Submitted to: Joint Meeting of the American Phytopathological Society and Society of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: 7/28/2007
Publication Date: N/A
Technical Abstract: Rhizoctonia root rot, bare patch, and damping-off of wheat are yield-limiting diseases caused by Rhizoctonia solani AG-8 and R. oryzae. Detection and quantification of Rhizoctonia spp. are essential for evaluating pathogen distribution and management, but extraction of DNA from these pathogens is hampered by the tough, monilioid hyphae found in soil. Low soil population densities of Rhizoctonia render DNA extraction inconsistent. The Pressure Cycling Technology Sample Preparation System (PCT SPS) is a novel, efficient, and reproducible extraction system that uses cycles of hydrostatic pressure (from ambient to up to 35,000 psi) to extract cellular materials from hard-to-extract samples under controlled conditions. Using the PCT SPS, we obtained Rhizoctonia DNA from wheat roots that were previously recalcitrant to homogenization. DNA was recovered in high enough amounts to allow quantification using real-time PCR. The PCT SPS also improved the extraction and quantification of Rhizoctonia DNA from agricultural soils up to 16-fold compared to a bead beating extraction protocol. As the PCT SPS is a closed system, samples were free from contamination that can occur during conventional extraction procedures. Furthermore, PCT extractions were so consistent that pathogen quantification generally could be derived from two rather than three or four replicated extracts.