virus and viroid plant pathogens

Virus and Viroid Plant Pathogens

Kenneth L. Johnson IIUSDA National Needs FellowUniversity of Florida Plant Medicine ProgramIPM Florida- IPM Apprentice

Kirk W. Martin SM(NRCM), CBSPUSDA National Needs FellowUniversity of Florida Plant Medicine ProgramIPM Florida-IPM Technical Information Specialist

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Begomovirus-Bean golden yellow mosaic virus

Family: Geminiviridae

Description: Virions consist of a capsid. Virus capsid is not enveloped. Capsid is elongated and exhibits icosahedral symmetry. The capsid is geminate and has a diameter of 18-20 nm. Capsids appear hexagonal in outline. The capsomer arrangement is not obvious. The capsid consists of 22 capsomers. With a length of dimers 30 nm. (ICTV database)

R.G. Milne, Istituto di Virologia, CRN, Torino, Italy

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Family: GeminiviridaeHost(s): Wild bush bean, Macroptilium lathyroides, Common bush bean, Phaseolus vulgaris, Sieva bean, P. lunatus, Threelobe false mallow, Malvastrum coromandelianum

Leaf symptoms: vein yellow net,

interveinal chlorosis

Howard F. Schwartz, Colorado State University, Bugwood.org




Host(s): Wild bush bean, Macroptilium lathyroides, Common bush bean, Phaseolus vulgaris, Sieva bean, P. lunatus, Threelobe false mallow, Malvastrum coromandelianum

Leaf symptoms: vein yellow net,

interveinal chlorosis





Diagnostic viral inclusions:

Nuclear

Rounded dense bodies

Ring-shaped (rare)

Brittle crystals

UF IFAS Extension Plant Disease Clinic



Closterovirus-Citrus tristeza virus (CTV) Family: Closteroviridae

Description:Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous with a length of 2000 nm and a width of 12 nm.

M. Bar-JosephVolcani Centre, Bet Dagan, Israel

Closterovirus-Citrus tristeza virus (CTV)Family: Closteroviridae

Host(s): Citrus ssp. grafted onto Citrus aurantium (sour orange) root stock — quick decline, pitted stems. C. paradisi (grapefruit) — stunt. C. aurantifolia (lime) — die-back. C. aurantifolia (Seville orange) — seedling yellows. C. reticulata (mandarin) — decline. Aeglopsis chevalieri, Afraegle paniculata (Nigerian powder-flask-fruit )), Pamburus missionis, Passiflora gracilis (Annual passionflower), Citropsis gilletiana, Microcitrus australis

Disorders:TristezaStem-pittingSeedling-yellowsLime dieback

Diseases:Quick decline

L. Navarro, Instituto Valenciano de Investigaciones Agrarias, Bugwood.org

Closterovirus-Citrus tristeza virus (CTV)

Family: Closteroviridae

Symptomology Sweet orange-(Sweet orange stem pitting strains)Sour orange-(Seedling yellows) severe stunting and yellowing Grapefruit-(Seedling yellows)severe stunting and yellowing , (Stem-pitting) stunted, the fruit is small and misshapen, and yields are considerably reduced; the wood of the trunk and large limbs is pitted with longitudinal depressions; in some instances, the main scaffold branches are twisted and distorted.Lime-(Lime die-back strain) vein flecking on young leaves, severe pitting of wood of twigs and branches, stunting of trees, and die-back with eventual deathLemon-(Seedling yellows) severe stunting and yellowing

Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org


Family: ClosteroviridaeVectors: Brown citrus aphid, Toxoptera citricida and Melon aphid, Aphis gossypii.

Diagnostic techniques:Visual symptomsIndexing on biological indicators

Management:Disease-resistant cultivarsDisease-resistant rootstocks (will not work on plants that virus attacks directly i.e. certain lime, grapefruit, pummelos, Pera sweet orange and others (Reuther, 1978)Possible cross-protection from less mild strains of tristeza virus

Tristeza virus affected fruit on right

Melon aphid, Aphis gossypiiLyle Buss, University of Florida

Brown citrus aphid, Toxoptera citricida Lyle Buss, University of Florida

L. Navarro, Instituto Valenciano de Investigaciones Agrarias, Bugwood.org


Family: Closteroviridae

Diagnostic techniques:Visual symptomsIndexing on biological indicators


All cytoplasmic

Para-crystals

Banded bodies

Densely stained phloem with

many vacuoles.

CTV petiole inclusions

CTV stem inclusions

CTV root inclusions




Cucumovirus-Cucumber mosaic virus (CMV) Family: BromoviridaeDescription:Virions consist of a capsid. Virus capsid is not enveloped, round with icosahedral symmetry. The isometric capsid has a diameter of 29-29.33-30 nm. Capsids appear round, or hexagonal in outline. The capsomer arrangement is clearly visible, or is not obvious. The capsid consists of 32 capsomers. Virus preparations contain more than one particle component. Capsids all have the same appearance. (ICTV database).

R.G. Milne, Istituto di Virologia, CRN, Torino, Italy.

Cucumovirus-Cucumber mosaic virus (CMV)

Family: BromoviridaeHosts:Cucumber, Cucumis sativus and many other cucurbits — mosaics and stunting, reduced fruit yield. Tomato, Lycopersicon esculentum — mosaic, reduction of leaf laminae ("fernleaf") and stunting. Spinach, Spinacia oleracea — severe chlorosis and stunting.

CMV Infected cucumber

David B. Langston, University of Georgia, Bugwood.org

CMV infected celery

William M. Brown Jr., Bugwood.org


Family: BromoviridaeVectors: Aphids transmit in a non-persistent manner

CMV infected cucumbers

Cucumber infected by Cucumber mosaic virus




Family: BromoviridaeDiagnostic viral inclusions:

Cytoplasmic

Vacuolate

Vesiculate

Crystalline cubes

Spheres

Hollow spheres


Dr. R. G. Christie, UF IFAS Department of Plant Pathology


Begomovirus-Cucurbit leaf crumple virus (CuLCrV) Family: GeminiviridaeDescription:No official descriptionGeneral Begomovirus description:Virions consist of a capsid. Virus capsid is not enveloped. Capsid is elongated and exhibits icosahedral symmetry. The capsid is geminate, or prolate in shape and has a diameter of 15-20 nm. Capsids appear round, or hexagonal in outline. The capsomer arrangement is clearly visible, or is not obvious. The capsid consists of 22 capsomers. With a length of 25-30 nm.

Zucchini squash infected with Cucurbit leaf crumple virus. Note silverleaf symptoms in background due to feeding of immature whiteflies. http://edis.ifas.ufl.edu/in716

Begomovirus-Cucurbit leaf crumple virus (CuLCrV)

Family: GeminiviridaeDescription:Hosts:Watermelon, Citrullus lanatusCantaloupe andHoneydew melon, Cucumis melo Squash and pumpkins, Cucurbita palmate and C. maxima, C. pepo

Zucchini squash infected with Cucurbit leaf crumple virus. Note silverleaf symptoms in background due to feeding of immature whiteflies. http://edis.ifas.ufl.edu/in716

Florida Department of Agriculture and Consumer Services


Family: GeminiviridaeCucurbits that were notsusceptible were acorn squash, ananasmelon, butternut squash, casaba melon,Galia melon, golden crenshaw melon, andhoneydew melon. Non-susceptible cropsincluded cotton, pepper, soybean, andtomato.

Cucurbit leaf crumple virus symptoms on cucumber

Cucurbit leaf crumple virus symptoms on yellow straight-necked squash



Vector:Silverleaf whitefly, Bemisia argentifolii

Silverleaf whitefly, Bemisia argentifolii-vector of cucurbit leaf crumple virus. Photo by Lyle Buss-University of Florida



Nuclear


Ring-shaped (rare)

Brittle Crystals

Bean golden mosaic virus inclusions (pictured) look very similar to Cucurbit leaf crumple virus

Bean golden mosaic virus inclusions (pictured) close-up

R. Cullen and M. Gooch, UF IFAS Extension Plant Disease Clinic

R. Cullen and M. Gooch, UF IFAS Extension Plant Disease Clinic

Potexvirus-Cymbidium mosaic virus (CymMV)Family: FlexiviridaeDescription:Virions have a simple construction (round or elongated or spherical, unenveloped virions); consist(s) of a capsid (including inner and outer capsid). Virus capsid is not enveloped. Capsid/nucleocapsid is elongated; exhibits helical symmetry; capsid. Capsid shape of elongated unenveloped virion or tail of phage is filamentous, is flexuous. Elongated capsid, nucleocapsid or phage tail is cross-striated. Elongated capsids, nucleocapsids or tails have only or longest length(s) of 470 to 580 nm; is 13 nm wide. Axial canal is distinct or indistinct, 3.4 to 12 with median 6.3 nm in diameter. Basic helix is obvious or obscure. Pitch of helix is 2.8 to 3.5 with median 3.331 nm. Crude virus preparation contains few virions or many virions.

Cymbidium mosaic virusVirus particles from purified preparation in uranyl acetate. Bar represents 500 nm. http://www.dpvweb.net/dpv/showdpv.php?dpvno=27

R. I. B. FranckiDepartment of Plant Pathology, Waite Agricultural Research Institute, University of Adelaide, South Australia

Potexvirus-Cymbidium mosaic virus (CymMV)

Family: FlexiviridaeHosts:•Cymbidium ssp. — mosaic, necrosis. •Cattleya ssp. — mosaic, flower necrosis. •Phalaenopsis ssp. — mosaic, water soaked local lesions. •Vanda ssp. — chlorotic flecks. •Epidendrum ssp., •Laelia ssp., •Laeliocattleya ssp., •Oncidium ssp., •Zygopetalum ssp., •Vanilla fragrans


Cymbidium mosaic virus symptoms

http://ucce.ucdavis.edu/files/repositoryfiles/ca601p3-71680.pdf

Cymbidium mosaic symptoms in Cymbidium leaves.

Potexvirus-Cymbidium mosaic virus (CymMV)

Family: FlexiviridaeViral inclusions:Widely distributed in host tissuesAggregates of virus particles

Long axis parallelBanded bodies

Can be susceptible to destruction

Dense bodiesPara-crystals

Cymbidium mosaic virus-banded inclusions

Cymbidium mosaic viral inclusions (see arrows)



Potyvirus-Dasheen mosaic virus (DsMV)

Family: PotyviridaeDescription:Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous with a clear modal length with a length of 750 nm (approximately). Axial canal is indistinct. Basic helix is obscure.

Zettler, Univ. Florida 1970

Filamentous virus particles mounted in phosphotungatate..


Family: PotyviridaeHosts:Aglaonema, Alocasia, Amorphophallus, Arisaema, Caladium, Cyrtosperma ssp. — mosaic. Cryptocoryne, Dieffenbachia, Philodendron, Richardia, Zantedeschia ssp. — mosaic and leaf malformation. Colocasia, Xanthosoma ssp. — mosaic, chlorotic feathering. Comments on host and host range: there are conflicting reports on the susceptibility of non-aroids; in European studies some are susceptible, but, in tests Florida and Venezuela, non-aroids were not infected (Zettler and Hartman, 1986).

Chlorosis of Philodendron selloum leaf

Dasheen mosaic virus in Taro

Photo by: F.W. Zettler

N.J.Ko Florida Department of Agriculture and Consumer Services



Mosaic and distortion of P. selloum leaf

Dasheen mosaic virus in Dieffenbachia

N.J.Ko Florida Department of Agriculture and Consumer Services

Photo by: F.W. Zettler



Mosaic of taro (Colocasia esculenta) leaf

ICTVdB - The Universal Virus Database

Potyvirus-Dasheen mosaic virus (DsMV)Family: PotyviridaeDiagnostic viral inclusions:Cytoplasmic cylindirical inclusions

ProteinaceousPinwheel and scrolls in C-sectionLaminated aggregate

Amorphous cytoplasmic inclusionsProtein & ribonucleo-proteinIrregular in shapeVary in sizeVary in number

Nuclear inclusionsProteinaceousMost crystalline

Cytoplasmic microbodiesHealthy cellsProteinaceous crystalsincrease in number & aggregate with some Potyvirus infections

Electron micrograph of cylindrical inclusions in cell of calla lily (Zantedeschia elliotiana). Bar represents 500 nm.

I = Cylindrical Inclusions N=Nucleus



Hostuviroid-Hop stunt viroid (Citrus viroid II) (HSVd)

Family: PospiviroidaeDescription:Viroids are unencapsidated, low molecular weight, circular, single-stranded infectious RNAs pathogenic to plants. Sequences are the primary basis for comparison. The sequence of the central conserved region allows all characterised viroids to be classed into four groups. Variation occurs within each viroid "species" and an arbitrary level of 90% sequence similarity currently separates variants from species.

Photo of potato spindle tuber viroid which closely resembles Hop stunt viroid (Citrus viroid II)


Hostuviroid-Hop stunt viroid (Citrus viroid II) (HSVd)

Family: PospiviroidaeHosts: Hop stunt viroid Hop stunt viroid - almond Hop stunt viroid - apricot Hop stunt viroid - citrus Hop stunt viroid - cucumber Hop stunt viroid - grapevine Hop stunt viroid - peach Hop stunt viroid - pear Hop stunt viroid - plum Citrus cachexia viroid Cucumber pale fruit viroid Peach dapple viroid Plum dapple viroid David Gent, USDA

Agricultural Research Service, Bugwood.org

Common hops (Humulus lupulus L.)A common hop plant showing symptoms of hop stunt viroid infection in a field at Oregon, USA.

http://www.apsnet.org/publications/imageresources/Pages/Nov_88-11-1.aspx

Green streaks observed under cracks induced by Hop stunt viroid and Citrus viroid IV in trifoliate orange photo by C. Vernière et al.

Tospovirus-Impatiens necrotic spot virus (INSV)

Family: BunyaviridaeDescription:Virions consist of an envelope and a nucleocapsid. Virus capsid is enveloped. Virions are spherical to pleomorphic. Surface projections are embedded in a lipid bilayer that is 5 nm thick. Capsid/nucleocapsid is elongated with helical symmetry. The ribonucleocapsid is filamentous and has a width of 2-2.5 nm. Nucleocapsids are circular.


Family: BunyaviridaeHosts:Impatiens spp.most leaves symptomless, some necrotic spots with necrotic rings in young leaves. Other hosts:GloxiniaGerbera daisyOncidium orchidChrysanthemumTomatoColeusWild geranium

Impatiens necrotic spot virus symptoms on chrysanthemum

Impatients necrotic spot virus symptoms on coleus

Department of Plant Pathology Archive, North Carolina State University, Bugwood.org



Family: BunyaviridaeHosts:Impatiens spp.most leaves symptomless, some necrotic spots with necrotic rings in young leaves. Other hosts:GloxiniaGerbera daisyOncidium orchidChrysanthemumTomatoColeusWild geranium

Impatiens necrotic spot virus symptoms on gloxinia

Impatients necrotic spot virus symptoms on tomato fruit


Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org


Family: BunyaviridaeVector:Western flower thrips, Frankliniella occidentalis

Lyle Buss University of Florida


Family: BunyaviridaeDiagnostic viral inclusions:

Vacuolate

Dense, irregular with

projections

Crystalline

All photographs by Florida Department of Agriculture and Consumer Services

Tobamovirus-Odontoglossum ringspot virus (ORSV)

Family: UnassignedDescription:Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is rod-shaped, straight with a clear modal length with a length of mostly 300 nm (but also shorter, broken virions, width of 18 nm. Axial canal is distinct.



Family: UnassignedHosts:

Vector:Virus is not transmitted by a vector. Virus is transmitted by mechanical inoculation.

Juliana Frettas-Astua Florida Department of Agriculture and Consumer Services

Juliana Frettas-Astua Florida Department of Agriculture and Consumer Services


Family: UnassignedDiagnostic viral inclusions:All cytoplasmic

Hexagonal platesVirus particles

Stacked platesVirus particles

ParacrystalsVirus particles - old infection

X - BodiesVacuolate

Inclusions stained with Orange Green

Tobamovirus inclusions stain in Azure A stain with heat only. Photograph by Nan-Jing Ko

Photograph bu Nan-Jing Ko

Photograph bu Nan-Jing Ko

Potyvirus-Papaya ringspot virus (PRSV)

Family: PotyviridaeDescription:Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous with a clear modal length with a length of 760-800 nm and a width of 12 nm.

Alberto Pantoja, USDA Agricultural Research Service, Bugwood.org


Family: PotyviridaeHosts:Vector:Virus is transmitted by aphids. Virus is also transmitted by mechanical inoculation; not transmitted by seeds.

Alberto Pantoja, USDA Agricultural Research Service, Bugwood.org


Family: PotyviridaeDiagnostic viral inclusions:Cytoplasmic cylindirical inclusions






Pospiviroid-Potato spindle tuber viroid (PSTVd)

Family: PospiviroidaeHosts:Nucleic acid is non-encapsidated, circular, single-stranded RNA

Potato spindle tuber viroid



Family: PospiviroidaeHosts:Potato, Solanum tuberosumTomato, Solanum esculentum

Potato cv ‘Kennebec’, Solanum tuberosum, center plant infected with Potato spindle tuber viroid, outer two plants are healthy

Tomato, Solanum esculentum infected by Potato spindle tuber viroid

R.P. Singh, Bugwood.org

Central Science Laboratory, Harpenden Archive, British Crown, Bugwood.org


Family: PospiviroidaeHosts:Potato, Solanum tuberosumTomato, Solanum esculentum

Potatoes infected with potato spindle tuber viroid. Healthy potato on left others diseased

First and third rows of potatoes from top are healthy; second and fourth rows are infected with the potato spindle tuber viroid

USDA Agricultural Research Service Archive, USDA ARS, Bugwood.org

Plant Protection Service Archive, Plant Protection Service, Bugwood.org

Potyvirus-Potato virus Y (PVY)

Family: PotyviridaeDescription:Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous with a clear modal length with a length of 684 nm (from purified preparations (Delgado-Sanchez and Grogan, 1966)), or 730 nm and a width of 11 nm. Axial canal is indistinct; 2-3 nm in diameter. Basic helix is obscure. Pitch of helix is 3.3 nm (Varma et al., 1968).

Potato virus Y

Rothamsted Research.


Family: PotyviridaeHosts:Potato, Solanum tuberosumTobacco, Nicotiana tabacumPepper, Capsicum annuumVector: transmitted by aphids, mechanical means or transmission by grafting.

Rugose leaf symptoms on potato infected with potato virus Y

Potato infected with potato virus Y

Bruce Watt, University of Maine, Bugwood.org

Bruce Watt, University of Maine, Bugwood.org







Cylindrical

Amorphous

Microcrystals

Stomata guard cells filled with inclusions of PVY



Ipomovirus-Squash vein yellowing virus (SqVYV)

Family: PotyviridaeDescription:The virus, for which the name Squash vein yellowing virus (SqVYV) is proposed, has flexuous rod-shaped particles of ~840 nm in length.


Family: PotyviridaeSquash Vein Yellowing Virus, Causal Agent of Watermelon VineDecline in FloridaHosts:The host range of SqVYV appears to be limited to cucurbits including two weedy varieties ofcucurbits found in Florida, Momordica charantia L. (Balsam-apple) and Melothria pendula L. (creepingcucumber) (Adkins et al. 2008). These weeds may be important reservoirs for SqVYV and help it tosurvive between crops.Vectors:Whitefly, Bemesia tabaci

Early symptoms of WVD. Photography credit: Scott Adkinshttp://www.freshfromflorida.com/pi/enpp/pathology/pathcirc/pp407.pdf

Symptoms several weeks later. Photography credit: Scott Adkinshttp://www.freshfromflorida.com/pi/enpp/pathology/pathcirc/pp407.pdf

Scott Adkins, 2008 . Plant Disease

Scott Adkins,, FDACS DPI


Family: PotyviridaeHosts:The host range of SqVYV appears to be limited to cucurbits including two weedy varieties ofcucurbits found in Florida, Momordica charantia L. (Balsam-apple) and Melothria pendula L. (creepingcucumber) (Adkins et al. 2008). These weeds may be important reservoirs for SqVYV and help it tosurvive between crops.Vectors:Whitefly, Bemesia tabaci

Melothria pendula a cucurbit weed that can potentially serve as a viral reservoir

Watermelon rind damaged by the Squash vein yellowing virus causing WVD symptoms. Photography credit: Scott Adkins http://www.freshfromflorida.com/pi/enpp/pathology/pathcirc/pp407.pdf

Scott Adkins, 2008 . Plant Disease

Scott Adkins,, FDACS DPI







CI=Cylindrical inclusions; N=NucleusSquash vein yellowing virushttp://www.freshfromflorida.com/pi/enpp/pathology/florida_viruses/Cucurbits/SqVYV/SqVYVpage.htm

Florida Department of Agriculture and Consumer Svcs., Department of Plant Industry

Potyvirus-Sugarcane mosaic virus (SCMV)

Family: PotyviridaeDescription:MorphologyVirions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous with a clear modal length with a length of 730-755 nm and a width of 13 nm. Axial canal is indistinct. Basic helix is obscure.

Filamentous particles of sugarcane mosaic virus strain H mounted in phosphotungstate. Bar represents 200 nm.http://www.dpvweb.net/dpv/showfig.php?dpvno=88&figno=05


Family: PotyviridaeHosts:Saccharum sp. — systemic mosaic. Sorghum bicolor — necrotic local lesion, then systemic mosaic, necrosis. S. halepense — systemic mosaic. Zea mays — systemic mosaic, ringspots. Most dicotyledonous plants.

Photograph 1 Sugarcane variety C.P.31-294 systemically infected by sugarcane mosaic virus strain B. (Courtesy A. G. Gillaspie.)http://www.dpvweb.net/dpv/showfig.php?dpvno=88&figno=01

Photograph 2 Sugarcane variety C.P.31-294 systemically infected by sugarcane mosaic virus strain D. (Courtesy A. G. Gillaspie.)http://www.dpvweb.net/dpv/showfig.php?dpvno=88&figno=02

Photograph 6 Systemic necrosis produced by sugarcane mosaic virus strain A in sorghum.http://www.dpvweb.net/dpv/showfig.php?dpvno=88&figno=06

Photograph 7 Local necrotic lesions produced in Atlas sorghum by sugarcane mosaic virus strain E. (Courtesy J. L. Dean.) http://www.dpvweb.net/dpv/showfig.php?dpvno=88&figno=07


Family: PotyviridaeVector:Virus is transmitted non-persitently by the aphids:Dactynotus ambrosiae, Rusty plum aphid, Hysteroneura setariae, Corn leaf aphid, Rhopalosiphum maidis, Toxoptera graminum. Transmission:Virus is transmitted by mechanical inoculation; transmitted by grafting; transmitted by seeds; not transmitted by pollen.

Corn leaf aphid , Rhopalosiphum maidis

Merle Shepard, Gerald R.Carner, and P.A.C Ooi, Insects and their Natural Enemies Associated with Vegetables and Soybean in Southeast Asia, Bugwood.org







Cylindrical inclusions of sugar cane mosaic in Zea mays (corn). The inclusion at the far right is next to a nucleus.

Potyvirus-Tobacco etch virus (TEV)

Family: PotyviridaeDescription:Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous with a clear modal length with a length of 730-750 nm and a width of 12-13 nm. Basic helix is obvious (in UF).

Potyvirus photograph from IACR Rothamsted


Family: PotyviridaeHosts:Cassia obtusifolia — leaf mottling, malformation and necrosis, stunting and reduced seed yield. Capsicum annuum — mottling, mosaic and leaf malformation, fruit malformation, stunting. Datura stramonium — leaf mottling, vein banding and malformation, suppression of fruit spines. Lycopersicon esculentum — leaf mottling and distortion, severe yield reductions. Nicotiana tabacum — mottling and necrotic leaf etching. Physalis ssp. — leaf chlorosis.




Family: PotyviridaeHosts:Cassia obtusifolia — leaf mottling, malformation and necrosis, stunting and reduced seed yield. Capsicum annuum — mottling, mosaic and leaf malformation, fruit malformation, stunting. Datura stramonium — leaf mottling, vein banding and malformation, suppression of fruit spines. Lycopersicon esculentum — leaf mottling and distortion, severe yield reductions. Nicotiana tabacum — mottling and necrotic leaf etching. Physalis ssp. — leaf chlorosis.

Tobacco etch virus symptoms on tobacco

Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org


Family: PotyviridaeVector: Aphids especially Green peach aphid, Myzus persicae

Winged green peach aphid Myzus persicae



Adult female green peach aphid Myzus persicae







Inclusion

Nucleus

Microcrystals

Pinwheel Inclusions


Tobamovirus-Tobacco mosaic virus (TMV)

Family: No family assignedDescription: Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is rod-shaped, straight with a clear modal length with a length of 300 nm and a width of 18 nm. Axial canal is distinct; 2 nm in diameter. Basic helix is obvious. Pitch of helix is 2.3 nm.

Dr. Robley Williams


Family: No family assignedHost: Nicotiana tabacum — leaf mosaic, severe crop losses. Also found in many other plant species.Vector/Transmission:Virus is not transmitted by a vector. Virus is transmitted by mechanical inoculation; transmitted by grafting; transmitted by contact between hosts; transmitted by seeds (occasionally transmitted through the testa, but not through the embryo, not transmitted by pollen. Transmitted by dodder, Cuscuta campestris, C. japonica and C. subinclusa

Symptoms of TMV in Nicotiana tabacum cv Turkish Samsun. Photographed three weeks post-inoculation.

Local necrotic lesions produced upon TMV infection in Nicotiana tabacum of the NN genotype. Photographed one week post-inoculation.

Milton Zaitlin

Milton Zaitlin


Family: No family assignedDiagnostic viral inclusions: All cytoplasmic



ParacrystalsVirus particles – old infection

X - BodiesVacuolate


Tobravirus-Tobacco rattle virus (TRV)

Family: No family assignedDescription:Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is rod-shaped, straight with a clear modal length with a length of 46-114 nm (T), or 180-197 nm (B, width of 22 nm. Axial canal is distinct; 4 nm in diameter. Basic helix is obvious. Pitch of helix is 2.5 nm.

IACR Rothamsted


Family: No family assignedHosts:Stellaria media, Viola arvensis — few symptoms, mottling. Beta vulgaris, Spinacia oleracea — chlorotic or necrotic local lesions; systemic mottle. Capsicum annuum — ringspots or line patterns. Solanum tuberosum — necrotic local lesions; systemic chlorotic or necrotic spots and streaks. Nicotiana tabacum — necrotic local lesions, necrotic or chlorotic ringspots; systemic necrosis, ringspots or line patterns, mottling. Narcissus pseudonarcissus, Tulipa sp., Hyacinthus sp. — mottling.

Symptoms of Tobacco rattle virus on peony

G. Chastagner1 and H. R. Pappu, Washington State Univ.

Tobacco Rattle virus on hosta 'ananuma'

Ben Lockhart, University of Minnesota Extension


Family: No family assignedTransmission/ Vectors:Virus is transmitted by a vector. Virus is transmitted by mechanical inoculation; transmitted by grafting; not transmitted by contact between hosts; transmitted by seeds (up to 40% in Viola arvensis or only to 1% in Capsella bursa-pastoris). Vector Transmission: Virus is transmitted by nematodes; family Trichodoridae; Paratrichodorus allius, P. anemones, P. christiei, P. nanus, P. pachydermus, P. teres, Trichodorus minor, T. primitivus, T. viruliferus.

Anterior of Paratrichodorus minor a vector of Tobacco rattle virus http://plpnemweb.ucdavis.edu/nemaplex/Taxadata/G097S1.HTM


Family: No family assignedDiagnostic viral inclusions:

(Pictures taken from "Light and Electron Microscopy of Plant Virus Inclusions" by R. G. Christie and J. R. Edwardson)

Inclusions of Tobacco rattle virus in subveinal epidermal cells of an inoculated leaf (Nicotiana tabaccum) stained with Azure A.

Nepovirus-Tobacco ringspot virus (TRSV)

Family: ComoviridaeDescription:Virions consist of a capsid. Virus capsid is not enveloped, round with icosahedral symmetry. The isometric capsid has a diameter of 25-29 nm (virions may swell at pH 8.0). Capsids appear hexagonal in outline. The capsomer arrangement is not obvious.


Family: ComoviridaeHosts:Cucumis sativus, Glycine max, Lycopersicon esculentum, Nicotiana tabacum — necrotic spots, mottling, chlorotic ringspots and vein banding.

Tobacco ringspot virus symptoms on tobaccoVirginia Tech Learning Resources Center, Virginia

Tobacco ringspot virus symptoms on bean

Virginia Tech Learning Resources Center, Virginia Polytechnic Institute and State University, Bugwood.org



Family: ComoviridaeVector:

Anterior view of Trichodorus ssp. nematodehttp://plpnemweb.ucdavis.edu/Nemaplex/images/TrichodorusAnt.JPG

Trichodorus ssp., a nematode vector of Tobacco ringspot virus. http://plpnemweb.ucdavis.edu/Nemaplex/images/Trichodorus6.JPG


Family: ComoviridaeDiagnostic viral inclusions:Vacuolate - VesiculateVirus crystals & aggregatesXylem blockageUneven distribution

Glandular hair cellsGuard cellsPhloemSub-veinal

Irregular vacuolateIrregular non-vacuolateCrystalloidMicrocrystal

Nicotiana benthamiana 1000X



Crinivirus-Tomato infectious chlorosis virus (TICV)

Family: ClosteroviridaeDescription:Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous with a length of 850-900 nm and a width of 12 nm.


Family: ClosteroviridaeHosts:Lycopersicon esculentum — interveinal yellowing, necrosis and severe yield loss.tomato, (Lycopersicon esculentum), tomatillo (Physalis ixocarpa), potato (Solanum tuberosum), artichoke (Cynara scolymus), lettuce (Lactuca sativa) and petunia (Petunia hybrida).

Vector:Trialeurodes vaporariorum transmission by Bemisia spp.Is uncertain

Tomato plant infected with Tomato infectious chlorosis virus showing interveinal chlorosis and mild necrosis on leaflet http://www.agf.gov.bc.ca/cropprot/emergingviruses.htm

Tomato plant infected with Tomato infectious chlorosis virus showing interveinal chlorosis and mild necrosis on leaflethttp://www.agf.gov.bc.ca/cropprot/emergingviruses.htm

W. M. Wintermantel, USDA-ARS, Salinas, CA, USA.

W. M. Wintermantel, USDA-ARS, Salinas, CA, USA.


Family: ClosteroviridaeDiagnostic viral inclusions:All cytoplasmic

Paracrystals

Banded bodies

Densely stained phloem

with many vacuoles.

Tospovirus-Tomato spotted wilt virus (TSWV)Family: BunyaviridaeDescription:Virions consist of an envelope and a nucleocapsid. Virus capsid is enveloped. Virions are spherical to pleomorphic measuring 80-100 nm in diameter. The envelope surrounds three nucleocapsids. Surface projections are distinctive spikes that are surrounded by a prominent fringe. Surface projections are embedded in a lipid bilayer that is 5 nm thick. Surface projections are 5-10 nm long. Capsid/nucleocapsid is elongated and exhibits helical symmetry. The ribonucleocapsid is filamentous with a length of 200-3000 nm (depending on arrangement) and a width of 2-2.5 nm. Nucleocapsids are circular.

Tomato spotted wilt virus

IACR Rothamsted

Tospovirus-Tomato spotted wilt virus (TSWV) Family: BunyaviridaeHosts:Ananas comosus, Bidens pilosa, Capsicum annuum, Datura stramonium, Helianthus annuus, Ipomoea congesta, Lactuca sativa, Malva parviflora, Nicandra physalodes, Phaseolus vulgaris, Physalis peruviana, Zinnia elegans, Arachis hypogaea, Canavalia gladiata, C. obtusifolia, C. occidentalis, Crotalaria juncea, Desmodium triflorum, Glycine max, Pisum sativum, Tephrosia purpurea, Vicia faba, Vigna mungo, V. radiata, V. unguiculata, Lycopersicon esculentum, Nicotiana tabacum, Solanum melongena, S. capsicastrum, S. tuberosum and many other species

Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services, Bugwood.org


Tospovirus-Tomato spotted wilt virus (TSWV)

Family: BunyaviridaeSymptoms:necrotic and chlorotic local lesions, systemic wilting, necrosis, spotting, streaking, mosaic, mottling, leaf shape malformation, vein yellowing, ringspots, line patterns, yellow netting and flower colour-breaking.



Tomato spotted wilt symptoms on pepper leaves

Tomato spotted wilt symptoms on pepper


Family: Bunyaviridae

Vector:Nine species are reported as vectors: Frankliniella occidentalis (western flower thrips); F schultzei, F fusca (tobacco thrips); Thrips tabaci (onion thrips); T setosus, T moultoni; F tenuicornis, Lithothrips dorsalis, and Scirtothrips dorsalis. The first four are considered the most important vectors because of their wide distribution and the overlapping host ranges of these species and TSWV.

J.P. Sanderson, Cornell University, Ithaca, NY

Western flower thrips larvae, Frankliniella occidentalis

Tobacco thrips, Frankliniella fusca

Lyle Buss, University of Florida


Family: Bunyaviridae


Vacuolate

Dense, Irregular with

projections

Crystalline

Tomato spotted wilt virus inclusions



Begomovirus-Tomato yellow leaf curl virus (TSWV)

Family: GeminiviridaeDescription:Virions consist of a capsid. Virus capsid is not enveloped. Capsid is elongated and exhibits icosahedral symmetry. The capsid is geminate and has a diameter of 20 nm. Capsids appear hexagonal in outline. The capsomer arrangement is not obvious. With a length of dimers 30 nm.


Family: GeminiviridaeHosts:• In tomato, symptoms are more severe when infectedat an earlier age and vary somewhat among thedifferent cultivars.• In tomato, upward curling of leaves; mottling andoften chlorotic leaf margins.• In tomato, leaves are reduced in size.• In tomato, plants are stunted.• Flower abscission in tomato resulting in greatlyreduced fruit set.• No symptoms are observed in pepper.

Florida Department of Agriculture and Consumer Svcs, Bugwood.org

Don Ferrin, Louisiana State Univ. Agric. Ctr. Bugwood.org


Family: GeminiviridaeVector: Virus is transmitted by immature and adult white flies, Bemesia tabaci. Virus is transmitted by mechanical inoculation (poorly, transmitted by grafting; not transmitted by contact between hosts).

Don Ferrin, Louisiana State Univ. Agric. Ctr. Bugwood.org


Family: GeminiviridaeDiagnostic viral inclusion:

Nuclear


Ring-shaped (rare)

Brittle crystals

UF IFAS Extension Plant Disease ClinicUF IFAS Extension Plant Disease Clinic

Florida Department of Agriculture and Consumer Svcs, Bugwood.org

Potyvirus-Watermelon mosaic virus (WMV-2)

Family: PotyviridaeDescription:Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous with a length of 730-765 nm. Axial canal is indistinct. Basic helix is obscure.

Flexuous particles in leaf extract, negatively stained with potassium phosphotungstate.http://www.dpvweb.net/dpv/showfig.php?dpvno=293&figno=05

Purcifull & Batchelor, Bull. Fla agric. Exp. Stn, 1977


Family: PotyviridaeHosts: Cucurbita pepo, Cucumis melo, C. sativus, Citrullus lanatus and some legumes — mosaic, mottling, leaf shape malformation. Persistent symptoms.

Both Photographs by: Texas A&M Extension Servicehttp://aggie-horticulture.tamu.edu/publications/cucurbitproblemsolver/fruit/watermelon_mosaic.html


Family: PotyviridaeVector: Virus is transmitted by insects of the order Hemiptera, family Aphididae; Myzus persicae, Aphis craccivora, Aphis citricola, Aphis gossypii; at least 38 species of aphid in 19 genera transmit watermelon mosaic virus 2.

Green peach aphid, Myzus persicae

Cotton/Melon aphid, Aphis gossypii

Lyle Buss, Univ. of Florida

Lyle Buss, Univ. of Florida


Family: PotyviridaeViral diagnostic inclusions:Cytoplasmic cylindirical inclusions





Inclusion of WMV in pumpkin epidermal cells(image courtesty of R.Cullen and M Gooch)

Inclusions of WMV in pumpkin(C.A. Baker)

Potyvirus-Zucchini yellow mosaic virus (ZYMV)

Family: PotyviridaeDescription:Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous with a clear modal length with a length of 750 nm and a width of 11 nm. Axial canal is indistinct. Basic helix is obscure.

Purified Zucchini yellow mosiac virus particles in uranyl acetate.

V. LisaIstituto di Fitovirologia applicata del C.N.R., Torino, ItalyH. LecoqStation de Pathologie Vegetale INRA, Montfavet, France


Family: PotyviridaeHosts: zucchini squash (Cucurbita pepo), muskmelon (Cucumis melo), cucumber (Cucumis sativus) and watermelon (Citrullus lanatus).

Vector: transmitted in non-persistent manner by Aphis citricola , A. gossypii, Myzus persicae and Macrosiphum euphorbiae .

Leaf deformation, shoe-stringing and mosaic in naturally infected zucchini squash.

Fruit deformation in field-raised /infected zucchini squash after infection by ZYMV ..


Family: PotyviridaeHosts: zucchini squash (Cucurbita pepo), muskmelon (Cucumis melo), cucumber (Cucumis sativus) and watermelon (Citrullus lanatus).

Vector: transmitted in non-persistent manner by Aphis citricola , A. gossypii, Myzus persicae and Macrosiphum euphorbiae .

Potyvirus-Zucchini yellow mosaic virus (ZYMV) Family: PotyviridaeViral diagnostic inclusions:Cytoplasmic cylindirical inclusions





Epidermal leaf strip of squash infected with ZYMV stained in OG. (I=cylindrical inclusions, N=nucleus)

Florida Department of Agriculture and Consumer Svcs.

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