Biotechnology and the Food Supply Proceedings of a Symposium (1988) / Chapter Skim
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2 The Impact of Biotechnology on Food Production
2 The Impact of Biotechnology on Food Production
Pages 9-18
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From page 9... ...
Therefore, this paper focuses mainly on the most recent advances in the transformation of plants, even though the creation of transgenic animals is actively being explored at the fundamental and applied levels. Advances in plant cell and tissue culture have made it possible in some cases to insert genetic information into the chromosome of an organism and then to regenerate whole plants from single cell cultures.
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and stably insert it into the nuclear DNA of the transformed cell. Since the T-DNA contains genetic information responsible for the synthesis of plant hormones as well as novel metabolites called opines, its transfer and insertion creates the crown gall tumor when these genes are expressed.
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The characteristics of these plasmids include a segment of the pBR322 DNA for replication in Escherichia colt, a portion of a Ti plasmid (pTiT37) containing the functional nopaline synthase gene for ease in scoring transformed plant cells, a streptomycin/spectinomycin resistance determinant from Tn7 for selection in A~robacterium, a portion of DNA from another Ti plasmid (pTiA6)
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The pea RuBPss retained its tissue-specific pattern of expression in leaves derived from regenerated transformed petunia plants. Subsequent studies using In vivo radiolabeling, followed by immunoprecipitation of ribulose-l, 5-bisphosphatecarboxylase, demonstrated that the heterologous RuBPss protein of the peas could be separated from the endogenous petunia RuBPss, thereby indicating that the pea RuBPss protein was correctly processed In vivo by petunia chloroplast (Fraley et al., 1986~.
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A cDNA clone encoding the soybean 7s c''-conglycinin protein was engineered into an appropriate A~robacterium plasmid and transferred into petunia cells (Fraley et al., 1986~. Analysis of subsequent petunia seeds indicated that there was regulated expression of the soybean storage protein gene in the petunia seed.
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From page 14... ...
Subsequent efforts led to the development of a chimeric gene construct consisting of a petunia EPSP synthase cDNA flanked by the cauliflower mosaic 35s 57 promoter and the nopaline synthase, 3' regulatory regions. Transformation of petunia cells with this construct resulted in herbicide resistance and the overproduction of EPSP synthase 30- to 60-fold.
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From page 15... ...
MICROORGANISMS Transformations of microorganisms that colonize plants are also expected to be useful in enhancing the productivity of plants. For example, transformed Pseudomonas florescens, which is a natural colonizer of roots in such major crops as corn and soybeans, has been engineered to carry and express the Bacillus thurin~iensis toxin gene mentioned earlier.
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From page 16... ...
For example, extensive efforts are being devoted to the development of higher levels of solids in tomatoes by enhancing the concentration of natural polymers normally present in tomatoes. Protein engineering may well see its first application in simple amino acid codon shifts in seed storage proteins to enhance their content of lysine (e.g., in corn)
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This knowledge is vital for our understanding of the genetic components involved in achieving such traits as frost tolerance, heat tolerance, drought tolerance, metal tolerance, disease resistance, and insect tolerance. Incentives have been provided to improve this situation, but additional resources must be directed toward improving plant tissue culture and regeneration; novel transformation systems, understanding of gene structure organization and function; the selection, isolation, and characterization of agronomically important genes; and the development of unique plantbreeding techniques.
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From page 18... ...
1986. Delay of disease development in transgenic plants that express the tobacco mosaic virus coat protein gene.
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