Cowpea mosaic virus: effects on host cell processes
Jeroen Pouwels, Jan E. Carette, Jan Van Lent1 and Joan Wellink
Laboratory of Molecular Biology and Virology1,
Graduate School for Experimental Plant Sciences, Wageningen University,
Wageningen, the Netherlands
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| Taxonomy: |
Cowpea mosaic virus (CPMV)
is the type member of the Comoviridae and bears a strong
resemblance to animal picornaviruses, both in gene organization and in the
amino acid sequence of replication proteins. Little systematic work has
been done to compare isolates of the virus from different parts of the
world. |
| Physical properties: |
Purified preparations of virus
contain three centrifugal components; empty protein shells without RNA (T)
and two nucleoprotein components (M and B), containing 24% and 34% RNA,
respectively. The icosahedral particles have with a diameter of
28 nm, consist of 60 copies of two coat proteins, and are heat
stable. |
| Hosts: |
CPMV causes one of the most
commonly reported virus diseases of cowpea (Vigna unguiculata), in
which it produces chlorotic spots with diffuse borders in inoculated
primary leaves. Trifoliate leaves develop a bright yellow or light green
mosaic of increasing severity in younger leaves. The host range is rather
limited, and few hosts are known outside the Leguminosae. The virus is
transmitted by various beetles with biting mouthparts. Reported in Africa,
the Philippines and Iran. Is apparently absent from North and South
America. |
| Useful websites: |
http://mmtsb.scripps.edu/viper/1cpmv.html
(structure)
http://image.fs.uidaho.edu/vide/descr254.htm
(general information) |
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Fig. 2 Electron micrographs of the
cytopathological structure in CPMV infected cowpea leaves. (A) An osmium
fixed thin section showing electron dense structures (Eds) and small
membranous vesicles (Ve). Ch, chloroplast; Va, vacuole. (B–D) Immunogold
labelled cryo-sections of electron-dense structures (B and D) and vesicles
(C and E) using anti-32K- (B and C), anti-VPg- (D and E) sera. With both
antisera, gold particles were found associated with both structures. Bar
represents 300 nm in (A) and 150 nm in (B–E). |
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