diversity of brevipalpus-transmitted plant viruses brevipalpus-transmitted plant viruses: an...
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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
Fapesp/Univ.Queensland Sprint Program 2017/50039-1
Brevipalpus-transmitted plant viruses: an overview
The viruses Cytoplasmic type-
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
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).
Ramos-González et al., 2016
Phylogenetic reconstruction based on nucleoprotein N.
Selected genera of the family Rhabdoviridae.
Dichorhavirus CytorhabdovirusNucleorhabdovirus Varicosavirus
Ramos-González et al., 2017
-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.