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  • 1
    Electronic Resource
    Electronic Resource
    Gene expression and carbohydrate content during stolon to tuber transition in potatoes (Solanum tuberosum) (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 90 (1994), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In using an efficient and synchronised in vitro tuberisation system the transition of axillary buds from stolons to tubers in Solanum tuberosum L. cv. Bintje was followed. After 5 or 6 days on tuber-inducing medium all axillary buds had formed tubers which increased in size until the experiment was ended at day 10. Concomitantly with the visible appearance of tubers the fresh weight of the axillary buds increased as well as their starch content. Soluble sugar content, notably glucose, increased until tuberisation occurred and dropped after that. In the daily sampled explants gene expression was studied at several levels. RNA was isolated from the different explants during the whole tuberisation experiment and northern blots were probed with cDNAs encoding genes involved in starch- and patatin-biosynthesis. It was shown that in the very early stages of development hardly any transcript could be detected. Only one day before visible swelling occurred were clear signals obtained for all the genes investigated. Although it was evident that coordinate expression of starch biosynthetic genes did occur, it was not in a similar fashion for all the genes. Sucrose synthase and ADPG-pyrophosphorylase B were expressed in an identical fashion which was different from ADPG-pyrophosphorylase S, granule-bound starch synthase and branching enzyme. The RNA levels of these three latter genes reached a maximum at day 5, remaining constant until the experiment was finished. The transcript levels of sucrose synthase and ADPG-pyrophosphorylase B reached their highest level at day 5 after which they dropped to a lower level at day 10. Patatin gene expression was clearly different from that of the starch biosynthetic genes: it steadily increased from day 4 until the end of the experiment. Enzyme activities of sucrose synthase. ADPG-pyrophosphorylase and branching enzyme confirmed the RNA expression data and showed that ADPG-pyrophosphorylase enzyme activity reached a maximum at day 4 after which it dropped. The other two enzyme activities could be detected at or one day after tuberisation occurred and increased until the experiment was ended.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1994.tb00389.x
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of the non-specific lipid transfer protein EP2 from carrot (Daucus carota L.) (1993)
    Springer
    Molecular and cellular biochemistry 123 (1993), S. 159-166 
    Details
    ISSN: 1573-4919
    Keywords: lipid transfer protein ; plant (carrot) ; fatty acid-binding ; cutin synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The extracellular protein EP2 was previously identified as non-specific lipid transfer protein based on its cDNA-derived amino acid sequence. Here, the purification of the EP2 protein from the medium of somatic embryo cultures is described. After two cycles of ion-exchange and gel permeation chromatography, a single silver-stained protein band with an apparent molecular mass of 10 kDa was observed on SDS-PAGE. This protein band was recognized by the antiserum raised against a EP2-β-galactosidase fusion-protein. Employing a fluorescent phospholipid analog, it was shown that the purified EP2 protein is capable of binding phospholipids and is able to enhance their transfer between artificial membranes. Employing a gel permeation assay, it could be demonstrated that the EP2 protein is also capable of binding palmitic and oleic acid as well as oleyl-CoA. Because in plants these fatty acids are used as precursor molecules for cutin, these results are in support of the proposed role of the EP2 protein to transport cutin monomers from their site of synthesis through the cell wall of epidermal cells to sites of cutin polymerization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01076488
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  • 3
    Electronic Resource
    Electronic Resource
    Description of somatic-embryo-forming single cells in carrot suspension cultures employing video cell tracking (1994)
    Springer
    Planta 194 (1994), S. 565-572 
    Details
    ISSN: 1432-2048
    Keywords: Cell tracking ; Daucus ; Development (single cell) ; 2,4-Dichlorophenoxyacetic acid ; Phytagel (cell immobilisation) ; Somatic embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cell-tracking system was established to determine the capability of individual single suspension cells of carrot (Daucus carota L.) to develop into somatic embryos. When immobilised in phytagel, 127 out of 30 318 single suspension cells smaller than 22 μm in diameter developed into a somatic embryo. Single cells present at the start of the experiment were classified on the basis of their morphology into five groups: small spherical vacuolated cells; small spherical cytoplasm-rich cells; oval vacuolated cells; elongated vacuolated cells and cells that could not be classified into either one of these groups. Single cells of all morphologically distinguishable single cell types developed into somatic embryos with a frequency that varied between 19 and 100 somatic embryos per 10 000 cells. This suggests that the capability of individual single cells to form somatic embryos is not restricted to a particular cell type distinguishable on the basis of its morphology. Three major pathways were observed during development. Oval and elongated cells developed into somatic embryos via an asymmetrical cell cluster. Spherical cells developed via a symmetrical cell cluster into somatic embryos. Before formation of a somatic embryo, cells of a more variable initial morphology first developed aberrantly shaped cell clusters. This suggests that the developmental pathway leading to a somatic embryo can be predicted by the initial single-cell morphology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00714471
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  • 4
    Electronic Resource
    Electronic Resource
    Expression of the JIM8 cell wall epitope in carrot somatic embryogenesis (1996)
    Springer
    Planta 200 (1996), S. 167-173 
    Details
    ISSN: 1432-2048
    Keywords: Arabinogalactan protein epitope ; Cell tracking ; Daucus ; Monoclonal antibody (JIM8) ; Somatic embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Certain single cells in carrot (Daucus carota L.) suspension cultures react with the monoclonal antibody JIM8, and it has been proposed that these cells represent a transitional stage in somatic embryo formation. Shortly after isolation of the single cells by sieving, up to 80% of the cells react with JIM8. Within 4 d, JIM8 labelling becomes restricted to 1% of the single cells. To obtain evidence for the proposed correlation between expression of the JIM8 cell wall epitope and somatic embryo formation the developmental fate of carrot single cells labelled with JIM8 was determined by cell tracking. The results, obtained by recording 43 000 cells, show that only few JIM8-labelled cells give rise to embryos, and most somatic embryos develop from cells devoid of the JIM8 cell wall epitope. We therefore conclude that the presence of the JIM8 cell wall epitope does not coincide with the ability of single suspension cells to form embryos.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00208305
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  • 5
    Electronic Resource
    Electronic Resource
    Cellular location of peroxidase isoenzymes in leaf tissue of Petunia and their affinity for Concanavalin A-Sepharose (1985)
    Springer
    Planta 164 (1985), S. 89-95 
    Details
    ISSN: 1432-2048
    Keywords: Concanavalin A ; Leaf (peroxidases) ; Peroxidase isoenzymes ; Petunia (peroxidases)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cellular location of three peroxidase isoenzymes (PRX) in mature leaf tissue of Petunia and their affinity for Concanavalin A-Sepharose were investigated. The isoenzymes PRXa, PRXb and PRXc were identified by their positions in starch-gel zymograms. The fast-moving anodic and cathodic peroxidase bands, the isoenzymes PRXa and PRXc respectively, were the most active peroxidases in extracellular extracts. The molecular forms of PRXa showed a tissue-specific distribution between midrib and remaining leaf tissue. An intermediate-moving anodic peroxidase band, the isoenzyme PRXb, was the most active peroxidase released after extraction of isolated mesophyll protoplasts. Small amounts of the peroxidase isoenzymes were present in cell-wall-bound fractions. Incubation of a crude protein fraction with Concanavalin A-Sepharose showed that the isoenzyme PRXb bound more firmly to Concanavalin A-Sepharose than the isoenzymes PRXa and PRXc, of which only one molecular form bound partly. The results are discussed with respect to a possible function of one of the peroxidase isoenzymes, and a possible role of oligosaccharide chains in determining the cellular location of plant peroxidases is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391030
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  • 6
    Electronic Resource
    Electronic Resource
    Use of the growth retardant tetcyclacis for potato tuber formation in vitro (1994)
    Springer
    Plant growth regulation 14 (1994), S. 257-265 
    Details
    ISSN: 1573-5087
    Keywords: growth retardant ; in vitro culture ; potato ; tetcyclacis ; tuber formation ; tuber-specific genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of the plant growth retardant tetcyclacis on in vitro tuber formation in potatoes was studied, using two different approaches: 1. tuber formation in various lines that did not or hardly form tubers under control conditions, and 2. tuber formation by the variety Bintje, which readily forms tubers. The ABA-deficient (droopy) lines of S. phureja hardly formed tubers without the addition of tetcyclacis. In the presence of this growth retardant tuberization was nearly 100%, within three weeks of in vitro culture, even in the absence of cytokinin. A series of somatic hybrids between S. tuberosum and S. brevidens, that did not form tubers in field and pot experiments, were tested. They all formed tubers in vitro in the presence of tetcyclacis. Stoloniferous shoots formed on single-node cuttings from in vitro grown Solanum tuberosum var Bintje plantlets were transferred to media containing a high level of sucrose. In the presence of tetcyclacis, tuber formation started after 4 days, reaching a maximum level of 80% at day 7. Tubers formed in the presence of tetcyclacis, accumulated starch and expressed several tuber-specific genes. These effects were fully antagonized by gibberellic acid. It is concluded that the growth retardant tetcyclacis is a potent tool in the study of tuber formation in potatoes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00024801
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  • 7
    Electronic Resource
    Electronic Resource
    Patatin and four serine proteinase inhibitor genes are differentially expressed during potato tuber development (1991)
    Springer
    Plant molecular biology 17 (1991), S. 385-394 
    Details
    ISSN: 1573-5028
    Keywords: gene expression (patatin, proteinase inhibitors) ; patatin (gene expression) ; potato (Solanum tuberosum L. cv. Bintje) ; proteinase inhibitors (gene expression) ; tuber development (gene expression) ; tuberization (in vitro, axillary buds)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A highly efficient and synchronousin vitro tuberization system is described. One-node stem pieces from potato (Solanum tuberosum cv. Bintje) plants grown under short day-light conditions containing an axillary bud were cultured in the dark on a tuber-inducing medium. After 5 or 6 days all axillary buds started to develop tubers. To study gene expression during tuber development, RNA isolated from tuberizing axillary buds was used for bothin vitro translation and northern blot hybridizations. The genes encoding the proteinase inhibitors I and II (PI-I and PI-II), a Kunitz-and a Bowman-Birk-type proteinase inhibitor were already expressed in uninduced axillary buds. The length of the day-light conditions differently influenced the expression level of the individual genes. In addition, the expression of each of these genes changed specifically during the development of the axillary bud to tuber. In contrast to the expression of these proteinase inhibitor genes, patatin gene expression was only detectable from the day tuberization was manifested as a radial expansion of the axillary bud. These results are discussed with respect to the regulation of the expression of the genes studied in relation to the regulation of tuber development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040633
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  • 8
    Electronic Resource
    Electronic Resource
    Characterzation of chitinases able to rescue somatic embryos of the temperature-sensitive carrot variantts11 (1996)
    Springer
    Plant molecular biology 31 (1996), S. 631-645 
    Details
    ISSN: 1573-5028
    Keywords: plant class IV endochitinase (EC 3.2.1.14) ; class I acidic endochitinase ; class II acidic endochitinase ; carrot ; somatic embryos,ts11
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To characterize the acidic endochitinase EP3, able to rescue somatic embryos of the carrot cell linets11, the enzyme was purified from the medium of wild-type suspension cultures. Peptide sequences, deduced amino acid sequences of corresponding PCR-generated cDNA clones, serological relation and biochemical properties showed that there were at least five closely related chitinases, four of which could be identified as class IV EP3 chitinases with an apparent size of 30 kDa. Two other proteins were identified as a serologically related class I acidic chitinase (DcChitI) of 34 kDa, and a serologically unrelated 29 kDa class II acidic chitinase (DcChitII), respectively. Additional cDNA sequences, Western and Southern analysis showed the presence of a least two, but possibly more, highly homologous class IV EP3 genes in the carrot genome. Two class IV EP3 chitinases were tested and found to be able to increase the number ofts11 globular embryos formed under non-permissive conditions. One of the class IV EP3 chitinases as well as the class I chitinase DcChitI promoted the transition from globular to heart-stagets11 embryos. The class II endochitinase and a heterologous class IV chitinase from sugar-beet were not active onts11. This suggests that there are differences in the specificity of chitinases in terms of their effect on plant somatic embryos.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00042235
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  • 9
    Electronic Resource
    Electronic Resource
    Cloning of β-1,3-glucanases expressed during Cichorium somatic embryogenesis (2000)
    Springer
    Plant molecular biology 42 (2000), S. 377-386 
    Details
    ISSN: 1573-5028
    Keywords: β-1,3-glucanases ; cDNA cloning ; Cichorium ; gene expression analysis ; RT-PCR ; somatic embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three different β-1,3-glucanase cDNA fragments, CG1, CG2 and CG3, were obtained by RT-PCR from RNA isolated from Cichorium hybrid `474' leaf fragments cultured for 11 days under somatic embryogenesis-inducing conditions. When expressed in Escherichia coli the proteins encoded by the three cDNAs were recognized by antibodies raised against 38 kDa extracellular β-1,3-glucanases studied previously (Helleboid et al., Planta 205 (1998) 56–63). The CG2 and CG3 cDNAs may represent expressed alleles of one gene because their sequences showed a very high identity (98.5%) and are only 70% identical with CG1. Southern blot analysis revealed the presence of 3–4 genes coding for β-1,3-glucanases in the Cichorium genome. Expression analysis of the genes corresponding to the three clones analysed by semi-quantitative RT-PCR indicated that CG1 mRNAs were only detectable in Cichorium hybrid `474' leaf fragments from day 3 of somatic embryogenesis induction, whereas CG2-CG3 mRNAs were already present in non-induced leaf tissue of both the embryogenic hybrid `474' and a non-embryogenic genotype. The level of CG1 mRNAs was particularly high when embryogenic cells were dividing to produce embryos, and when the amount of callose deposited in cell walls surrounding embryogenic cells and young embryos decreased. These results indicate that expression of the CG1 gene is correlated to the somatic embryogenesis process and that it encodes a 38 kDa β-1,3-glucanase protein that may be involved in the degradation of callose localized around embryogenic cells and young embryos. A full-length CG1 cDNA clone was obtained using 3′ and 5′ RACE-PCR, and its sequence revealed that it encodes a β-1,3-glucanase that is equally homologous to both class III and class IV plant β-1,3-glucanases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006344024877
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  • 10
    Electronic Resource
    Electronic Resource
    Transient reduction in secreted 32 kD chitinase prevents somatic embryogenesis in the carrot (Daucus carota L.) variant ts11 (1995)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 16 (1995), S. 332-343 
    Details
    ISSN: 0192-253X
    Keywords: Somatic embryogenesis ; temperature-sensitive mutant ts11 ; chitinase ; carrot (Daucus carota L.) ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: At the nonpermissive temperature, somatic embryos of the temperature-sensitive (ts) carrot (Daucus carota L.) cell variant ts11 only proceed beyond the globular embryo stage in the presence of medium conditioned by wild-type cells. The causative component in the conditioned medium has been identified as an acidic 32 kD endochitinase. An antiserum raised against the 32 kD chitinase detected this protein in culture medium from ts11 embryo cultures grown at the permissive temperature as well as at the nonpermissive temperature. No difference in biochemical characteristics or in effect on ts11 embryo development could be detected between the 32 kD chitinase purified from wild-type cultures and the chitinase from ts11 cultures grown at the permissive or at the nonpermissive temperature. Compared to the amount present in a ts11 embryo culture at the permissive temperature, a reduction in the amount of 32 kD chitinase was observed during the temperature-sensitive period at the nonpermissive temperature. These results imply that the arrested embryo phenotype of ts11 is not the result of a structural difference in its 32 kD chitinase, but is the result of a transient decrease in the amount of 32 kD chitinase present. Morphological observations indicate that the ts11 phenotype is pleiotropic and also affects the cell wall of nonembryogenic cells. © 1995 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020160406
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