Occurrence, purification and properties of narcissus tip necrosis virus

Abstract

SUMMARYNarcissus tip necrosis virus (NTNV), a previously undescribed virus, was detected in the Netherlands and the United Kingdom in plants of twenty‐one cultivars of trumpet, large‐cupped, small‐cupped, double, tazetta and poeticus narcissus. In some cultivars distinct leaf symptoms were sometimes associated with infection but in others infected plants remained symptomless and detection was dependent on serological tests. The virus was readily transmitted by manual inoculation to narcissus, but it failed to infect any of forty‐six other plant species from fourteen families. Up to 50 mg of virus/kg of tissue were obtained by differential centrifugation of narcissus leaf extracts previously clarified with either diethyl ether, n‐butanol or a mixture of n‐butanol and chloroform. The virus particles are isometric, c. 30 nm in diameter, have a sedimentation coefficient (s°20 w) Of 123 S a buoyant density of 1·356 g/cm3, migrate as a single component in polyacrylamide gel electrophoresis, and contain a single RNA species of mol. wt 1·6×106 and two major polypeptides of mol. wt 42000 and 39000. Although NTNV resembles tombusviruses it showed no serological relationship to the type member or six putative members of this group or to thirty‐four other viruses with isometric particles. Its present cryptogram is R/*:1.6/(18):S/S:S/*.