Previous Article | Next Article ![]()
J. Virol., Feb 1995, 916-922, Vol 69, No. 2
ME Taliansky and F Garcia-Arenal
Direct evidence is presented for a host-specific role of the cucumovirus
capsid protein in long-distance movement within infected plants. Cucumber
(Cucumis sativus L.) is a systemic host for cucumber mosaic cucumovirus
(CMV). Tomato aspermy cucumovirus, strain 1 (1-TAV), multiplied to the
levels of CMV (i.e., replicated, moved from cell to cell, and formed
infectious particles) in the inoculated leaves of cucumbers but was
completely unable to spread systemically. The defective long-distance
systemic movement of 1-TAV was complemented by CMV in mixed infections.
Coinfection of cucumbers with 1-TAV RNA with various combinations of
transcripts from full-length cDNA clones of CMV genomic RNA 1, RNA2, and
RNA3 showed that CMV RNA3 alone complemented 1- TAV long-distance movement.
We obtained mutants containing mutations in the two open reading frames in
CMV RNA3 encoding the 3a protein and the capsid protein (CP), both of which
are necessary for cell-to-cell movement of CMV. Complementation experiments
with mutant CMV RNA3 showed that only 3a protein mutants, i.e., those with
an intact CP, complemented the long-distance movement of 1-TAV in
cucumbers. Since CMV and TAV have common systemic host plants, the results
presented here are strong evidence for an active, host-specific function of
the CPs of these two cucumoviruses for long-distance spread in the phloem.
The results also suggest that the plasmodesmata in the vascular system
and/or at the boundary between the mesophyll and the vascular system,
involved in long-distance movement through the phloem, and those in the
mesophyll, involved in cell-to-cell movement, differ functionally.
Copyright © 1995, American Society for Microbiology
Role of cucumovirus capsid protein in long-distance movement within the infected plant
Departamento de Patologia Vegetal, E.T.S.I. Agronomos, Ciudad Universitaria, Madrid, Spain.
This article has been cited by other articles:
| J. Bacteriol. | Mol. Cell. Biol. | Microbiol. Mol. Biol. Rev. |
|---|
| Clin. Vaccine Immunol. | ALL ASM JOURNALS |
|---|