Plant Pathology (2012) 61, 867-876

A.K. Lees, L. Sullivan, J.S. Lynott and D.W. Cullen (2012)
Development of a quantitative real-time PCR assay for Phytophthora infestans and its applicability to leaf, tuber and soil samples
Plant Pathology 61 (5), 867-876
Abstract: A sensitive real-time polymerase chain reaction (PCR) assay was developed for the quantification of Phytophthora infestans, the cause of foliar and tuber late blight in potato. A primer pair (PinfTQF/PinfTQR) and a fluorogenic probe (PinfTQPR) were designed to perform a quantitative assay for the detection of P. infestans in leaves, tubers and soils. The assay was shown to be specific to P. infestans and the very closely taxonomically related non-potato pathogen species P. mirabilis, P. phaseoli and P. ipomoea, but did not detect the potato pathogens P. erythroseptica and P. nicotianae. The assay was able to reliably detect P. infestans DNA at 100 fg per reaction and was effective in quantifying P. infestans in infected leaf tissue from 24 h after inoculation and also in infected symptomless tubers and diseased tubers. Attempts to detect oospores of P. infestans in naturally and artificially infested soil samples are described and compared with baiting tests and previous literature. It was not possible to detect oospores in soil samples due to problems with DNA extraction from the oospores themselves. However, the assay was shown to detect even very low levels of asexual inoculum (sporangia and mycelium) in soil. This work assembles all the necessary features of a quantitative P. infestans assay, which have previously been somewhat disparate: the sensitivity, specificity and quantitation are fully validated, the assay is shown to work in common applications in leaf and tuber tissue and the problems with P. infestans oospore detection are explored and tested experimentally.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Alison K. Lees

Research topic(s) for pests/diseases/weeds:
identification/taxonomy
surveys/sampling/distribution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Phytophthora infestans	Potato (Solanum tuberosum)