Cowpea mosaic virus (CPMV) is a non-enveloped

plant virus Plant viruses are viruses that affect plants. Like all other viruses, plant viruses are obligate intracellular parasites that do not have the molecular machinery to replicate without a host. Plant viruses can be pathogenic to higher plants. M ...

of the

comovirus ''Comovirus'' is a genus of viruses in the order ''Picornavirales'', in the family ''Secoviridae'', in the subfamily ''Comovirinae''. Plants serve as natural hosts. There are 15 species in this genus. Taxonomy The genus contains the following s ...

group. Infection of a susceptible

cowpea The cowpea (''Vigna unguiculata'') is an annual herbaceous legume from the genus ''Vigna''. Its tolerance for sandy soil and low rainfall have made it an important crop in the semiarid regions across Africa and Asia. It requires very few input ...

leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

causes a "mosaic" pattern in the leaf, and results in high virus yields (1-2 g/kg). Its

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...

consists of 2 molecules of

positive-sense In molecular biology and genetics, the sense of a nucleic acid molecule, particularly of a strand of DNA or RNA, refers to the nature of the roles of the strand and its complement in specifying a sequence of amino acids. Depending on the context, ...

RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...

(RNA-1 and RNA-2) which are separately encapsidated. Both RNA1 and RNA2 have a

VPg VPg (viral protein genome-linked) is a protein that is covalently attached to the 5′ end of positive strand viral RNA and acts as a primer (molecular biology), primer during RNA synthesis in a variety of virus families including Picornaviridae, ...

(virus genome-linked protein) at the 5'end, and

polyadenylation Polyadenylation is the addition of a poly(A) tail to an RNA transcript, typically a messenger RNA (mRNA). The poly(A) tail consists of multiple adenosine monophosphates; in other words, it is a stretch of RNA that has only adenine bases. In euk ...

at the 3' end. Genomic RNA1 and RNA2 are expressed by a polyprotein processing strategy. RNA1 encodes

helicase Helicases are a class of enzymes thought to be vital to all organisms. Their main function is to unpack an organism's genetic material. Helicases are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separatin ...

, VPg,

protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the ...

and RdRp. RNA2 encodes

movement protein In order for a virus to infect a plant, it must be able to move between cells so it can spread throughout the plant. Plant cell walls make this moving/spreading quite difficult and therefore, for this to occur, movement proteins must be present. A ...

and coat protein. The virus particles are 28 nm in diameter and contain 60 copies each of a Large (L) and Small (S) coat protein. The structure is well characterised to atomic resolution, and the viral particles are thermostable. The identification of the virus is attributed to Lister and Thresh in 1955, but it is now known as a variant of the Sunn-hemp mosaic virus. CPMV displays a number of features that can be exploited for

nanoscale The nanoscopic scale (or nanoscale) usually refers to structures with a length scale applicable to nanotechnology, usually cited as 1–100 nanometers (nm). A nanometer is a billionth of a meter. The nanoscopic scale is (roughly speaking) a lo ...

biomaterial fabrication. Its genetic, biological and physical properties are well characterised, and it can be isolated readily from plants. There are many stable mutants already prepared that allow specific modification of the

capsid A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may ...

surface. It is possible to attach a number of different chemicals to the virus surface and to construct multilayer

array An array is a systematic arrangement of similar objects, usually in rows and columns. Things called an array include: {{TOC right Music * In twelve-tone and serial composition, the presentation of simultaneous twelve-tone sets such that the ...

s of such

nanoparticle A nanoparticle or ultrafine particle is usually defined as a particle of matter that is between 1 and 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 1 ...

s on solid surfaces. This gives the natural or genetically engineered nanoparticles a range of properties which could be useful in nanotechnological applications such as

biosensor A biosensor is an analytical device, used for the detection of a chemical substance, that combines a biological component with a physicochemical detector. The ''sensitive biological element'', e.g. tissue, microorganisms, organelles, cell recep ...

catalysis Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

and nanoelectronic devices. One example use of CPMV particles is to amplify signals in

microarray A microarray is a multiplex lab-on-a-chip. Its purpose is to simultaneously detect the expression of thousands of genes from a sample (e.g. from a tissue). It is a two-dimensional array on a solid substrate—usually a glass slide or silicon t ...

based sensors. In this application, the virus particles separate the

fluorescent Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, tha ...

dye A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution an ...

s used for signaling in order to prevent the formation of non-fluorescent

dimer Dimer may refer to: * Dimer (chemistry), a chemical structure formed from two similar sub-units ** Protein dimer, a protein quaternary structure ** d-dimer * Dimer model, an item in statistical mechanics, based on ''domino tiling'' * Julius Dimer ( ...

s that act as quenchers. Another example is the use of CPMV as a nanoscale

breadboard A breadboard, solderless breadboard, or protoboard is a construction base used to build semi-permanent prototypes of electronic circuits. Unlike a perfboard or stripboard, breadboards do not require soldering or destruction of tracks and are ...

for molecular electronics. CPMV particles have also shown potential for in-situ vaccination in cancer immunotherapy

References

External links

Separation and recovery of intact gold-virus complex
by agarose electrophoresis and electroelution: Application to the purification of cowpea mosaic virus and colloidal gold complex
ICTVdB—The Universal Virus Database: Cowpea mosaic virus
*ICTV Virus Taxonomy 200
UniProt Taxonomy
{{DEFAULTSORT:Cowpea Mosaic Virus Comoviruses Viral plant pathogens and diseases