Tobacco etch virus
Encyclopedia
Tobacco etch virus is a plant pathogenic virus in the genus Potyvirus
and the virus family Potyviridae
. Like other members of the Potyvirus genus, TEV is a monopartite strand of positive-sense, single-stranded RNA surrounded by a capsid made for a single viral encoded protein. The virus is a filamentous particle that measures about 730 nm in length. It is transmissible in a non-persistent manner by more than 10 species of aphids including Myzus persicae
. It also is easily transmitted by mechanical means but is not known to be transmitted by seeds.
. Agriculturally important crops that it infects include several species of Capsicum
(i.e. C. annuum, C. frutescens), tomato (Lycopersicon esculentum), and tobacco
(Nicotiana
spp.).
It also infects many perennial weed species that can act as virus reservoirs for susceptible agricultural crops. These weed species include Solanum nigrum
(nightshade), S. aculeatissimum (soda apple), Chenopodium album
(pigweed), Datura stramonium
(jimson weed), Linaria canadensis (blue toadflax), and Physalis
spp. (ground cherry). Thus, recommendations for the control of this virus include the control of weeds in and around susceptible solanaceous crops.
(See this reference for pictures of symptoms and inclusions.)
Like other potyviruses, TEV makes viral inclusions that can be seen in the light microscope if properly stained.
. This particular potyvirus makes two kinds of inclusions that can be diagnostic in a known host. One of the inclusions is the cylindrical inclusions found in the cytoplasm of infected cells and the second inclusion is found in the nucleus. Neither inclusion type stains in the nucleic acid stain (AzureA).
Inclusions of Tobacco etch virus (in various hosts).
The TEV protease
is a highly site-specific protease that biochemists have used to their advantage to create a protein purification
system by incorporating TEV protease's recognition site into protein purification tags.
A gene construct is created containing the protein of interest fused to a TEV protease recognition site, followed by an affinity tag, such as a Polyhistidine-tag
. Following affinity chromatography
, the purified protein is then treated with TEV protease. TEV protease cleaves at its recognition site, removing the affinity tag. This allows for affinity purification of proteins that are not well-behaved when fused to protein tags. PMID 12963335
Potyvirus
Potyviruses infect plants and belong to the family Potyviridae. The genus is named after the type virus - Potato Virus Y.The Potyvirus, like the Begomoviruses, have ~30% of the currently known plant viruses and have at least 180 definitive and possible members...
and the virus family Potyviridae
Potyviridae
The Potyviridae are a family of plant viruses. They are . Their genome is composed of positive-sense RNA which is surrounded by a protein coat made up of a single viral encoded protein called a capsid. All induce the formation of virus inclusion bodies called in their hosts...
. Like other members of the Potyvirus genus, TEV is a monopartite strand of positive-sense, single-stranded RNA surrounded by a capsid made for a single viral encoded protein. The virus is a filamentous particle that measures about 730 nm in length. It is transmissible in a non-persistent manner by more than 10 species of aphids including Myzus persicae
Myzus persicae
Myzus persicae, known as the green peach aphid, is a small green aphid. It is the most significant aphid pest of peach trees, causing decreased growth, shriveling of the leaves and the death of various tissues...
. It also is easily transmitted by mechanical means but is not known to be transmitted by seeds.
Host Range
This virus infects many species of SolanaceaeSolanaceae
Solanaceae are a family of flowering plants that include a number of important agricultural crops as well as many toxic plants. The name of the family comes from the Latin Solanum "the nightshade plant", but the further etymology of that word is unclear...
. Agriculturally important crops that it infects include several species of Capsicum
Capsicum
Capsicum is a genus of flowering plants in the nightshade family, Solanaceae. Its species are native to the Americas where they have been cultivated for thousands of years, but they are now also cultivated worldwide, used as spices, vegetables, and medicines - and have become are a key element in...
(i.e. C. annuum, C. frutescens), tomato (Lycopersicon esculentum), and tobacco
Tobacco
Tobacco is an agricultural product processed from the leaves of plants in the genus Nicotiana. It can be consumed, used as a pesticide and, in the form of nicotine tartrate, used in some medicines...
(Nicotiana
Nicotiana
Nicotiana is a genus of herbs and shrubs of the nightshade family indigenous to North and South America, Australia, south west Africa and the South Pacific. Various Nicotiana species, commonly referred to as tobacco plants, are cultivated and grown to produce tobacco. Of all Nicotiana species,...
spp.).
It also infects many perennial weed species that can act as virus reservoirs for susceptible agricultural crops. These weed species include Solanum nigrum
Solanum nigrum
Solanum nigrum is a species in the Solanum genus, native to Eurasia and introduced in the Americas, Australasia and South Africa.-Description:Black...
(nightshade), S. aculeatissimum (soda apple), Chenopodium album
Chenopodium album
Chenopodium album is a fast-growing weedy annual plant in the genus Chenopodium.Though cultivated in some regions, the plant is elsewhere considered a weed...
(pigweed), Datura stramonium
Datura stramonium
Datura stramonium, known by the common names Jimson weed, devil's trumpet, devil's weed, thorn apple, tolguacha, Jamestown weed, stinkweed, locoweed, datura, pricklyburr, devil's cucumber, Hell's Bells, moonflower and, in South Africa, malpitte and mad seeds, is a common weed in the...
(jimson weed), Linaria canadensis (blue toadflax), and Physalis
Physalis
Physalis is a genus of plants in the nightshade family , native to warm temperate and subtropical regions throughout the world. The genus is characterised by the small orange fruit similar in size, shape and structure to a small tomato, but partly or fully enclosed in a large papery husk derived...
spp. (ground cherry). Thus, recommendations for the control of this virus include the control of weeds in and around susceptible solanaceous crops.
Signs and Symptoms
Symptoms seen on plants infected with this virus can vary depending on the plant. However typical symptoms include vein clearing, mottling, and necrotic lines or etching. Symptoms can occur on leaves and fruit and the plants can become stunted.(See this reference for pictures of symptoms and inclusions.)
Like other potyviruses, TEV makes viral inclusions that can be seen in the light microscope if properly stained.
. This particular potyvirus makes two kinds of inclusions that can be diagnostic in a known host. One of the inclusions is the cylindrical inclusions found in the cytoplasm of infected cells and the second inclusion is found in the nucleus. Neither inclusion type stains in the nucleic acid stain (AzureA).
Inclusions of Tobacco etch virus (in various hosts).
Geographic Distribution
TEV appears to be a virus that evolved in the New World. It has been reported from Canada, the USA (including Hawaii), Mexico and Puerto Rico in North America and from Venezuela in South America.(2)Beyond Plant Disease
Potyvirus RNA codes for at least 7 different proteins. One of them is a protease.The TEV protease
TEV protease
The TEV protease is a highly site-specific cysteine protease that is found in the Tobacco Etch Virus . The optimum recognition site for this enzyme is the sequence Glu-Asn-Leu-Tyr-Phe-Gln- and cleavage occurs between the Gln and Gly/Ser residues. Some of the advantages of this enzyme are its high...
is a highly site-specific protease that biochemists have used to their advantage to create a protein purification
Protein purification
Protein purification is a series of processes intended to isolate a single type of protein from a complex mixture. Protein purification is vital for the characterization of the function, structure and interactions of the protein of interest. The starting material is usually a biological tissue or...
system by incorporating TEV protease's recognition site into protein purification tags.
A gene construct is created containing the protein of interest fused to a TEV protease recognition site, followed by an affinity tag, such as a Polyhistidine-tag
Polyhistidine-tag
A polyhistidine-tag is an amino acid motif in proteins that consists of at least five histidine residues, often at the N- or C-terminus of the protein. It is also known as hexa histidine-tag, 6xHis-tag, and by the trademarked name His-tag...
. Following affinity chromatography
Affinity chromatography
Affinity chromatography is a method of separating biochemical mixtures and based on a highly specific interaction such as that between antigen and antibody, enzyme and substrate, or receptor and ligand.-Uses:Affinity chromatography can be used to:...
, the purified protein is then treated with TEV protease. TEV protease cleaves at its recognition site, removing the affinity tag. This allows for affinity purification of proteins that are not well-behaved when fused to protein tags. PMID 12963335