Plant Pathology (2021) 70, 2165-2178

Amanda C. Saville, Federico La Spada, Roberto Faedda, Quirico Migheli, Bruno Scanu, Paolo Ermacora, Giovanna Gilardi, Giorgia Fedele, Vitorrio Rossi, Nicolo Lenzi, Antonino Testa, Mohamed Bechir Allagui, Marwa Moumni, Enza Dongiovanni, Fatma Zohra Rekad, David E.L. Cooke, Antonella Pane, Santa O. Cacciola and Jean B. Ristaino (2021)
Population structure of Phytophthora infestans collected on potato and tomato in Italy
Plant Pathology 70 (9), 2165-2178
Abstract: Late blight caused by the oomycete Phytophthora infestans is a disease of potato and tomato of worldwide relevance and is widespread throughout Europe and the Mediterranean region. While pathogen populations in northern Europe have been sampled and characterized for many years, the genetic structure of populations from southern Europe, including Italy, has been less studied. Between 2018 and 2019, we collected 91 samples of P. infestans from potato and tomato crops in Italy, Algeria, and Tunisia on FTA cards and genotyped them using 12-plex microsatellites. These samples were compared to genotypes of P. infestans previously collected within the framework of the EuroBlight network and from published sources. Four clonal lineages were identified: 13_A2 (Blue 13), 2_A1, 23_A1, and 36_A2. Two other isolates collected could not be matched to any currently known clonal lineage. The 13_A2 and 36_A2 lineages were found exclusively in southern Italy and Algeria, while 2_A1 was only found in Algeria. This is the first report of the 36_A2 lineage in Italy. Two isolates from Solanum nigrum were 13_A2, suggesting this weed host could be a reservoir of inoculum. The 23_A1 lineage was found widely on infected tomato crops in Italy and is the same as the lineage US-23 that is widespread in North America. Differences in genotypes across the country suggests that there may be different sources of introduction into Italy, possibly via infected seed tubers from other countries in Europe, tubers for consumption from North Africa, or tomatoes.
(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): Quirico Migheli, Mohamed Béchir Allagui, David E.L. Cooke, Santa O. Cacciola, Jean Beagle Ristaino

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
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)	Italy
	Phytophthora infestans	Potato (Solanum tuberosum)	Algeria
	Phytophthora infestans	Potato (Solanum tuberosum)	Tunisia
	Phytophthora infestans	Tomato (Solanum lycopersicum)	Italy