Articles
RECENT DEVELOPMENTS IN TECHNIQUES FOR IDENTIFICATION AND DETECTION OF PLANT VIRUSES
Article number
432_13
Pages
118 – 118
Language
Abstract
Plant viruses are generally identified by particle morphology, host range and the serological properties of the coat protein.
Cross-reactivity of antisera raised against viruses from different groups has frequently been used for classification and for the establishment of taxonomic relationships.
However, nucleic acid sequence data are accumulating rapidly and allow more accurate relationships to be established between the individual members of virus groups than serological methods do.
Identification of a virus by sequencing parts of its genome is often done if extensive serological analysis cannot provide conclusive data about the nature of the virus.
This approach requires the purification and isolation of the virus particles and the subsequent cloning of parts of the virus genome.
However, with novel molecular tools like virus group specific PCR, sequence data from new viruses can be obtained, even without the need to purify a virus or to clone parts of its genome.
Sequences obtained by such methods can reveal close and distant relationships between new and existing viruses from a single group as will be demonstrated for the group of potyviruses which is the main group of plant viruses occurring in bulbous crops.
Characterization of new potyviruses appeared to be possible even in case of mixed infections.
For the identification of new potyviruses several general PCR primer sets have been developed which allow the amplification of the complete 3′-end of the potyvirus genome including the coat protein cistron and part of the replicase Nlb cistron.
For several other groups of plant viruses similar PCR primer sets are available.
Once identification of a virus has been accomplished by nucleic acid sequencing, specific PCR primer sets can be designed for very sensitive detection of the virus.
However, to compete with current serological methods for mass detection of plant viruses, the development of fast and reliable PCR protocols including automated sample preparation is a major challenge to overcome.
Alternatively, the molecular approach provides new possibilities to the development of very specific and sensitive antisera against individual viruses or (sub)groups of viruses.
The expression of parts of a virus coat protein as recombinant fusion products can provide insight in the location of epitopes on the coat protein’s amino acid sequence recognized by existing virus specific and virus (sub)group specific antisera.
Then, virus specific epitopes can be isolated from group specific epitopes in recombinant fusion products for production of pure antigens in bacteria, yeast or other cell systems.
Such antigens will provide an infinite source for the production of a new generation of virus specific antisera.
Cross-reactivity of antisera raised against viruses from different groups has frequently been used for classification and for the establishment of taxonomic relationships.
However, nucleic acid sequence data are accumulating rapidly and allow more accurate relationships to be established between the individual members of virus groups than serological methods do.
Identification of a virus by sequencing parts of its genome is often done if extensive serological analysis cannot provide conclusive data about the nature of the virus.
This approach requires the purification and isolation of the virus particles and the subsequent cloning of parts of the virus genome.
However, with novel molecular tools like virus group specific PCR, sequence data from new viruses can be obtained, even without the need to purify a virus or to clone parts of its genome.
Sequences obtained by such methods can reveal close and distant relationships between new and existing viruses from a single group as will be demonstrated for the group of potyviruses which is the main group of plant viruses occurring in bulbous crops.
Characterization of new potyviruses appeared to be possible even in case of mixed infections.
For the identification of new potyviruses several general PCR primer sets have been developed which allow the amplification of the complete 3′-end of the potyvirus genome including the coat protein cistron and part of the replicase Nlb cistron.
For several other groups of plant viruses similar PCR primer sets are available.
Once identification of a virus has been accomplished by nucleic acid sequencing, specific PCR primer sets can be designed for very sensitive detection of the virus.
However, to compete with current serological methods for mass detection of plant viruses, the development of fast and reliable PCR protocols including automated sample preparation is a major challenge to overcome.
Alternatively, the molecular approach provides new possibilities to the development of very specific and sensitive antisera against individual viruses or (sub)groups of viruses.
The expression of parts of a virus coat protein as recombinant fusion products can provide insight in the location of epitopes on the coat protein’s amino acid sequence recognized by existing virus specific and virus (sub)group specific antisera.
Then, virus specific epitopes can be isolated from group specific epitopes in recombinant fusion products for production of pure antigens in bacteria, yeast or other cell systems.
Such antigens will provide an infinite source for the production of a new generation of virus specific antisera.
Authors
Simon A. Langeveld
Keywords
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