J B Power

University of Nottingham, Nottingham, ENG, United Kingdom

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Publications (250)514.57 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Gibberellins (GAs) control many aspects of plant development, including seed germination, shoot growth, flower induction and growth and fruit expansion. Leaf explants of Solanum nigrum (Black Nightshade; Solanaceae) were used for Agrobacterium-mediated delivery of GA-biosynthetic genes to determine the influence of their encoded enzymes on the production of bioactive GAs and plant stature in this species. Constructs were prepared containing the neomycin phosphotransferase (nptII) gene for kanamycin resistance as a selectable marker, and the GA-biosynthetic genes, their expression under the control of the CaMV 35S promoter. The GA-biosynthetic genes comprised AtGA20ox1, isolated from Arabidopsis thaliana, the product from which catalyses the formation of C(19)-GAs, and MmGA3ox1 and MmGA3ox2, isolated from Marah macrocarpus, which encode functionally different GA 3-oxidases that convert C(19)-GAs to biologically active forms. Increase in stature was observed in plants transformed with AtGA20ox1, MmGA3ox2 and MmGA3ox1 + MmGA3ox2, their presence and expression being confirmed by PCR and RT-PCR, respectively, accompanied by an increase in GA(1) content. Interestingly, MmGA3ox1 alone did not induce a sustained increase in plant height, probably because of only a marginal increase in bioactive GA(1) content in the transformed plants. The results are discussed in the context of regulating plant stature, since this strategy would decrease the use of chemicals to promote plant growth.
    Plant Cell Reports 01/2012; 31(5):945-53. · 2.94 Impact Factor
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    ABSTRACT: The genus Nicotiana includes diploid and tetraploid species, with complementary ecological, agronomic and commercial characteristics. The species are of economic value for tobacco, as ornamentals, and for secondary plant-product biosynthesis. They show substantial differences in disease resistance because of their range of secondary products. In the last decade, sexual hybridization and transgenic technologies have tended to eclipse protoplast fusion for gene transfer. Somatic hybridization was exploited in the present investigation to generate a new hybrid combination involving two sexually incompatible tetraploid species. The somatic hybrid plants were characterized using molecular, molecular cytogenetic and phenotypic approaches. Mesophyll protoplasts of the wild fungus-resistant species N. debneyi (2n = 4x = 48) were electrofused with those of the ornamental interspecific sexual hybrid N. × sanderae (2n = 2x = 18). From 1570 protoplast-derived cell colonies selected manually in five experiments, 580 tissues were sub-cultured to shoot regeneration medium. Regenerated plants were transferred to the glasshouse and screened for their morphology, chromosomal composition and disease resistance. Eighty-nine regenerated plants flowered; five were confirmed as somatic hybrids by their intermediate morphology compared with parental plants, cytological constitution and DNA-marker analysis. Somatic hybrid plants had chromosome complements of 60 or 62. Chromosomes were identified to parental genomes by genomic in situ hybridization and included all 18 chromosomes from N. × sanderae, and 42 or 44 chromosomes from N. debneyi. Four or six chromosomes of one ancestral genome of N. debneyi were eliminated during culture of electrofusion-treated protoplasts and plant regeneration. Both chloroplasts and mitochondria of the somatic hybrid plants were probably derived from N. debneyi. All somatic hybrid plants were fertile. In contrast to parental plants of N. × sanderae, the seed progeny of somatic hybrid plants were resistant to infection by Peronospora tabacina, a trait introgressed from the wild parent, N. debneyi. Sexual incompatibility between N. × sanderae and N. debneyi was circumvented by somatic hybridization involving protoplast fusion. Asymmetrical nuclear hybridity was seen in the hybrids with loss of chromosomes, although importantly, somatic hybrids were fertile and stable. Expression of fungal resistance makes these somatic hybrids extremely valuable germplasm in future breeding programmes in ornamental tobacco.
    Annals of Botany 08/2011; 108(5):809-19. · 3.45 Impact Factor
  • Plant Cell Culture: Essential Methods, 03/2010: pages 153 - 173; , ISBN: 9780470686522
  • Davey MR, Anthony P, Patel D, Power JB
    Plant Cell Culture: Essential Methods. 01/2010;
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    ABSTRACT: Poinsettia (Euphorbia pulcherrima) is one of the most popular ornamental pot plants. Conventional propagation is by cuttings, generally focused on a period prior to the most intensive time of sales. Rapid multiplication of elite clones, the production of pathogen-free plants and more rapid introduction of novel cultivars (cvs.) with desirable traits, represent important driving forces in the poinsettia industry. In recent years, different strategies have been adopted to micropropagate poinsettia, which could assist breeders to meet consumer demands. The development of reliable in vitro regeneration procedures is likely to play a crucial role in future production systems. Stem nodal explants cultured on semi-solid MS-based medium supplemented with benzylaminopurine (BAP) and naphthalene acetic acid (NAA) develop shoots from adventitious/axillary buds after 7 weeks of culture. Rooting of in vitro regenerated shoots is achieved in semi-solid MS-based medium containing the auxin indole-3-acetic acid (IAA). Four to six weeks after transfer to root-inducing medium, regenerated plants can be transferred to compost and acclimatized in the glasshouse. Direct shoot regeneration from cultured explants is important to minimize somaclonal variation in regenerated plants.
    Methods in molecular biology (Clifton, N.J.) 01/2010; 589:67-75. · 1.29 Impact Factor
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    ABSTRACT: Supplementation of semi-solid R2 culture medium with a commercial bovine haemoglobin (Hb) solution (Erythrogen™) at 1:50-1:500 (v:v), had beneficial effects on the growth, following cryopreservation, of cells of the Indica rice, Oryza sativa cv. Pusa Basmati 1. The mean absorbance, as assessed by triphenyl tetrazolium chloride reduction, of rice cells at 8 d post-thawing, was increased by up to 60% (P < 0.05), compared to cells recovered in the absence of Hb. Eryihrogen™ (1:50-1:500 v:v) promoted an increase in biomass, of up to 25% over control (P < 0.05), at 24 d post-thawing. Cell suspensions, re-established by transfer to liquid medium of cells initially thawed and cultured with Erythrogen™ for 24 d, exhibited increased (up to 2-fold) growth rates over a subsequent 20-d period, compared to cells recovered without Hb.
    07/2009; 27(2):163-169.
  • Chapter: Ornamentals
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    ABSTRACT: Ornamentals are an important economical factor worldwide. Often underestimated, ornamental plant production even exceeds vegetable and fruit production in many countries of the world. However, scientific research on genetics and molecular biology has only been conducted on a few species. There are several reasons for this situation: The group of ornamental plants is very large, comprising hundreds of different species from various taxonomic groups. Therefore, even the most important species, for example, roses, carnations, and gerberas, have a smaller individual market share compared with the major agricultural crops, for example, corn, wheat, and soybean. Furthermore, many ornamental species are polyploids with characters that hamper genetic characterization, for example, high heterozygosity, low seed set, and crossing barriers.
    Compendium of Transgenic Crop Plants, 04/2009; , ISBN: 9781405181099
  • Compendium of Transgenic Crop Plants, 04/2009; , ISBN: 9781405181099
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    ABSTRACT: Global production of ornamental plants is increasing each year with fierce competition between producers, stimulated by increasing consumer demand. Innovations are required in terms of new products at competitive prices to attract consumers. Thus, the industry is under constant pressure to create novel traits. Manipulating the concentration of endogenous growth regulators, such as gibberellins (GAs), in plants can potentially modify shoot architecture. In this investigation, genes from the GA metabolic pathway have been expressed ectopically using the CaMV 35S constitutive promoter in Solanum nigrum and Nicotiana sylvestris. Plants showed statistically significant alteration to their architecture (t-test at 0.01 probability). The feasibility of using tissue-specific promoters was also evaluated in relation to the modification of stature. The technology may lead to decreased dependence on chemical growth regulators, over which there are concerns in relation to human health and potential environmental consequences.
    Acta horticulturae 01/2009; 817:135-142.
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    ABSTRACT: Withania sominifera (Indian ginseng) was transformed by Agrobacterium rhizogenes. Explants from seedling roots, stems, hypocotyls, cotyledonary nodal segments, cotyledons and young leaves were inoculated with A. rhizogenes strain R1601. Hairy (transformed) roots were induced from cotyledons and leaf explants. The transgenic status of hairy roots was confirmed by polymerase chain reaction using nptII and rolB specific primers and, subsequently, by Southern analysis for the presence of nptII and rolB genes in the genomes of transformed roots. Four clones of hairy roots were established; these differed in their morphology. The doubling time of faster growing cultures was 8-14 d with a fivefold increase in biomass after 28 d compared with cultured, non-transformed seedling roots. MS-based liquid medium was superior for the growth of transformed roots compared with other culture media evaluated (SH, LS and N6), with MS-based medium supplemented with 40 g/L sucrose being optimal for biomass production. Cultured hairy roots synthesized withanolide A, a steroidal lactone of medicinal and therapeutic value. The concentration of withanolide A in transformed roots (157.4 microg/g dry weight) was 2.7-fold more than in non-transformed cultured roots (57.9 microg/g dry weight).
    Journal of Integrative Plant Biology 09/2008; 50(8):975-81. · 3.75 Impact Factor
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    ABSTRACT: Random amplified polymorphic DNA (RAPD) analysis was applied to eight commercial cultivars of pineapple, two intergroup hybrids and two wild species. Morphologically, pineapple is divided into the Cayenne, Queen, Spanish, Maipure and Abacaxi groups. Members of the first three groups have been analysed in this study. The cultivars ‘Tradsithong’, ‘Phuket’, ‘Sawee’ and ‘Tainan’, with spiny leaves, form the Queen group. In ‘Pattavia’, ‘Nanglae’ and ‘Petburi no. 2’ (Cayenne group), spines are confined to the leaf tips. ‘Intrachitdang’ is normally placed in the Spanish group, which is morphologically similar to the Queen group, but with inferior quality fruit. DNA amplification products were compared from 16 arbitrary 10-mer primers from which a dendrogram was constructed. The results confirmed morphological classifications for seven of the eight commercial cultivars, with the Queen and Cayenne groups as separate clusters. However, the cv. ‘Intrachitdang’ was more closely related to the Cayenne group. Two hybrids from reciprocal Cayenne × Queen group crosses, were more closely allied to the Queen group. The two wild species were outside the groups. RAPD analysis can be exploited to investigate relationships within pineapple germplasm.
    Plant Breeding 06/2008; 120(3):265 - 267. · 1.18 Impact Factor
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    ABSTRACT: Gibberellins (GAs) are endogenous hormones that play a predominant role in regulating plant stature by increasing cell division and elongation in stem internodes. The product of the GA 2-oxidase gene from Phaseolus coccineus (PcGA2ox1) inactivates C(19)-GAs, including the bioactive GAs GA(1 )and GA(4), by 2beta-hydroxylation, reducing the availability of these GAs in plants. The PcGA2ox1 gene was introduced into Solanum melanocerasum and S. nigrum (Solanaceae) by Agrobacterium-mediated transformation with the aim of decreasing the amounts of bioactive GA in these plants and thereby reducing their stature. The transgenic plants exhibited a range of dwarf phenotypes associated with a severe reduction in the concentrations of the biologically active GA(1) and GA(4). Flowering and fruit development were unaffected. The transgenic plants contained greater concentrations of chlorophyll b (by 88%) and total chlorophyll (11%), although chlorophyll a and carotenoid contents were reduced by 8 and 50%, respectively. This approach may provide an alternative to the application of chemical growth retardants for reducing the stature of plants, particularly ornamentals, in view of concerns over the potential environmental and health hazards of such compounds.
    Plant Cell Reports 04/2008; 27(3):463-70. · 2.94 Impact Factor
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    ABSTRACT: The development of increasingly sensitive chemiluminescent substrates and the ability to label probes with digoxigenin (DIG) by polymerase chain reaction (PCR) (1) has resulted in nonradioactive Southern analysis becoming the preferred method, in many plant research laboratories, for the detection of single-copy genes in DNA from transgenic plants. The previous, well established procedure for single-copy gene detection required the utilization of 32P-labeled probes. However, as well as safety issues, isotopic probes require labeling immediately prior to use with exposure times ranging from 1 d to 7 d. Isotopic probes are therefore laborious and time consuming. The procedure outlined here is rapid and simple and employs modification of two published protocols (1,2), using DIG-labeled nucleotides (3) that are incorporated into nucleic acid probes by PCR (1,4,5). The analysis of a fragment of dissected transgene, attached to plant genomic DNA (border fragment analysis), gives information on transgene integrity and integration pattern into plant DNA, as well as transgene copy number. The number of bands, following chemilumi-nescent detection, corresponds to the number of transgene copies (see Fig. 1). The analysis of either the whole or part of the transgene, which has been dissected from the plant genomic DNA using restriction enzymes (internal fragment analysis), provides information on transgene copy number and integrity, but not the integration pattern. Fig. 1.Southern blot of DNA from transgenic lettuce plants (lanes 1–3 and 5–7) digested with HindIII to produce border fragments, followed by hybridization with a PCR-DIG-labeled luc (luciferase reporter gene) probe. Lanes 1, 3, 5, 6, and 7 represent transgenic plants with single-copy gene inserts; lane 2 is a transgenic plant containing two gene inserts, while lane 4, in which the sample does not hybridize to the PCR-DIG labeled luc probe, represents DNA derived from a nontransformed lettuce plant.
    02/2008: pages 211-222;
  • Ornamentals. 01/2008;
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    ABSTRACT: A key requirement to enhance our understanding of the response of biological organisms to different levels of gravity is the availability of experimental systems that can simulate microgravity and hypergravity in ground-based laboratories. This paper compares the results obtained from analysing gene expression profiles of Drosophila in space versus those obtained in a random position machine (RPM) and by centrifugation. The correlation found validates the use of the RPM simulation technique to establish the effects of real microgravity on biological systems. This work is being extended to investigate Drosophila development in another gravity modifying instrument, the levitation magnet.
    Journal of gravitational physiology: a journal of the International Society for Gravitational Physiology 01/2007; 14:125-126.
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    ABSTRACT: Gravity is an important environmental factor that controls plant growth and development. Studies have shown that the perception of gravity is not only a property of specialized cells, but can also be performed by undifferentiated cultured cells. In this investigation, callus of Arabidopsis thaliana cv. Columbia was used to investigate the initial steps of gravity-related signalling cascades, through altered expression of transcription factors (TFs). TFs are families of small proteins that regulate gene expression by binding to specific promoter sequences. Based on microarray studies, members of the gene families WRKY, MADS-box, MYB, and AP2/EREBP were selected for investigation, as well as members of signalling chains, namely IAA 19 and phosphoinositol-4-kinase. Using qRT-PCR, transcripts were quantified within a period of 30 min in response to hypergravity (8g), clinorotation [2-D clinostat and 3-D random positioning machine (RPM)] and magnetic levitation (ML). The data indicated that (1) changes in gravity induced stress-related signalling, and (2) exposure in the RPM induced changes in gene expression which resemble those of magnetic levitation. Two dimensional clinorotation resulted in responses similar to those caused by hypergravity. It is suggested that RPM and ML are preferable to simulate microgravity than clinorotation.
    Advances in Space Research 01/2007; · 1.18 Impact Factor
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    ABSTRACT: The localization was determined of the triterpenoids, asiaticoside and madecassoside, in different organs of glasshouse-grown plants and cultured material, including transformed roots, of two phenotypes of Centella asiatica (L.) Urban of Malaysian origin. Methanolic extracts of asiaticoside and madecassoside were prepared for gradient HPLC analysis. The two phenotypes of C. asiatica exhibited differences in terpenoid content that were tissue specific and varied between glasshouse-grown plants and tissue culture-derived material. Terpenoid content was highest in leaves, with asiaticoside (0.79 ± 0.03 and 1.15 ± 0.10 % of dry mass) and madecassoside [0.97 ± 0.06 and 1.65 ± 0.01 %(d.m.)] in the fringed (F) and smooth leaf (S) phenotypes, respectively. Roots of the F-phenotype contained the lowest content of asiaticoside [0.12 ± 0.01 %(d.m.)], whereas petioles of S-phenotype plants contained the lowest content of asiaticoside [0.16 ± 0.01 %(d.m.)] and madecassoside [0.18 ± 0.14 %(d.m.)]. Transformed roots were induced using Agrobacterium rhizogens and their growth was maximal on Murashige and Skoog basal medium supplemented with 60 g dm−3 sucrose. However, asiaticoside and madecassoside were undetectable in transformed roots and undifferentiated callus.
    Biologia Plantarum 01/2007; 51(1):34-42. · 1.69 Impact Factor
  • Comparative Biochemistry and Physiology A-molecular & Integrative Physiology - COMP BIOCHEM PHYSIOL PT A. 01/2007; 146(4).
  • Chapter: Lettuce
    12/2006: pages 221-249;
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    ABSTRACT: Pineapple plants transformed with the bar gene for bialaphos resistance were evaluated for transgene stability, gene expression and tolerance to glufosinate ammonium, the active ingredient of the herbicide Basta® X, under field conditions. Genetically modified plants of the cv. Phuket were micropropagated, rooted and established in a shade house before transfer to an experimental plot. Seven months after transfer to the field, plants were tolerant to 1600 ml/rai of the herbicide Basta® X (stock concentration 15% w/v glufosinate ammonium), this being twice the dose recommended for field application of the herbicide. Genetically modified plants remained green and healthy following spraying with the herbicide. In contrast, non-transformed pineapple plants of the same cv. became necrotic and died within 21 days of spraying with the herbicide at a reduced concentration of 800 ml/rai. Bar gene stability and expression in clonally-derived plants were assessed by PCR, RT-PCR and Southern analyses at 120, 210, 240, 270 and 380 days following transfer of the plants to the field. The bar gene was stable and expressed in transgenic plants throughout the duration of the trial. Fruit characteristics and yield were not affected by transgene introduction and expression. Transgenic plants tolerant to glufosinate ammonium should facilitate more effective weed control in pineapple plantations without damage to the crop.
    Plant Breeding 07/2006; 125(4):411 - 413. · 1.18 Impact Factor

Publication Stats

3k Citations
514.57 Total Impact Points


  • 1970–2012
    • University of Nottingham
      • • School of Biosciences
      • • School of Life Sciences
      Nottingham, ENG, United Kingdom
  • 2008
    • Karnatak University, Dharwad
      • Department of Botany
      Dārwhā, State of Maharashtra, India
  • 2001
    • Park University
      Parkville, Missouri, United States
    • Gyeongsang National University
      Shinshū, South Gyeongsang, South Korea
  • 1999–2001
    • Babeş-Bolyai University
      • Faculty of Biology and Geology
      Cluj-Napoca, Judetul Cluj, Romania
  • 2000
    • Selcuk University
      Conia, Konya, Turkey
  • 1996
    • Loughborough University
      • Department of Chemistry
      Loughborough, ENG, United Kingdom
    • University of Leicester
      Leiscester, England, United Kingdom
  • 1995
    • Abertay University
      Derby, England, United Kingdom
    • Nottingham Trent University
      Nottigham, England, United Kingdom
  • 1994
    • University of Chittagong
      • Department of Botany
      Chittagong Ghat, Chittagong, Bangladesh
  • 1990
    • East Malling Research
      Maidstone, England, United Kingdom