The obligate parasite Synchytrium endobioticum is a soil-borne chytridiomycete that infects susceptible potato cultivars. Potato plants develop unsightly warty growths on tubers, which renders crops unmarketable. The fungus develops thick-walled resting sporangia which remain viable for years in infested soil. These plots are “scheduled” and agricultural cultivation is suspended for years. The pest is endemic in the Netherlands and parts of Canada, and must be restricted from entering uninfected regions since its spread could have a substantial economic impact on the potato industry.
Infested plots are checked periodically over years to determine the number of disease-causing sporangia in the soil. Current testing methods rely on microscopic identification by skilled trained personnel and take about 1 day to complete, followed by bioassays which require weeks to obtain a result. A quick, easy, and inexpensive method of detecting the presence of S. endobioticum in field samples is proposed by using hybridization-induced gold nanoparticle aggregation. Gold nanoparticles functionalized with two separate thiolated probes (150 nM final concentration) were mixed and changed color from dark red to purple within minutes after the addition of target DNA down to 75 nM (unoptimized). Microliter probe volumes are used and the test is performed at room temperature, eliminating the need for expensive equipment, reagents, and rinsing.
Duy, J. Smith, R. L. and Connell, L.B. (2009) Development of a field-deployable bioassay based on gold nanoparticle aggregation for the detection of potato wart fungus, Synchytrium endobioticum. Presented at the Potato Association of America Conference, at Fredericton, New Brunswick.
Check out our Potato Wart Photo Gallery
The Canadian Food Inspection Agency has more background info on the potato wart.
- Duy, J, L B Connell, W Eck, S D Collins and R L Smith (2010)."Preparation of surfactant-stabilized gold nanoparticle–peptide nucleicacid conjugates." Journal of Nanoparticle Research on line. doi:10.1007/s11051-010-9996-0. [VIEW PDF]
- Duy, J, R L Smith, S D Collins and L B Connell (2012). "A field-deployable colorimetric bioassay for the rapid and specific detection of ribosomal RNA." Biosensors and Bioelectricronics.doi: 10.1016/j.bios.2012.05.039.
- Bratcher, A. and L. Connell. (2009) Development of a detection method for potato wart fungus, Synchytrium endobioticum, using surface plasmon resonance and molecular probes. Potato Association of America Annual Meeting at Fredericton, New Brunswick.
L. B., Bratcher, A. R., Duy, J. (2009) Development of rapid field-based
detection methods for Synchytrium endobioticum. American
Phytopathological Society Annual Meeting; Portland, OR.
J., Connell, L. B., Eck, W., Collins, S. D., Smith, R. L. (2009)
Preparation of surfactant-stabilized gold nanoparticle-peptide nucleic
acid conjugates. Submitted.
- Duy, J., Collins, S. D., Smith, R. L., Connell, L. B. (2009) Colorimetric bioassay for field-based detection of red tide organisms using gold nanoparticle aggregation. IGERT PI Meeting; Alexandria, VA.
National Institute of Food and Agriculture
Formerly USDA Cooperative State Research, Education, and Extension Service