Poster Presentation Science Protecting Plant Health 2017

Complete genome sequence of Clerodendrum chlorotic spot virus, a putative dichorhavirus (#217)

Camila Chabi-Jesus 1 2 , Pedro Ramos-González 2 , Renata Calegario 3 , Orlene Guerra-Peraza 2 , Aline Tassi 1 , Elliot W. Kitajima 1 , Ricardo Harakava 2 , Juliana Freitas-Astúa 2 4
  1. Universidade de Sao Paulo, Piracicaba, SP, Brazil
  2. Instituto Biológico, São Paulo, SP, Brazil
  3. Universidade Federal do Paraná, Curitiba, PR, Brazil
  4. Embrapa - Brazilian Agricultural Research Corporation, Sao Paulo, SP, Brazil

Clerodendrum chlorotic spot virus (ClCSV), which is considered a tentative member of the genus Dichorhavirus (family Rhabdoviridae, order Mononegavirales), causes non-systemic chlorotic and necrotic lesions in the leaves of several plant species of the genus Clerodendrum, family Lamiaceae. Rod-shaped particles of this virus (ca. 40 nm x 100-110 nm) occur in nuclear electro-lucent inclusions, and adjacent to the membranous systems of both the nuclear envelope and the endoplasmic reticulum of the infected cells. Leaves of a Clerodendrum sp. plant showing chlorotic and necrotic symptoms were collected in a residential garden in Piracicaba, State of São Paulo, Brazil, in 2015. Mites from that plant were anatomically identified as Brevipalpus yothersi. Presence of putative ClCSV particles and the typical cytopathic effects associated to their infection were confirmed by transmission electron microscopy. ClCSV RNA was detected by RT-PCR using primers that specifically amplify its L gene. Five hundred ng of RNA extracted from the leaf lesions were sequenced by NGS. In silico analyses revealed that the viral genome is split into two RNA molecules and, similar to other dichorhaviruses, it harbors six ORFs in the 3’-5’ orientation. Five of these ORFs, N, P, MP, M and G genes are arranged in the RNA1, whereas the L gene is in the RNA2. ClCSV RNA1 and RNA2 show 52-72% and 60-76% nucleotide sequence identity, respectively, with the cognate molecules of orchid fleck virus, coffee ringspot virus (CoRSV) and citrus leprosis virus N. Best identity scores of each ORF both at nucleotide and amino acid levels were always obtained in comparison with CoRSV. Molecular data confirm the results of previous biological tests that suggested ClCSV as a putative dichorhavirus and support the assignation of this virus to a new species of the genus.