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Poster: Diseases of Plants: Disease Detection & Diagnosis


On-site detection of Pythium ultimum in potatoes using loop-mediated isothermal amplification (LAMP)
J. WOODHALL (1), P. Wharton (2), S. Dangi (2), K. Perkins (3), J. Azcona (3) (1) University of Idaho, U.S.A.; (2) University of Idaho, U.S.A.; (3) Fera Science Ltd, United Kingdom

Pythium ultimum is a soil-borne plant pathogen that causes damping off and root rot diseases in a wide range of crops. In potatoes, Pythium leak caused by P. ultimum has been a major storage disease problem in the Pacific Northwest potato production areas for many years, but in recent years reported losses have increased. Since similar symptoms can be caused by other pathogens, rapid and robust tests are required to detect the pathogen. Loop-mediated isothermal amplification (LAMP) has great potential for diagnostic use offering fast, specific and sensitive detection. In this study a new LAMP assay was designed for P. ultimum and evaluated in terms of specificity and sensitivity. The assay was highly specific when tested with DNA from 30 other isolates consisting of closely related Pythium species and other potato pathogens. The assay was also highly sensitive detecting as little as 17.5 fg of DNA in less than 30 minutes when used with a GenieĀ® II for fluorescence measurement. A simple, rapid on site DNA extraction method for tubers was developed for use with the assay which resulted in a highly sensitive test capable of detecting the pathogen in range of both naturally infected asymptomatic and symptomatic tubers. In conclusion, LAMP assays can offer a rapid, sensitive, on-site test for the presence of P. ultimum in potato tubers.