diversity of brevipalpus-transmitted plant viruses · brevipalpus-transmitted plant viruses: an...
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SCIENCE PROTECTING PLANT HEALTH26-28 September, 2017, Brisbane, Australia
Diversity of Brevipalpus-transmitted plantviruses
EW Kitajima1, J Freitas-Astúa2,3, PL Ramos-González3 & RG Dietzgen4
1ESALQ/Universidade de São Paulo, Piracicaba, 13418-900 Piracicaba, SP, Brazil; 2Embrapa Cassava and Fruits, 4438-000 Cruz das Almas, BA, Brazil; 3Instituto Biológico, 04014-900 São Paulo, SP, Brazil; 4QAAFI, The University of Queensland, St.Lucia, QLD 4072, Australia
Fapesp/Univ.Queensland Sprint Program 2017/50039-1
Brevipalpus-transmitted plant viruses: an overview
The virusesCytoplasmic type-
CilevirusHigrevirus
Nuclear typeDichorhavirus
The vectorBrevipalpus spp.(Tenuipalpidae)
SymptomsLocalized, non systemiclesions in infected host plants
Ligustrum leprosis virusL. sinensis Brunfelsia uniflora
Hibiscus leafinfected withHGSV
Local necrotic lesions onbean leaf experimentallyinfected with CiLV-C
Geographic distribution of BTV (except OFV, present worldwide)
BTV- CYTOPLASMIC TYPECilevirus: bipartite (5 & 9 kb) ssRNA (+). Short, bacilliform, membrane boundedparticles. Accumulate in the ER. Dense, vacuolated viroplasma in the cytoplasm.Type member- CiLV-C; recognized member- CiLV-C2
Higrevirus: similar but tripartiteType and sole member- HGSV-2
BTV- NUCLEAR TYPEDichorhavirus: bipartite (2 x 6kb) ssRNA (-), member of Rhabdoviridae. Short, rod-like particles in the nucleus and cytoplasm. Electron lucent nuclear viroplasm.Type member: OFV; recognized member- CoRSV
Economically important diseases-Citrus leprosis-Coffee ringspot-Passion fruit green spot-Orchid fleck
Citrus leprosis
CoRSV
PfGSV
OFV
Genome organization of BTV
BTV-CCilevirusCiLV-C(Locali et al., 2006)
BTV-NDichorhavirus(Rhabdoviridae)OFV(Kondo et al., 2006)
Virus vector relationship
BTV-C persistent, circulative type
BTV-N persistent, circulative, propagative type
*
Virions (arrows) presentbetween membranes ofadjacent cells
Viroplasm (*) in the nucleusand virions either in thenucleus or in the cytoplasm(arrows)
Vector speciesB. phoenicis s.s. (CiLV-N), B. yothersi (CiLV-C, CiLV-C2, LigLV), B. yothersi aff. (CiCSV, ClCSV), B. papayensis (CoRSV, CiLV-C, LigRSV), B. californicus (OFV), B. obovatus(SvRSV, CesRSV)
BTV – so far, found naturally infecting more than 40 different plantspecies, mostly ornamental. However, few have been characterizedmolecularly.
Recently sequenced BTV
Cilevirus: Citrus leprosis virus C SJP (CiLV-C SJP), Solanum violaefoliumringspot virus (SvRSV), Ligustrum leprosis virus (LigLV), Passionfruit green spot virus (PfGSV)
Dichorhavirus: Citrus leprosis virus N (CiLV-N), Citrus chlorotic spot virus(CiCSV), Clerodendrum chlorotic spot virus (ClCSV), Cestrumringspot virus (CesRSV)
Phylogenetic reconstruction based on RdRp2 (protein motif).
Cilevirus
Tobamovirus
Negevirus
Unassigned
Blunervirus
Tobravirus
Virgaviridae
Higrevirus
Closteroviridae
Ramos-González et al., 2016
BTV-C
Phylogenetic reconstruction based on nucleoprotein N.
Selected genera of the family Rhabdoviridae.
Dichorhavirus CytorhabdovirusNucleorhabdovirus Varicosavirus
Ramos-González et al., 2017
CiLV-N Br
BTV-N
FINAL COMMENTS
-BTV, likely are present in other geographic regionsoutside the Americas and Hawaiian islands.
-Isolates of OFV were found infecting citrus (Mexico,Colombia) and an ornamental in Australia, and similarincidents may have occurred elsewhere, since this virusis distributed worldwide.
-Significant diversity has been found within Cilevirus andDichorhavirus.