APS Homepage

Oral: Isothermal Pathogen Detection


Rapid LAMP diagnostics for detection and disease alerts of Phytophthora infestans
J. RISTAINO (1), A. Saville (1), R. Guenter (1), C. Lagaly (1), D. Cooper (2) (1) North Carolina State University, U.S.A.; (2) Mobile Assay, U.S.A.

Phytophthora infestans, causal agent of the Irish potato famine, is a threat to food security globally and an important pathogen in the US on tomato and potato. In 2009, late blight epidemics in the eastern US were the worst in modern history due to widespread inoculum distribution from infected tomato transplants and favorable weather. That year the US-22 lineage was identified as the dominant lineage. USABlight (www.usablight.org) was launched in 2011 to improve disease detection and communication between researchers, growers, the industry, and the public about late blight. A total of 1094 late blight reports were recorded between 2011-2015. Of these, 64% were from tomato and a third primarily in the NE US. A shift in the dominant clonal lineage from mefenoxam sensitive US-22 to US-23 occurred and 82% of genotyped strains were US-23. Disease outbreaks begin each year in Florida winter tomatoes. Spread through movement of tomato fruit is suspected. We developed a loop-mediated isothermal amplification (LAMP) assay specific for detection of P. infestans. The assay can be run in the field at 65C, needs no thermocycling, and can detect 100-10 pg/ul of pathogen DNA. A prototype mobile reader developed by Mobile Assay has been used for in-field detection using a SYBR green stain and hand-held tablet. This mobile reader and LAMP assay is being tested in both the US and East Africa to improve pathogen detection and will be used to develop an Afriblight tracking database.