J B Power

University of Nottingham, Nottingham, ENG, United Kingdom

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Publications (199)421.68 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
  • Davey MR, Anthony P, Patel D, Power JB
    Plant Cell Culture: Essential Methods. 01/2010;
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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.
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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: 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
  • 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
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    ABSTRACT: Two hexaploid somatic hybrids [Sh; L. esculentum (+) L. Peruvianum] accessions 6 and 18 were back-crossed with two diploid L. Esculentum cultivars ‘Moneymaker’ (mm) and ‘pusa Ruby’ (pr). Twenty-two plants of the bc2 generation were produced by backcrossing 7 bcl plants (mm x sh, 6, 18) with five tomato cultivars. Fourteen of the bc2 plants were self-fertile, five produced anther cones with anthocyanin pigmentation not present in the parents. A bc3 generation was developed by crossing the four cultivars as female parent with three bc2 generation plants. The bc3 progeny derived from one pollen parent plant were produced without the need to culture immature seeds. They segregated with respect to pigmented anther cones and were self-fertile. The anther cone pigmentation of the pollen parent plant was associated with increased seed set, greater fruit size and an orange-red fruit colour. These features were transmitted to the fertile bc3 generation. Conversely, bc3 offspring involving the other two parent plants were only recovered by culture of immature seeds. The recovery of diploid plants in BCl and self-fertility in BC2 resulted in almost total recovery of the tomato cultivar characteristics (fruit size, colour and number of seeds) by BC3.
    Plant Breeding 04/2006; 111(4):273 - 282. · 1.18 Impact Factor
  • M. SANTALLA, J. B. POWER, M. R. DAVEY
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    ABSTRACT: Knowledge of the genetic relationships among landraces is useful to gene bank managers because it permits a better organization of the crop's gene pool management, more efficient sampling of the available germplasm resources and better access to useful genetic variation for breeders. Genetic diversity of 19 landraces of the cultivated mung bean, Vigna radiate, and three weedy and wild relatives including Vigna mungo, Vigna luteola and Vigna radiate var. sublobata, was investigated at the DNA level with the random amplified polymorphic DNA (RAPD) procedure. Sixty random decamer primers were employed in amplification reactions; 28 of these were informative and yielded 246 bands, of which 229 were polymorphic with a mean of 8.2 bands per primer. A genetic distance matrix based on Nei and Li coefficient was converted to a dendrogram and a two-dimensional plot using multidimensional scaling (MDS). The accessions studied were separated into three main clusters, which included V. radiate landraces, V. mungo and V. luteola, respectively. The variation of this cluster supports the view that the genetic distance of V. mungo and V. luteola varies considerably from the accession VO2955 (V. radiata). The multidimensional scaling plot confirmed that V. mungo, V. luteola and most of the accessions of V. radiata formed distinct clusters with no overlap, and two mung bean accessions (PI177493 and VO4134–1 from Turkey and India, respectively) were genetically distant from other V. radiata landraces. V. radiata and V. mungo are positioned in separate botanical species and V. radiata var. sublobata is classified within other V. radiata landraces. Based on the limited range of accessions tested, the approach holds promise for the classification of mung bean germplasm, identification of mung bean landraces and applications of molecular markers to mung bean breeding.
    Plant Breeding 04/2006; 117(5):473 - 478. · 1.18 Impact Factor
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    ABSTRACT: Critical parameters influencing somatic embryogenesis include growth regulators and oxygen supply. Consequently, the present investigation has focused on optimization of a somatic embryogenic system for peanut (Arachis hypogaea L.) through media supplementation with the auxin, picloram. The latter at 30 mg L(-1) was optimal for inducing regeneration of somatic embryos from cultured explants of zygotic embryos. In contrast, somatic embryogenesis did not occur in the absence of this growth regulator. An assessment has also been made of the beneficial effect on somatic embryogenesis and plant regeneration of the commercial hemoglobin (Hb) solution, Erythrogen. Hemoglobin at 1:50 and 1:100 (v:v) stimulated increases in mean fresh weight (up to a maximum of 57% over control), mean number of explants producing somatic embryos (15%) and mean number of somatic embryos per explant (29%).
    Artificial Cells Blood Substitutes and Biotechnology 03/2004; 32(1):149-57. · 0.85 Impact Factor
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    ABSTRACT: The effects of the non-ionic surfactant, Pluronic F-68, on the growth of shoots regenerated from seedlings (14 days post-germination) of Hypericum perforatum L. were studied. The supplementation of agar-solidified medium with 0.001% (w/v) of Pluronic increased the mean fresh weight of the regenerants after 60 days by 40% and the mean number of plant regenerants recovered per seedling by 34%; a less pronounced increase in the number of regenerants occurred with 0.01% (w/v) of the surfactant. By contrast, the mean fresh weight of the regenerants cultured in the presence of 0.1% (w/v) Pluronic F-68 was 15% lower than untreated controls, although the mean number of regenerants per seedling remained unaltered. The growth of seedling leaf-derived Hypericum callus after 60 days was unaffected by all the concentrations of Pluronic tested. However, there was a tendency for callus cells grown in the presence of Pluronic to be more highly pigmented with anthocyanins. The cultivation of leaf explants with 0.001% or 0.01% (w/v) Pluronic did not affect either the mean fresh weight of the regenerants or the mean number of regenerants per explant. However, decreases in both the mean fresh weight and the mean number of regenerants (both 33.0% lower than the control) occurred following the cultivation with 0.1% (w/v) Pluronic.
    Acta Biotechnologica 02/2004; 14(4):347 - 353.
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    ABSTRACT: The flavonoid naringenin has been investigated as a possible vir gene inducer in Agrobacteriummediated transformation in Passiflora mollissima, P. giberti and Nicotiana tabacum cv. Xanthi. The transformation efficiency percentage of explants showing blue GUS expression and the extent of staining following inoculation with Agrobacterium tumefaciens strains EHA 105 and 1065, carrying gus and nptII genes was enhanced with the supplementation of the co-cultivation medium with naringenin. Supplementation of medium with 100mM (strain EHA 105) and 300 mM (strain 1065) naringenin was most effective at enhancing mean (±s.e.m., n=3) GUS activity in leaf explants (20.3 ± 2.4%, strain EHA; 105; 6.0 ± 0.57%, strain 1065) and nodal segments (16.7 ± 2.4% strain EHA 105; 8.3 ± 0.57% strain 1065) of P. mollissima. In P. giberti and N. tabacum maximum GUS activity was obtained in leaf and root explants with 100mM naringenin for both strains analysed. Additionally, when naringenin was added to Luria Bertani (LB) medium, both bacterial growth via optical density and colony forming units were higher when compared to control. This is the first report of the use of naringenin to enhance gene transfer from Agrobacterium to plants. These findings suggest that naringenin can be used as an alternative to acetosyringone for vir gene induction in Agrobacterium. This approach may be especially useful in plants that are generally recalcitrant to Agrobacterium-mediated transformation
    Universitas Scientiarum 01/2004; 9(1):47-57.
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    ABSTRACT: The promotory effects have been studied of the non-ionic surfactant, Pluronic F-68, on bud induction/shoot regeneration in epicotyl and cotyledon explants of Citrus depressa and on shoot regeneration from leaf segments of 4–6 week-old axenic nodal segment-derived in vitro plants of Passiflora mollissima, P. giberti and P. edulis var. flavicarpa. For epicotyls of C. depressa, supplementation of agar-solidified MS-based bud induction/shoot regeneration medium with 0.5% [w/v] Pluronic F-68 significantly (P < 0.05) increased mean fresh weight gain of cultures, percentage of explants giving shoots and number of shoots per explant. The same Pluronic concentration also enhanced the mean percentage of cotyledons exhibiting bud induction and the number of buds regenerated per cotyledon explant. Fresh weight gain was unaffected across the range of concentrations (0.001–0.5% w/v) of Pluronic F-68 evaluated for this latter explant source. For leaf explants from axenic shoot cultures of P. mollissima, supplementation of NN-based medium, containing 3 mg/l 6-benzyladenine and 2.0 mg/l kinetin with 0.001–0.5% [w/v] Pluronic F-68, significantly (P < 0.05) increased mean (± s.e.m.) biomass gain by a maximum of 2.7 ± 0.1 g fresh weight (g f.wt.) over the control. Similarly, for leaf explants of P. giberti, 0.001–0.5% [w/v] Pluronic F-68 in MS-based medium, containing 1.0 mg/l 6-BAP and 0.5 mg/l kinetin significantly (P < 0.05) increased mean percentage of explants undergoing shoot regeneration. For P. edulis leaf explants, mean f.wt. gain was also significantly (P < 0.05) higher with Pluronic F-68 at 0.001–0.5% [w/v].
    Acta Biotechnologica 11/2003; 23(4):349 - 358.
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    ABSTRACT: The forces on suspended particles in acoustic fields are reviewed briefly and the theoretical model-ling of ultrasonic separators based on piezoelectrically excited layered resonators is described. The so-called h-shaped ultrasonic separator is analysed by combin-ing the mathematical modelling of the laminar flow with the acoustic force based velocity field of the par-ticles relative to the suspension medium. This allows a complete modelling of the resonator's particle separa-tion performance. An example for separation chamber design optimized by use of the mathematical model is presented and the calculated particle traces in the h-resonator are shown and compared with experimental results. The presented results are of importance for ultrasonic separation of plant (algae) cells under low gravity conditions, where the sedimentation concept fails.
    WCU - World Congress on Ultrasonics; 09/2003

Publication Stats

2k Citations
421.68 Total Impact Points

Institutions

  • 1970–2012
    • University of Nottingham
      • • School of Biosciences
      • • School of Life Sciences
      Nottingham, ENG, United Kingdom
  • 2001
    • Park University
      Parkville, Missouri, United States
  • 1999–2001
    • Babeş-Bolyai University
      • Faculty of Biology and Geology
      Cluj-Napoca, Judetul Cluj, Romania
  • 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