Genetic engineering of virus resistance: a successful genetical alchemy

1992 ◽  
Vol 99 (3-4) ◽  
pp. 61-77
Author(s):  
B. D. Harrison
Keyword(s):  
Genetic Engineering ◽  
Resistance Genes ◽  
Virus Resistance ◽  
Crop Improvement ◽  
Genetically Engineered ◽  
Satellite Rna ◽  
Virus Diseases ◽  
Naturally Occurring ◽  
Resistance To Infection ◽  
Specific Tolerance

SynopsisSome of the most successful early applications of genetic engineering in crop improvement have been in the production of virus-resistant plants. This has been achieved not by the transfer of naturally occurring resistance genes from one plant species or variety to another but by transformation with novel resistance genes based on nucleotide sequences derived from the viruses themselves or from virus-associated nucleic acids. Transformation of plants with a DNA copy of the particle protein gene of viruses that have positive-sense single-stranded RNA genomes typically confers resistance to infection with the homologous and closely related viruses. Transformation with a gene that is transcribed to produce a benign viral satellite RNA can confer virus-specific tolerance of infection. In addition, recent work with viral poly-merase gene-related sequences offers much promise, and research is active on other strategies such as the use of virus-specific ribozymes.Already the field trialling of plants incorporating transgenic virus resistance has begun, with encouraging results, and effects on virus spread are being studied. Deployment strategies for the resistant plants must now be devised and the conjectural hazards of growing them assessed. Genetically engineered virus resistance promises to make a major contribution to the control of plant virus diseases by non-chemical methods.

scholarly journals 995 GENETIC ENGINEERING FOR CROP VIRUS RESISTANCE

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 572a-572
Author(s):  
Rebecca Grumet
Keyword(s):  
Coat Protein ◽  
Genetic Engineering ◽  
Resistance Genes ◽  
Virus Resistance ◽  
Plant Virus ◽  
Unique Feature ◽  
Genetically Engineered ◽  
Different Types ◽  
Commercial Applications ◽  
Plant Virus Resistance

One of the first major successes in the genetic engineering of useful traits into plants has been the engineering of virus resistance. The first example of genetically-engineered virus resistance was published in 1986, since then there have been more than 50 reports of genetically engineered plant virus resistance. These examples span a range of virus types, a variety of plant species, and have utilized several different types of genes. A unique feature of the genetically-engineered virus resistance is that the resistance genes came from the virus itself, rather than the host plant. Most examples have utilized coat protein genes, but more recently, replicase-derived genes have proved highly effective. Other strategies include the use of antisense or sense-defective sequences, and satellite or defective interfering RNAs. This talk will provide an overview of the different approaches, possible mechanisms, the crops and viruses to which they have been applied, and progress toward commercial applications.

scholarly journals 652 Challenges and Opportunities for Application of Genetic Engineering to Horticultural Crop Improvement

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 560B-560
Author(s):  
David A. Somers
Keyword(s):  
Genetic Engineering ◽  
Crop Improvement ◽  
Genetically Engineered ◽  
Marker Genes ◽  
Horticultural Crop ◽  
Technical Problems ◽  
Plant Improvement ◽  
Complex Genetics ◽  
Genetically Engineer ◽  
Improvement Programs

Genetic engineering offers numerous potentially useful genetic manipulations for the improvement of horticultural crops. Nevertheless, there are several impediments to the efficient integration of genetic engineering into plant improvement programs. The ability to regenerate plants from tissue cultures and, therefore, to genetically engineer most plant species is limited to specific genotypes. This may constrain introduction of genetically engineered traits into crops that have complex genetics, are highly heterozygous, or are propagated by asexual reproduction. Even in crops that are self-compatible, diploids, genotypic specificity of the transformation process often necessitates backcrossing for transfer of genetically engineered traits into elite lines and to reduce problems associated with tissue culture-induced genetic variation. This limits progress in improving other traits compared to other breeding strategies. Other challenges to applying genetic engineering exist. The major genomics initiatives currently underway for gene discovery from a broad range of organisms will provide plant improvers access to most genes. Yet there remains a dearth in tissue-specific, developmentally timed, and environmentally responsive promoters for appropriate expression of introduced genes (transgenes). Furthermore, transgene expression is not as controllable as desired due to transgene silencing. Transgene integration is a random process and further refinements of targeted DNA integration will likely enhance the stability of expression of transgenic traits. The availability of other tools, such as selectable marker genes, will become limiting as multiple transgenic traits are combined within a species. In addition to technical problems, there likely will be problems of access to proprietary technology and testing to meet federal regulations and public acceptance. While these various challenges and limitations currently may constrain progress in application of genetic engineering to horticultural crop improvement, it is foreseeable that with further improvements of genetic engineering technology and development of the appropriate molecular tools, genetic engineering will become a component of most plant improvement programs.

VIRUS DISEASES IN PORTUGUESE ALMOND TREES: DIAGNOSIS, IN SITU DETECTION AND GENETIC ENGINEERING FOR VIRUS RESISTANCE

2002 ◽  
pp. 581-584
Author(s):  
H. Raquel ◽  
C. Silva ◽  
R. Batista ◽  
A. Margarida Santos ◽  
T. Lourenço ◽  
...  
Keyword(s):  
Genetic Engineering ◽  
Virus Resistance ◽  
Virus Diseases ◽  
Almond Trees ◽  
In Situ Detection

scholarly journals Milestones in research on tobacco mosaic virus

1999 ◽  
Vol 354 (1383) ◽  
pp. 521-529 ◽  
Author(s):  
B. D. Harrison ◽  
T. M. A. Wilson
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Virus Resistance ◽  
Dominant Role ◽  
Biological Properties ◽  
Mosaic Disease ◽  
Genetically Engineered ◽  
High Yield ◽  
Past Century ◽  
Avirulence Genes

Beijerinck's (1898) recognition that the cause of tobacco mosaic disease was a novel kind of pathogen became the breakthrough which led eventually to the establishment of virology as a science. Research on this agent, tobacco mosaic virus (TMV), has continued to be at the forefront of virology for the past century. After an initial phase, in which numerous biological properties of TMV were discovered, its particles were the first shown to consist of RNA and protein, and X–ray diffraction analysis of their structure was the first of a helical nucleoprotein. In the molecular biological phase of research, TMV RNA was the first plant virus genome to be sequenced completely, its genes were found to be expressed by cotranslational particle disassembly and the use of subgenomic mRNA, and the mechanism of assembly of progeny particles from their separate parts was discovered. Molecular genetical and cell biological techniques were then used to clarify the roles and modes of action of the TMV non–structural proteins: the 126 kDa and 183 kDa replicase components and the 30 kDa cell–to–cell movement protein. Three different TMV genes were found to act as avirulence genes, eliciting hypersensitive responses controlled by specific, but different, plant genes. One of these (the N gene) was the first plant gene controlling virus resistance to be isolated and sequenced. In the biotechnological sphere, TMV has found several applications: as the first source of transgene sequences conferring virus resistance, in vaccines consisting of TMV particles genetically engineered to carry foreign epitopes, and in systems for expressing foreign genes. TMV owes much of its popularity as a research model to the great stability and high yield of its particles. Although modern methods have much decreased the need for such properties, and TMV may have a less dominant role in the future, it continues to occupy a prominent position in both fundamental and applied research.

Genetically-Engineered Protease-Activated Triggers in a Pore-Forming Protein

1993 ◽  
Vol 330 ◽  
Author(s):  
Barbara Walker ◽  
Nathan Walsh ◽  
Hagan Bayley
Keyword(s):  
Genetic Engineering ◽  
Cancer Cells ◽  
Pore Formation ◽  
Polypeptide Chain ◽  
Genetically Engineered ◽  
Recognition Sequence ◽  
Selective Activation ◽  
Selective Destruction ◽  
Pore Forming Proteins ◽  
Central Loop

ABSTRACTProtease-activated triggers have been introduced Into a pore-forming protein, staphylococcal a-hemolysin (αHL). The hemolysin was remodeled by genetic engineering to form two-chain constructs with redundant polypeptide sequences at the central loop, the Integrity of which Is crucial for efficient pore formation. The new hemolysins are activated when the polypeptide extensions are removed by proteases. By alterating the protease recognition sequence in the loop, selective activation by specified proteases can be obtained. Protease-triggered pore-forming proteins might be used for the selective destruction of cancer cells that bear tumor-associated proteases. When certain two-chain constructs are treated with proteases, a full-length polypeptide chain forms as the result of a protease-mediated transpeptidation reaction. This reaction might be used to produce chimeric hemolysins that are Inaccessible by conventional routes.

EMBRYO MANIPULATION AND GENE TRANSFER IN LIVESTOCK

1985 ◽  
Vol 65 (3) ◽  
pp. 527-538 ◽  
Author(s):  
R. B. CHURCH ◽  
F. J. SCHAUFELE ◽  
K. MECKLING
Keyword(s):  
Gene Transfer ◽  
Genetic Engineering ◽  
Embryo Transfer ◽  
Dna Sequences ◽  
Recombinant Dna ◽  
Fusion Gene ◽  
Bovine Genome ◽  
Monozygotic Twins ◽  
Genetically Engineered ◽  
Livestock Species

In the past few years significant progress has been made in manipulation of reproduction and in development of genetic engineering techniques which can be applied to animal species. Artificial insemination and embryo transfer are now used widely in the livestock industry. The advent of non-surgical embryo collection and transfer, embryo freezing and splitting along with estrus synchronization has allowed the industry to move from the laboratory to the farm. Embryo manipulation now involves embryo splitting to produce monozygotic twins, in vitro fertilization, cross-species fertilization, embryo sexing, and chimeric production of tetraparental animals among others. Advances in recombinant DNA, plasmid construction and embryo manipulation technologies allow the production of genetically engineered animals. The application of recombinant DNA technology involves the isolation and manipulation of desired genes which have potential for significant changes in productivity in genetically engineered livestock. Recombinant DNA constructs involve the coupling of promoter, enhancer, regulatory and structural DNA sequences to form a "fusion gene" which can then be multiplied, purified, assayed and expressed in cell culture prior to being introduced into an animal genome. Such DNA gene constructs are readily available for many human and mouse genes. However, they are not readily available for livestock species because the detailed molecular biology has not yet been established in these species. Gene transfer offers a powerful new tool in animal research. Transfer of genes into the bovine genome has been accomplished. However, successful directed expression of these incorporated genes has not been achieved to date. New combinations of fusion genes may be an effective way of producing transgenic domestic animals which show controlled expression of the desired genes. Embryo manipulation and genetic engineering in livestock species is moving rapidly. The problems being addressed at present in numerous laboratories will result in enhanced livestock production in the not too distant future. Key words: Embryo transfer, embryo manipulation, transgenic livestock, genetic engineering, gene transfer, monozygotic twins

Progress in Genetic Engineering of Cowpea for Insect Pest and Virus Resistance

2020 ◽  
pp. 115-137
Author(s):  
J. Muthuvel ◽  
Manalisha Saharia ◽  
Sanjeev Kumar ◽  
Moses Akindele Abiala ◽  
Gundimeda J. N. Rao ◽  
...  
Keyword(s):  
Genetic Engineering ◽  
Virus Resistance ◽  
Insect Pest

Using genetic engineering to combat disease-spreading mosquitoes

2020 ◽  
Vol 187 (7) ◽  
pp. 252-252
Keyword(s):  
Genetic Engineering ◽  
Genetically Engineered ◽  
Disease Spreading

Genetically engineered mosquitoes could help control the spread of diseases such as dengue, reports Kathryn Clark

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