Development of a PCR method of Peach latent mosaic viroid and Hop stunt viroid detection for certification of planting material

A high incidence of Peach latent mosaic viroid (PLMVd) and Hop stunt viroid (HSVd) infections in peach trees has been recently found in the Czech Republic. In the frame of setting up a certification system for fruit trees planting material, an RT-PCR detection method had to be developed. For this purpose, several primers pairs were designed according to the published sequences. Different plant materials (leaves, petioles and bark) collected during the year and several RNA extraction methods were tested. RT-PCR with different primer pairs gave reliable results. The best period for detecting both viroids was late spring and early summer, taking leaves as the testing material and using any of the RNA extraction methods assayed. For older leaves in late summer the use of a commercial kit for RNA extraction is recommended. Detection of both viroids in bark was possible even during winter but results were not always reliable.