Real-time detection of airborne Erysiphe necator (grape powdery mildew) inoculum with loop-mediated isothermal amplification (LAMP)
L. D. THIESSEN (1), W. Mahaffee (2), J. A. Keune (1), G. Grove (3). (1) Oregon State University, Corvallis, OR, U.S.A.; (2) USDA-ARS, Corvallis, OR, U.S.A.; (3) Washington State University, Prosser, WA, U.S.A.
Turbidimetric loop-mediated isothermal amplification (LAMP) detection of <i>Erysiphe necator</i> (grape powdery mildew) inoculum has been shown to be a useful tool in managing spray programs in the Willamette Valley of Oregon; however, the visual inspection of turbidity introduces a high risk for subjectivity and misinterpretation in amplification results. Using an assimilating probe in a real-time LAMP reaction provides more objective, consistent results than turbidity observations, and allows for quantification. In 2012, impaction spore traps were placed in a research vineyard at the Oregon State University Botany and Plant Pathology Farm, and samples were collected daily and biweekly pre-bud break until véraison. The samples were processed using real-time LAMP and quantitative PCR (qPCR). Compared to qPCR, real-time LAMP was 91.8% accurate and had 98.6% sensitivity. Spore traps were also distributed to 16 commercial vineyards to assess the viability of using real-time LAMP for the detection of grape powdery mildew as a management tool. Samples were collected from 23 impaction spore traps bi-weekly from bud break until July 3, 2012. Samples were analyzed using real-time LAMP, which proved to be semi-quantitative. Initial pathogen detection occurred on May 21, 2012. Most spore detections observed in the commercial vineyard trial were below 100 spore quantities. Disease pressure in 2012 was extremely low, and visual field scouting data agreed with the real-time LAMP data.
View Presentation |
