Comparison of Tissue-Disruption Methods for PCR-Based Detection of Plant Pathogens

Polymerase chain reaction-based detection of plant-associated microbes depends on physical disruption of tissues of the host and microorganism in order to liberate nucleic acids during extraction. Using six types of plant tissues as well as an oospore preparation of Phytophthora capsici, we evaluated the use of pressure-cycling technology (PCT) compared with several common techniques for physical tissue disruption. With all tissues tested, bead-beating provided excellent yields of amplifiable nucleic acid, with a few inconsistent exceptions. The use of PCT did not consistently improve nucleic acid yields or "amplifiability". The use of a mortar and pestle to physically disrupt plant tissue also provided good results at low cost, though it was not consistently as effective as the bead-beater. Furthermore, handling of ground tissues in an open mortar may present more challenges in minimizing cross-contamination than working with tissues pulverized in a bead-beater tube.