The use of biomagnetic separation to recover DNA suitable for PCR from Claviceps species

DNA analysis of agriculturally important fungi using polymerase chain react ion (PCR)-based methods is becoming routine in research and for diagnostic purposes. Rapid, small-scale DNA isolation methods that take advantage of t he sensitivity, speed and automation potential of PCR technology are needed for timely analysis of important plant pathogens. DNA isolated from Clavic eps africana (causal agent of ergot of sorghum) using several standard DNA extraction protocols was found to be unamplifiable using PCR. The standard methods apparently failed to separate DNA from substances inhibitory to the Taq polymerase enzyme. We obtained DNA amenable to PCR analysis using a no vel method involving magnetic beads and high salt extraction buffer. The bi omagnetic purification method allowed us to obtain reliable PCR amplificati on of the internal transcribed spacer (ITS) regions of rDNA of Claviceps af ricana, making genetic comparisons possible.