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

ewkitaji@usp.br

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.