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  • 1
    Electronic Resource
    Electronic Resource
    The sulphur-rich Brazil nut 2S albumin is specifically formed in transgenic seeds of the grain legume Vicia narbonensis (1955)
    Springer
    Euphytica 85 (1955), S. 181-192 
    Details
    ISSN: 1573-5060
    Keywords: Vicia narbonensis ; gene transfer ; gene expression ; seeds ; 2S albumin ; methionine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Epicotyl explants were co-cultivated with Agrobacterium tumefaciens EHA101 to transfer a chimeric 2S albumin gene construct carried in the binary Ti plasmid vectors pGSGLUC1 or pGA472 into the grain legume Vicia narbonensis. This gene encoding the sulphur-rich Brazil nut albumin was under the control of either the CaMV 35S promoter which permits gene expression in all organs, or the Vicia faba legumin B4 promoter which elicits seed-specific gene expression. After callus formation and selection for kanamycin resistance, somatic embryos were induced which, in the case of transformation with the vector pGSGLUC1, were screened for GUS activity. Embryos that produced GUS were in addition analysed for 2S albumin formation. Selected transgenic embryos were cloned by multiple shoot regeneration. Rooted and fertile plants were obtained by grafting transgenic shoots on the appropriate seedlings. R1 and R2 generations were raised and analysed for GUS as well as 2S albumin gene expression. Expression of the 35S promoter/2S albumin gene fusion took place in all organs of the transgenic plants including the cotyledons of seeds, whereas seed-specific gene expression was found in transformants with the legumin promoter/2S albumin gene fusion. The 2S albumin accumulated in the 2S protein fraction of transgenic seeds and its primary translation product was processed into the 9 and 3 kDa polypeptide chains. The foreign protein was localised in the protein bodies of the grain legume. Analysis of the R2 plants indicated Mendelian inheritance of the 2S albumin gene. In homozygous V. narbonensis plants the amounts of 2S albumin were twice that present in the corresponding heterozygous plants. Whereas only low level formation of the foreign protein was achieved if the gene was under the control of the 35S promoter, approximately 3.0% of the soluble seed protein was 2S albumin if seed-specific gene expression was directed by the legumin B4 promoter. Some of these transformants exhibited a three-fold increase in the methionine content of the salt-soluble protein fraction extracted from seeds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023947
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Stable expression of vicilin fromVicia faba with eight additional single methionine residues but failure of accumulation of legumin with an attached peptide segment in tobacco seeds (1995)
    Springer
    Molecular breeding 1 (1995), S. 245-258 
    Details
    ISSN: 1572-9788
    Keywords: legumin ; methionine ; modification ; nutritional value ; Vicia faba ; vicilin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two different attempts have been undertaken to improve the amino acid composition of storage proteins from field bean (Vicia faba) by genetic engineering. First, legumin was modified to generate a new peptide sequence at the C-terminus containing 4 methionine residues. Second, vicilin was modified by generating 8 single methionine residues distributed over the peptide sequence. The genes were expressed in different systems includingin vitro transcription and translation and stable transformation into tobacco. The modified legumin was found to be unstable when expressed in tobacco seeds. Although specific mRNA was detected on RNA gel blots, no protein could be found by using protein gel blotting and ELISA. Furthermore, a protease preparation able to process the original legumin precursorin vitro degraded the modified legumin precursor. Contrary, the modified vicilin was accumulated in seeds of tobacco transformed with the gene under the control of the seed specific USP promoter. Both the original and the modified vicilin could be detected on protein gel blots at the expected position. Two-dimensional electrophoresis was employed to analyse the expression of original vicilin. Three vicilin-specific products of almost equal size were observed, indicating a slight modification leading to a change of pI. Quantitative determination using competitive ELISA showed that there is no significant difference in accumulation between original and modified vicilin. In both cases, three plants were found with vicilin amounts in the range of 1–3% of total globulin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02277425
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    Paper (German National Licenses)
    Fulltext
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