Virion stability and aphid vector transmissibility of Cucumber mosaic virus mutants

Virology. 2005 Feb 5;332(1):397-405. doi: 10.1016/j.virol.2004.11.021.

Abstract

The physical stability of virions of Cucumber mosaic virus (CMV) mutants was investigated to determine if relative stability correlated with efficiency of aphid transmission. Virion stability was evaluated by a urea disruption assay and by testing the infectivity of virus following purifications. All viruses were infectious when purified using a low salt buffer without organic solvent, whereas two of seven viruses were less stable and inactivated following purification with a high salt buffer and chloroform. These two viruses were both reassortants derived from the spontaneous transmission-defective mutant CMV-M (F1F2M3 and F1F2M3-L129P). F1F2M3 was relatively unstable, being disrupted between 0 and 1 M urea versus the wild-type CMV-Fny (F1F2M3) that was destabilized at 3-4 M urea. Modifications of F1F2M3 at three amino acid positions (129, 162, 168), singly or in combination, increased the relative stability of virions. A second class of transmission-defective CMVs with engineered mutations in the betaH-betaI surface loop of the CMV-Fny capsid protein (CP) exhibited near wild-type levels of stability. Lastly, a single Pro to Leu substitution at CP position 129 of CMV-Fny (F1F2M3-P129L) conferred the induction of necrosis in tobacco plants and reduced aphid transmissibility, but did not markedly alter the physical stability of virions. Thus, only among CMV-M derivatives harboring the CP mutation of Thr to Ala at position 162 were increases in stability correlated with restoration of transmissibility by the aphid Aphis gossypii.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Substitution
  • Animals
  • Aphids / virology*
  • Cucumovirus / pathogenicity
  • Cucumovirus / physiology*
  • Insect Vectors*
  • Reassortant Viruses
  • Recombinant Fusion Proteins / biosynthesis
  • Urea / pharmacology
  • Virion / drug effects
  • Virion / physiology*

Substances

  • Recombinant Fusion Proteins
  • Urea