title: Infection Efficiency of Four Phytophthora infestans Clonal Lineages and DNA-Based Quantification of Sporangia.
abstract: The presence and abundance of pathogen inoculum is with host resistance and environmental conditions a key factor in epidemic development. Therefore, several spore-sampling devices have been proposed to monitor pathogen inoculum above fields. However, to make spore sampling more reliable as a management tool and to facilitate its adoption, information on infection efficiency and molecular tools for estimating airborne sporangia concentration are needed. Experiments were thus undertaken in a growth chamber to study the infection efficiency of four clonal lineages of P. infestans (US-8, US-11, US-23, and US-24) by measuring the airborne sporangia concentration and resulting disease intensity. The relationship between the airborne sporangia concentration and the number of lesions per leaf was exponential. For the same concentration, the sporangia of US-23 caused significantly more lesions than the sporangia of the other clonal lineages did. Under optimal conditions, an airborne sporangia concentration of 10 sporangia m-3 for US-23 was sufficient to cause one lesion per leaf, whereas for the other clonal lineages, it took 15 to 25 sporangia m-3 to reach the same disease intensity. However, in terms of diseased leaf area, there was no difference between clonal lineages US-8, US-23 and US-24. Also, a sensitive quantitative real-time polymerase chain reaction (qPCR) tool was developed to quantify P. infestans airborne sporangia with detection sensitivity of one sporangium. The specificity of the qPCR assay was rigorously tested for airborne inoculum and was either similar to, or an improvement on, other published PCR assays. This assay allows rapid and reliable detection and quantification of P. infestans airborne sporangia and thereby, facilitates the implementation of spores-sampling network.
authors: Department of Biology, University of Sherbrooke, Sherbrooke, Quebec, Canada; Horticulture Research and Development Centre, Agriculture and Agri-Food Canada, St-Jean-sur-le-Richelieu, Quebec, Canada.
authors: Mamadou Lamine
authors: ML
authors: Fall
authors: Horticulture Research and Development Centre, Agriculture and Agri-Food Canada, St-Jean-sur-le-Richelieu, Quebec, Canada.
authors: David Mathieu
authors: DM
authors: Tremblay
authors: Compagnie de recherche Phytodata inc., Sherrington, Quebec, Canada.
authors: Mélanie
authors: M
authors: Gobeil-Richard
authors: Horticulture Research and Development Centre, Agriculture and Agri-Food Canada, St-Jean-sur-le-Richelieu, Quebec, Canada; Compagnie de recherche Phytodata inc., Sherrington, Quebec, Canada.
authors: Julie
authors: J
authors: Couillard
authors: Central Experimental Farm, Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada.
authors: Hélène
authors: H
authors: Rocheleau
authors: Compagnie de recherche Phytodata inc., Sherrington, Quebec, Canada.
authors: Hervé
authors: H
authors: Van der Heyden
authors: Central Experimental Farm, Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada.
authors: Camile André
authors: CA
authors: Lévesque
authors: Department of Biology, University of Sherbrooke, Sherbrooke, Quebec, Canada.
authors: Carole
authors: C
authors: Beaulieu
authors: Horticulture Research and Development Centre, Agriculture and Agri-Food Canada, St-Jean-sur-le-Richelieu, Quebec, Canada.
authors: Odile
authors: O
authors: Carisse
mesh_terms: D005659:Fungicides, Industrial / Q000494:pharmacology; D010838:Phytophthora; D055750:Phytophthora infestans / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D010935:Plant Diseases / Q000382:microbiology / Q000517:prevention & control*; D018515:Plant Leaves / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology; D011198:Solanum tuberosum / Q000187:drug effects / Q000235:genetics / Q000382:microbiology*; D058432:Sporangia / Q000235:genetics / Q000254:growth & development
chemical_list: D005659:Fungicides, Industrial