Detection of pome fruit viroids by enzymatic cDNA amplification.

We have studied the detection of apple scar skin, dapple apple, and pear rusty skin viroids in nucleic acid extracts of infected pome fruit tissues by reverse transcription-polymerase chain reaction (RT-PCR) with viroid cDNA-specific primers. Analysis of RT-PCR-amplified products by gel electrophoresis or by Southern blot hybridization indicated that the new procedure is more sensitive than existing detection methods and provides information about viroid detection without requiring large samples or using molecular hybridization. Our results also suggest the potential utility of the PCR technology in detecting other viroids and possibly other plant pathogens.