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  • SCIENCE PROTECTING PLANT HEALTH 26-28 September, 2017, Brisbane, Australia

    Diversity of Brevipalpus-transmitted plant viruses

    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 viruses Cytoplasmic type-

    Cilevirus Higrevirus

    Nuclear type Dichorhavirus

    The vector Brevipalpus spp. (Tenuipalpidae)

    Symptoms Localized, non systemic lesions in infected host plants

    Ligustrum leprosis virus L. sinensis Brunfelsia uniflora

    Hibiscus leaf infected with HGSV

    Local necrotic lesions on bean leaf experimentally infected with CiLV-C

  • Geographic distribution of BTV (except OFV, present worldwide)

  • BTV- CYTOPLASMIC TYPE Cilevirus: bipartite (5 & 9 kb) ssRNA (+). Short, bacilliform, membrane bounded particles. Accumulate in the ER. Dense, vacuolated viroplasma in the cytoplasm. Type member- CiLV-C; recognized member- CiLV-C2

    Higrevirus: similar but tripartite Type and sole member- HGSV-2

    BTV- NUCLEAR TYPE Dichorhavirus: 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-C Cilevirus CiLV-C (Locali et al., 2006)

    BTV-N Dichorhavirus (Rhabdoviridae) OFV (Kondo et al., 2006)

  • Virus vector relationship

    BTV-C persistent, circulative type

    BTV-N persistent, circulative, propagative type

    *

    Virions (arrows) present between membranes of adjacent cells

    Viroplasm (*) in the nucleus and virions either in the nucleus or in the cytoplasm (arrows)

    Vector species B. 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 plant species, mostly ornamental. However, few have been characterized molecularly.

    Recently sequenced BTV

    Cilevirus: Citrus leprosis virus C SJP (CiLV-C SJP), Solanum violaefolium ringspot virus (SvRSV), Ligustrum leprosis virus (LigLV), Passion fruit green spot virus (PfGSV)

    Dichorhavirus: Citrus leprosis virus N (CiLV-N), Citrus chlorotic spot virus (CiCSV), Clerodendrum chlorotic spot virus (ClCSV), Cestrum ringspot 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 regions outside the Americas and Hawaiian islands.

    -Isolates of OFV were found infecting citrus (Mexico, Colombia) and an ornamental in Australia, and similar incidents may have occurred elsewhere, since this virus is distributed worldwide.

    -Significant diversity has been found within Cilevirus and Dichorhavirus.