Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 6/29/2005
Publication Date: 7/25/2005
Citation: Barnes, C.W., Szabo, L.J., Johnson, J.L., Bowersox, V.C., Krupa, S.V., Gay, D.A., Harlin, K.S. 2005. An early warning system for detection of aerially transported plant pathogens: Puccinia graminis as a test case. In: Proceedings of American Phytopathological Society, Ontario Region Annual Meeting. June 29-30. Winsor, Ontario, Canada.
Technical Abstract: Atmospheric transport and deposition in rain is a common dispersal mechanism of certain rust fungi. Trap nurseries of susceptible plant material are labor intensive and reflective of previous infection events. An early warning system is needed. Puccinia graminis was used as a model to test whether real-time PCR can detect rust spores in rain samples. Weekly precipitation samples from 19 National Atmospheric Deposition Program (NADP) sites in the "Puccinia Pathway" of the Great Plains were used. The assay utilizes primers specific for rust fungi and a P. graminis specific TaqMan probe nested within a general primer pair within the ITS1 region of the rDNA. Lower limits of the assay are roughly 1-10 spores per sample based on spiking experiments. P. graminis spores were detected by June 1, 2004, in Minnesota and North Dakota, roughly one month prior to the first field observations in Minnesota. Frequency of detection increased through June, was weekly in July and August, and decreased by September. This study demonstrated that use of a PCR assay to detect spores in rain samples collected at geographically dispersed NADP sites can serve as a powerful early warning system for the movement of P. graminis. This methodology may be useful for monitoring the movement of other plant pathogens dispersed in the atmosphere.