PCR-based techniques for the detection of plant viruses and viroids

Ten years after the original reports demonstrating the feasibility of the detection of plant viruses and viroids by PCR-based techniques, a large body of literature describes the development of PCR primer pairs and of very sensitive assays for essentially all groups of viral pathogens. The tests developed show, in general, a sensitivity in great excess (up to several thousand-fold) of that reported for serological assays. Yet, the assays reported have so far and to a very large extent been confined to laboratory scale set-ups. Transition from this situation to the real-life, large scale application of these techniques will require further validation as well as development of automated or semi-automated pre- and post-PCR steps. Past and current achievements as well as future perspectives are discussed.