Partial genome sequence of a Potyvirus and of a virus in the order Tymovirales found in Senna macranthera in Brazil

Abstract

Senna macranthera is a common tropical tree native to South-and Northeastern Brazil. In July 2006, symptoms of chlorotic spots in the young leaves and mild mosaic in the old leaves were observed in S. macranthera trees at Viçosa, State of Minas Gerais, Brazil. Electron microscopy examination of leaf dip preparations from the young leaves revealed the presence of flexuous rods. Viral RNA was extracted from purified virion preparations and used as a template for the RT-PCR-based cloning of viral genomic fragments. Two fragments (0.9 kb and 2.0 kb in length) were cloned. Sequence analysis of the 0.9 kb fragment indicated that it corresponded to the NIb coding region of a potyvirus, with nucleotide (nt) identity level of 72% for Pepper mottle virus (PepMoV) and Peru tomato mosaic virus (PTV), while analysis of the 2.0 kb fragment indicated that it corresponded to the putative replicase ORF, which displayed 74% nt identity with the ORF1 (replicase) of Garlic virus A (GarV-A). Based on molecular analysis and the isolates' host range, it is concluded that the viral fragments represent new viruses, for which we propose the names Senna virus Y (genus Potyvirus, family Potyviridae) and Senna virus X (unassigned genus, order Tymovirales). Key words: Senna virus X, Senna virus Y, molecular characterization. RESUMO Sequências genômicas parciais de um Potyvírus e um vírus da ordem Tymovirales encontrados em Senna macranthera no BrasilSenna macranthera é uma árvore tropical nativa do Sudeste e Nordeste brasileiro. Em julho de 2006, sintomas de manchas cloróticas nas folhas jovens e de mosaico leve nas folhas mais velhas foram observados em plantas de S. macranthera em Viçosa, Estado de Minas Gerais, Brasil. A observação de preparações "leaf-dip" em microscópio eletrônico de transmissão revelou a presença de partículas alongado-flexuosas. O RNA viral foi extraído de vírions purificados e utilizado como molde para RT-PCR e clonagem de fragmentos do genoma viral. Dois fragmentos (0,9 kb e 2,0 kb de tamanho) foram clonados. A análise da sequência do fragmento de 0,9 kb indicou que este corresponde à região codificadora da proteína NIb de um potyvírus, com 72% de identidade de nucleotídeos com o Pepper mottle virus (PepMoV) e Peru tomato mosaic virus (PTV), enquanto a análise do fragmento de 2,0 kb indicou que este corresponde à ORF que codifica a possível replicase de um vírus classificado na recém-estabelecida ordem Tymovirales, com 74% de identidade de nucleotídeos com o Garlic virus A (GarV-A). Com base na análise molecular e na gama de hospedeiros, conclui-se que os fragmentos virais clonados representam novas espécies, para as quais sugerem-se os nomes Senna virus Y (gênero Potyvirus, família Potyviridae) e Senna virus X (ordem Tymovirales, gênero não definido). Palavras-chave: Senna virus X, Senna virus Y, caracterização molecular.

The Sisal Virome: Uncovering the Viral Diversity of Agave Varieties Reveals New and Organ-Specific Viruses

“…The family Alphaflexiviridae includes three species in our samples, sharing similarities on BLASTx with plant-infecting species in this same family; Alternanthera mosaic virus [ 89 ], Cassia mild mosaic virus [ 90 ], and Nerine virus X [ 91 ]. As well as Betaflexiviridae, this family does not display an expression pattern to the family level.…”

Allexivirus: review and perspectives

“…Based on sequence analyses, the unassigned viruses share a high degree of nucleotide (nt) and amino acid (aa) sequence similarity with the existing members of Allexivirus. The unassigned viruses comprised four species: SMbLV that was identified as ShVX isolate (GeneBank accession EU835196.1), Allexivirus DS-2013/CZE isolate (JX682826.1), and cassia mild mosaic virus (CaMMV) isolate (partial sequence GU481094.1) (Beserra et al 2011). The Senna macranthera isolate was given the name cassia mild mosaic virus based on particle morphology and host range (J.E.A Beserra, personal communication).…”

“…The Senna macranthera isolate was given the name cassia mild mosaic virus based on particle morphology and host range (J.E.A Beserra, personal communication). However, since there was no available information about the nucleotide sequence of the virus, the authors referred to the newly identified allexivirus as Senna virus X (SVX) (Beserra et al, 2011).…”

“…ApV, AVS, BE, VLV, and SSYMV have been reported to naturally infect dicotyledonous plants in the Rosaceae, Fabaceae, Orchidaceae and Caricaceae (Table 3). The unclassified allexivirus PaVA was detected in Carica papaya L. (Read et al, 2020) and CaMMV was detected in S. macranthera (Beserra et al, 2011).…”

Molecular Characterization of Hovenia Dulcis-Associated Virus 1 (HDaV1) and 2 (HDaV2): New Tentative Species within the Order Picornavirales

“…However, the characterization of viruses infecting trees, especially in Neotropical areas, is yet scarce [4]. In Brazil, the pioneering studies on the characterization of viruses on natural forest ecosystems started in the late 1970s [5], allowing the identification of virus species classified in the genera Carlavirus, Orthotospovirus, Potyvirus, and Tymovirus [6][7][8][9].…”