title: A distinct tymovirus infecting Cassia                      hoffmannseggii in Brazil.
abstract: Leaves of Cassia hoffmannseggii, a wild fabaceous species found in the Atlantic Forest, with a severe mosaic symptom were collected in Pernambuco State, Brazil. By transmission electron microscopy, two types of virus particles were found: the first was recognized as particles of a potyvirus, which was later identified as Cowpea aphid-borne mosaic virus; and the second was isometric and present in high concentration. The observation of vesicles at the periphery of chloroplasts suggested a tymovirus infection, which was confirmed by subsequent assays. A serological assay against several tymovirus antisera resulted in positive reaction of this tymo-like virus with an antiserum of Passion fruit yellow mosaic virus. By means of RT-PCR and using degenerated primers for the conserved region of RNA-dependent RNA polymerase (RdRp) gene of tymoviruses, a specific DNA fragment was amplified and sequenced. Based on this sequence, a specific forward primer was synthesized and successfully used to amplify the 3' terminal genome region, containing the partial RdRp gene and the complete coat protein (CP) sequences. The CP was 188 amino acids (aa) long, and the highest CP aa identity was observed with Kennedya yellow mosaic virus (61 %). Based on the current ICTV demarcation criterion, this isolate was considered as a distinct tymovirus and tentatively named as Cassia yellow mosaic-associated virus.
authors.affiliation: Laboratório de Fitovirologia, Departamento de Agronomia, Universidade Federal Rural de Pernambuco, Recife, PE 52171-900, Brazil.
authors.forename: C
authors.initials: C
authors.lastname: Nicolini
authors.forename: G
authors.initials: G
authors.lastname: Pio-Ribeiro
authors.forename: G P
authors.initials: GP
authors.lastname: Andrade
authors.forename: F L
authors.initials: FL
authors.lastname: Melo
authors.forename: V C
authors.initials: VC
authors.lastname: Oliveira
authors.forename: F C
authors.initials: FC
authors.lastname: Guimarães
authors.forename: R O
authors.initials: RO
authors.lastname: Resende
authors.forename: E W
authors.initials: EW
authors.lastname: Kitajima
authors.forename: J A M
authors.initials: JA
authors.lastname: Rezende
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nagata
mesh_terms: D001938:Brazil; D036022:Capsid Proteins / Q000235:genetics; D002366:Cassia / Q000145:classification / Q000821:virology*; D017931:DNA Primers; D010802:Phylogeny; D010935:Plant Diseases / Q000821:virology*; D018515:Plant Leaves / Q000821:virology*; D012367:RNA, Viral / Q000235:genetics; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017806:Tymovirus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D036022:Capsid Proteins; D017931:DNA Primers; D012367:RNA, Viral; D012324:RNA-Dependent RNA Polymerase