Análise ultra-estrutural de folhas de três espécies de Solanaceae após inoculação com o vírus da necrose branca do tomateiro (VNBT - Tymovirus)

Abstract

-(Ultrastructural analysis of leaves from three species of Solanaceae after inoculation with the tomato white necrosis virus (TWNV -Tymovirus)). The leaf ultrastructure of Nicotiana glutinosa L., Lycopersicon pimpinellifolium L., and Physalis angulata L. inoculated with the tomato white necrosis virus (TWNV -Tymovirus) was analysed. Plants were kept in a greenhouse at 25°C and inoculated with the virus when tree to four leaves were totally developed. Fifteen days after inoculation, samples were collected from the median third of the 3 rd or 4 th leaf from the apex. The samples were prepared for analysis using conventional transmission electron microscope techniques. The ultrastructural analysis of the chlorenquima cells showed vesiculation and vacuolation of the chloroplasts and mitochondria, presence of multivesicular bodies, and a slight dilation of the plasmodesmata in N. glutinosa and L. pimpinellifolium. In these two species, virus-like particles were seen in the cytoplasm and vacuoles. P. angulata plants did not show subcellular alterations. Macroscopic observations, retroinoculation tests, and ultrastructural analysis showed the presence of local and systemic symptoms in N. glutinosa, latency in L. pimpinellifolium, and immunity in P. angulata. RESUMO -(Análise ultra-estrutural de folhas de três espécies de Solanaceae após inoculação com o vírus da necrose branca do tomateiro (VNBT -tymovirus)). Foi estudada a ultra-estrutura foliar das solanáceas Nicotiana glutinosa L., Lycopersicon pimpinellifolium L. e Physalis angulata L. inoculadas com o vírus da necrose branca do tomateiro (VNBT -Tymovirus).As plantas mantidas em casa-de-vegetação com temperatura constante de 25°C foram inoculadas quando apresentavam três a quatro folhas totalmente expandidas. Quinze dias após a inoculação, foram coletadas amostras do terço médio do limbo da 3ª ou da 4ª folha a partir do ápice. As amostras foram preparadas para análise em microscopia eletrônica de transmissão segundo técnicas convencionais. A análise ultra-estrutural das células do clorênquima revelou principalmente vesiculação e vacuolação dos cloroplastos e de mitocôndrias, além da ocorrência de corpos multivesiculares e ligeira dilatação dos plasmodesmos em N. glutinosa e L. pimpinellifolium. Nestas duas espécies foram observadas "virus-like-particles" no citoplasma e nos vacúolos. Plantas de P. angulata não mostraram alterações de ultra-estrutura. As observações macroscópicas, os testes de retroinoculação e as análises ultra-estruturais revelaram sintomas locais e sistêmicos em N. glutinosa, latência em L. pimpinellifolium e imunidade em P. angulata.

Complete Genome Sequence of a Tobacco-Infecting, Tomato-Blistering Mosaic Virus

“…The tymoviruses (family Tymoviridae , genus Tymovirus ) are icosahedric, non-enveloped, single-stranded positive sense RNA viruses ( 1 ). To date, only five tymoviruses infecting different plant species were reported in Brazil: (i) cassia yellow mosaic-associated virus ( 2 ), (ii) eggplant mosaic virus (EMV) ( 3 , 4 ), (iii) passion fruit yellow mosaic virus ( 5 ), (iv) petunia vein banding virus ( 6 ), and (v) tomato blistering mosaic virus (ToBMV) ( 7 ). Most of these viruses were identified as distinct tymoviruses based on biological, biochemical, and serological properties, and no complete genomic RNA sequences are available for these viruses, except for the recently described ToBMV ( 7 ) (GenBank accession no.…”

Assembly of tomato blistering mosaic virus-like particles using a baculovirus expression vector system

“…A subgenomic promoter composed of a 16 conserved nucleotides, referred to as the "tymobox", is responsible for the expression of CP [4]. Viral replication takes place in the cytoplasm in association with the double membrane-bounded vesicles that line the periphery of the chloroplasts and/or mitochondria [3,5]. Interestingly, previous studies have shown that the CP of physalis mottle virus (PhyMV) and turnip yellow mosaic virus (TYMV) are able to self-assemble into virus-like particles (VLPs) when expressed in Escherichia coli [6,7].…”