Detection of potato spindle tuber viroid (PSTVd) in minute amounts of potato (Solanum tuberosum L.) leaf tissue by hybridization techniques and, together with potato viruses, by multiplex RT-PCR

Abstract

Potato spindle tuber viroid (PSTVd) is one of the major constraints for the improvement of potato production worldwide. Sensitive and sophisticated diagnostic procedures such as multiplex RT-PCR will help to control the spread of this and other pathogens, but are technically demanding and expensive. We therefore analyzed the usefulness of hybridization techniques for detection of PSTVd in minute amounts of tissue from potato plants raised through in vitro culture, which is the routine way of potato production. Tissue print, dot blot and Northern blot hybridization with a digoxigenin-labeled PSTVd specific riboprobe allowed detection of PSTVd on a nylon membrane at a minimum quantity of 10 pg per spot or, correspondingly, in RNA extracted from microgram quantities of potato leaf tissue. These findings underlined the usefulness of hybridization techniques in PSTVd diagnosis. The application of multiplex RT-PCR for PSTVd detection in the presence of five potato viruses clearly demonstrated the advantages of this technique, but its potential drawbacks, when used under field conditions in developing countries, must not be underestimated.