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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research » Research » Publications at this Location » Publication #329195

Research Project: Exotic and Emerging Plant Diseases of Horticultural Crops

Location: Horticultural Crops Research

Title: Early detection of airborne inoculum of Magnaporthe oryzae in turfgrass fields using a quantitative LAMP assay

Author
item Villari, Caterina
item Mahaffee, Walter - Walt
item Mitchell, Thomas
item Pedley, Kerry
item Pieck, Michael
item Peduto Hand, Francesca

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2016
Publication Date: 1/1/2017
Citation: Villari, C., Mahaffee, W.F., Mitchell, T.K., Pedley, K.F., Pieck, M.L., Peduto Hand, F. 2017. Early detection of airborne inoculum of Magnaporthe oryzae in turfgrass fields using a quantitative LAMP assay. Plant Disease. 101(1):170-177. doi: 10.1094/PDIS-06-16-0834-RE.

Interpretive Summary: A diagnostic technique for monitoring the presence Gray leaf spot (GLS) in perennial ryegrass is presented. Early diagnosis is crucial for effective disease management and the implementation of Integrated Pest Management practices. We developed a pathogen-specific quantitative loop-mediated isothermal amplification (qLAMP) assay coupled with a spore trap system for rapid detection and quantification of airborne inoculum of Magnaporthe oryzae perennial ryegrass pathotype, and tested its suitability for implementation in GLS-infected turfgrass fields. In summer 2015, two perennial ryegrass plots were artificially inoculated with the pathogen, with four continuously running custom impaction spore traps placed in each plot. Results indicated that the assay-trap system was able to detect as low as 10 conidia up to 12 days before symptoms developed in the field. LAMP technology is particularly appropriate for field implementation by non-technical users, and has the potential to be a powerful decision support tool to guide timing of fungicide applications for GLS management.

Technical Abstract: Gray leaf spot (GLS) is a destructive disease of perennial ryegrass caused by a host specific pathotype of the ascomycete Magnaporthe oryzae. Early diagnosis is crucial for effective disease management and the implementation of Integrated Pest Management practices. However, a rapid diagnostic protocol for the detection of low levels of airborne inoculum is still missing. We developed a pathogen-specific quantitative loop-mediated isothermal amplification (qLAMP) assay coupled with a spore trap system for rapid detection and quantification of airborne inoculum of M. oryzae perennial ryegrass pathotype, and tested its suitability for implementation in GLS-infected turfgrass fields. In summer 2015, two perennial ryegrass plots were artificially inoculated with the pathogen, with four continuously running custom impaction spore traps placed in each plot. Sampling units were replaced daily and tested with the developed qLAMP assay, while plots were monitored for symptoms development. Results confirmed that the qLAMP assay-trap system was able to detect as low as 10 conidia up to 12 days before symptoms developed in the field. LAMP technology is particularly appropriate for field implementation by non-technical users, and has the potential to be a powerful decision support tool to guide timing of fungicide applications for GLS management.