Infection Efficiency of Four Phytophthora infestans Clonal Lineages and DNA-Based Quantification of Sporangia

• Published in: PloS one Vol. 10; no. 8; p. e0136312
• Main Authors: Fall, Mamadou Lamine, Tremblay, David Mathieu, Gobeil-Richard, Mélanie, Couillard, Julie, Rocheleau, Hélène, Van der Heyden, Hervé, Lévesque, Camile André, Beaulieu, Carole, Carisse, Odile
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 24.08.2015; Public Library of Science (PLoS)
• Subjects: Airborne infection; Airborne sensing; Assaying; Biology; Botrytis; Decision making; Deoxyribonucleic acid; Development and progression; DNA; Efficiency; Environmental conditions; Epidemics; Famine; Food; Fungicides, Industrial - pharmacology; Genetic aspects; Genomes; Growth chambers; Horticulture; Infections; Inoculum; Leaf area; Leaves; Lesions; Molecular chains; Pathogens; Pesticides; Physiological aspects; Phytophthora; Phytophthora diseases; Phytophthora infestans; Phytophthora infestans - genetics; Phytophthora infestans - growth & development; Phytophthora infestans - pathogenicity; Plant diseases; Plant Diseases - microbiology; Plant Diseases - prevention & control; Plant Leaves - genetics; Plant Leaves - growth & development; Plant Leaves - microbiology; Polymerase chain reaction; R&D; Research & development; Sampling; Solanum tuberosum - drug effects; Solanum tuberosum - genetics; Solanum tuberosum - microbiology; Sporangia; Sporangia - genetics; Sporangia - growth & development; Spores; Canada; Ottawa Ontario Canada; United States > US; North America; Quebec Canada
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0136312

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.