Indexing of Citrus Viroids by Imprint Hybridisation

A method based on the hybridisation of tissue imprints was developed for routine indexing of citrus viroids. For maximum sensitivity and reliability, the inoculation of Citrus medica (Etrog citron) as a viroid amplification host is required. Hybridisation against Digoxigenin-labelled RNA- or DNA-probes followed by detection of viroid-probe hybrids using anti-DIG-alkaline phosphate conjugate and the chemiluminescence substrate CSPD was suitable for the detection of all citrus viroids with the same sensitivity as other available methods. The overall process is extremely simple and allows quick analysis of large numbers of samples by easily trained personnel and minimum equipment.