Stability of Cucumber Necrosis Virus at the Quasi-6-Fold Axis Affects Zoospore Transmission.

(CNV) is a member of the genus and has a monopartite positive-sense RNA genome. CNV is transmitted in nature via zoospores of the fungus As with other members of the genus, the CNV capsid swells when exposed to alkaline pH and EDTA. We previously demonstrated that a P73G mutation blocks the virus from zoospore transmission while not significantly affecting replication in plants (K.

Atomic structure of Cucumber necrosis virus and the role of the capsid in vector transmission.

Cucumber Necrosis Virus (CNV) is a member of the genus Tombusvirus and has a monopartite positive-sense RNA genome packaged in a T=3 icosahedral particle. CNV is transmitted in nature via zoospores of the fungus Olpidium bornovanus. CNV undergoes a conformational change upon binding to the zoospore that is required for transmission, and specific polysaccharides on the zoospore surface have been implicated in binding.

A highly basic KGKKGK sequence in the RNA-binding domain of the Cucumber necrosis virus coat protein is associated with encapsidation of full-length CNV RNA during infection.

The Cucumber necrosis virus particle is a T=3 icosahedron consisting of 180 identical coat protein (CP) subunits. The N-terminal 58 aa residue segment of the CP R domain is believed to bind viral RNA within virions and during assembly. We report results of in vivo experiments that examine the role of the R domain in assembly.

Induction of particle polymorphism by cucumber necrosis virus coat protein mutants in vivo.

The Cucumber necrosis virus (CNV) particle is a T=3 icosahedron consisting of 180 identical coat protein (CP) subunits. Plants infected with wild-type CNV accumulate a high number of T=3 particles, but other particle forms have not been observed. Particle polymorphism in several T=3 icosahedral viruses has been observed in vitro following the removal of an extended N-terminal region of the CP subunit.

Interactions between the West Nile virus capsid protein and the host cell-encoded phosphatase inhibitor, I2PP2A.

The West Nile virus (WNV) capsid protein functions in virus assembly to package genomic RNA into nucleocapsid structures. It is becoming clear, that in addition to their structural roles, capsid proteins of RNA viruses have non-structural functions. For example, the WNV capsid protein has been implicated as a pathogenic determinant.

Structures of T=1 and T=3 particles of cucumber necrosis virus: evidence of internal scaffolding.

Cucumber necrosis virus (CNV) is a member of the genus Tombusvirus, of which tomato bushy stunt virus (TBSV) is the type member. The capsid protein for this group of viruses is composed of three major domains: the R domain, which interacts with the RNA genome: the S domain, which forms the tight capsid shell: and the protruding P domain, which extends approximately 40 Angstrom from the surface. Here, we present the cryo-transmission electron microscopy structures of both the T=1 and T=3 capsids to a resolution of approximately 12 Angstrom.

Molecular aspects of plant virus transmission by olpidium and plasmodiophorid vectors.

The genome structures of a large number of viruses transmitted by olpidium and plasmodiophorid vectors have been determined. The viruses are highly diverse, belonging to 12 genera in at least 4 families. Plasmodiophorids are now classified as protists rather than true fungi.

Evidence that vector transmission of a plant virus requires conformational change in virus particles.

Transmission of Cucumber necrosis virus (CNV) by zoospores of its fungal vector, Olpidium bornovanus, involves specific adsorption of virus particles onto the zoospore plasmalemma prior to infestation of cucumber roots by virus-bound zoospores. Previous work has shown that specific components of both CNV and zoospores are required for successful CNV/zoospore recognition. Here, we show that limited trypsin digestion of CNV following in vitro CNV/zoospore binding assays, results in the production of specific proteolytic digestion products under conditions where native CNV is resistant.

Evidence that binding of cucumber necrosis virus to vector zoospores involves recognition of oligosaccharides.

Despite the importance of vectors in natural dissemination of plant viruses, relatively little is known about the molecular features of viruses and vectors that permit their interaction in nature. Cucumber necrosis virus (CNV) is a small spherical virus whose transmission in nature is facilitated by zoospores of the fungus Olpidium bornovanus. Previous studies have shown that specific regions of the CNV capsid are involved in transmission and that transmission defects in several CNV transmission mutants are due to inefficient attachment of virions to the zoospore surface.