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Takashi Handa - One of the best experts on this subject based on the ideXlab platform.

  • a rapid agrobacterium mediated transformation of Antirrhinum Majus l by using direct shoot regeneration from hypocotyl explants
    Plant Science, 2004
    Co-Authors: Minlong Cui, Hiroshi Kamada, Shigeo Nishimura, Hiroshi Ezura, Takashi Handa
    Abstract:

    Abstract A rapid genetic transformation of Antirrhinum Majus L. was developed using direct shoot regeneration from hypocotyl explants inoculated with Agrobacterirum tumefaciens. We used the binary vectors pBI121 containing the neomycin phosphotransferase (NPT II) gene as a selectable marker and the β-glucuronidase (GUS) gene as a reporter and pIG121-Hm harboring NPT II and the hygromycin phosphotransferase (hpt) gene as selectable markers and GUS as a reporter. Transformed shoots directly emerged at the end of hypocotyl explants inoculated with Agrobacterium strain GV2260/pIG121-Hm or GV3101/ pBI121 after 4–6 weeks of culturing on selection medium. The transformed shoots were rooted after 3 weeks of culturing on rooting medium. The transformation efficiency reached to 1% of inoculated explants. Putative transformants were identified using kanamycin selection and GUS activity. The PCR and Southern blot analysis confirmed the integration of GUS into the genomes of transformants. Using the developed protocol, transgenic A. Majus is produced after 10 weeks of Agrobacterium inoculation.

  • efficient shoot regeneration from hairy roots of Antirrhinum Majus l transformed by the rol type mat vector system
    Plant Cell Reports, 2001
    Co-Authors: Minlong Cui, Kenji Takayanagi, Hiroshi Kamada, Shigeo Nishimura, Takashi Handa
    Abstract:

    Eleven independent GUS-positive hairy roots were induced by co-cultivation of leaf explants of Antirrhinum Majus L. with Agrobacterium tumefaciens strain GV2260 containing the rol type MAT vector pNPI702. The MAT vector pNPI702 possesses a GUS gene under the 35 S promoter and a removal element in which the 7.6-kb DNA fragments containing the rolA, B, C and D genes and recombinase gene with a 35 S promoter are located between two directly oriented recombination site sequences. A total of 326 adventitious shoots regenerated from 11 independent hairy root lines cultured on 1/2MS medium without plant growth regulators at 25 °C under a 16/8 h (day/night) photoperiod after 8 weeks of stock-culture of hairy roots and 4 weeks of culture of the green segments of hairy roots. Regenerated plants showed either a normal or dwarf morphology. GUS activity was observed in the hairy roots and regenerated shoots. The presence of the GUS gene in the regenerated, morphologically normal plants was confirmed by PCR analysis.

  • transformation of Antirrhinum Majus l by a rol type multi auto transformation mat vector system
    Plant Science, 2000
    Co-Authors: Cui Minlong, Kenji Takayanagi, Hiroshi Kamada, Shigeo Nishimura, Takashi Handa
    Abstract:

    A total of 11 independent beta-glucuronidase (GUS) positive hairy roots were induced following co-cultivation of leaf explants of Antirrhinum Majus L. with Agrobacterium tumefaciens strain GV2260 containing rol-type multi-auto-transformation (MAT) vector pNPI702. A total of 326 adventitious shoots were regenerated from the hairy root lines on 1/2 MS medium without plant growth regulators at 25 degrees C under a 16 h/day photoperiod condition 4 months after infection of the A. tumefaciens GV2260. The absence of the rol genes in five plants was verified by polymerase chain reaction (PCR) and Southern blot analysis. Acclimatized transformants exhibited normal phenotypes in height and in the morphology of leaves and flowers. Furthermore, the GUS gene was strongly expressed in the leaves, inflorescence of the transformed plant, and the progeny. This result demonstrates that the rol-type MAT vector can be used to study gene functions controlling the morphogenesis of Antirrhinum Majus plants.

  • genetic transformation of Antirrhinum Majus l and inheritance of altered phenotype induced by ri t dna
    Plant Science, 1992
    Co-Authors: Takashi Handa
    Abstract:

    Abstract Hairy roots were obtained from snapdragon ( Antirrhinum Majus L.) plants infected with Agrobacterium rhizogenes harbouring the agropine type Ri plasmid (pRiA4). Plant regeneration occurred spontaneously on Linsmaier-Skoog (LS) medium lacking phytohormones under a 16-h/day photoperiod. Phenotypic alterations such as dwarfness, decrease in apical dominance, increase in number of flowers and stimulation of root production were observed in transformed plants. Opine analysis suggested the integration of TR-DNA and Southern analysis confirmed multiple integrations of TL-DNA. One of the transformed plants was fertile, and the progeny also exhibited the dwarf phenotype and had small flowers and elliptical leaves. Progeny expressing phenotypic alterations retained core T-DNA including rol genes.

Benoit Pujol - One of the best experts on this subject based on the ideXlab platform.

  • Genetic variation underlies the plastic response to shade of snapdragon plants ( Antirrhinum Majus L.)
    Botany Letters, 2021
    Co-Authors: Mathilde Mousset, Sara Marin, Juliette Archambeau, Christel Blot, Vincent Bonhomme, Laura Garaud, Benoit Pujol
    Abstract:

    A classic example of phenotypic plasticity in plants is the set of traits that change in response to shade. There is widespread evidence that plants in low light conditions often avoid shade by growing taller or by increasing their photosynthetic efficiency, i.e. the shade avoidance syndrome. Whether this plasticity might evolve in response to natural selection depends upon the presence of its standing genetic variation in wild populations. There is limited evidence for heritable standing variation in the plastic response of plants to shade. In this study, we used an experimental common garden approach to investigate this plastic response in snapdragon plants (Antirrhinum Majus L.) originating from four natural populations from the Mediterranean region. Our results showed that individual plants reacted strongly to the presence of shade by growing longer shoots, longer internodes, and increasing their specific leaf area in these four populations. Our results also revealed genetic variation for the plastic response within these populations, as well as little genetic constraints to its evolution. Our findings imply that natural populations of A. Majus harbour standing genetic variation for phenotypic plasticity in response to shade, providing them the potential to evolve in response to selection.

  • Phenotypic response to light versus shade associated with DNA methylation changes in Snapdragon plants (Antirrhinum Majus)
    Genes, 2021
    Co-Authors: Pierick Mouginot, Sara Marin, Delphine Gourcilleau, Mathieu Latutrie, Nelia Luviano Aparicio, Jean-louis Hemptinne, Christoph Grunau, Benoit Pujol
    Abstract:

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

  • Assessing Global DNA Methylation Changes Associated with Plasticity in Seven Highly Inbred Lines of Snapdragon Plants (Antirrhinum Majus)
    Genes, 2019
    Co-Authors: Delphine Gourcilleau, Mathilde Mousset, Sara Marin, Mathieu Latutrie, Alain Delaunay, Stéphane Maury, Benoit Pujol
    Abstract:

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

  • Genotype by environment interactions for the shade avoidance syndrome in the plant Antirrhinum Majus, the snapdragon
    2018
    Co-Authors: Mathilde Mousset, Sara Marin, Juliette Archambeau, Christel Blot, Vincent Bonhomme, Laura Garaud, Benoit Pujol
    Abstract:

    A classical example of phenotypic plasticity in plants is the set of trait changes in response to shade, i.e. the shade avoidance syndrome. There is widespread evidence that plants in low light conditions often avoid shade by growing taller or by increasing their photosynthetic efficiency. This plastic response is expected to have evolved in response to selection in several species, yet there is limited evidence for its genetic variation within populations, which is required for any evolutionary response to selection. In this study, we investigated the shade avoidance syndrome in snapdragon plants (Antirrhinum Majus) by using a common garden approach on four natural populations from the Mediterranean region. Our results showed that, in the four populations, individual plants reacted strongly to the presence of shade by growing longer shoots, longer internodes, and increasing their specific leaf area. Our results also revealed genetic variation for the plastic response within these populations, as well as few genetic constraints to its evolution. Our findings imply that the plastic response to shade has the potential to evolve in response to selection in natural populations of A. Majus.

  • Mountain landscape connectivity and subspecies appurtenance shape genetic differentiation in natural plant populations of the snapdragon (Antirrhinum Majus L.)
    2018
    Co-Authors: Benoit Pujol, Sara Marin, Juliette Archambeau, Aurore Bontemps, Mylène Lascoste, Alexandre Meunier
    Abstract:

    This dataset provides the raw data for the population genetic analyses for the article: "Mountain landscape connectivity and subspecies appurtenance shape genetic differentiation in natural plant populations of the snapdragon (Antirrhinum Majus L.)" by Benoit Pujol; Juliette Archambeau; Aurore Bontemps; Mylène Lascoste; Sara Marin; and Alexandre Meunier found in the journal "Botany Letters", Vol 164 pp. 111-119 (DOI: 10.1080/23818107.2017.1310056). Link to journal open access article: http://www.tandfonline.com/doi/pdf/10.1080/23818107.2017.1310056 Link to Zenodo article reporsitory: https://zenodo.org/record/801169 The datafile includes three data sheets: Data, which contains for each plant : the name of the population, the name of the sampled individual, the subspecies, the latitude of the population, the longitude of the population, the altitudinal elevation of the population in meters, and the microsatellite genotype of each plant. Genotype data is recorded by locus (two columns for the two alleles at one locus). Locus name is found as the title of the column. The record for each allele is its allele size. valleys 1 and valleys 2, which contains the association between populations and valleys following the two scenarios that we analyzed in the paper. Microsatelite loci were developed during previous work: see the following paper for more details: Debout, G., E. Lhuillier, P.-J. Malé, B. Pujol, and C. Thébaud. 2012. Development and characterization of 24 polymorphic microsatellite loci in two Antirrhinum Majus subspecies (Plantaginaceae) using pyrosequencing technology. Conservation Genetics Resources 4:75-79.

Hans Sommer - One of the best experts on this subject based on the ideXlab platform.

  • rosina rsi a novel protein with dna binding capacity acts during floral organ development in Antirrhinum Majus
    Plant Journal, 2005
    Co-Authors: Mario Roccaro, Heinz Saedler, Simona Masiero, Hans Sommer
    Abstract:

    *† ‡ Summary Petal and stamen identity of the Antirrhinum Majus flower is under the genetic control of the floral homeotic geneDEFICIENS (DEF). To isolate factors involved in the regulation of DEFgene activity, a promoter segment of this B-function gene, containing cis-acting regulatory elements, was used to identify the novel trans-acting factor ROSINA (RSI). RSI does not show an extended similarity with any gene product present in the database. Rather RSI constitutes a protein that contains domains similar to known proteins from organisms of different phyla. The capacity of RSI to bind a sequence element of the DEF promoter, its spatial and temporal expression pattern together with the phenotype of RSI-RNAi interference plants as well as RSI over-expression in Arabidopsis thaliana suggest that RSI is a putative regulator of DEF gene activity in A. Majus.

  • ntglo a tobacco homologue of the globosa floral homeotic gene of Antirrhinum Majus cdna sequence and expression pattern
    Molecular Genetics and Genomics, 1993
    Co-Authors: Genevieve Hansen, Hans Sommer, Juan Jose Estruch, Angelo Spena
    Abstract:

    We report the cloning and DNA sequence of a cDNA from Nicotiana tabacum, NTGLO, as well as the pattern of expression of the NTGLO gene in wild-type tobacco plants. The NTGLO cDNA encodes a protein of 209 amino acids, which shows 73% identity with the GLO protein encoded by the GLO gene of Antirrhinum Majus, a homeotic gene involved in the genetic control of flower development. Northern blot analysis shows that the NTGLO gene is expressed mainly in floral organs and, within the flower, expression is restricted to petals and stamens. The NTGLO gene most probably represents a true homologue of the GLO gene because: i) the MADS boxes, of the two genes are highly homologous (56 out of 58 amino acids are identical): ii) at the carboxyterminal a block of 19 amino acids is perfectly conserved between the NTGLO and GLO proteins and iii) their expression patterns in floral organs are identical.

  • bracteomania an inflorescence anomaly is caused by the loss of function of the mads box gene squamosa in Antirrhinum Majus
    The EMBO Journal, 1992
    Co-Authors: Peter Huijser, Heinz Saedler, Wolfekkehard Lonnig, Jan Klein, H Meijer, Hans Sommer
    Abstract:

    Abstract Anomalous flowering of the Antirrhinum Majus mutant squamosa (squa) is characterized by excessive formation of bracts and the production of relatively few and often malformed or incomplete flowers. To study the function of squamosa in the commitment of an inflorescence lateral meristem to floral development, the gene was cloned and its genomic structure, a well as that of four mutant alleles, was determined. SQUA is a member of a family of transcription factors which contain the MADS-box, a conserved DNA binding domain. In addition, we analysed the temporal and spatial expression pattern of the squa gene. Low transcriptional activity of squa is detectable in bracts and in the leaves immediately below the inflorescence. High squa transcript levels are seen in the inflorescence lateral meristems as soon as they are formed in the axils of bracts. Squa transcriptional activity persists through later stages of floral morphogenesis, with the exception of stamen differentiation. Although necessary for shaping a normal racemose inflorescence, the squa function is not absolutely essential for flower development. We discuss the function of the gene during flowering, its likely functional redundancy and its possible interaction with other genes participating in the genetic control of flower formation in Antirrhinum.

  • the transposable element tam1 from Antirrhinum Majus shows structural homology to the maize transposon en spm and has no sequence specificity of insertion
    Molecular Genetics and Genomics, 1991
    Co-Authors: Wolfgang Nacken, Heinz Saedler, Ralf Piotrowiak, Hans Sommer
    Abstract:

    We present the genomic structure of Tam1, a transposable element from Antirrhinum Majus. The Taml element is 15.2 kb long and includes two genes that are transcribed to produce a 2.4 kb (tnpl) and a 5 kb mRNA (tnp2). These transcripts partially overlap and the exons are scattered over the whole element. Tnp1 encodes a 53 kDa protein as deduced from the cDNA sequence. The 5 kb transcript of tnp2 contains an open reading frame that shares 45% homology with part of the tnpD gene of En/Spm from maize and 48% homology with an open reading frame of the Tgm element from Glycine max. We discuss the possible functions of these genes by analogy with En/Spm. Additionally, a number of flanking sequences of Taml insertions were analysed to investigate the sequence specificity of insertion. From these studies we conclude that Taml transposes predominantly into AT-rich regions that can be unique as well as repetitive. No specific target sequence of insertion could be found.

  • Molecular analysis of tap2, an anther-specific gene from Antirrhinum Majus.
    FEBS letters, 1991
    Co-Authors: Wolfgang Nacken, Heinz Saedler, Peter Huijser, Hans Sommer
    Abstract:

    Deficiens is a floral homeotic gene of Antirrhinum Majus, mutation of which results in transformation of petals to sepals and stamens to carpels. In a search for putative target genes, controlled by this regulatory locus, cDNA clones representing genes, that are expressed in wild type but not in the deficiens mutant flowers, were isolated by differential screening. The molecular structure and the expression pattern of one of these genes, tap2, is described. Tap2 is transiently and tissue-specifically expressed in the tapetum of the anthers. It encodes a 131 amino-acids-long protein with a hydrophobic N-terminus, displaying all characteristic features of a signal peptide. This indicates that the TAP2 protein may be secreted.

Heinz Saedler - One of the best experts on this subject based on the ideXlab platform.

  • rosina rsi a novel protein with dna binding capacity acts during floral organ development in Antirrhinum Majus
    Plant Journal, 2005
    Co-Authors: Mario Roccaro, Heinz Saedler, Simona Masiero, Hans Sommer
    Abstract:

    *† ‡ Summary Petal and stamen identity of the Antirrhinum Majus flower is under the genetic control of the floral homeotic geneDEFICIENS (DEF). To isolate factors involved in the regulation of DEFgene activity, a promoter segment of this B-function gene, containing cis-acting regulatory elements, was used to identify the novel trans-acting factor ROSINA (RSI). RSI does not show an extended similarity with any gene product present in the database. Rather RSI constitutes a protein that contains domains similar to known proteins from organisms of different phyla. The capacity of RSI to bind a sequence element of the DEF promoter, its spatial and temporal expression pattern together with the phenotype of RSI-RNAi interference plants as well as RSI over-expression in Arabidopsis thaliana suggest that RSI is a putative regulator of DEF gene activity in A. Majus.

  • the homeotic macho mutant of Antirrhinum Majus reverts to wild type or mutates to the homeotic plena phenotype
    Molecular Genetics and Genomics, 1994
    Co-Authors: Wolfekkehard Lonnig, Heinz Saedler
    Abstract:

    Plants of Antirrhinum Majus carrying the semidominant Macho alleles of the plena gene display carpelloid sepals and staminoid petals, but the two inner flower whorls of stamens and carpels are normal and produce fertile gametes. In the recessive plena mutant, in contrast, the two outer whorls are normal whereas the stamens are largely or entirely petaloid and the carpels sepaloid, thus producing weakly male-fertile or fully sterile lines. Two new plena and two new Macho alleles have been induced in transposon tagging experiments. Genetic and molecular analysis revealed that the two contrasting mutant phenotypes are caused by mutations in one and the same gene: Several wild-type plants appeared among 27 000 F1 plants of a cross between Macho female plants and wild-type males bearing the active transposons Taml and Tam3. One of these plants segregated plena mutants, three showed reversions to wild-type and another two segregated Macho plants, possibly representing somatic reversions. Additional evidence was provided by an allelism test of Macho × plena. Molecular analysis has independently corroborated the genetical results. Moreover, the double mutant Macho/deficiens shows only carpels and plena/deficiens only sepals, which is in accord with combinatorial models for homeotic flower formation presented recently.

  • molecular biology of flower development in Antirrhinum Majus snapdragon
    Gene, 1993
    Co-Authors: Heinz Saedler, Peter Huijser
    Abstract:

    In recent years, isolation of several genes affecting flower development in Antirrhinum Majus made this species a major model system to study this important developmental process. Genes like SQUAMOSA and FLORICAULA are involved in determination of the floral meristem. Their mutation results in the development of bract-forming shoots at positions where normally flowers would develop. The phenotypes obtained upon mutation of the genes found to affect floral organogenesis fall into three major categories. In each category, always the floral organs in two adjacent whorls become homeotically transformed. Based on this observation a simple genetic model has been proposed to explain the establishment of floral organ identity in the four concentric whorls of the flower. The model hypothesizes the independent induction of two developmental pathways specifying floral organ identity after the formation of sepals as the basic type of organ following induction of a floral meristem. One of these pathways is under the control of the PLENA gene, the other is controlled by the DEFICIENS and GLOBOSA genes. These genes, as well as SQUAMOSA, encode transcription factors sharing a conserved DNA binding domain: the MADS-box. In vitro DNA-binding studies complemented with molecular genetic analysis of the respective mutants show that the DEF and GLO proteins may act together in the form of a heterodimer in the regulation of their target genes as well as in autoregulation. The possible interactions between other MADS-box proteins and their role in flower development is under current investigation.

  • bracteomania an inflorescence anomaly is caused by the loss of function of the mads box gene squamosa in Antirrhinum Majus
    The EMBO Journal, 1992
    Co-Authors: Peter Huijser, Heinz Saedler, Wolfekkehard Lonnig, Jan Klein, H Meijer, Hans Sommer
    Abstract:

    Abstract Anomalous flowering of the Antirrhinum Majus mutant squamosa (squa) is characterized by excessive formation of bracts and the production of relatively few and often malformed or incomplete flowers. To study the function of squamosa in the commitment of an inflorescence lateral meristem to floral development, the gene was cloned and its genomic structure, a well as that of four mutant alleles, was determined. SQUA is a member of a family of transcription factors which contain the MADS-box, a conserved DNA binding domain. In addition, we analysed the temporal and spatial expression pattern of the squa gene. Low transcriptional activity of squa is detectable in bracts and in the leaves immediately below the inflorescence. High squa transcript levels are seen in the inflorescence lateral meristems as soon as they are formed in the axils of bracts. Squa transcriptional activity persists through later stages of floral morphogenesis, with the exception of stamen differentiation. Although necessary for shaping a normal racemose inflorescence, the squa function is not absolutely essential for flower development. We discuss the function of the gene during flowering, its likely functional redundancy and its possible interaction with other genes participating in the genetic control of flower formation in Antirrhinum.

  • the transposable element tam1 from Antirrhinum Majus shows structural homology to the maize transposon en spm and has no sequence specificity of insertion
    Molecular Genetics and Genomics, 1991
    Co-Authors: Wolfgang Nacken, Heinz Saedler, Ralf Piotrowiak, Hans Sommer
    Abstract:

    We present the genomic structure of Tam1, a transposable element from Antirrhinum Majus. The Taml element is 15.2 kb long and includes two genes that are transcribed to produce a 2.4 kb (tnpl) and a 5 kb mRNA (tnp2). These transcripts partially overlap and the exons are scattered over the whole element. Tnp1 encodes a 53 kDa protein as deduced from the cDNA sequence. The 5 kb transcript of tnp2 contains an open reading frame that shares 45% homology with part of the tnpD gene of En/Spm from maize and 48% homology with an open reading frame of the Tgm element from Glycine max. We discuss the possible functions of these genes by analogy with En/Spm. Additionally, a number of flanking sequences of Taml insertions were analysed to investigate the sequence specificity of insertion. From these studies we conclude that Taml transposes predominantly into AT-rich regions that can be unique as well as repetitive. No specific target sequence of insertion could be found.

H J Newbury - One of the best experts on this subject based on the ideXlab platform.

  • transformation of Antirrhinum Majus using agrobacterium rhizogenes
    Journal of Experimental Botany, 1995
    Co-Authors: P Holford, R N Cooley, H J Newbury
    Abstract:

    Hairy roots were produced following the co-cultivation of Agrobacterium rhizogenes cells with hypocotyls of five varieties of Antirrhinum Majus. The use of a strain containing a binary plasmid with T-DNA bearing the β-glucuronidase reporter gene resulted in the co-transformation of some root clones. Regeneration of shoots from hairy roots occurred only with variety Golden Monarch. Regenerated plants, some of which were GUS-positive, exhibited the abnormal morphology common among hairy root regenerants ; they were dwarfed, had an altered leaf shape, a poor root system and were very delayed in their flowering. Attempts to allow segregation of the two introduced T-DNAs during crossing of primary co-transformants with wild-type plants were not successful since all GUS-positive progeny possessed the abnormal morphology. However, 'semi-dwarf' plants with morphology much more similar to wild-type were produced by the vegetative propagation of selected side-shoots from the transformants.

  • factors influencing the efficiency of t dna transfer during co cultivation of Antirrhinum Majus with agrobacterium tumefaciens
    Plant Cell Reports, 1992
    Co-Authors: P Holford, N Hernandez, H J Newbury
    Abstract:

    The effects of varying the pH of the cocultivation medium, additons of vir-inducing phenolic compounds and the strains of wild-type agrobacteria on transformation rates of a number of different varieties of Antirrhinum Majus were studied. In general, optimal transformation was found with strains C58 or A281 and was favoured by low pH and the inclusion of acetosyringone in the co-cultivation medium. However, maximal transformation of the least susceptible variety was achieved at high pH and in the presence of syringaldehyde. This demonstrates the need for the optimization of a wide range of culture conditions when working with new genotypes and offers a rational approach towards the development of Agrobacterium-mediated transformation of new species or varieties.

  • the effects of antibiotics and their breakdown products on the in vitro growth of Antirrhinum Majus
    Plant Cell Reports, 1992
    Co-Authors: P Holford, H J Newbury
    Abstract:

    The effects of various antibiotics on the development of hypocotyls of Antirrhinum Majus in tissue culture have been studied. The penicillins, carbenicillin and penicillin G, have been shown to stimulate callus growth, have little impact on shoot production and may stimulate root formation. The cephalosporins, cephotaxime and cephalosporin, have no effect on callus production and reduce shoot and root formation. HPLC, GC and GC-MS analyses have shown that concentrations of carbenicillin and penicillin G, commonly used in plant tissue culture, break down to give physiologically active levels of the auxin phenylacetic acid. This offers a mechanism for the stimulation of growth caused by these two antibiotics.