, our findings, suggest a two-phase model for C. elegans synapsis: an early phase, in which initial synapsis interactions are driven primarily by recombination-independent assessment of homology near PCs and by a propensity for pairwise SC assembly, and a later phase in which mature synaptic interactions are promoted by recombination.

  18. Genome evolution in alpine oat-like grasses through homoploid hybridization and polyploidy.

    Science.gov (United States)

    Winterfeld, Grit; Wölk, Alexandra; Röser, Martin

    2016-01-01

    Hybridization and polyploidization can radically impact genome organization from sequence level to chromosome structure. As a result, often in response to environmental change and species isolation, the development of novel traits can arise and will tend to result in the formation of homoploid or polyploid hybrid species. In this study we focus on evidence of hybridization and polyploidization by ascertaining the species parentage of the endemic alpine Helictotrichon parlatorei group. This group comprises five taxa; the diploids H. parlatorei, Helictotrichon setaceum subsp. setaceum and subsp. petzense, their putative hybrid Helictotrichon ×krischae and the hexaploid Helictotrichon sempervirens. For molecular analyses, cloned nuclear Topoisomerase VI genes of H. sempervirens and H. ×krischae were sequenced and compared with sequences of the diploids to estimate the evolutionary history in this group. In addition, detailed chromosome studies were carried out including fluorescence in situ hybridization (FISH) with 5S and 45S ribosomal and satellite DNA probes, and fluorochrome staining with chromomycin and DAPI. Two distinct types of Topoisomerase VI sequences were identified. One of them (SET) occurs in both subspecies of H. setaceum, the other (PAR) in H. parlatorei. Both types were found in H. ×krischae and H. sempervirens Karyotypes of H. parlatorei and H. setaceum could be distinguished by chromosomes with a clearly differentiated banding pattern of ribosomal DNAs. Both patterns occurred in the hybrid H. ×krischae Hexaploid H. sempervirens shares karyotype features with diploid H. parlatorei, but lacks the expected chromosome characteristics of H. setaceum, possibly an example of beginning diploidization after polyploidization. The geographic origin of the putative parental species and their hybrids and the possible biogeographical spread through the Alps are discussed.

  19. Meiotic chromosome behaviour in Cenchrus ciliaris

    Directory of Open Access Journals (Sweden)

    N. C. Visser

    1998-12-01

    Full Text Available A basic chromosome number of x = 9 has been confirmed for Cenchrus ciliaris L. Polyploidy is common and levels vary from tetraploid to hexaploid. Aneuploidv is reported for a single specimen, where two chromosomes of a single genome were lost. Various meiotic irregularities were observed. The highest incidence of meiotic abnormalities was observed in the pentaploid specimens. This was attributed to their uneven polyploid level All specimens varied from segmental alloploid to alloploid.

  20. Genome evolution in alpine oat-like grasses through homoploid hybridization and polyploidy.

    Science.gov (United States)

    Winterfeld, Grit; Wölk, Alexandra; Röser, Martin

    2016-01-01

    Hybridization and polyploidization can radically impact genome organization from sequence level to chromosome structure. As a result, often in response to environmental change and species isolation, the development of novel traits can arise and will tend to result in the formation of homoploid or polyploid hybrid species. In this study we focus on evidence of hybridization and polyploidization by ascertaining the species parentage of the endemic alpine Helictotrichon parlatorei group. This group comprises five taxa; the diploids H. parlatorei, Helictotrichon setaceum subsp. setaceum and subsp. petzense, their putative hybrid Helictotrichon ×krischae and the hexaploid Helictotrichon sempervirens. For molecular analyses, cloned nuclear Topoisomerase VI genes of H. sempervirens and H. ×krischae were sequenced and compared with sequences of the diploids to estimate the evolutionary history in this group. In addition, detailed chromosome studies were carried out including fluorescence in situ hybridization (FISH) with 5S and 45S ribosomal and satellite DNA probes, and fluorochrome staining with chromomycin and DAPI. Two distinct types of Topoisomerase VI sequences were identified. One of them (SET) occurs in both subspecies of H. setaceum, the other (PAR) in H. parlatorei. Both types were found in H. ×krischae and H. sempervirens Karyotypes of H. parlatorei and H. setaceum could be distinguished by chromosomes with a clearly differentiated banding pattern of ribosomal DNAs. Both patterns occurred in the hybrid H. ×krischae Hexaploid H. sempervirens shares karyotype features with diploid H. parlatorei, but lacks the expected chromosome characteristics of H. setaceum, possibly an example of beginning diploidization after polyploidization. The geographic origin of the putative parental species and their hybrids and the possible biogeographical spread through the Alps are discussed. PMID:27255513

  1. Retrotransposon Proliferation Coincident with the Evolution of Dioecy in Asparagus

    Science.gov (United States)

    Harkess, Alex; Mercati, Francesco; Abbate, Loredana; McKain, Michael; Pires, J. Chris; Sala, Tea; Sunseri, Francesco; Falavigna, Agostino; Leebens-Mack, Jim

    2016-01-01

    Current phylogenetic sampling reveals that dioecy and an XY sex chromosome pair evolved once, or possibly twice, in the genus Asparagus. Although there appear to be some lineage-specific polyploidization events, the base chromosome number of 2n = 2× = 20 is relatively conserved across the Asparagus genus. Regardless, dioecious species tend to have larger genomes than hermaphroditic species. Here, we test whether this genome size expansion in dioecious species is related to a polyploidization and subsequent chromosome fusion, or to retrotransposon proliferation in dioecious species. We first estimate genome sizes, or use published values, for four hermaphrodites and four dioecious species distributed across the phylogeny, and show that dioecious species typically have larger genomes than hermaphroditic species. Utilizing a phylogenomic approach, we find no evidence for ancient polyploidization contributing to increased genome sizes of sampled dioecious species. We do find support for an ancient whole genome duplication (WGD) event predating the diversification of the Asparagus genus. Repetitive DNA content of the four hermaphroditic and four dioecious species was characterized based on randomly sampled whole genome shotgun sequencing, and common elements were annotated. Across our broad phylogenetic sampling, Ty-1 Copia retroelements, in particular, have undergone a marked proliferation in dioecious species. In the absence of a detectable WGD event, retrotransposon proliferation is the most likely explanation for the precipitous increase in genome size in dioecious Asparagus species. PMID:27342737

  2. Comparative cytogenetic analysis of diploid and hexaploid Chenopodium album Agg

    Directory of Open Access Journals (Sweden)

    Bożena Kolano

    2011-04-01

    Full Text Available Two cytotypes of Chenopodium album, diploid (2n=2x=18 and hexaploid (2n=6x=54, were analysed using flow cytometry and a FISH experiment. The genome size was indicated as 1.795 pg for the diploid and 3.845 pg for the hexaploid plants which suggested genome downsizing in the evolution of hexaploid cytotype. Double FISH with 25S rDNA and 5S rDNA allowed three to five homologue chromosome pairs to be distinguished depending on the cytotype. The Variation in size and number of rDNA sites between the polyploid C. album and its putative diploid ancestor indicated that rDNA loci underwent rearrangements after polyploidization. Flow cytometry measurements of the relative nuclear DNA content in the somatic tissue of C. album revealed extensive endopolyploidization resulting in tissues comprising a mixture of cells with a different DNA content (from 2C to 32C in varying proportions. The pattern of endopolyploidy was characteristic for the developmental stage of the plant and for the individual organ. Polysomaty was not observed in the embryo tissues however endopolyploidization had taken place in most tested organs of seedlings. The endopolyploidy in diploid and hexaploid C. album was compared to find any relationship between the pattern of polysomaty and polyploidy level in this species. This revealed that polyploid plants showed a decline in the number of endocycles as well as in the frequency of endopolyploidy cells compared to diploid plants.

  3. Whole-genome duplication as a key factor in crop domestication.

    Science.gov (United States)

    Salman-Minkov, Ayelet; Sabath, Niv; Mayrose, Itay

    2016-08-01

    Polyploidy is commonly thought to be associated with the domestication process because of its concurrence with agriculturally favourable traits and because it is widespread among the major plant crops(1-4). Furthermore, the genetic consequences of polyploidy(5-7) might have increased the adaptive plasticity of those plants, enabling successful domestication(6-8). Nevertheless, a detailed phylogenetic analysis regarding the association of polyploidy with the domestication process, and the temporal order of these distinct events, has been lacking(3). Here, we have gathered a comprehensive data set including dozens of genera, each containing one or more major crop species and for which sufficient sequence and chromosome number data exist. Using probabilistic inference of ploidy levels conducted within a phylogenetic framework, we have examined the incidence of polyploidization events within each genus. We found that domesticated plants have gone through more polyploidy events than their wild relatives, with monocots exhibiting the most profound difference: 54% of the crops are polyploids versus 40% of the wild species. We then examined whether the preponderance of polyploidy among crop species is the result of two, non-mutually-exclusive hypotheses: (1) polyploidy followed by domestication, and (2) domestication followed by polyploidy. We found support for the first hypothesis, whereby polyploid species were more likely to be domesticated than their wild relatives, suggesting that the genetic consequences of polyploidy have conferred genetic preconditions for successful domestication on many of these plants.

  4. Karyomorphology of Taiwanese Begonia (Begoniaceae): taxonomic implications.

    Science.gov (United States)

    Oginuma, Kazuo; Peng, Ching-I

    2002-06-01

    The karyomorphology of all 14 species of Taiwanese Begonia was investigated to elucidate their chromosome features and chromosomal evolution. Among all species investigated, differences in chromosome features are found in: (1) chromosome number 2 n = 22, 26, 36, 38, 52, 60, 64, 82, and (2) frequencies of chromosomes with secondary, tertiary, and/or small constrictions of polyploids, ranging from 23% to 63%, which is higher than the expected value of about 9%. It is suggested that after polyploidization from the diploid species (i.e., 2 n = 22 and frequencies of chromosomes with secondary, tertiary, and/or small constrictions of polyploids of about 9%), chromosome translocations occurred, followed by a decrease in chromosome number, and subsequently stabilized genomes were formed in various species in Taiwan. The karyomorphological evidence also suggested that the chromosome morphology has evolved in parallel in the begonias belonging to different sections in Taiwan. The variation in chromosomal features is more complex than the variation in floral and fruit morphologies. Karyomorphological data also supports the recognition of five new species in Taiwan: Begonia bouffordii, B. chuyunshanensis, B. pinglinensis, B. tengchiana, and B. wutaiana. Based on detailed karyomorphological analyses, the taxonomic implications, speciation, and chromosomal evolution in Taiwanese Begoniaare discussed.

  5. Mining transcriptomic data to study the origins and evolution of a plant allopolyploid complex

    Directory of Open Access Journals (Sweden)

    Aureliano Bombarely

    2014-05-01

    Full Text Available Allopolyploidy combines two progenitor genomes in the same nucleus. It is a common speciation process, especially in plants. Deciphering the origins of polyploid species is a complex problem due to, among other things, extinct progenitors, multiple origins, gene flow between different polyploid populations, and loss of parental contributions through gene or chromosome loss. Among the perennial species of Glycine, the plant genus that includes the cultivated soybean (G. max, are eight allopolyploid species, three of which are studied here. Previous crossing studies and molecular systematic results from two nuclear gene sequences led to hypotheses of origin for these species from among extant diploid species. We use several phylogenetic and population genomics approaches to clarify the origins of the genomes of three of these allopolyploid species using single nucleotide polymorphism data and a guided transcriptome assembly. The results support the hypothesis that all three polyploid species are fixed hybrids combining the genomes of the two putative parents hypothesized on the basis of previous work. Based on mapping to the soybean reference genome, there appear to be no large regions for which one homoeologous contribution is missing. Phylogenetic analyses of 27 selected transcripts using a coalescent approach also are consistent with multiple origins for these allopolyploid species, and suggest that origins occurred within the last several hundred thousand years.

  6. Mixoploidy and cytotypes: a study of possible vegetative species differentiation in stapeliads (Asclepiadaceae

    Directory of Open Access Journals (Sweden)

    F. Albers

    1991-12-01

    Full Text Available Mixoploidy is common in proembryos and embryos as well as in meristems of radicles, primary, secondary and adventitious roots and in innovation shoots of stapeliad species (Asclepiadaceae. The proportion of polyploid cells in the meristem of single adventitious roots is significantly higher than in meristems of primary and secondary roots. This may lead to a complete polyploidisation of adventitious roots. Innovation shoots display a low percentage of polyploid cells, comparable to the condition found in primary and secondary roots. Nevertheless cells of different euploid levels are frequently found. During field studies, however, individuals of a given population were always found to have the same chromosome number: infraspecific polyploidy was found in only three out of 305 investigated stapeliad species. Genera with an orthotropic growth form were found to be diploid throughout, whereas the genera of which the members spread vegetatively by means of innovation shoots, comprise di-, tetra- and polyploid species. This phenomenon can be ascribed to ecological rather than morphological factors. The often proposed hypothesis that new cytotypes can have a vegetative origin is not found to be acceptable.

  7. Tissue culture and generation of autotetraploid plants of Sophora flavescens Aiton

    Directory of Open Access Journals (Sweden)

    Wei Kun-Hua

    2010-01-01

    Full Text Available Background: Sophora flavescens Aiton is an important medicinal plant in China. Early in vitro researches of S. flavescens were focused on callus induction and cell suspension culture, only a few were concerned with in vitro multiplication. Objective: To establish and optimize the rapid propagation technology of S. flavescens and to generate and characterize polyploid plants of S. flavescens. Materials and Methods: The different concentrations of 6-benzylaminopurine (BAP, indole-3-acetic acid (IAA and kinetin (KT were used to establish and screen the optimal rapid propagation technology of S. flavescens by orthogonal test; 0.2% colchicine solution was used to induce polyploid plants and the induced buds were identified by root-tip chromosome determination and stomatal apparatus observation. Results: A large number of buds could be induced directly from epicotyl and hypocotyl explants on the Murashige and Skoog medium (MS; 1962 supplemented with 1.4-1.6 mg/l 6-benzylaminopurine (BAP and 0.3 mg/l indole-3-acetic acid (IAA. More than 50 lines of autotetraploid plants were obtained. The chromosome number of the autotetraploid plantlet was 2n = 4x = 36. All tetraploid plants showed typical polyploid characteristics. Conclusion: Obtained autotetraploid lines will be of important genetic and breeding value and can be used for further selection and plant breeding.

  8. Comparison of leaf proteomes of cassava (Manihot esculenta Crantz cultivar NZ199 diploid and autotetraploid genotypes.

    Directory of Open Access Journals (Sweden)

    Feifei An

    Full Text Available Cassava polyploid breeding has drastically improved our knowledge on increasing root yield and its significant tolerance to stresses. In polyploid cassava plants, increases in DNA content highly affect cell volumes and anatomical structures. However, the mechanism of this effect is poorly understood. The purpose of the present study was to compare and validate the changes between cassava cultivar NZ199 diploid and autotetraploid at proteomic levels. The results showed that leaf proteome of cassava cultivar NZ199 diploid was clearly differentiated from its autotetraploid genotype using 2-DE combined MS technique. Sixty-five differential protein spots were seen in 2-DE image of autotetraploid genotype in comparison with that of diploid. Fifty-two proteins were identified by MALDI-TOF-MS/MS, of which 47 were up-regulated and 5 were down-regulated in autotetraploid genotype compared with diploid genotype. The classified functions of 32 up-regulated proteins were associated with photosynthesis, defense system, hydrocyanic acid (HCN metabolism, protein biosynthesis, chaperones, amino acid metabolism and signal transduction. The remarkable variation in photosynthetic activity, HCN content and resistance to salt stress between diploid and autotetraploid genotypes is closely linked with expression levels of proteomic profiles. The analysis of protein interaction networks indicated there are direct interactions between the 15 up-regulation proteins involved in the pathways described above. This work provides an insight into understanding the protein regulation mechanism of cassava polyploid genotype, and gives a clue to improve cassava polyploidy breeding in increasing photosynthesis and resistance efficiencies.

  9. Ever since Klekowski: testing a set of radical hypotheses revives the genetics of ferns and lycophytes.

    Science.gov (United States)

    Haufler, Christopher H

    2014-12-01

    There have been three periods of significant discovery in the exploration of fern and lycophyte genetics. First, during the 1930s, Andersson-Kottö conducted crossing studies on ferns. The publication of Manton's magnum opus on fern chromosomes in 1950 stimulated the second. The third emerged from Klekowski's 1973 American Journal of Botany publication that posed hypotheses linking breeding system dynamics and polyploid genetic architecture. Although Klekowski's assertions (predominant inbreeding and active polyploid genomes) were not supported, his hypotheses served as the impetus for improving our knowledge of the evolutionary mechanisms of ferns and lycophytes. It is now understood that (1) homosporous vascular plants are genetically diploid at high chromosome numbers and (2) both heterosporous and homosporous plants store and release genetic variation through a similar range of breeding systems. However, the seeming paradox of diploid genetic expression in homosporous vascular plants with high chromosome numbers remains unresolved. Ongoing and future research should include (1) more studies of gametophyte biology to elucidate the range and frequency of different breeding systems; (2) genomic analyses and new research on the mechanisms controlling bivalent formation to help discover how and why homosporous plant chromosomes appear so structurally stable; (3) considering whether the frequency of allopolyploidy in lineages can help explain why some are highly polyploid; and (4) chromosome painting studies to identify the dynamics of chromosome behavior in homosporous vascular plants. These open questions and continuing investigations demonstrate the longstanding impact of Klekowski's stimulating contribution.

  10. Cytogenetics and characterization of microsatellite loci for a South American pioneer tree species, Croton floribundus.

    Science.gov (United States)

    Silvestrini, Milene; Pinto-Maglio, Cecília A F; Zucchi, Maria I; dos Santos, Flavio A M

    2013-12-01

    Despite the recent advances in plant population genetic studies, the lack of information regarding pedigree, ploidy level, or mode of inheritance for many polyploids can compromise the analysis of the molecular data produced. The aim of this study was to examine both microsatellite and cytogenetic characteristics of the pioneer tree Croton floribundus Spreng. (Euphorbiaceae) to test for the occurrence of polyploidy in the species and to evaluate its implications for the appropriate use of SSR markers. Seven microsatellite markers were developed and screened for 62 individuals from a semi-deciduous tropical forest in Brazil. Chromosome number, meiotic behavior, and pollen viability were evaluated from male flower buds. All SSR loci were highly polymorphic. The number of bivalents observed in meiosis n = 56 (2n = 8× = 112) and the maximum number of alleles per individual (Ni = 8) demonstrated the occurrence of polyploidy in C. floribundus. The normal meiotic pairing and the high pollen viability suggested that C. floribundus is a regular and stable polyploid, most likely an allopolyploid. The combined SSR and cytogenetic data provided new evidence on the origin and evolution of the species as well as assured the accurate use of SSR loci for population genetic studies of the polyploid pioneer species.

  11. Differential transcriptome analysis between Paulownia fortunei and its synthesized autopolyploid.

    Science.gov (United States)

    Zhang, Xiaoshen; Deng, Minjie; Fan, Guoqiang

    2014-01-01

    Paulownia fortunei is an ecologically and economically important tree species that is widely used as timber and chemical pulp. Its autotetraploid, which carries a number of valuable traits, was successfully induced with colchicine. To identify differences in gene expression between P. fortunei and its synthesized autotetraploid, we performed transcriptome sequencing using an Illumina Genome Analyzer IIx (GAIIx). About 94.8 million reads were generated and assembled into 383,056 transcripts, including 18,984 transcripts with a complete open reading frame. A conducted Basic Local Alignment Search Tool (BLAST) search indicated that 16,004 complete transcripts had significant hits in the National Center for Biotechnology Information (NCBI) non-redundant database. The complete transcripts were given functional assignments using three public protein databases. One thousand one hundred fifty eight differentially expressed complete transcripts were screened through a digital abundance analysis, including transcripts involved in energy metabolism and epigenetic regulation. Finally, the expression levels of several transcripts were confirmed by quantitative real-time PCR. Our results suggested that polyploidization caused epigenetic-related changes, which subsequently resulted in gene expression variation between diploid and autotetraploid P. fortunei. This might be the main mechanism affected by the polyploidization. Our results represent an extensive survey of the P. fortunei transcriptome and will facilitate subsequent functional genomics research in P. fortunei. Moreover, the gene expression profiles of P. fortunei and its autopolyploid will provide a valuable resource for the study of polyploidization. PMID:24663058

  12. Differential Transcriptome Analysis between Paulownia fortunei and Its Synthesized Autopolyploid

    Directory of Open Access Journals (Sweden)

    Xiaoshen Zhang

    2014-03-01

    Full Text Available Paulownia fortunei is an ecologically and economically important tree species that is widely used as timber and chemical pulp. Its autotetraploid, which carries a number of valuable traits, was successfully induced with colchicine. To identify differences in gene expression between P. fortunei and its synthesized autotetraploid, we performed transcriptome sequencing using an Illumina Genome Analyzer IIx (GAIIx. About 94.8 million reads were generated and assembled into 383,056 transcripts, including 18,984 transcripts with a complete open reading frame. A conducted Basic Local Alignment Search Tool (BLAST search indicated that 16,004 complete transcripts had significant hits in the National Center for Biotechnology Information (NCBI non-redundant database. The complete transcripts were given functional assignments using three public protein databases. One thousand one hundred fifty eight differentially expressed complete transcripts were screened through a digital abundance analysis, including transcripts involved in energy metabolism and epigenetic regulation. Finally, the expression levels of several transcripts were confirmed by quantitative real-time PCR. Our results suggested that polyploidization caused epigenetic-related changes, which subsequently resulted in gene expression variation between diploid and autotetraploid P. fortunei. This might be the main mechanism affected by the polyploidization. Our results represent an extensive survey of the P. fortunei transcriptome and will facilitate subsequent functional genomics research in P. fortunei. Moreover, the gene expression profiles of P. fortunei and its autopolyploid will provide a valuable resource for the study of polyploidization.

  13. Biosystematics and evolutionary studies in Indian Drimia species

    Institute of Scientific and Technical Information of China (English)

    Neetin DESAI; Hemant KAWALKAR; Ghansham DIXIT

    2012-01-01

    The taxonomic position and genetic relationship within Indian Drimia species is controversial due to their morphological similarities and genomic complexities.The present work gives an insight on the genetic relationship between Indian Drimia species on the basis of their karyotype,pollen morphology,flower opening characteristics,hybridization behavior,and by use of DNA sequence of two molecular markers (internal transcribed spacers [ITS]and maturase K [matK]).The karyotypic studies of Indian Drimia species revealed various polyploid forms making their identification and delimitation more difficult.The five species of Indian Drimia are grouped into two complexes,indica complex and wightii complex on the basis of their pollen morphology,karyotype,and hybridization behavior.These two groups were found to be evolving separately.The cytomorphological studies of wightii complex revealed that it is evolving through polyploid and chromosome repatterning,while indica complex have adapted polyploid as well as hybridization for evolution.Phylogeny obtained from DNA sequences of molecular markers (ITS and matK)confirmed that the indica complex and wightii complex are evolving parallely,by grouping them in two clusters.Thus,a combination of conventional and molecular methods proved to be of great use for delimiting a small but complex group of Indian Drimia species.

  14. The Roles of Telomerase in the Generation of Polyploidy during Neoplastic Cell Growth

    Directory of Open Access Journals (Sweden)

    Agni Christodoulidou

    2013-02-01

    Full Text Available Polyploidy contributes to extensive intratumor genomic heterogeneity that characterizes advanced malignancies and is thought to limit the efficiency of current cancer therapies. It has been shown that telomere deprotection in p53-deficient mouse embryonic fibroblasts leads to high rates of polyploidization. We now show that tumor genome evolution through whole-genome duplication occurs in ∼15% of the karyotyped human neoplasms and correlates with disease progression. In a panel of human cancer and transformed cell lines representing the two known types of genomic instability (chromosomal and microsatellite, as well as the two known pathways of telomere maintenance in cancer (telomerase activity and alternative lengthening of telomeres, telomere dysfunction-driven polyploidization occurred independently of the mutational status of p53. Depending on the preexisting context of telomere maintenance, telomerase activity and its major components, human telomerase reverse transcriptase (hTERT and human telomerase RNA component (hTERC, exert both reverse transcriptase-related (canonical and noncanonical functions to affect tumor genome evolution through suppression or induction of polyploidization. These new findings provide a more complete mechanistic understanding of cancer progression that may, in the future, lead to novel therapeutic interventions.

  15. Phylogeny of a genomically diverse group of elymus (poaceae allopolyploids reveals multiple levels of reticulation.

    Directory of Open Access Journals (Sweden)

    Roberta J Mason-Gamer

    Full Text Available The grass tribe Triticeae (=Hordeeae comprises only about 300 species, but it is well known for the economically important crop plants wheat, barley, and rye. The group is also recognized as a fascinating example of evolutionary complexity, with a history shaped by numerous events of auto- and allopolyploidy and apparent introgression involving diploids and polyploids. The genus Elymus comprises a heterogeneous collection of allopolyploid genome combinations, all of which include at least one set of homoeologs, designated St, derived from Pseudoroegneria. The current analysis includes a geographically and genomically diverse collection of 21 tetraploid Elymus species, and a single hexaploid species. Diploid and polyploid relationships were estimated using four molecular data sets, including one that combines two regions of the chloroplast genome, and three from unlinked nuclear genes: phosphoenolpyruvate carboxylase, β-amylase, and granule-bound starch synthase I. Four gene trees were generated using maximum likelihood, and the phylogenetic placement of the polyploid sequences reveals extensive reticulation beyond allopolyploidy alone. The trees were interpreted with reference to numerous phenomena known to complicate allopolyploid phylogenies, and introgression was identified as a major factor in their history. The work illustrates the interpretation of complicated phylogenetic results through the sequential consideration of numerous possible explanations, and the results highlight the value of careful inspection of multiple independent molecular phylogenetic estimates, with particular focus on the differences among them.

  16. Analysis of cytosine methylation in early generations of resynthesized Brassica napus

    Institute of Scientific and Technical Information of China (English)

    RAN Li-ping; FANG Ting-ting; RONG Hao; JIANG Jin-jin; FANG Yu-jie; WANG You-ping

    2016-01-01

    DNA methylation, an important epigenetic modiifcation, serves as a key function in the polyploidization of numerous crops. In this study, early generations of resynthesizedBrassica napus (F1, S1–S3), ancestral parentsB. rapaandB. oleracea were analyzed to characterize their DNA methylation status during polyploidization, applying DNA methylation-sensitive ampliifca-tion polymorphism (MSAP) and high-performance liquid chromatography methods. InF1, 53.4% fragments were inherited from both A- and C-genomes. Besides, 5.04 and 8.87% fragments inF1 were inherited from A- and C- genome, respectively. 5.85 and 0.8% fragments were newly appeared and disappeared in resynthesizedB. napus, respectively. 13.1% of these gene sites were identiifed with methylation changes inF1, namely, hypermethylation (7.86%) and hypomethylation (5.24%). The lowest methylation status was detected inF1 (38.7%) compared with in S1–S3. In S3, 40.32% genes were methylated according to MSAP analysis. Sequencing of methylated fragments indicated that genes involved in multiple biological processes were modiifed, including transcription factors, protein modiifcation, and transporters. Expression ananlysis of DNA methyltransferase 1 andDNA methyltransferase chromomethylase 3 in different materials was consistent to the DNA methylation status. These results can generaly facilitate dissection of how DNA methylation contributes to genetic stability and improvement ofB. napus during polyploidization.

  17. Comparison of leaf proteomes of cassava (Manihot esculenta Crantz) cultivar NZ199 diploid and autotetraploid genotypes.

    Science.gov (United States)

    An, Feifei; Fan, Jie; Li, Jun; Li, Qing X; Li, Kaimian; Zhu, Wenli; Wen, Feng; Carvalho, Luiz J C B; Chen, Songbi

    2014-01-01

    Cassava polyploid breeding has drastically improved our knowledge on increasing root yield and its significant tolerance to stresses. In polyploid cassava plants, increases in DNA content highly affect cell volumes and anatomical structures. However, the mechanism of this effect is poorly understood. The purpose of the present study was to compare and validate the changes between cassava cultivar NZ199 diploid and autotetraploid at proteomic levels. The results showed that leaf proteome of cassava cultivar NZ199 diploid was clearly differentiated from its autotetraploid genotype using 2-DE combined MS technique. Sixty-five differential protein spots were seen in 2-DE image of autotetraploid genotype in comparison with that of diploid. Fifty-two proteins were identified by MALDI-TOF-MS/MS, of which 47 were up-regulated and 5 were down-regulated in autotetraploid genotype compared with diploid genotype. The classified functions of 32 up-regulated proteins were associated with photosynthesis, defense system, hydrocyanic acid (HCN) metabolism, protein biosynthesis, chaperones, amino acid metabolism and signal transduction. The remarkable variation in photosynthetic activity, HCN content and resistance to salt stress between diploid and autotetraploid genotypes is closely linked with expression levels of proteomic profiles. The analysis of protein interaction networks indicated there are direct interactions between the 15 up-regulation proteins involved in the pathways described above. This work provides an insight into understanding the protein regulation mechanism of cassava polyploid genotype, and gives a clue to improve cassava polyploidy breeding in increasing photosynthesis and resistance efficiencies.

  18. Retrotransposon Proliferation Coincident with the Evolution of Dioecy in Asparagus

    Directory of Open Access Journals (Sweden)

    Alex Harkess

    2016-09-01

    Full Text Available Current phylogenetic sampling reveals that dioecy and an XY sex chromosome pair evolved once, or possibly twice, in the genus Asparagus. Although there appear to be some lineage-specific polyploidization events, the base chromosome number of 2n = 2× = 20 is relatively conserved across the Asparagus genus. Regardless, dioecious species tend to have larger genomes than hermaphroditic species. Here, we test whether this genome size expansion in dioecious species is related to a polyploidization and subsequent chromosome fusion, or to retrotransposon proliferation in dioecious species. We first estimate genome sizes, or use published values, for four hermaphrodites and four dioecious species distributed across the phylogeny, and show that dioecious species typically have larger genomes than hermaphroditic species. Utilizing a phylogenomic approach, we find no evidence for ancient polyploidization contributing to increased genome sizes of sampled dioecious species. We do find support for an ancient whole genome duplication (WGD event predating the diversification of the Asparagus genus. Repetitive DNA content of the four hermaphroditic and four dioecious species was characterized based on randomly sampled whole genome shotgun sequencing, and common elements were annotated. Across our broad phylogenetic sampling, Ty-1 Copia retroelements, in particular, have undergone a marked proliferation in dioecious species. In the absence of a detectable WGD event, retrotransposon proliferation is the most likely explanation for the precipitous increase in genome size in dioecious Asparagus species.

  19. Retrotransposon Proliferation Coincident with the Evolution of Dioecy in Asparagus.

    Science.gov (United States)

    Harkess, Alex; Mercati, Francesco; Abbate, Loredana; McKain, Michael; Pires, J Chris; Sala, Tea; Sunseri, Francesco; Falavigna, Agostino; Leebens-Mack, Jim

    2016-01-01

    Current phylogenetic sampling reveals that dioecy and an XY sex chromosome pair evolved once, or possibly twice, in the genus Asparagus Although there appear to be some lineage-specific polyploidization events, the base chromosome number of 2n = 2× = 20 is relatively conserved across the Asparagus genus. Regardless, dioecious species tend to have larger genomes than hermaphroditic species. Here, we test whether this genome size expansion in dioecious species is related to a polyploidization and subsequent chromosome fusion, or to retrotransposon proliferation in dioecious species. We first estimate genome sizes, or use published values, for four hermaphrodites and four dioecious species distributed across the phylogeny, and show that dioecious species typically have larger genomes than hermaphroditic species. Utilizing a phylogenomic approach, we find no evidence for ancient polyploidization contributing to increased genome sizes of sampled dioecious species. We do find support for an ancient whole genome duplication (WGD) event predating the diversification of the Asparagus genus. Repetitive DNA content of the four hermaphroditic and four dioecious species was characterized based on randomly sampled whole genome shotgun sequencing, and common elements were annotated. Across our broad phylogenetic sampling, Ty-1 Copia retroelements, in particular, have undergone a marked proliferation in dioecious species. In the absence of a detectable WGD event, retrotransposon proliferation is the most likely explanation for the precipitous increase in genome size in dioecious Asparagus species. PMID:27342737

  20. [RAPD analysis of the intraspecific and interspecific variation and phylogenetic relationships of Aegilops L. species with the U genome].

    Science.gov (United States)

    Goriunova, S V; Chikida, N N; Kochieva, E Z

    2010-07-01

    RAPD analysis was used to study the genetic variation and phylogenetic relationships of polyploid Aegilops species with the U genome. In total, 115 DNA samples of eight polyploid species containing the U genome and the diploid species Ae. umbellulata (U) were examined. Substantial interspecific polymorphism was observed for the majority of the polyploid species with the U genome (interspecific differences, 0.01-0,2; proportion of polymorphic loci, 56.6-88.2%). Aegilops triuncialis was identified as the only alloploid species with low interspecific polymorphism (interspecific differences, 0-0.01, P = 50%) in the U-genome group. The U-genome Aegilops species proved to be separated from other species of the genus. The phylogenetic relationships were established for the U-genome species. The greatest separation within the U-genome group was observed for the US-genome species Ae. kotschyi and Ae. variabilis. The tetraploid species Ae. triaristata and Ae. columnaris, which had the UX genome, and the hexaploid species Ae. recta (UXN) were found to be related to each other and separate from the UM-genome species. A similarity was observed between the U M-genome species Ae. ovata and Ae. biuncialis, which had the UM genome, and the ancestral diploid U-genome species Ae. umbellulata. The UC-genome species Ae. triuncialis was rather separate and slightly similar to the UX-genome species.

  1. Assessment of single and combined X-ray and colchicine treatment on Trichosanthes anguina L

    International Nuclear Information System (INIS)

    The results of the present experiment on combined treatment with 18 kR X-rays followed by treatment with 0.25, 0.50 and 1.00 per cent aqueous solution of colchicine on white fruit colour variety of T. anguina have been found to be very interesting. The treatments have led to an increase in surviving plants till maturity, reduction in percentage of pollen mother cells with chromosomal aberrations and increase in pollen fertility. Analysis of root tip mitosis has shown that treatment with X-rays produces dicentric bridge and fragment while only polyploid cells were observed after treatment with colchicine. Combined treatment with X-rays and colchicine, produces both chromosomal aberrations and polyploid cells. Simultaneously, it reduces the percentage of cells with chromosomal aberrations and those with polyploid chromosome numbers. Desirable variability in seed number, seed weight and size, seed oil and punicic acid content were observed in both combined and individual treatment. (author). 6 refs., 3 tabs

  2. Studies on the physiologic effects of ion implantation on rice seed of single and twin seedlings

    International Nuclear Information System (INIS)

    Dry rice seeds of single and twin seedlings were treated by ion implantation. These seeds have differences as compared with control seeds in respect to the physilogic effects. The germination percentage and the survival seedling rate were lower than the check, but higher than those for γ-roy treated seeds. Ultra weak bioluminescence value of dry seeds treated by ion implantation was higher than that of the check, lower than that of seeds treated by γ-ray. The results also show that seeds treated by ion implantation possess a lower percentage of twin seedling than the comparisons do. It is worthy mentioning that there are more twin seedlings possessed independent two-mesocotyls which is a very meaningful apomictic material in rice selecting

  3. Effect of gelling agents on shoot growth and multiple shoot formation of mangosteen

    Directory of Open Access Journals (Sweden)

    Sompong Te-chato

    2005-12-01

    Full Text Available Apomict seeds of mangosteen were cultured as a whole or half seed on MS medium supplemented with 5 mg/l 6-benzyladenine (BA. The medium was solidified with various gelling agents. After culture for 2 months, multiple shoot formation, morphological and physiological characters of the shoot were investigated. The results revealed that 1.5% agarose gave the highest seed forming shoot (98% and number of shoots per culture seed (20.7. Wounding the seed by sectioning into half promoted higher callus formation (47-88% in all gelling agents. Phytagel (0.17% resulted in the highest callus formation (100% and hyperhydric shoots (11-31%. Those shoots produced translucent, thin and brittle leaves and stems, and malformed stoma. Those leaves had the lowest content of chlorophyll a, b and total chlorophyll.

  4. Chromosome numbers and meiotic analysis in the pre-breeding of Brachiaria decumbens (Poaceae)

    Indian Academy of Sciences (India)

    Gléia Cristina Laverde Ricci; Alice Maria De Souza-Kaneshima; Mariana Ferrari Felismino; Andrea Beatriz Mendes-Bonato; Maria Suely Pagliarini; Cacilda Borges Do Valle

    2011-08-01

    A total of 44 accessions of Brachiaria decumbens were analysed for chromosome count and meiotic behaviour in order to identify potential progenitors for crosses. Among them, 15 accessions presented $2n = 18$; 27 accessions, $2n = 36$; and 2 accessions, $2n = 45$ chromosomes. Among the diploid accessions, the rate of meiotic abnormalities was low, ranging from 0.82% to 7.93%. In the 27 tetraploid accessions, the rate of meiotic abnormalities ranged from 18.41% to 65.83%. The most common meiotic abnormalities were related to irregular chromosome segregation, but chromosome stickiness and abnormal cytokinesis were observed in low frequency. All abnormalities can compromise pollen viability by generating unbalanced gametes. Based on the chromosome number and meiotic stability, the present study indicates the apomictic tetraploid accessions that can act as male genitor to produce interspecific hybrids with B. ruziziensis or intraspecific hybrids with recently artificially tetraploidized accessions.

  5. Characterization of microsatellite markers for the vulnerable grassland forb Senecio macrocarpus (Asteraceae)1

    Science.gov (United States)

    Ahrens, Collin W.; James, Elizabeth A.

    2013-01-01

    • Premise of the study: Development of microsatellite markers for the vulnerable forb Senecio macrocarpus was performed to begin an assessment of its population structure and breeding method to aid in the conservation of the species in Victoria, Australia. • Methods and Results: Fifteen microsatellite markers were developed for S. macrocarpus from 454 pyrosequencing. The markers were tested on 104 individuals from four populations. The markers produced between two and seven alleles per locus while the expected heterozygosity ranged from 0.20 to 0.67 and the observed heterozygosity ranged from 0.00 to 1.00. The observed heterozygosity is suggestive that the populations may be apomictic. • Conclusions: The microsatellite markers developed for S. macrocarpus are intended to be used on future studies that aim to assess the population genetics and local breeding dynamics of the species with an emphasis on conservation. PMID:25202496

  6. Characterization of Microsatellite Markers for the Vulnerable Grassland Forb Senecio macrocarpus (Asteraceae

    Directory of Open Access Journals (Sweden)

    Collin W. Ahrens

    2013-10-01

    Full Text Available Premise of the study: Development of microsatellite markers for the vulnerable forb Senecio macrocarpus was performed to begin an assessment of its population structure and breeding method to aid in the conservation of the species in Victoria, Australia. Methods and Results: Fifteen microsatellite markers were developed for S. macrocarpus from 454 pyrosequencing. The markers were tested on 104 individuals from four populations. The markers produced between two and seven alleles per locus while the expected heterozygosity ranged from 0.20 to 0.67 and the observed heterozygosity ranged from 0.00 to 1.00. The observed heterozygosity is suggestive that the populations may be apomictic. Conclusions: The microsatellite markers developed for S. macrocarpus are intended to be used on future studies that aim to assess the population genetics and local breeding dynamics of the species with an emphasis on conservation.

  7. Meiotic analysis in induced tetraploids of Brachiaria decumbens Stapf

    Directory of Open Access Journals (Sweden)

    Carine Simioni

    2011-01-01

    Full Text Available The meiotic behavior of three tetraploid plants (2n=4x=36 originated from somatic chromosome duplication ofsexually reproducing diploid plants of Brachiaria decumbens was evaluated. All the analyzed plants presented abnormalities relatedto polyploidy, such as irregular chromosome segregation, leading to precocious chromosome migration to the poles and micronucleiduring both meiotic divisions. However, the abnormalities observed did not compromise the meiotic products which were characterizedby regular tetrads and satisfactory pollen fertility varying from 61.36 to 64.86%. Chromosomes paired mostly as bivalents indiakinesis but univalents to tetravalents were also observed. These studies contributed to the choice of compatible fertile sexualgenitors to be crossed to natural tetraploid apomicts in the B. decumbens by identifying abnormalities and verifying pollen fertility.Intraespecific crosses should reduce sterility in the hybrids produced in the breeding program of Brachiaria, a problem observedwith the interspecific hybrids produced so far.

  8. Plant germline formation: common concepts and developmental flexibility in sexual and asexual reproduction.

    Science.gov (United States)

    Schmidt, Anja; Schmid, Marc W; Grossniklaus, Ueli

    2015-01-15

    The life cycle of flowering plants alternates between two heteromorphic generations: a diploid sporophytic generation and a haploid gametophytic generation. During the development of the plant reproductive lineages - the germlines - typically, single sporophytic (somatic) cells in the flower become committed to undergo meiosis. The resulting spores subsequently develop into highly polarized and differentiated haploid gametophytes that harbour the gametes. Recent studies have provided insights into the genetic basis and regulatory programs underlying cell specification and the acquisition of reproductive fate during both sexual reproduction and asexual (apomictic) reproduction. As we review here, these recent advances emphasize the importance of transcriptional, translational and post-transcriptional regulation, and the role of epigenetic regulatory pathways and hormonal activity.

  9. The Parthenogenetic Cosmopolitan Chironomid, Paratanytarsus grimmii, as a New Standard Test Species for Ecotoxicology: Culturing Methodology and Sensitivity to Aqueous Pollutants.

    Science.gov (United States)

    Gagliardi, Bryant S; Long, Sara M; Pettigrove, Vincent J; Hoffmann, Ary A

    2015-09-01

    Chironomids from the genus Chironomus are widely used in laboratory ecotoxicology, but are prone to inbreeding depression, which can compromise test results. The standard Chironomus test species (C. riparius, C. dilutus and C. yoshimatsui) are also not cosmopolitan, making it difficult to compare results between geographic regions. In contrast, the chironomid Paratanytarsus grimmii is cosmopolitan, and not susceptible to inbreeding depression because it reproduces asexually by apomictic parthenogenesis. However, there is no standardised culturing methodology for P. grimmii, and a lack of acute toxicity data for common pollutants (metals and pesticides). In this study, we developed a reliable culturing methodology for P. grimmii. We also determined 24-h first instar LC50s for the metals Cu, Pb, Zn, Cd and the insecticide imidacloprid. By developing this culturing methodology and generating the first acute metal and imidacloprid LC50s for P. grimmii, we provide a basis for using P. grimmii in routine ecotoxicological testing.

  10. Cytogenetic evidence for genome elimination during microsporogenesis in interspecific hybrid between Brachiaria ruziziensis and B. brizantha (Poaceae

    Directory of Open Access Journals (Sweden)

    Andréa Beatriz Mendes-Bonato

    2006-01-01

    Full Text Available Microsporogenesis was analyzed in an interspecific hybrid between an artificially tetraploidized sexual accession of Brachiaria ruziziensis (R genome and a natural apomictic tetraploid accession of B. brizantha (B genome. Chromosomes associated predominantly as bivalents. From this phase to the end of meiosis, chromosomes presented irregular segregation and abnormal arrangement in the metaphase plate. During metaphase I, in 27.8% of meiocytes, bivalents were distributed in two metaphase plates. In anaphase I, two distinct and typical bipolar spindles were formed. In 29.7% of pollen mother cells, one genome did not divide synchronically, with chromosomes lagging behind or not segregating at all. The second division was very irregular, resulting in polyads. Based on previous results from analysis of a triploid hybrid between these species, where the R genome was eliminated by asynchrony during meiosis, it is suggested that the laggard genome in this hybrid also belongs to B. ruziziensis.

  11. Adaptabilidade e estabilidade em genótipos apomíticos do gênero Paspalum

    Directory of Open Access Journals (Sweden)

    Emerson André Pereira

    2015-08-01

    Full Text Available The objective of this study was to analyze the adaptability and the stability in apomictic genotypes of the genus Paspalum across the main characters of forage interest evaluated in different years and locations. The experiment was conducted in the years 2010 and 2011 in the municipalities of Eldorado do Sul and Augusto Pestana, RS, Brazil, in a randomized complete block design with three replications. Analyses of adaptability and stability were calculated by the Traditional and the Eberhart and Russel method. The genotypes of P. guenoarum Baio anda Azulão shows high biomass production but adapted to favorable environments and reduced stability. The genotypes of P. lepton 28C show the total dry mass specific adaptability to unfavorable environment and in the dry leaf adaptability with stability

  12. Chromosome numbers, meiotic behavior and pollen fertility in a collection of Paspalum nicorae Parodi accessions

    Directory of Open Access Journals (Sweden)

    Camila Aparecida de Oliveira dos Reis

    2008-01-01

    Full Text Available Chromosome number, meiotic behavior and pollen viability were evaluated in a collection of 53 Paspalumnicorae Parodi accessions, which are part of a breeding project of the species. All accessions are tetraploid, with 2n=4x=40.Despite the invariable chromosome numbers, there was variation among accessions in the frequencies of different chromosomeconfigurations at diakinesis and metaphase I, such as univalents, trivalents and quadrivalents. Other abnormalities asbridges and laggards were also observed at anaphase and telophase I. Meiotic indexes ranged from 82.00 to 99.50% andpollen viability from 88.99 to 95.06%. As the species is pseudogamous apomictic, fertile pollen is necessary for endospermformation. Results show that all plants are meiotically stable and have enough fertile pollen to be used as male parents incontrolled crosses.

  13. Gene discovery and molecular marker development, based on high-throughput transcript sequencing of Paspalum dilatatum Poir.

    Directory of Open Access Journals (Sweden)

    Andrea Giordano

    Full Text Available BACKGROUND: Paspalum dilatatum Poir. (common name dallisgrass is a native grass species of South America, with special relevance to dairy and red meat production. P. dilatatum exhibits higher forage quality than other C4 forage grasses and is tolerant to frost and water stress. This species is predominantly cultivated in an apomictic monoculture, with an inherent high risk that biotic and abiotic stresses could potentially devastate productivity. Therefore, advanced breeding strategies that characterise and use available genetic diversity, or assess germplasm collections effectively are required to deliver advanced cultivars for production systems. However, there are limited genomic resources available for this forage grass species. RESULTS: Transcriptome sequencing using second-generation sequencing platforms has been employed using pooled RNA from different tissues (stems, roots, leaves and inflorescences at the final reproductive stage of P. dilatatum cultivar Primo. A total of 324,695 sequence reads were obtained, corresponding to c. 102 Mbp. The sequences were assembled, generating 20,169 contigs of a combined length of 9,336,138 nucleotides. The contigs were BLAST analysed against the fully sequenced grass species of Oryza sativa subsp. japonica, Brachypodium distachyon, the closely related Sorghum bicolor and foxtail millet (Setaria italica genomes as well as against the UniRef 90 protein database allowing a comprehensive gene ontology analysis to be performed. The contigs generated from the transcript sequencing were also analysed for the presence of simple sequence repeats (SSRs. A total of 2,339 SSR motifs were identified within 1,989 contigs and corresponding primer pairs were designed. Empirical validation of a cohort of 96 SSRs was performed, with 34% being polymorphic between sexual and apomictic biotypes. CONCLUSIONS: The development of genetic and genomic resources for P. dilatatum will contribute to gene discovery and expression

  14. The effect of sub-lethal doses on the ploidy level in rats hepatocytes with aging

    International Nuclear Information System (INIS)

    It has been shown that the polyploidization levels in rat's hepatocytes increased with aging. The high LET ionizing radiation also induce cell polyploidization by two different means: cells and nuclei fusion, and mitosis restriction after DNA replication. The purpose of the present study was to determine the kinetic of rat's hepatocytes polyploidization with ageing, and the late effects of low doses of gamma irradiation on polyploidization. To this end, three groups of rats were used. Each group composed of 175 four weeks old animals. The first was served as a control, the second and the third groups were irradiated with 4 and 2 Gy respectively, of gamma irradiation at the age of one month. Of each group, 7-8 animals were monthly scarified (for two years), and their liver tissues were used to obtain cell suspensions which were further fixed in gradual series concentrations of ethanol. After staining with Propidum Iodide 'PI' (106 cells per ml of PI used at 10-5 M final concentration), the cells were analyzed on a FACS Vantage Flow Cytometer (Becton Dickinson). In the control, the results showed: 1) A decrease of cell fraction that contained normal diploid until steady level. 2) Biphasic changes of fraction tetraploidy cells (increase until age of 4 month followed by decrease). 3) The fraction of octaploidy cells appeared at age of 3-4 month and increased continuously with the aging. In accompanied to life-span reductions of 4 Gy irradiated animals, the DNA contents were similar to those in control groups in addition to some quantities variation due to a programmed cell death (Apoptosis) induced by irradiation and regenerations. These variations persisted till the age of 7 month, in additional to reduce the spin-life of irradiated animals. The irradiation with 2 Gy induced some quantities variation in comparison with nonirradiated group, appeared in the reduction of rate conversion from one ploidy class to another, and in shift with 2-3 months of the second pike of

  15. Deciphering the complex leaf transcriptome of the allotetraploid species Nicotiana tabacum: a phylogenomic perspective

    Directory of Open Access Journals (Sweden)

    Bombarely Aureliano

    2012-08-01

    Full Text Available Abstract Background Polyploidization is an important mechanism in plant evolution. By analyzing the leaf transcriptomes taken from the allotetraploid Nicotiana tabacum (tobacco and parental genome donors, N. sylvesteris (S-Genome and N. tomentosiformis (T-Genome, a phylogenomic approach was taken to map the fate of homeologous gene pairs in this plant. Results A comparison between the genes present in the leaf transcriptomes of N. tabacum and modern day representatives of its progenitor species demonstrated that only 33% of assembled transcripts could be distinguished based on their sequences. A large majority of the genes (83.6% of the non parent distinguishable and 87.2% of the phylogenetic topology analyzed clusters expressed above background level (more than 5 reads showed similar overall expression levels. Homeologous sequences could be identified for 968 gene clusters, and 90% (6% of all genes of the set maintained expression of only one of the tobacco homeologs. When both homeologs were expressed, only 15% (0.5% of the total showed evidence of differential expression, providing limited evidence of subfunctionalization. Comparing the rate of synonymous nucleotide substitution (Ks and non-synonymous nucleotide substitution (Kn provided limited evidence for positive selection during the evolution of tobacco since the polyploidization event took place. Conclusions Polyploidization is a powerful mechanism for plant speciation that can occur during one generation; however millions of generations may be necessary for duplicate genes to acquire a new function. Analysis of the tobacco leaf transcriptome reveals that polyploidization, even in a young tetraploid such as tobacco, can lead to complex changes in gene expression. Gene loss and gene silencing, or subfunctionalization may explain why both homeologs are not expressed by the associated genes. With Whole Genome Duplication (WGD events, polyploid genomes usually maintain a high percentage of

  16. Genetic dissection of fruit quality traits in the octoploid cultivated strawberry highlights the role of homoeo-QTL in their control.

    Science.gov (United States)

    Lerceteau-Köhler, E; Moing, A; Guérin, G; Renaud, C; Petit, A; Rothan, C; Denoyes, Béatrice

    2012-04-01

    Fruit quality traits are major breeding targets in the Rosaceae. Several of the major Rosaceae species are current or ancient polyploids. To dissect the inheritance of fruit quality traits in polyploid fleshy fruit species, we used a cultivated strawberry segregating population comprising a 213 full-sibling F1 progeny from a cross between the variety 'Capitola' and the genotype 'CF1116'. We previously developed the most comprehensive strawberry linkage map, which displays seven homoeology groups (HG), including each four homoeology linkage groups (Genetics 179:2045-2060, 2008). The map was used to identify quantitative trait loci (QTL) for 19 fruit traits related to fruit development, texture, colour, anthocyanin, sugar and organic acid contents. Analyses were carried out over two or three successive years on field-grown plants. QTL were detected for all the analysed traits. Because strawberry is an octopolyploid species, QTL controlling a given trait and located at orthologous positions on different homoeologous linkage groups within one HG are considered as homoeo-QTL. We found that, for various traits, about one-fourth of QTL were putative homoeo-QTL and were localised on two linkage groups. Several homoeo-QTL could be detected the same year, suggesting that several copies of the gene underlying the QTL are functional. The detection of some other homoeo-QTL was year-dependent. Therefore, changes in allelic expression could take place in response to environmental changes. We believe that, in strawberry as in other polyploid fruit species, the mechanisms unravelled in the present study may play a crucial role in the variations of fruit quality.

  17. Evolution of a transposon in Daphnia hybrid genomes

    Directory of Open Access Journals (Sweden)

    Vergilino Roland

    2013-02-01

    Full Text Available Abstract Background Transposable elements play a major role in genome evolution. Their capacity to move and/or multiply in the genome of their host may have profound impacts on phenotypes, and may have dramatic consequences on genome structure. Hybrid and polyploid clones have arisen multiple times in the Daphnia pulex complex and are thought to reproduce by obligate parthenogenesis. Our study examines the evolution of a DNA transposable element named Pokey in the D. pulex complex. Results Portions of Pokey elements inserted in the 28S rRNA genes from various Daphnia hybrids (diploids and polyploids were sequenced and compared to sequences from a previous study to understand the evolutionary history of the elements. Pokey sequences show a complex phylogenetic pattern. We found evidence of recombination events in numerous Pokey alleles from diploid and polyploid hybrids and also from non-hybrid diploids. The recombination rate in Pokey elements is comparable to recombination rates previously estimated for 28S rRNA genes in the congener, Daphnia obtusa. Some recombinant Pokey alleles were encountered in Daphnia isolates from multiple locations and habitats. Conclusions Phylogenetic and recombination analyses showed that recombination is a major force that shapes Pokey evolution. Based on Pokey phylogenies, reticulation has played and still plays an important role in shaping the diversity of the D. pulex complex. Horizontal transfer of Pokey seems to be rare and hybrids often possess Pokey elements derived from recombination among alleles encountered in the putative parental species. The insertion of Pokey in hotspots of recombination may have important impacts on the diversity and fitness of this transposable element.

  18. Gene expression in a paleopolyploid: a transcriptome resource for the ciliate Paramecium tetraurelia

    Directory of Open Access Journals (Sweden)

    Kapusta Aurélie

    2010-10-01

    Full Text Available Abstract Background The genome of Paramecium tetraurelia, a unicellular model that belongs to the ciliate phylum, has been shaped by at least 3 successive whole genome duplications (WGD. These dramatic events, which have also been documented in plants, animals and fungi, are resolved over evolutionary time by the loss of one duplicate for the majority of genes. Thanks to a low rate of large scale genome rearrangement in Paramecium, an unprecedented large number of gene duplicates of different ages have been identified, making this organism an outstanding model to investigate the evolutionary consequences of polyploidization. The most recent WGD, with 51% of pre-duplication genes still in 2 copies, provides a snapshot of a phase of rapid gene loss that is not accessible in more ancient polyploids such as yeast. Results We designed a custom oligonucleotide microarray platform for P. tetraurelia genome-wide expression profiling and used the platform to measure gene expression during 1 the sexual cycle of autogamy, 2 growth of new cilia in response to deciliation and 3 biogenesis of secretory granules after massive exocytosis. Genes that are differentially expressed during these time course experiments have expression patterns consistent with a very low rate of subfunctionalization (partition of ancestral functions between duplicated genes in particular since the most recent polyploidization event. Conclusions A public transcriptome resource is now available for Paramecium tetraurelia. The resource has been integrated into the ParameciumDB model organism database, providing searchable access to the data. The microarray platform, freely available through NimbleGen Systems, provides a robust, cost-effective approach for genome-wide expression profiling in P. tetraurelia. The expression data support previous studies showing that at short evolutionary times after a whole genome duplication, gene dosage balance constraints and not functional change are

  19. Evolutionary and Taxonomic Implications of Variation in Nuclear Genome Size: Lesson from the Grass Genus Anthoxanthum (Poaceae.

    Directory of Open Access Journals (Sweden)

    Zuzana Chumová

    Full Text Available The genus Anthoxanthum (sweet vernal grass, Poaceae represents a taxonomically intricate polyploid complex with large phenotypic variation and its evolutionary relationships still poorly resolved. In order to get insight into the geographic distribution of ploidy levels and assess the taxonomic value of genome size data, we determined C- and Cx-values in 628 plants representing all currently recognized European species collected from 197 populations in 29 European countries. The flow cytometric estimates were supplemented by conventional chromosome counts. In addition to diploids, we found two low (rare 3x and common 4x and one high (~16x-18x polyploid levels. Mean holoploid genome sizes ranged from 5.52 pg in diploid A. alpinum to 44.75 pg in highly polyploid A. amarum, while the size of monoploid genomes ranged from 2.75 pg in tetraploid A. alpinum to 9.19 pg in diploid A. gracile. In contrast to Central and Northern Europe, which harboured only limited cytological variation, a much more complex pattern of genome sizes was revealed in the Mediterranean, particularly in Corsica. Eight taxonomic groups that partly corresponded to traditionally recognized species were delimited based on genome size values and phenotypic variation. Whereas our data supported the merger of A. aristatum and A. ovatum, eastern Mediterranean populations traditionally referred to as diploid A. odoratum were shown to be cytologically distinct, and may represent a new taxon. Autopolyploid origin was suggested for 4x A. alpinum. In contrast, 4x A. odoratum seems to be an allopolyploid, based on the amounts of nuclear DNA. Intraspecific variation in genome size was observed in all recognized species, the most striking example being the A. aristatum/ovatum complex. Altogether, our study showed that genome size can be a useful taxonomic marker in Anthoxathum to not only guide taxonomic decisions but also help resolve evolutionary relationships in this challenging grass genus.

  20. Transposable element distribution, abundance and role in genome size variation in the genus Oryza

    Directory of Open Access Journals (Sweden)

    Collura Kristi

    2007-08-01

    Full Text Available Abstract Background The genus Oryza is composed of 10 distinct genome types, 6 diploid and 4 polyploid, and includes the world's most important food crop – rice (Oryza sativa [AA]. Genome size variation in the Oryza is more than 3-fold and ranges from 357 Mbp in Oryza glaberrima [AA] to 1283 Mbp in the polyploid Oryza ridleyi [HHJJ]. Because repetitive elements are known to play a significant role in genome size variation, we constructed random sheared small insert genomic libraries from 12 representative Oryza species and conducted a comprehensive study of the repetitive element composition, distribution and phylogeny in this genus. Particular attention was paid to the role played by the most important classes of transposable elements (Long Terminal Repeats Retrotransposons, Long interspersed Nuclear Elements, helitrons, DNA transposable elements in shaping these genomes and in their contributing to genome size variation. Results We identified the elements primarily responsible for the most strikingly genome size variation in Oryza. We demonstrated how Long Terminal Repeat retrotransposons belonging to the same families have proliferated to very different extents in various species. We also showed that the pool of Long Terminal Repeat Retrotransposons is substantially conserved and ubiquitous throughout the Oryza and so its origin is ancient and its existence predates the speciation events that originated the genus. Finally we described the peculiar behavior of repeats in the species Oryza coarctata [HHKK] whose placement in the Oryza genus is controversial. Conclusion Long Terminal Repeat retrotransposons are the major component of the Oryza genomes analyzed and, along with polyploidization, are the most important contributors to the genome size variation across the Oryza genus. Two families of Ty3-gypsy elements (RIRE2 and Atlantys account for a significant portion of the genome size variations present in the Oryza genus.

  1. Allopolyploid speciation and ongoing backcrossing between diploid progenitor and tetraploid progeny lineages in the Achillea millefolium species complex: analyses of single-copy nuclear genes and genomic AFLP

    Directory of Open Access Journals (Sweden)

    Ehrendorfer Friedrich

    2010-04-01

    Full Text Available Abstract Background In the flowering plants, many polyploid species complexes display evolutionary radiation. This could be facilitated by gene flow between otherwise separate evolutionary lineages in contact zones. Achillea collina is a widespread tetraploid species within the Achillea millefolium polyploid complex (Asteraceae-Anthemideae. It is morphologically intermediate between the relic diploids, A. setacea-2x in xeric and A. asplenifolia-2x in humid habitats, and often grows in close contact with either of them. By analyzing DNA sequences of two single-copy nuclear genes and the genomic AFLP data, we assess the allopolyploid origin of A. collina-4x from ancestors corresponding to A. setacea-2x and A. asplenifolia-2x, and the ongoing backcross introgression between these diploid progenitor and tetraploid progeny lineages. Results In both the ncpGS and the PgiC gene tree, haplotype sequences of the diploid A. setacea-2x and A. asplenifolia-2x group into two clades corresponding to the two species, though lineage sorting seems incomplete for the PgiC gene. In contrast, A. collina-4x and its suspected backcross plants show homeologous gene copies: sequences from the same tetraploid individual plant are placed in both diploid clades. Semi-congruent splits of an AFLP Neighbor Net link not only A. collina-4x to both diploid species, but some 4x individuals in a polymorphic population with mixed ploidy levels to A. setacea-2x on one hand and to A. collina-4x on the other, indicating allopolyploid speciation as well as hybridization across ploidal levels. Conclusions The findings of this study clearly demonstrate the hybrid origin of Achillea collina-4x, the ongoing backcrossing between the diploid progenitor and their tetraploid progeny lineages. Such repeated hybridizations are likely the cause of the great genetic and phenotypic variation and ecological differentiation of the polyploid taxa in Achillea millefolium agg.

  2. Conditions in home and transplant soils have differential effects on the performance of diploid and allotetraploid anthericum species.

    Directory of Open Access Journals (Sweden)

    Lucie Černá

    Full Text Available Due to increased levels of heterozygosity, polyploids are expected to have a greater ability to adapt to different environments than their diploid ancestors. While this theoretical pattern has been suggested repeatedly, studies comparing adaptability to changing conditions in diploids and polyploids are rare. The aim of the study was to determine the importance of environmental conditions of origin as well as target conditions on performance of two Anthericum species, allotetraploid A. liliago and diploid A. ramosum and to explore whether the two species differ in the ability to adapt to these environmental conditions. Specifically, we performed a common garden experiment using soil from 6 localities within the species' natural range, and we simulated the forest and open environments in which they might occur. We compared the performance of diploid A. ramosum and allotetraploid A. liliago originating from different locations in the different soils. The performance of the two species was not affected by simulated shading but differed strongly between the different target soils. Growth of the tetraploids was not affected by the origin of the plants. In contrast, diploids from the most nutrient poor soil performed best in the richest soil, indicating that diploids from deprived environments have an increased ability to acquire nutrients when available. They are thus able to profit from transfer to novel nutrient rich environments. Therefore, the results of the study did not support the general expectation that the polyploids should have a greater ability than the diploids to adapt to a wide range of conditions. In contrast, the results are in line with the observation that diploids occupy a wider range of environments than the allotetraploids in our system.

  3. The effect of γ-irradiation on the toxicity of malathion in V79 hamster cells and Molt-4 human lymphocytes

    International Nuclear Information System (INIS)

    There is a growing interest in irradiation of food and agricultural products for insect disinfestation, sprout inhibition, delayed ripening and the reduction of microbiological loads. Irradiation to a maximum dose of 10 kGy is recognized as safe by national and international regulatory agencies. To address the question, whether irradiation of pesticide residues might produce radiation products that were less or more toxic than the original pesticide, effects were observed of 10 kGy of γ-radiation on malathion as measured by sister-chromatid exchange (SCE), micronuclei formation, cell survival, growth rate and polyploid formation. No significant differences were found between effects of irradiated and unirradiated malathion on any of these end- points. Polyploid formation was the most dramatic effect of both irradiated and control malathion on V79 Chinese hamster cells. Cell survival, polyploid formation and growth rate were slightly better in cells treated with irradiated malathion. In Molt-4 human lymphocyte cell, micronuclei formation was not affected by unirradiated or irradiated malathion. Compared to malathion alone, the lack of such biological effects indicates that none of the presumed radiation-induced breakdown products increased or decreased the endpoints studied. The number of SCE was consistently, but not significantly, higher in cells treated with irradiated malathion. There were no significant differences in cell survival or micronucleus formation in the human lymphocyte cell line Molt-4 treated with irradiated or control malathion. Thus, the irradiation of the pesticide malathion to 10 kGy, a recommended upper dose for most food irradiations, does not significantly alter its toxicity in these in vitro systems. (author). 23 refs.; 4 figs.; 3 tabs

  4. A diploid wheat TILLING resource for wheat functional genomics

    Directory of Open Access Journals (Sweden)

    Rawat Nidhi

    2012-11-01

    Full Text Available Abstract Background Triticum monococcum L., an A genome diploid einkorn wheat, was the first domesticated crop. As a diploid, it is attractive genetic model for the study of gene structure and function of wheat-specific traits. Diploid wheat is currently not amenable to reverse genetics approaches such as insertion mutagenesis and post-transcriptional gene silencing strategies. However, TILLING offers a powerful functional genetics approach for wheat gene analysis. Results We developed a TILLING population of 1,532 M2 families using EMS as a mutagen. A total of 67 mutants were obtained for the four genes studied. Waxy gene mutation frequencies are known to be 1/17.6 - 34.4 kb DNA in polyploid wheat TILLING populations. The T. monococcum diploid wheat TILLING population had a mutation frequency of 1/90 kb for the same gene. Lignin biosynthesis pathway genes- COMT1, HCT2, and 4CL1 had mutation frequencies of 1/86 kb, 1/92 kb and 1/100 kb, respectively. The overall mutation frequency of the diploid wheat TILLING population was 1/92 kb. Conclusion The mutation frequency of a diploid wheat TILLING population was found to be higher than that reported for other diploid grasses. The rate, however, is lower than tetraploid and hexaploid wheat TILLING populations because of the higher tolerance of polyploids to mutations. Unlike polyploid wheat, most mutants in diploid wheat have a phenotype amenable to forward and reverse genetic analysis and establish diploid wheat as an attractive model to study gene function in wheat. We estimate that a TILLING population of 5, 520 will be needed to get a non-sense mutation for every wheat gene of interest with 95% probability.

  5. HapTree: a novel Bayesian framework for single individual polyplotyping using NGS data.

    Directory of Open Access Journals (Sweden)

    Emily Berger

    2014-03-01

    Full Text Available As the more recent next-generation sequencing (NGS technologies provide longer read sequences, the use of sequencing datasets for complete haplotype phasing is fast becoming a reality, allowing haplotype reconstruction of a single sequenced genome. Nearly all previous haplotype reconstruction studies have focused on diploid genomes and are rarely scalable to genomes with higher ploidy. Yet computational investigations into polyploid genomes carry great importance, impacting plant, yeast and fish genomics, as well as the studies of the evolution of modern-day eukaryotes and (epigenetic interactions between copies of genes. In this paper, we describe a novel maximum-likelihood estimation framework, HapTree, for polyploid haplotype assembly of an individual genome using NGS read datasets. We evaluate the performance of HapTree on simulated polyploid sequencing read data modeled after Illumina sequencing technologies. For triploid and higher ploidy genomes, we demonstrate that HapTree substantially improves haplotype assembly accuracy and efficiency over the state-of-the-art; moreover, HapTree is the first scalable polyplotyping method for higher ploidy. As a proof of concept, we also test our method on real sequencing data from NA12878 (1000 Genomes Project and evaluate the quality of assembled haplotypes with respect to trio-based diplotype annotation as the ground truth. The results indicate that HapTree significantly improves the switch accuracy within phased haplotype blocks as compared to existing haplotype assembly methods, while producing comparable minimum error correction (MEC values. A summary of this paper appears in the proceedings of the RECOMB 2014 conference, April 2-5.

  6. Herbicide resistance-endowing ACCase gene mutations in hexaploid wild oat (Avena fatua): insights into resistance evolution in a hexaploid species.

    Science.gov (United States)

    Yu, Q; Ahmad-Hamdani, M S; Han, H; Christoffers, M J; Powles, S B

    2013-03-01

    Many herbicide-resistant weed species are polyploids, but far too little about the evolution of resistance mutations in polyploids is understood. Hexaploid wild oat (Avena fatua) is a global crop weed and many populations have evolved herbicide resistance. We studied plastidic acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicide resistance in hexaploid wild oat and revealed that resistant individuals can express one, two or three different plastidic ACCase gene resistance mutations (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg). Using ACCase resistance mutations as molecular markers, combined with genetic, molecular and biochemical approaches, we found in individual resistant wild-oat plants that (1) up to three unlinked ACCase gene loci assort independently following Mendelian laws for disomic inheritance, (2) all three of these homoeologous ACCase genes were transcribed, with each able to carry its own mutation and (3) in a hexaploid background, each individual ACCase resistance mutation confers relatively low-level herbicide resistance, in contrast to high-level resistance conferred by the same mutations in unrelated diploid weed species of the Poaceae (grass) family. Low resistance conferred by individual ACCase resistance mutations is likely due to a dilution effect by susceptible ACCase expressed by homoeologs in hexaploid wild oat and/or differential expression of homoeologous ACCase gene copies. Thus, polyploidy in hexaploid wild oat may slow resistance evolution. Evidence of coexisting non-target-site resistance mechanisms among wild-oat populations was also revealed. In all, these results demonstrate that herbicide resistance and its evolution can be more complex in hexaploid wild oat than in unrelated diploid grass weeds. Our data provide a starting point for the daunting task of understanding resistance evolution in polyploids.

  7. Biased Gene Fractionation and Dominant Gene Expression among the Subgenomes of Brassica rapa

    OpenAIRE

    Feng Cheng; Jian Wu; Lu Fang; Silong Sun; Bo Liu; Ke Lin; Guusje Bonnema; Xiaowu Wang

    2012-01-01

    Polyploidization, both ancient and recent, is frequent among plants. A ‘‘two-step theory’’ was proposed to explain the meso-triplication of the Brassica ‘‘A’’ genome: Brassica rapa. By accurately partitioning of this genome, we observed that genes in the less fractioned subgenome (LF) were dominantly expressed over the genes in more fractioned subgenomes (MFs: MF1 and MF2), while the genes in MF1 were slightly dominantly expressed over the genes in MF2. The results indicated that the dominant...

  8. Relationships in the barley genus (Hordeum): An electrophoretic examination of proteins

    DEFF Research Database (Denmark)

    Bagger Jørgensen, Rikke

    1986-01-01

    The relationships between all known Hordeum species except H. guatemalense were inferred from the electrophoresis of the six enzyme systems Got, 6-Pgd, Mdh, Idh, .alpha.- and.beta.- amylases. A total of eleven loci were scored for in these systems. Maximum likelihood clusters and Wagner networks ...... originated as alloploids. Phylogenetic links between diploid and polyploid taxa are suggested from the enzyme phenotypes. An evolutionary theory for the genus Hordeum is proposed, with two centres of differentiation, in South-West Asia and South America, respectively....

  9. Cytophotometric investigation of DNA and RNA content in nuclei of active Strasburger cells in Pinus nigra var. austriaca (Hoess) Badoux.

    Science.gov (United States)

    Sauter, J J; Ulrich, H

    1977-01-01

    The nuclei of active, sieve cell-associated Strasburger cells in the secondary phloem of Pinus nigra var. austriaca (Hoess) Badoux have been studied for their structure and DNA and RNA content. No difference in size compared to those of ordinary ray cells was found. The nuclear surface is often increased by an ameboid or lobed shape. The amount of highly decondensed chromatin is greatly increased. Cytophotometric measurements of DNA content of both Feulgen and gallocyanine chromalum-stained nuclei showed normal DNA levels and proved absence of endomitotic polyploidization. RNA content, however, was significantly increased as compared to nuclei of young Strasburger cells and of ordinary ray parenchyma cells. PMID:24420510

  10. PollenCALC: Software for estimation of pollen compatibility of self-incompatible allo- and autotetraploid species

    DEFF Research Database (Denmark)

    Aguirre, Andrea A; Wollenweber, Bernd; Frei, Ursula K;

    2012-01-01

    Background Self-incompatibility (SI) is a biological mechanism to avoid inbreeding in allogamous plants. In grasses, this mechanism is controlled by a two-locus system (S-Z). Calculation of male and female gamete frequencies is complex for tetraploid species. We are not aware of any software...... available for predicting pollen haplotype frequencies and pollen compatibility in tetraploid species. Results PollenCALC is a software tool written in C++ programming language that can predict pollen compatibility percentages for polyploid species with a two-locus (S, Z) self-incompatibility system. The...

  11. Pollen—embryogenesis and chromosomal variability in anther culture of Brassica hirta Moench (Sinapis alba L)

    Institute of Scientific and Technical Information of China (English)

    BAJAJYPS; DMOHAPTRA

    1990-01-01

    The anther cultures of Brassica hirta underwent pollenembryogenesis and callusing,which showed a wide range of chromosome numbers varying from 9 (n=12) to a highly polyploid.For embryogenesis,pretreatment of floral buds in 0.4 M sucrose solution for 72 hrs at 4℃ was superior to freshly cultured anthers.Culture temperature of 30℃ for 14 days before maintenance of cultures at 25℃ was significantly beneficial for embryo yield in comparison to cultures continuously incubated at 25℃.Dark treatment during culture was more effective for pollen-embryo yield.

  12. TagDigger: user-friendly extraction of read counts from GBS and RAD-seq data

    OpenAIRE

    Clark, Lindsay V.; Sacks, Erik J.

    2016-01-01

    Background In genotyping-by-sequencing (GBS) and restriction site-associated DNA sequencing (RAD-seq), read depth is important for assessing the quality of genotype calls and estimating allele dosage in polyploids. However, existing pipelines for GBS and RAD-seq do not provide read counts in formats that are both accurate and easy to access. Additionally, although existing pipelines allow previously-mined SNPs to be genotyped on new samples, they do not allow the user to manually specify a su...

  13. The Relationship between Chromosome Number and its Variation in the Plants and Habitats%植物染色体数目及其变异与生境关系初探

    Institute of Scientific and Technical Information of China (English)

    王琼; 苏智先; 宋会兴; 汤泽生

    2001-01-01

    Based on the data collected on chromosome number of 1027 species and ecological environment of plants,the relationships between environmental factors and the changing rules of chromosome number,polyploidy,B chromosome were discussed.The results showed that under different light,moisture content and soil conditions,the chromosome number of plant is different in multiformity,variation extent and the highest frequency.The frequency of polyploid is relative to habitats and growing habits.The plant with B chromosome is often distributed over the subtropics and humid environment.

  14. The ploidy effects in plant gene expression: Progress, problems and prospects

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Polyploidy and haploid are widely employed in the studies of genetics and evolution, and great pro-gress has been made in these fields, inspiring the enthusiasm of scientists to explore the ploidy effects in gene expression. In this paper, we review the gene expression and its regulation in polyploids, es-pecially in autopolyploids. We summarize some limitations in previous reports on polyploidy gene ex-pression and its regulation, especially the limitations in the research materials. We propose an idea to create homologous ploidy series with twin-seedlings and to employ high-throughput techniques to investigate the polyploidy transcriptome and its regulation.

  15. Sequencing and analyses of the hexaploid wheat chromosome 3B

    OpenAIRE

    Choulet, Frédéric; Wincker, P.; Quesneville, Hadi; Brunel, Dominique; Gill, B.; Appels, R.; Keller, Beat; Feuillet, Catherine

    2010-01-01

    Because of its large (17 Gb, 5x the human genome and 40x the one of rice), polyploid (3 homoeologous A-, B- and D-genomes within a same nucleus) and highly repetitive (>80% of DNA corresponding to transposable elements) genome, the development of wheat genomics has been lagging behind the one of the other major crops. Two years after the establishment of the first physical map of the biggest wheat chromosome, the 3B, which represents 1 Gb (Paux et al. Science 2008), its complete sequencing is...

  16. The ploidy effects in plant gene expression: Prosress, problems and prospects

    Institute of Scientific and Technical Information of China (English)

    PENG Hai; ZHANG Jing; WU XianJun

    2008-01-01

    Polyploidy and haploid are widely employed in the studies of genetics and evolution, and great progress has been made in these fields, inspiring the enthusiasm of scientists to explore the ploidy effects in gene expression. In this paper, we review the gene expression and its regulation in polyploids, especially in autopolyploids. We summarize some limitations in previous reports on polyploidy gene expression and its regulation, especially the Iimitstions in the research materials. We propose an idea to create homologous ploidy series with twin-seedlings and to employ high-throughput techniques to Investigate the polyploidy transcriptome and its regulation.

  17. DNA content in reactive hyperplasia, precancerosis, and carcinomas of the oral cavity. A cytophotometric study.

    Science.gov (United States)

    Doseva, D; Christov, K; Kristeva, K

    1984-01-01

    Cytophotometry has been used to study DNA content in oral epithelial cells of Feulgen-stained specimens from a total of 43 patients: 3 with erythema exudativum multiforme (EEM), 5 with pemphigus, 3 with stomatitis aphtosa, 5 with lichen ruber planus, 8 with leukoplakia, and 19 with carcinomas. In contrast to reactive hyperplasia (EEM, pemphigus, stomatitis aphthosa) leukoplakia has histograms closest to those of carcinoma, with a high percentage of cells in the polyploid regions. This emphasizes the significance of cytophotometry for diagnosis of preneoplastic and neoplastic lesions of the oral cavity.

  18. High Frequency Production of Doubled Haploid Rapeseed Plants by Direct Colchicine Treatment of Isolated Microspores%油菜小孢子秋水仙素直接处理增加纯合两倍体植株频率

    Institute of Scientific and Technical Information of China (English)

    周伟军; Per,H

    2000-01-01

    @@ Techniques for microspore culture of Brassica napus have been improved rapidly, and embryogenesis has been achieved in a wide range of genotypes. Plants regenerated from microspore-derived embryoids can be haploid, diploid or polyploid. From rapeseed microspore culture it is reported that 70%-90% of regenerated plants are haploid. The usual methods of chromosome doubling involve soaking roots (most common) or whole plants in a colchicine solution, or culturing plantlets in colchicine-containing medium in the greenhouse. Other alternatives are injecting colchicine into the secondary buds or applying colchicine-soaked cotton plugs to axillary buds.

  19. Species interactions and plant polyploidy.

    Science.gov (United States)

    Segraves, Kari A; Anneberg, Thomas J

    2016-07-01

    Polyploidy is a common mode of speciation that can have far-reaching consequences for plant ecology and evolution. Because polyploidy can induce an array of phenotypic changes, there can be cascading effects on interactions with other species. These interactions, in turn, can have reciprocal effects on polyploid plants, potentially impacting their establishment and persistence. Although there is a wealth of information on the genetic and phenotypic effects of polyploidy, the study of species interactions in polyploid plants remains a comparatively young field. Here we reviewed the available evidence for how polyploidy may impact many types of species interactions that range from mutualism to antagonism. Specifically, we focused on three main questions: (1) Does polyploidy directly cause the formation of novel interactions not experienced by diploids, or does it create an opportunity for natural selection to then form novel interactions? (2) Does polyploidy cause consistent, predictable changes in species interactions vs. the evolution of idiosyncratic differences? (3) Does polyploidy lead to greater evolvability in species interactions? From the scarce evidence available, we found that novel interactions are rare but that polyploidy can induce changes in pollinator, herbivore, and pathogen interactions. Although further tests are needed, it is likely that selection following whole-genome duplication is important in all types of species interaction and that there are circumstances in which polyploidy can enhance the evolvability of interactions with other species. PMID:27370313

  20. Mutations in AtPS1 (Arabidopsis thaliana parallel spindle 1 lead to the production of diploid pollen grains.

    Directory of Open Access Journals (Sweden)

    Isabelle d'Erfurth

    2008-11-01

    Full Text Available Polyploidy has had a considerable impact on the evolution of many eukaryotes, especially angiosperms. Indeed, most--if not all-angiosperms have experienced at least one round of polyploidy during the course of their evolution, and many important crop plants are current polyploids. The occurrence of 2n gametes (diplogametes in diploid populations is widely recognised as the major source of polyploid formation. However, limited information is available on the genetic control of diplogamete production. Here, we describe the isolation and characterisation of the first gene, AtPS1 (Arabidopsis thaliana Parallel Spindle 1, implicated in the formation of a high frequency of diplogametes in plants. Atps1 mutants produce diploid male spores, diploid pollen grains, and spontaneous triploid plants in the next generation. Female meiosis is not affected in the mutant. We demonstrated that abnormal spindle orientation at male meiosis II leads to diplogamete formation. Most of the parent's heterozygosity is therefore conserved in the Atps1 diploid gametes, which is a key issue for plant breeding. The AtPS1 protein is conserved throughout the plant kingdom and carries domains suggestive of a regulatory function. The isolation of a gene involved in diplogamete production opens the way for new strategies in plant breeding programmes and progress in evolutionary studies.

  1. High-throughput sequencing and mutagenesis to accelerate the domestication of Microlaena stipoides as a new food crop.

    Science.gov (United States)

    Shapter, Frances M; Cross, Michael; Ablett, Gary; Malory, Sylvia; Chivers, Ian H; King, Graham J; Henry, Robert J

    2013-01-01

    Global food demand, climatic variability and reduced land availability are driving the need for domestication of new crop species. The accelerated domestication of a rice-like Australian dryland polyploid grass, Microlaena stipoides (Poaceae), was targeted using chemical mutagenesis in conjunction with high throughput sequencing of genes for key domestication traits. While M. stipoides has previously been identified as having potential as a new grain crop for human consumption, only a limited understanding of its genetic diversity and breeding system was available to aid the domestication process. Next generation sequencing of deeply-pooled target amplicons estimated allelic diversity of a selected base population at 14.3 SNP/Mb and identified novel, putatively mutation-induced polymorphisms at about 2.4 mutations/Mb. A 97% lethal dose (LD₉₇) of ethyl methanesulfonate treatment was applied without inducing sterility in this polyploid species. Forward and reverse genetic screens identified beneficial alleles for the domestication trait, seed-shattering. Unique phenotypes observed in the M2 population suggest the potential for rapid accumulation of beneficial traits without recourse to a traditional cross-breeding strategy. This approach may be applicable to other wild species, unlocking their potential as new food, fibre and fuel crops.

  2. High-throughput sequencing and mutagenesis to accelerate the domestication of Microlaena stipoides as a new food crop.

    Directory of Open Access Journals (Sweden)

    Frances M Shapter

    Full Text Available Global food demand, climatic variability and reduced land availability are driving the need for domestication of new crop species. The accelerated domestication of a rice-like Australian dryland polyploid grass, Microlaena stipoides (Poaceae, was targeted using chemical mutagenesis in conjunction with high throughput sequencing of genes for key domestication traits. While M. stipoides has previously been identified as having potential as a new grain crop for human consumption, only a limited understanding of its genetic diversity and breeding system was available to aid the domestication process. Next generation sequencing of deeply-pooled target amplicons estimated allelic diversity of a selected base population at 14.3 SNP/Mb and identified novel, putatively mutation-induced polymorphisms at about 2.4 mutations/Mb. A 97% lethal dose (LD₉₇ of ethyl methanesulfonate treatment was applied without inducing sterility in this polyploid species. Forward and reverse genetic screens identified beneficial alleles for the domestication trait, seed-shattering. Unique phenotypes observed in the M2 population suggest the potential for rapid accumulation of beneficial traits without recourse to a traditional cross-breeding strategy. This approach may be applicable to other wild species, unlocking their potential as new food, fibre and fuel crops.

  3. CLASSICAL AND MOLECULAR CYTOGENETIC STUDIES FOR BREEDING AND SELECTION OF TULIPS

    Directory of Open Access Journals (Sweden)

    Aurel Popescu

    2012-12-01

    Full Text Available Due to their extreme popularity as fresh cut flowers and garden plants, and being used extensively for landscaping, tulips undergone a continuous process of selective breeding. For almost nine decades, classical cytogenetic studies, mainly the chromosome counts, have been an important part in the breeding programme for polyploid tulips. The efficiency of breeding is greatly aided by a thorough knowledge of the occurrence of polyploidy in the plant material. While the traditional cytogenetic approaches are still highly useful in selecting polyploids and aneuploids arising from crosses involving (most often parents of different ploidy or from the material subjected to ploidy manipulation, the new strategies for inducing polyploidy in tulips, either in vivo or in vitro, and advances in molecular cytogenetics are expected to allow a significant increase in breeding efficiency. Together with the shortening of breeding cycle, major genetic improvements could be made for specific traits. In this we review the development of cytogenetic studies in tulips, and the most relevant achievements so far, providing an overview of what we consider to be valuable tools for the processes of selective breeding .

  4. AliquotG: an improved heuristic algorithm for genome aliquoting.

    Directory of Open Access Journals (Sweden)

    Zelin Chen

    Full Text Available An extant genome can be the descendant of an ancient polyploid genome. The genome aliquoting problem is to reconstruct the latter from the former such that the rearrangement distance (i.e., the number of genome rearrangements necessary to transform the former into the latter is minimal. Though several heuristic algorithms have been published, here, we sought improved algorithms for the problem with respect to the double cut and join (DCJ distance. The new algorithm makes use of partial and contracted partial graphs, and locally minimizes the distance. Our test results with simulation data indicate that it reliably recovers gene order of the ancestral polyploid genome even when the ancestor is ancient. We also compared the performance of our method with an earlier method using simulation data sets and found that our algorithm has higher accuracy. It is known that vertebrates had undergone two rounds of whole-genome duplication (2R-WGD during early vertebrate evolution. We used the new algorithm to calculate the DCJ distance between three modern vertebrate genomes and their 2R-WGD ancestor and found that the rearrangement rate might have slowed down significantly since the 2R-WGD. The software AliquotG implementing the algorithm is available as an open-source package from our website (http://mosas.sysu.edu.cn/genome/download_softwares.php.

  5. Selective Amplification of the Genome Surrounding Key Placental Genes in Trophoblast Giant Cells.

    Science.gov (United States)

    Hannibal, Roberta L; Baker, Julie C

    2016-01-25

    While most cells maintain a diploid state, polyploid cells exist in many organisms and are particularly prevalent within the mammalian placenta [1], where they can generate more than 900 copies of the genome [2]. Polyploidy is thought to be an efficient method of increasing the content of the genome by avoiding the costly and slow process of cytokinesis [1, 3, 4]. Polyploidy can also affect gene regulation by amplifying a subset of genomic regions required for specific cellular function [1, 3, 4]. This mechanism is found in the fruit fly Drosophila melanogaster, where polyploid ovarian follicle cells amplify genomic regions containing chorion genes, which facilitate secretion of eggshell proteins [5]. Here, we report that genomic amplification also occurs in mammals at selective regions of the genome in parietal trophoblast giant cells (p-TGCs) of the mouse placenta. Using whole-genome sequencing (WGS) and digital droplet PCR (ddPCR) of mouse p-TGCs, we identified five amplified regions, each containing a gene family known to be involved in mammalian placentation: the prolactins (two clusters), serpins, cathepsins, and the natural killer (NK)/C-type lectin (CLEC) complex [6-12]. We report here the first description of amplification at selective genomic regions in mammals and present evidence that this is an important mode of genome regulation in placental TGCs.

  6. Accounting for genotype uncertainty in the estimation of allele frequencies in autopolyploids.

    Science.gov (United States)

    Blischak, Paul D; Kubatko, Laura S; Wolfe, Andrea D

    2016-05-01

    Despite the increasing opportunity to collect large-scale data sets for population genomic analyses, the use of high-throughput sequencing to study populations of polyploids has seen little application. This is due in large part to problems associated with determining allele copy number in the genotypes of polyploid individuals (allelic dosage uncertainty-ADU), which complicates the calculation of important quantities such as allele frequencies. Here, we describe a statistical model to estimate biallelic SNP frequencies in a population of autopolyploids using high-throughput sequencing data in the form of read counts. We bridge the gap from data collection (using restriction enzyme based techniques [e.g. GBS, RADseq]) to allele frequency estimation in a unified inferential framework using a hierarchical Bayesian model to sum over genotype uncertainty. Simulated data sets were generated under various conditions for tetraploid, hexaploid and octoploid populations to evaluate the model's performance and to help guide the collection of empirical data. We also provide an implementation of our model in the R package polyfreqs and demonstrate its use with two example analyses that investigate (i) levels of expected and observed heterozygosity and (ii) model adequacy. Our simulations show that the number of individuals sampled from a population has a greater impact on estimation error than sequencing coverage. The example analyses also show that our model and software can be used to make inferences beyond the estimation of allele frequencies for autopolyploids by providing assessments of model adequacy and estimates of heterozygosity.

  7. Relationships among the A Genomes of Triticum L. Species as Evidenced by SSR Markers, in Iran

    Directory of Open Access Journals (Sweden)

    Simon G. Krattinger

    2010-11-01

    Full Text Available The relationships among 55 wheat accessions (47 accessions collected from Iran and eight accessions provided by the Institute of Plant Biology of the University of Zurich, Switzerland belonging to eight species carrying A genome (Triticum monococcum L., T. boeoticum Boiss., T. urartu Tumanian ex Gandilyan, T. durum Desf., T. turgidum L., T. dicoccum Schrank ex Schübler, T. dicoccoides (Körn. ex Asch. & Graebner Schweinf. and T. aestivum L. were evaluated using 31 A genome specific microsatellite markers. A high level of polymorphism was observed among the accessions studied (PIC = 0.77. The highest gene diversity was revealed among T. durum genotypes, while the lowest genetic variation was found in T. dicoccoides accessions. The analysis of molecular variance (AMOVA showed a significant genetic variance (75.56% among these accessions, representing a high intra-specific genetic diversity within Triticum taxa in Iran. However, such a variance was not observed among their ploidy levels. Based on the genetic similarity analysis, the accessions collected from Iran were divided into two main groups: diploids and polyploids. The genetic similarity among the diploid and polyploid species was 0.85 and 0.89 respectively. There were no significant differences in A genome diversity from different geographic regions. Based on the genetic diversity analyses, we consider there is value in a greater sampling of each species in Iran to discover useful genes for breeding purposes.

  8. Characterization and phylogenetic analysis of -gliadin gene sequences reveals significant genomic divergence in Triticeae species

    Indian Academy of Sciences (India)

    Guang-Rong Li; Tao Lang; En-Nian Yang; Cheng Liu; Zu-Jun Yang

    2014-12-01

    Although the unique properties of wheat -gliadin gene family are well characterized, little is known about the evolution and genomic divergence of -gliadin gene family within the Triticeae. We isolated a total of 203 -gliadin gene sequences from 11 representative diploid and polyploid Triticeae species, and found 108 sequences putatively functional. Our results indicate that -gliadin genes may have possibly originated from wild Secale species, where the sequences contain the shortest repetitive domains and display minimum variation. A miniature inverted-repeat transposable element insertion is reported for the first time in -gliadin gene sequence of Thinopyrum intermedium in this study, indicating that the transposable element might have contributed to the diversification of -gliadin genes family among Triticeae genomes. The phylogenetic analyses revealed that the -gliadin gene sequences of Dasypyrum, Australopyrum, Lophopyrum, Eremopyrum and Pseudoroengeria species have amplified several times. A search for four typical toxic epitopes for celiac disease within the Triticeae -gliadin gene sequences showed that the -gliadins of wild Secale, Australopyrum and Agropyron genomes lack all four epitopes, while other Triticeae species have accumulated these epitopes, suggesting that the evolution of these toxic epitopes sequences occurred during the course of speciation, domestication or polyploidization of Triticeae.

  9. Karyotypes of two cytotypes of Paspalum quadrifarium Lam. (Poaceae: an alternative technique for small chromosomes in plants

    Directory of Open Access Journals (Sweden)

    Pablo Speranza

    2003-12-01

    Full Text Available Paspalum quadrifarium Lam. is a bunchgrass native to Uruguay, Argentina, and southern Brazil. Diploid, triploid, tetraploid and hexaploid cytotypes have been reported for this species of the Quadrifaria group of Paspalum. In this group, a high degree of cytogenetic homology between the genomes of several diploid species has been reported, based on meiotic pairing in interspecific hybrids; multivalent associations would thus be expected in polyploid hybrids. Karyotype analysis could provide useful information about the genomic architecture of polyploid plants; however, the fully condensed mitotic chromosomes of Paspalum do not provide enough morphological features for such an analysis. In this paper, we used mitotic prometaphase chromosomes treated with 70% acetic acid at 40 °C after cover slip removal. This process removes cytoplasm that remains from chromosome squashes and makes prometaphases available for karyological analysis. The karyotypes of a triploid (2n = 3x = 30 and a tetraploid (2n = 4x = 40 accession of Paspalum quadrifarium were studied using this technique, and evidence of segmental allopolyploidy was found in both cases. In both accessions, meiotic behavior was in accordance with that origin. This technique greatly improved the number and quality of analyzable metaphases and prometaphases on otherwise conventional slides and is recommended for plants with small chromosomes.

  10. Reticulate evolution in stick insects: the case of Clonopsis (Insecta Phasmida

    Directory of Open Access Journals (Sweden)

    Milani Liliana

    2010-08-01

    Full Text Available Abstract Background Phasmids show noteworthy abilities to overcome species-specific reproductive isolation mechanisms, including hybridization, polyploidy, parthenogenesis, hybridogenesis and androgenesis. From an evolutionary standpoint, such tangled reproductive interactions lead to the complex phyletic relationships known as "reticulate evolution". Moroccan stick insects of the genus Clonopsis include one bisexual (C. felicitatis and two closely related parthenogenetic forms (C. gallica, C. soumiae, which represent a polyploid series in chromosome number, but with apparent diploid karyotypes. Moreover, two Clonopsis strains of ameiotic males have been described, C. androgenes-35 and C. androgenes-53. As a consequence, Clonopsis stick insects may have experienced complex micro-evolutionary events, which we try to disentangle in this study. Results Mitochondrial cox2 analysis supports a recent divergence of Clonopsis, while AFLPs evidence genetic differentiation not linked to karyotypes, so that parthenogenetic C. gallica and C. soumiae appear to be a mix of strains of polyphyletic origin rather than single parthenogenetic species. Moreover, an admixed hybrid origin seems to be confirmed for C. androgenes. Conclusion On the whole, Clonopsis is an intriguing case of reticulate evolution. Actually, complex cladogenetic events should be taken into account to explain the observed genetic structure, including diploidization of polyploid karyotypes, possibly coupled with hybridization and androgenesis. We also proposed a "working hypothesis" to account for the observed data, which deserves further studies, but fits the observed data very well.

  11. Exploitation of induced 2n-gametes for plant breeding.

    Science.gov (United States)

    Younis, Adnan; Hwang, Yoon-Jung; Lim, Ki-Byung

    2014-02-01

    Unreduced gamete formation derived via abnormal meiotic cell division is an important approach to polyploidy breeding. This process is considered the main driving force in spontaneous polyploids formation in nature, but the potential application of these gametes to plant breeding has not been fully exploited. An effective mechanism for their artificial induction is needed to attain greater genetic variation and enable efficient use of unreduced gametes in breeding programs. Different approaches have been employed for 2n-pollen production including interspecific hybridization, manipulation of environmental factors and treatment with nitrous oxide, trifluralin, colchicine, oryzalin and other chemicals. These chemicals can act as a stimulus to produce viable 2n pollen; however, their exact mode of action, optimum concentration and developmental stages are still not known. Identification of efficient methods of inducing 2n-gamete formation will help increase pollen germination of sterile interspecific hybrids for inter-genomic recombination and introgression breeding to develop new polyploid cultivars and increase heterozygosity among plant populations. Additionally, the application of genomic tools and identification and isolation of genes and mechanisms involved in the induction of 2n-gamete will enable increased exploitation in different plant species, which will open new avenues for plant breeding. PMID:24311154

  12. Chromosome duplication in Lolium multiflorum Lam.

    Directory of Open Access Journals (Sweden)

    Roselaine Cristina Pereira

    2014-11-01

    Full Text Available Artificial chromosome duplication of diploid genotypes of Lolium multiflorum (2n=2x=14 is worthy to breeding, and aims to increase the expression of traits with agronomic interest. The purpose of this study was to obtain polyploid plants of L. multiflorum from local diploid populations in order to exploit adaptation and future verification of the effects of polyploidy in agronomic traits. Seedlings were immersed in different colchicine solutions for an exposure time of 3h and 24h. Ploidy determination was made by the DNA content and certified by chromosomes counts. The plants confirmed as tetraploids were placed in a greenhouse, and, at flowering, pollen viability was evaluated, and seeds were harvested to assess the stability of the progenies. The percentage of polyploids obtained was 20%. Pollen viability of the tetraploids generated ranged from 58% to 69%. The tetraploid plants obtained in the experiment generated 164 progenies, of which 109 presented DNA content compatible with the tetraploid level, showing stability of chromosome duplication in the filial generation.

  13. [Evolutionary regularities of somatic polyploidy expansion in salivary glands of gastropod mollusks. V. Subclasses Opisthobranchia and Pulmonata].

    Science.gov (United States)

    Anisimov, A P; Ziumchenko, N E

    2012-01-01

    Salivary glands of 25 species of euthyneural gastropod mollusks (Opisthobranchia and Pulmonata) have been investigated by means of histochemical methods and DNA cytophotometry in nuclei of cells. The cells of three basic types are distinguished in glandular epithelim: granular cells (with glicoproteid granular inclusions), mucocytes-I (with sulfatic acid mucopolysaccharides) and mucocytes-II (with neutral and acid nonsulfatic polysaccharides and proteins) and so the epithelial ciliated cells and cells of the ducts. It was shown that glandular cells of salivary glands of all discovered mollusks' species are polyploid in different degree. The highest ploidy level estimated by means of DNA content in most of species is 64-128c. The giant polyploidy, attained to 4096c, is discovered in cells of salivary glands of Tritonia diomedea. The functional conditionality connected with features of feeding of different mollusk species and phylogenetic tendencies of expansion of somatic polyploidy in class Gastropoda are discussed. In comparison with allogenic, facultative and small polyploidy manifestation in Prosobranchia the obligatory polyploidization of high degree revealed in cells of salivary glands of Opisthobranchia and Pulmonata is consider to be the original cytological arogenesis. The probable causes of such differences are conneted with euthyneural type of organization of central nervous system and giant polyploidy of neurons in Opisthobranchia and Pulmonata mollusks. The causes, mechanisms and significance of such correlations are unclear for the present. PMID:22590930

  14. Mimulus peregrinus (Phrymaceae: A new British allopolyploid species

    Directory of Open Access Journals (Sweden)

    Mario Vallejo-Marin

    2012-07-01

    Full Text Available Polyploidization plays an important role in species formation as chromosome doubling results in strong reproductive isolation between derivative and parental taxa. In this note I describe a new species, Mimulus peregrinus (Phrymaceae, which represents the first recorded instance of a new British polyploid species of Mimulus (2n = 6x = 92 that has arisen since the introduction of this genus into the United Kingdom in the 1800’s. M. peregrinus presents floral and vegetative characteristics intermediate between M. guttatus and M. luteus, but can be distinguished from all naturalized British Mimulus species and hybrids based on a combination of reproductive and vegetative traits. M. peregrinus displays high pollen and seed fertility as well as traits usually associated with genome doubling such as increased pollen and stomata size. The intermediate characteristics of M. peregrinus between M. guttatus (2n = 2x = 28 and M. luteus (2n = 4x = 60-62, and its close affinity with the highly sterile, triploid (2n = 3x = 44-45 hybrid taxon M. × robertsii (M. guttatus × M. luteus, suggests that M. peregrinus may constitute an example of recent allopolyploid speciation.

  15. Accumulation of nonfunctional S-haplotypes results in the breakdown of gametophytic self-incompatibility in tetraploid Prunus.

    Science.gov (United States)

    Hauck, Nathanael R; Yamane, Hisayo; Tao, Ryutaro; Iezzoni, Amy F

    2006-02-01

    The transition from self-incompatibility (SI) to self-compatibility (SC) is regarded as one of the most prevalent transitions in Angiosperm evolution, having profound impacts on the genetic structure of populations. Yet, the identity and function of mutations that result in the breakdown of SI in nature are not well understood. This work provides the first detailed genetic description of the breakdown of S-RNase-mediated gametophytic self-incompatibility (GSI) in a polyploid species that exhibits genotype-dependent loss of SI. Genetic analyses of six natural sour cherry (Rosaceae, Prunus cerasus) selections identified seven independent, nonfunctional S-haplotypes with disrupted pistil component (stylar-S) and/or pollen component (pollen-S) function. A genetic model demonstrating that the breakdown of SI in sour cherry is due to the accumulation of a minimum of two nonfunctional S-haplotypes within a single individual is developed and validated. Our finding that sour cherry is SI when only one nonfunctional S-haplotype is present has significant evolutionary implications since nonfunctional S-haplotypes would be maintained in the population without causing an abrupt shift to SC. Furthermore, we demonstrate that heteroallelic sour cherry pollen is self-incompatible, which is counter to the well-documented phenomenon in the Solanaceae where SC accompanying polyploidization is frequently due to the SC of heteroallelic pollen. PMID:16219786

  16. Effect of gamma irradiation on sex chromatin body appearance and the sex chromosome aberrations in the potato tuber moth, phthorimaea operculella (Lepidoptera: Gelechiidae)

    International Nuclear Information System (INIS)

    Genetic sexing technique based on the construction of a Balanced Lethal Strain (BLS) has been proposed for Phthorimaea operculella (Zeller). The isolation of female with T(W. Z) translocation is a fundamental step to develop such strain. Gamma irradiation was used to induce the requested translocations. The availability of sex-linked morphological marker is required to facilitate the detection of such mutations. Since a visible sex-linked marker has not been found in P. operculella, therefore main aim of our study was to determine the possibility of using sex heterochromatin body as a marker to identify the required translocated females. The appearance of sex heterochromatin body and the analysis of sex chromosomes in F1 females of irradiated P. operculella females were investigated. The percentage of abnormality in sex heterochromatin body in highly polyploid Malpighian tubule nuclei was increased by increasing the applied dose. Based on the appearance of this body, 3 mutant lines were isolated: elongated, small, fragmented lines. W chromosome was easily distinguished from Z chromosome when the analysis of pachytene sex chromosome bivalents of P. operculella females was carried out. The aberrations involved W chromosome directly influenced the appearance of sex heterochromatin body in highly polyploid somatic cells of the isolated mutant lines. The results showed that sex heterochromatin could be used as sex determination and cytogenetic marker in P. operculella. (Author)

  17. Cytological, molecular mechanisms and temperature stress regulating production of diploid male gametes in Dianthus caryophyllus L.

    Science.gov (United States)

    Zhou, Xuhong; Mo, Xijun; Gui, Min; Wu, Xuewei; Jiang, Yalian; Ma, Lulin; Shi, Ziming; Luo, Ying; Tang, Wenru

    2015-12-01

    In plant evolution, because of its key role in sexual polyploidization or whole genome duplication events, diploid gamete formation is considered as an important component in diversification and speciation. Environmental stress often triggers unreduced gamete production. However, the molecular, cellular mechanisms and adverse temperature regulating diplogamete production in carnation remain poorly understood. Here, we investigate the cytological basis for 2n male gamete formation and describe the isolation and characterization of the first gene, DcPS1 (Dianthus Caryophyllus Parallel Spindle 1). In addition, we analyze influence of temperature stress on diploid gamete formation and transcript levels of DcPS1. Cytological evidence indicated that 2n male gamete formation is attributable to abnormal spindle orientation at male meiosis II. DcPS1 protein is conserved throughout the plant kingdom and carries domains suggestive of a regulatory function. DcPS1 expression analysis show DcPS1 gene probably have a role in 2n pollen formation. Unreduced pollen formation in various cultivation was sensitive to high or low temperature which was probably regulated by the level of DcPS1 transcripts. In a broader perspective, these findings can have potential applications in fundamental polyploidization research and plant breeding programs.

  18. Aberrant Classopollis pollen reveals evidence for unreduced (2n) pollen in the conifer family Cheirolepidiaceae during the Triassic–Jurassic transition

    Science.gov (United States)

    Kürschner, Wolfram M.; Batenburg, Sietske J.; Mander, Luke

    2013-01-01

    Polyploidy (or whole-genome doubling) is a key mechanism for plant speciation leading to new evolutionary lineages. Several lines of evidence show that most species among flowering plants had polyploidy ancestry, but it is virtually unknown for conifers. Here, we study variability in pollen tetrad morphology and the size of the conifer pollen type Classopollis extracted from sediments of the Triassic–Jurassic transition, 200 Ma. Classopollis producing Cheirolepidiaceae were one of the most dominant and diverse groups of conifers during the Mesozoic. We show that aberrant pollen Classopollis tetrads, triads and dyads, and the large variation in pollen size indicates the presence of unreduced (2n) pollen, which is one of the main mechanisms in modern polyploid formation. Polyploid speciation may explain the high variability of growth forms and adaptation of these conifers to different environments and their resistance to extreme growth conditions. We suggest that polyploidy may have also reduced the extinction risk of these conifers during the End-Triassic biotic crisis. PMID:23926159

  19. Draft genome of the peanut A-genome progenitor (Arachis duranensis) provides insights into geocarpy, oil biosynthesis, and allergens.

    Science.gov (United States)

    Chen, Xiaoping; Li, Hongjie; Pandey, Manish K; Yang, Qingli; Wang, Xiyin; Garg, Vanika; Li, Haifen; Chi, Xiaoyuan; Doddamani, Dadakhalandar; Hong, Yanbin; Upadhyaya, Hari; Guo, Hui; Khan, Aamir W; Zhu, Fanghe; Zhang, Xiaoyan; Pan, Lijuan; Pierce, Gary J; Zhou, Guiyuan; Krishnamohan, Katta A V S; Chen, Mingna; Zhong, Ni; Agarwal, Gaurav; Li, Shuanzhu; Chitikineni, Annapurna; Zhang, Guo-Qiang; Sharma, Shivali; Chen, Na; Liu, Haiyan; Janila, Pasupuleti; Li, Shaoxiong; Wang, Min; Wang, Tong; Sun, Jie; Li, Xingyu; Li, Chunyan; Wang, Mian; Yu, Lina; Wen, Shijie; Singh, Sube; Yang, Zhen; Zhao, Jinming; Zhang, Chushu; Yu, Yue; Bi, Jie; Zhang, Xiaojun; Liu, Zhong-Jian; Paterson, Andrew H; Wang, Shuping; Liang, Xuanqiang; Varshney, Rajeev K; Yu, Shanlin

    2016-06-14

    Peanut or groundnut (Arachis hypogaea L.), a legume of South American origin, has high seed oil content (45-56%) and is a staple crop in semiarid tropical and subtropical regions, partially because of drought tolerance conferred by its geocarpic reproductive strategy. We present a draft genome of the peanut A-genome progenitor, Arachis duranensis, and 50,324 protein-coding gene models. Patterns of gene duplication suggest the peanut lineage has been affected by at least three polyploidizations since the origin of eudicots. Resequencing of synthetic Arachis tetraploids reveals extensive gene conversion in only three seed-to-seed generations since their formation by human hands, indicating that this process begins virtually immediately following polyploid formation. Expansion of some specific gene families suggests roles in the unusual subterranean fructification of Arachis For example, the S1Fa-like transcription factor family has 126 Arachis members, in contrast to no more than five members in other examined plant species, and is more highly expressed in roots and etiolated seedlings than green leaves. The A. duranensis genome provides a major source of candidate genes for fructification, oil biosynthesis, and allergens, expanding knowledge of understudied areas of plant biology and human health impacts of plants, informing peanut genetic improvement and aiding deeper sequencing of Arachis diversity. PMID:27247390

  20. Genome management and mismanagement--cell-level opportunities and challenges of whole-genome duplication.

    Science.gov (United States)

    Yant, Levi; Bomblies, Kirsten

    2015-12-01

    Whole-genome duplication (WGD) doubles the DNA content in the nucleus and leads to polyploidy. In whole-organism polyploids, WGD has been implicated in adaptability and the evolution of increased genome complexity, but polyploidy can also arise in somatic cells of otherwise diploid plants and animals, where it plays important roles in development and likely environmental responses. As with whole organisms, WGD can also promote adaptability and diversity in proliferating cell lineages, although whether WGD is beneficial is clearly context-dependent. WGD is also sometimes associated with aging and disease and may be a facilitator of dangerous genetic and karyotypic diversity in tumorigenesis. Scaling changes can affect cell physiology, but problems associated with WGD in large part seem to arise from problems with chromosome segregation in polyploid cells. Here we discuss both the adaptive potential and problems associated with WGD, focusing primarily on cellular effects. We see value in recognizing polyploidy as a key player in generating diversity in development and cell lineage evolution, with intriguing parallels across kingdoms.

  1. Meiotic behavior and chromosome number of Urochloa adspersa (Trin.) R. D. Webster from the Brazilian Chaco.

    Science.gov (United States)

    Felismino, M F; Maior, R L S; Damasceno, G A; Pott, A; Pagliarini, M S

    2015-01-01

    This is the first report of meiotic division in Uro-chloa adspersa (Trin.) collected from the Brazilian Chaco. Meiotic analyses were performed on three specimens of U. adspersa named G10, G15, and G16. Inflorescences were collected and fixed in a mixture of ethanol and acetic acid (3:1, v/v) for 24 h and then stored in 70% alcohol. Diakinesis revealed different chromosome numbers and ploidy levels. All three plants were polyploids: G10 and G15 exhibited 2n = 6x = 54 chromosomes (arranged in 27 bivalents), while G16 exhibited 2n = 4x = 36 chromosomes (18 bivalents). Meiotic behavior was mainly normal in the hexaploid G15 and the tetraploid G16 (5.3 and 6.2% of the cells were abnormal, respective-ly), revealing only a few meiotic abnormalities that are common to polyploids, i.e., those related to irregular chromosome segregation. G10 exhibited other meiotic abnormalities during meiosis II, such as chromosome stickiness, irregular spindle orientation, and irregular cytokinesis, which led to the formation of a few triads, resulting in 16.9% of the cells being abnormal. The origin of these abnormalities is discussed, and we suggest that the genes that control meiotic steps may be present in the Urochloa gene pool. PMID:26214424

  2. Involvement of Disperse Repetitive Sequences in Wheat/Rye Genome Adjustment

    Directory of Open Access Journals (Sweden)

    Manuela Silva

    2012-07-01

    Full Text Available The union of different genomes in the same nucleus frequently results in hybrid genotypes with improved genome plasticity related to both genome remodeling events and changes in gene expression. Most modern cereal crops are polyploid species. Triticale, synthesized by the cross between wheat and rye, constitutes an excellent model to study polyploidization functional implications. We intend to attain a deeper knowledge of dispersed repetitive sequence involvement in parental genome reshuffle in triticale and in wheat-rye addition lines that have the entire wheat genome plus each rye chromosome pair. Through Random Amplified Polymorphic DNA (RAPD analysis with OPH20 10-mer primer we unraveled clear alterations corresponding to the loss of specific bands from both parental genomes. Moreover, the sequential nature of those events was revealed by the increased absence of rye-origin bands in wheat-rye addition lines in comparison with triticale. Remodeled band sequencing revealed that both repetitive and coding genome domains are affected in wheat-rye hybrid genotypes. Additionally, the amplification and sequencing of pSc20H internal segments showed that the disappearance of parental bands may result from restricted sequence alterations and unraveled the involvement of wheat/rye related repetitive sequences in genome adjustment needed for hybrid plant stabilization.

  3. Genome duplication and the evolution of physiological responses to water stress.

    Science.gov (United States)

    Maherali, Hafiz; Walden, Alison E; Husband, Brian C

    2009-11-01

    Whole-genome multiplication, or polyploidy, is common in angiosperms and many species consist of multiple cytotypes that have different physiological tolerances. However, the relative importance of genome duplication vs post-duplication evolutionary change in causing differentiation between cytotypes is not known. We examined the water relations of Chamerion angustifolium, a herbaceous perennial in which diploid and tetraploid cytotypes occupy different niches. To differentiate between the effects of genome duplication and evolutionary changes that followed polyploidization, we compared extant diploids and tetraploids with experimentally synthesized neotetraploids. Tetraploids had 32% higher xylem hydraulic conductivity (K(H)) than neotetraploids and 87% higher K(H) than diploids, but vulnerability to water stress induced cavitation and gas exchange sensitivity to water potential did not differ among cytotypes. Nevertheless, tetraploids took 22% and 30% longer to wilt than neotetraploids and diploids. A simple hydraulic model suggested that tetraploids deplete soil moisture to a greater degree than neotetraploids and diploids before reaching leaf water potentials that cause stomatal closure. We conclude that the different physiological tolerances and distribution of diploid and tetraploid C. angustifolium are unlikely to be caused solely by genome duplication. The enhanced ability of tetraploids to survive water stress likely evolved after polyploidization. PMID:19703115

  4. Mitochondrial DNA suggests a single maternal origin for the widespread triploid parthenogenetic pest species, Paratanytarsus grimmii, but microsatellite variation shows local endemism

    Institute of Scientific and Technical Information of China (English)

    Melissa Carew; Bryant Gagliardi; Ary A.Hoffmann

    2013-01-01

    Parthenogenesis is common among invasive pest species,with many parthenogenetic species also showing polyploidy.Parthenogenetic polyploid species often have multiple hybrid origins and the potential to rapidly spread over vast geographical areas.In this study,we examine patterns of mitochondrial and microsatellite variation in a widespread triploid parthenogenetic chironomid pest species,Paratanytarsus grimmii.Based on samples from five countries,including Australia,England,Germany,Japan,and Canada,we found extremely low mitochondrial diversity (< 0.14%),with most individuals sharing a common and widespread haplotype.In contrast,microsatellite diversity revealed 41 clonal variants,which were regionally endemic.These findings suggest a single invasive maternal lineage of P.grimmii is likely to have recently spread over a broad geographical range.High levels of genotypic endemism suggest P.grimmii populations have remained relatively isolated after an initial spread,with little ongoing migration.This,in part,can be attributed to rapid genetic differentiation via mutations of common clonal genotypes after P.grimmii spread,but multiple polyploidization and subsequent founder events are also likely to be contributing factors.

  5. Phylogenetic inferences in Avena based on analysis of FL intron2 sequences.

    Science.gov (United States)

    Peng, Yuan-Ying; Wei, Yu-Ming; Baum, Bernard R; Yan, Ze-Hong; Lan, Xiu-Jin; Dai, Shou-Fen; Zheng, You-Liang

    2010-09-01

    The development and application of molecular methods in oats has been relatively slow compared with other crops. Results from the previous analyses have left many questions concerning species evolutionary relationships unanswered, especially regarding the origins of the B and D genomes, which are only known to be present in polyploid oat species. To investigate the species and genome relationships in genus Avena, among 13 diploid (A and C genomes), we used the second intron of the nuclear gene FLORICAULA/LEAFY (FL int2) in seven tetraploid (AB and AC genomes), and five hexaploid (ACD genome) species. The Avena FL int2 is rather long, and high levels of variation in length and sequence composition were found. Evidence for more than one copy of the FL int2 sequence was obtained for both the A and C genome groups, and the degree of divergence of the A genome copies was greater than that observed within the C genome sequences. Phylogenetic analysis of the FL int2 sequences resulted in topologies that contained four major groups; these groups reemphasize the major genomic divergence between the A and C genomes, and the close relationship among the A, B, and D genomes. However, the D genome in hexaploids more likely originated from a C genome diploid rather than the generally believed A genome, and the C genome diploid A. clauda may have played an important role in the origination of both the C and D genome in polyploids.

  6. Psychosine-triggered endomitosis is modulated by membrane sphingolipids through regulation of phosphoinositide 4,5-bisphosphate production at the cleavage furrow.

    Science.gov (United States)

    Watanabe, Hiroshi; Okahara, Kyohei; Naito-Matsui, Yuko; Abe, Mitsuhiro; Go, Shinji; Inokuchi, Jinichi; Okazaki, Toshiro; Kobayashi, Toshihide; Kozutsumi, Yasunori; Oka, Shogo; Takematsu, Hiromu

    2016-07-01

    Endomitosis is a special type of mitosis in which only cytokinesis-the final step of the cell division cycle-is defective, resulting in polyploid cells. Although endomitosis is biologically important, its regulatory aspects remain elusive. Psychosine, a lysogalactosylceramide, prevents proper cytokinesis when supplemented to proliferating cells. Cytokinetic inhibition by psychosine does not inhibit genome duplication. Consequently cells undergo multiple rounds of endomitotic cell cycles, resulting in the formation of giant multiploid cells. Here we successfully quantified psychosine-triggered multiploid cell formation, showing that membrane sphingolipids ratios modulate psychosine-triggered polyploidy in Namalwa cells. Among enzymes that experimentally remodel cellular sphingolipids, overexpression of glucosylceramide synthase to biosynthesize glycosylsphingolipids (GSLs) and neutral sphingomyelinase 2 to hydrolyze sphingomyelin (SM) additively enhanced psychosine-triggered multiploidy; almost all of the cells became polyploid. In the presence of psychosine, Namalwa cells showed attenuated cell surface SM clustering and suppression of phosphatidylinositol 4,5-bisphosphate production at the cleavage furrow, both important processes for cytokinesis. Depending on the sphingolipid balance between GSLs and SM, Namalwa cells could be effectively converted to viable multiploid cells with psychosine. PMID:27170180

  7. Burst speciation processes and genomic expansion in the neotropical annual killifish genus Austrolebias (Cyprinodontiformes, Rivulidae).

    Science.gov (United States)

    García, G; Gutiérrez, V; Ríos, N; Turner, B; Santiñaque, F; López-Carro, B; Folle, G

    2014-02-01

    The extent to which genome sizes and other nucleotypic factors influence the phyletic diversification of lineages has long been discussed but remains largely unresolved. In the present work, we present evidence that the genomes of at least 16 species of the neotropical rivulid killifish genus Austrolebias are unusually large, with an average DNA content of about 5.95 ± 0.45 picograms per diploid cell (mean C-value of about 2.98 pg). They are thus larger than the genomes of very nearly all other diploid, i.e. non-(paleo) polyploid species of actinopterygian fishes so far reported. Austrolebias species appear to be conventional diploids in all other respects and there is no reason to believe that they arise from polyploid ancestors. The genome sizes reported for other rivulid killifishes, including a putative sister group, are considerably smaller and fall within the range typical of most other cyprinodontoid species. Therefore, it appears that the ancestor(s) of contemporary Austrolebias have undergone one or more episodes of genome expansion encompassing sudden speciation process during the Pleistocene. In addition, these findings are consistent with the hypothesis of a positive correlation between species richness and genome size.

  8. Sequence diversity and copy number variation of Mutator-like transposases in wheat

    Directory of Open Access Journals (Sweden)

    Nobuaki Asakura

    2008-01-01

    Full Text Available Partial transposase-coding sequences of Mutator-like elements (MULEs were isolated from a wild einkorn wheat, Triticum urartu, by degenerate PCR. The isolated sequences were classified into a MuDR or Class I clade and divided into two distinct subclasses (subclass I and subclass II. The average pair-wise identity between members of both subclasses was 58.8% at the nucleotide sequence level. Sequence diversity of subclass I was larger than that of subclass II. DNA gel blot analysis showed that subclass I was present as low copy number elements in the genomes of all Triticum and Aegilops accessions surveyed, while subclass II was present as high copy number elements. These two subclasses seemed uncapable of recognizing each other for transposition. The number of copies of subclass II elements was much higher in Aegilops with the S, Sl and D genomes and polyploid Triticum species than in diploid Triticum with the A genome, indicating that active transposition occurred in S, Sl and D genomes before polyploidization. DNA gel blot analysis of six species selected from three subfamilies of Poaceae demonstrated that only the tribe Triticeae possessed both subclasses. These results suggest that the differentiation of these two subclasses occurred before or immediately after the establishment of the tribe Triticeae.

  9. Inheritance and Variation of Genomic DNA Methylation in Diploid and Triploid Pacific Oyster (Crassostrea gigas).

    Science.gov (United States)

    Jiang, Qun; Li, Qi; Yu, Hong; Kong, Lingfeng

    2016-02-01

    DNA methylation is an important epigenetic mechanism that could be responsive to environmental changes indicating a potential role in natural selection and adaption. In order to evaluate an evolutionary role of DNA methylation, it is essential to first gain a better insight into inheritability. To address this question, this study investigated DNA methylation variation from parents to offspring in the Pacific oyster Crassostrea gigas using fluorescent-labeled methylation-sensitive amplified polymorphism (F-MSAP) analysis. Most of parental methylated loci were stably transmitted to offspring segregating following Medelian expectation. However, methylated loci deviated more often than non-methylated loci and offspring showed a few de novo methylated loci indicating DNA methylation changes from parents to offspring. Interestingly, some male-specific methylated loci were found in this study which might help to explore sex determination in oyster. Despite environmental stimuli, genomic stresses such as polyploidization also can induce methylation changes. This study also compared global DNA methylation level and individual methylated loci between diploid and triploid oysters. Results showed no difference in global methylation state but a few ploidy-specific loci were detected. DNA methylation variation during polyploidization was less than autonomous methylation variation from parents to offspring.

  10. GAMETAS NÃO REDUZIDOS NO MELHORAMENTO DE PLANTAS UNREDUCED GAMETES IN PLANT BREEDING

    Directory of Open Access Journals (Sweden)

    Maria Teresa Schifino-Wittmann

    2001-02-01

    Full Text Available Nesta revisão são abordados o papel dos gametas não reduzidos (gametas 2n, ou seja, aqueles com o número somático de cromossomos, na origem dos poliplóides, e sua utilização no melhoramento genético de plantas. Aceita-se que a origem dos poliplóides na natureza tenha ocorrido pela fusão de gametas não reduzidos e não pela duplicação somática. Esses gametas são formados por uma não redução cromossômica durante a meiose, que pode ocorrer de duas formas: na meiose I, pela RPD (restituição na primeira divisão, ou na meiose II, pela RSD (restituição na segunda divisão. Normalmente, são encontrados em baixíssimas freqüências em populações naturais, com notáveis exceções, e sua formação é influenciada por fatores genéticos e ambientais. A detecção dos gametas 2n, mais estudados na meiose masculina do que na feminina, é mais freqüentemente feita pela medida de grãos de pólen, ou pela presença de díades e tríades ao final da meiose II. No melhoramento, são utilizados basicamente de duas formas: na poliploidização sexual, uni ou bilateral, que mantém, no poliplóide, a heterozigose que é perdida durante a duplicação somática de cromossomos, e como uma ponte para transferir genes desejáveis de espécies silvestres diplóides para cultivadas poliplóides, como, por exemplo, no caso da alfafa. A manipulação de gametas não reduzidos deve ser considerada como uma ferramenta importante para o melhorista.The role of unreduced (2n gametes, those with the somatic chromosome number, in the origin of polyploids and in plant breeding are reviewed. It is accepted that polyploids originated in nature rather by fusion of unreduced gametes than by somatic duplication. These gametes are formed by meiotic non-reduction, in the first division restitution (FDR or in the second division restitution (SDR. They are normally found in natural populations in very low frequencies, with some remarkable exceptions, and are

  11. Spatial segregation of Darwinula stevensoni (Crustacea: Ostracoda genotypes in lentic and lotic habitats of Northern Italy

    Directory of Open Access Journals (Sweden)

    Andrea GANDOLFI

    2004-02-01

    Full Text Available The clonal structure of apomictic populations of Darwinula stevensoni from Northern Italy lacustrine and riverine habitats has been analysed by allozyme electrophoresis. Thirty two sites were sampled and a total of 748 individuals were analysed. Only one polymorphic locus, Gpi, turned out to have enough variation to be informative. Two thirds of all individuals were homozygous for the most frequent allele but the frequency of this genotype was significantly lower in rivers (16% than in lakes (92%. As a consequence homozygous clonal females are dominant in lacustrine habitats while heterozygous clonal females are dominant in riverine ones. Differences in genetic structure between habitats were observed even at distances of a few meters. Allele and genotype frequencies are significantly different between Lake Montorfano and its outflow (River Seveso and between Mantova lakes and their two tributaries, the River Mincio and Corniano Channel. The former is also the outflow of Lake Garda. By laboratory experiments, we previously reported difference between genotypes: homozygous females from Mantova lakes show significantly lower starvation tolerance than heterozygous females from River Mincio. We discuss the hypothesis that habitat segregation is related to this difference. Riverine females should be better adapted to low productivity ecosystems than lacustrine ones.

  12. Effects of soil moisture and floral herbivory on sexual expression in a gynodioecious orchid

    Institute of Scientific and Technical Information of China (English)

    Yang LU; Yi-Bo LUO; Shuang-Quan HUANG

    2012-01-01

    Compared to pollinator limitation and inbreeding avoidance,the role of ecological factors in sexual differentiation has received less attention in sexual dimorphic plants.The effect of soil moisture and florivory on two sexual morphs in a gynodioecious orchid,Satyrium ciliatum,was investigated in seven gynodioecious (with both female and hermaphrodite individuals) and 15 hermaphroditic (with only hermaphrodite individuals) populations.Our result showed that,compared to hermaphrodites,females tended to occur in drier sites in which soil water content was consistently lower than that of hermaphrodites in all gynodioecious populations.The soil water content where hermaphrodites grew was not significantly different between gynodioecious and hermaphroditic populations.We observed that females experienced less attack by insect florivores than hermaphrodites in gynodioecious populations,and hermaphroditic populations had higher insect attack than gynodioecious populations.Our results provide evidence for females being favored in stressful sites.However,the soil moisture and degree of florivory were not correlated to female frequency among populations,suggesting that the two ecological factors have not induced strong effects or other factors that may also influence the sex ratio in the facultative apomictic orchid.

  13. Reproductive biology of an Alpic paleo-endemic in a changing climate.

    Science.gov (United States)

    Guerrina, Maria; Casazza, Gabriele; Conti, Elena; Macrì, Carmelo; Minuto, Luigi

    2016-05-01

    Climate change is known to have a profound influence on plant reproduction, mainly because it affects plant/pollinator interactions, sometimes driving plants to extinction. Starting from the Neogene, the European climate was subjected to severe alterations. Nevertheless, several genera, including Berardia, survived these climatic changes. Despite the numerous studies performed about the relationship between climate change and plant reproductive biology, equivalent studies on ancient species are lacking, even though they may furnish crucial information on the strategies that allowed them to survive drastic climatic fluctuations. We investigated floral and reproductive features in Berardia subacaulis (Asteraceae), describing pollen vectors, capitulum and florets phenology, evaluating reproductive efficiency and defining the reproductive mode of the plant with bagging experiments and test of apomixis. B. subacaulis grows in habitats with low pollination services; it is self-compatible, but many typical features favouring cross-pollination are still present: florets are characterized by incomplete protandry, capitulum protogyny and high pollen-ovule ratio. The plant is not apomictic and self-fertilization is allowed within each capitulum. Similarly to other European Alpine endemics supposed to belong to the Mediterranean ancient tropical flora, the reproductive mode observed in the monospecific genus Berardia assured reproduction also under a pollinator decline. Differently from the other endemics, it took advantage of its spontaneous self-pollination and compatibility and its generalist pollination service, common both among high altitude plants and in the Asteraceae. PMID:26886434

  14. Integrating biotechnological advancements with induced mutagenesis: New opportunities for horticulture with special reference to Vitis vinifera

    International Nuclear Information System (INIS)

    Mutation assisted breeding (MAB) is a highly effective way of enhancing natural genetic resources. Increasing mutation rates is important when natural variation is insufficient, when a single trait in a desirable variety needs improvement or when the species is apomictic or seedless. Development of cell and tissue culture-based regeneration techniques in many horticultural crops and increased knowledge of biochemical pathways provide ample opportunities to exploit MAB at an advanced level. Traditionally buds, bulbs, corms, cuttings or whole plants are treated in vegetatively propagated crops, but this results in chimeras. We have initiated a collaborative project to use embryogenic cell lines of Sicilian and international cultivars of Vitis vinifera to produce mutant populations for use in genetic studies as well as for selecting disease-resistant mutants in vitro. We have established embryogenic cell lines of Sicilian and New Zealand cultivars and established the LD 20 for ethylmethane sulphonate for several cultivars. The cell lines will be subjected to treatment with mutagenic agents, and mutants with tolerance to Botrytis toxins will be selected in vitro and regenerated. With the genome sequencing of Vitis vinifera being completed and the resistance to genetically modified crops in both Europe and New Zealand very high, our mutant collection will provide a valuable resource for genetic studies of this species. (author)

  15. Limonium carvalhoi (Plumbaginaceae, una especie nueva endémica de las Islas Baleares

    Directory of Open Access Journals (Sweden)

    Rosselló, Josep A.

    1998-06-01

    Full Text Available Limonium carvalhoi Rosselló & L. Sáez is described from a single salt marsh locality in southwest Majorca. Morphologically, L. carvalhoi is close to L. inexpectans, L. migjornense and L. magallufianum, all Balearic endemics. The new species has an apomictic breeding system and shows a single pollen/stigma combination (B/papillate type. Chromosome number ranges from 2n = 24 to 2n = 26. Based on the occurrence of a long metacentric chromosome in all cells examined, it is suggested that the original chromosome complement is 2n = 26, the other chromosome numbers being derived by descending aneuploidy.Se describe Limonium carvalhoi Rosselló & L. Sáez de un marjal en una única localidad del sudoeste de Mallorca. Morfológicamente, la nueva especie es afín a otras tres también endémicas de las Baleares: L. inexpectans, L. migjornense y L. magallufianum. Limonium carvalhoi es apomíctica y presenta una combinación polen/estigma del tipo B/p. Los números cromosomáticos encontrados van de 1n = 24 a 2n = 26. Sobre la base de la presencia de un cromosoma metacéntrico largo en todas las células examinadas, se sugiere que el complemento cromosomático original es 2n = 26 y que los otros dos números se han derivado por aneuploidía descendente.

  16. Meiotic behavior of Brachiaria decumbens hybrids.

    Science.gov (United States)

    Souza, V F; Pagliarini, M S; Valle, C B; Bione, N C P; Menon, M U; Mendes-Bonato, A B

    2015-01-01

    Brachiaria decumbens is a forage grass of inestimable value for livestock in Brazil due to its production of good quality forage even when planted on acid and poor soils, although it is susceptible to pasture spittlebugs. Only one cultivar, cv. Basilisk, has been used as the pollen donor in crosses with Brachiaria ruziziensis since 1988 at Embrapa Gado de Corte Research Center. Breeding within the species only became possible from 2009 when sexual accessions were successfully tetraploidized using colchicine. Three sexual genotypes were obtained and hybridization within B. decumbens was finally achieved. Here, we evaluated microspore tetrads using conventional cytology and found meiotic indexes above 78% for all three female genitors (cD24-2, cD24-27, cD24-45), but a low meiotic index (crossed to D62, but these two did not differ. Apomictic hybrids such as S036 and X030 with low pollen sterility have the potential for use in cultivar development, whereas the sexual hybrids T012, X072, and X078 might be of use as female genitors in polycross blocks if they display good agronomic traits. PMID:26505437

  17. Effects of nickel on the fern Regnellidium diphyllum Lindm. (Marsileaceae).

    Science.gov (United States)

    Kieling-Rubio, M A; Droste, A; Windisch, P G

    2012-11-01

    The heterosporous fern Regnellidium diphyllum occurs in southern Brazil and some adjoining localities in Uruguay and Argentina. Currently it is on the list of threatened species in the state of Rio Grande do Sul. Anthropic alterations such as the conversion of wetlands into agricultural areas or water and soil contamination by pollutants may compromise the establishment and survival of this species. Nickel (Ni) is an essential nutrient for plants but increasing levels of this metal due to pollution can cause deleterious effects especially in aquatic macrophytes. Megaspore germination tests were performed using Meyer's solution, at concentrations of 0 (control), 0.05, 0.5, 1, 5, 10, 20, 30, 50 and 100 mg L(-1) of Ni. The initial development of apomictic sporophytes was studied using solutions containing 0 (control) to 4.8 mg L(-1) of Ni. A significant negative relation was observed between the different Ni concentrations and the megaspore germination/sporophyte formation rates. Primary roots, primary leaves and secondary leaves were significantly shorter at 3.2 and 4.8 mg L(-1) of Ni, when compared with the treatment without this metal. At 4.8 mg L(-1), leaves also presented chlorosis and necrosis. The introduction of pollutants with Ni in the natural habitat of Regnellidium diphyllum may inhibit the establishment of plants in the initial stage of development, a problem to be considered in relation to the conservation of this species. PMID:23295508

  18. Development of innovative techniques and principles that may be used as models to improve plant performance. Technical progress report, February 1, 1990--January 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Hanna, W.W.; Burton, G.W.

    1992-06-01

    Methods and techniques for transferring germplasm from wild to cultivated species are being developed. The transferred germplasm is being shown to be valuable in plant breeding and in cultivar development. In the primary gene pool of the grassy Pennisetum glaucum subspecies monodii germplasm, some cytoplasms are being identified that appear to have significant effects on forage yields and morphological characteristics. One cytoplasm, A{sub 4}, is very stable for male sterility and fertility is not easily restored by other lines. It should be a valuable cytoplasm for producing commercial forage hybrids. Disease resistance and yield genes transferred from monodii to cultivated pearl millet lines are having a major impact on increasing production of animals grazing disease resistant Tifleaf 2 pearl millet. Genes controlling resistance to many of the world-wide diseases on pearl millet are being identified in the monodii germplasm. Valuable germplasm has been transferred from the secondary gene pool P. purpuroum) which is used as the pollinator of the first pearl millet grain hybrid in the US Production of 7-chromosome gametes in 42-chromosome interspecific hybrids appears to be genotype specific and makes possible transfer of germplasm from the secondary gene pool to cultivated diploid pearl millet. Significant progress has been made in transferring genes controlling apomixis from P. squamulatum (tertiary gene pool) to cultivated pearl millet. Highly apomictic BC{sub 4} plants have been recovered, one of which sets five times as much seed as the best BC{sub 3} plant.

  19. Different aspects of reproduction strategies in crayfish: A review

    Directory of Open Access Journals (Sweden)

    Yazicioglu B.

    2016-01-01

    Full Text Available Study of the reproductive strategy of crayfish species is of great importance in the current astacological world. Crayfish are among the largest freshwater invertebrates, and as keystone species, they are able to regulate the structure of the benthic fauna in the freshwaters, demonstrating different ecological strategies and life spans ranging up to 20+ years. In order to bring together the various pieces of information related to this issue, this overview of published scientific reports was conducted. The majority of crayfish species studied show sexual dimorphism, with approximately equal numbers of males and females. However, over some decades numerous observations have been made for a few species that may have different modes of reproduction, such as hermaphroditism or intersex (e.g. Cherax quadricarinatus, Samastacus spinifrons, Parastacus virilastacus and Pacifastacus leniusculus and parthenogenesis (only Procambarus fallax f. virginalis. A recent study showed a new case of parthenogenesis as apomictic parthenogenesis (only Orconectes limosus. In addition, there are many investigations into the reproduction biology of crayfish, including using eyestalk ablation or androgenic gland ablation under various lab conditions and hybridization under natural conditions (e.g. Astacus astacus X Astacus leptodactylus, Orconectes rusticus X Orconectes propinquus. There are also some chemical factors which could possibly affect the reproduction system of crayfish in the wild.

  20. Inter-and intraspecific variation in fern mating systems after long-distance colonization: the importance of selfing

    Directory of Open Access Journals (Sweden)

    de Groot G Arjen

    2012-01-01

    Full Text Available Abstract Background Previous studies on the reproductive biology of ferns showed that mating strategies vary among species, and that polyploid species often show higher capacity for self-fertilization than diploid species. However, the amount of intraspecific variation in mating strategy and selfing capacity has only been assessed for a few species. Yet, such variation may have important consequences during colonization, as the establishment of any selfing genotypes may be favoured after long-distance dispersal (an idea known as Baker's law. Results We examined intra-and interspecific variation in potential for self-fertilization among four rare fern species, of which two were diploids and two were tetraploids: Asplenium scolopendrium (2n, Asplenium trichomanes subsp. quadrivalens (4n, Polystichum setiferum (2n and Polystichum aculeatum (4n. Sporophyte production was tested at different levels of inbreeding, by culturing gametophytes in isolation, as well as in paired cultures with a genetically different gametophyte. We tested gametophytes derived from various genetically different sporophytes from populations in a recently planted forest colonized through long-distance dispersal (Kuinderbos, the Netherlands, as well as from older, less disjunct populations. Sporophyte production in isolation was high for Kuinderbos genotypes of all four species. Selfing capacity did not differ significantly between diploids and polyploids, nor between species in general. Rather selfing capacity differed between genotypes within species. Intraspecific variation in mating system was found in all four species. In two species one genotype from the Kuinderbos showed enhanced sporophyte production in paired cultures. For the other species, including a renowned out crosser, selfing capacity was consistently high. Conclusions Our results for four different species suggest that intraspecific variation in mating system may be common, at least among temperate calcicole