Purified Avocado Sunblotch Viroid Causes Disease in Avocado Seedlings.

Abstract

Low mol. wt. nucleic acids were extracted from diseased avocado cv. Hass/SB-1 and the circular form of ASBV purified from this extract by 2 stages of PAGE. When glasshouse-grown, healthy avocado seedlings were inoculated with filter paper pieces moistened with the purified viroid, symptoms appeared 4-8 months later, compared with 2-5 months when bark from infected trees was used as inoculum. ASBV was confirmed in seedlings inoculated by both methods, by PAGE and cDNA probe. This is the 1st known report confirming that ASBV is the causal agent of avocado sunblotch disease.