Host range, purification and some properties of hop mosaic virus

Abstract

SUMMARYHop mosaic virus (HMV) causes severe symptoms in sensitive hop (Humulus Zupulus) cultivars, but over 90% of hop plants grown in England belong to tolerant cultivars and most of these plants are infected. HMV infected 11 herbaceous species symptomlessly but infection was systemic in only three of these: Nicotiana clevelandii, N. debneyi and Urtica urens. HMV did not infect 33 other species in 13 families. The virus was transmitted in the non‐persistent manner by the aphids Myzus persicae, Macrosiphum euphorbiae and Phorodon humuli. It was not seed‐borne in N. clevelandii, U. wens or hop.HMV was purified by precipitation from N. clevelandii extracts with polyethylene glycol followed by centrifugation in sucrose density gradients. The preparations contained filamentous particles c. 14 × 650 nm composed of c. 6% single‐stranded RNA of mol. wt c. 3.0 × 106 and a single protein species of mol. wt c. 34 000. HMV showed distant serological relationships to carnation latent, potato M, cowpea mild mosaic and hop latent viruses but it did not react with antisera to six other carlaviruses. The cryptogram for HMV is R/1: 3.0/(6): E/E: S/Ve/Ap.