> DETECTION OF POTATO VIRUS Y USING THE LIGASE CHAIN REACTION
> (LCR), IN COMBINATION WITH A MICROTITRE PLATE BASED METHOD
> FOR PRODUCT DETECTION
>> K J O'DONNELL, E CANNING and L G A YOUNG
> Scottish Agricultural Science Agency, East Craigs, Edinburgh, EH12 8NJ, UK
> email: odonnell at sasa.gov.uk>>> ABSTRACT
>> The Scottish Agricultural Science Agency (SASA) carries out diagnostic
> tests for viruses on potato leaf and tuber samples in support of the Scottish
> Seed Potato Classification Scheme. Currently, routine detection of potato
> viruses in submitted leaf samples is carried out using ELISA (enzyme-linked
> immunosorbent assay). However, ELISA is not sufficiently sensitive
> to consistently detect the small amounts of virus present in primary infected
> tubers. In this case, the dormancy of the tubers must first be broken and then
> the resulting plants tested by ELISA, a process which can take several weeks.
>> In order to reduce this period we have evaluated nucleic acid amplification
> techniques which can theoretically achieve the level of sensitivity necessary
> for virus detection directly from tubers. In this paper we report on the
> development of an assay for PVY based on the ligase chain reaction (LCR),
> a method based on the ligase-mediated exponential amplification of DNA probes
> specific to target DNA (or cDNA) of the pathogen. We have combined the
> LCR assay with a microtitre plate based detection system which removes the
> need to run electrophoresis gels to detect products of the assay. This method
> has the possibility of combining the sensitivity and specificity of nucleic
> acid-based techniques with the automation of ELISA. Preliminary results are
> shown which compare the performance of LCR with the standard ELISA method.
>> Dr Kevin O'Donnell "Nature is not cruel, only
> Diagnostics and Molecular Biology pitilessly indifferent."
> SASA - Richard Dawkins
> Edinburgh
>>Kevin.
I'd be really interested to see the preliminary results you
refer to. Was the comparison done on dormant tubers, or on tubers on
which dormancy had been broken? Also what were the comparative costs of
the two techniques? In my experience with molecular techniques, even when
labour costs are taken into account, the cost compared to ELISA can be
prohibitive. Seeing as ultimately the cost of any test is bourne by the
grower and farmers are notoriously 'careful with there money' this is an
important consideration. Any one else have any views?
Dave Jones
Virology
SCRI
Invergowrie
Dundee
