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Bragantia

On-line version ISSN 1678-4499

Bragantia vol.29 no.unico Campinas Jan. 1970

http://dx.doi.org/10.1590/S0006-87051970000100017 

Morfologia e aspectos intracelulares do vírus latente da couve1

 

Particle morphology and intracellular behavior of cole latent virus

 

 

E. W. KitajimaI; I. J. B. CamargoII; A. S. CostaIII, 2

IEngenheiro-agrônomo
IIBiologista
IIIEngenheiro-agrônomo, Seção de Virologia, Instituto Agronômico

 

 


SINOPSE

Partículas alongadas de 15 mµ de diâmetro e 650 mµ de comprimento normal foram consistentemente detectadas em exames electrono--microscópicos de preparações "leaf dip" de 6 espécies diferentes de plantas infetadas pelo vírus latente da couve (Brassica oleracea L. var. acephala) (VLC). Tais partículas são consideradas como sendo de um vírus que poderia ser incluído no grupo do vírus S da batata, na classificação dos vírus alongados de Brandes.
Exames de secções ultrafinas de tecidos foliar e radicular de couve infetada pelo VLC, demonstraram a ocorrência do VLC, formando agregados mais ou menos organizados no citoplasma. Não se notou alterações citológicas sensíveis como conseqüência da infecção, o que está de acordo com a ausência de sintomas externos em couve infetada pelo VLC.


SUMMARY

Electron microscopic examination of leaf dip preparations made from cole (Brassica oleraceaL. var. acephala), Chenopodium amaranticolorCoste & Reyn., radish (Raphanus sativusL.), mustard(Brassica albaBoiss. Rabenh.), bean (Phaseolus vulgaris L.)and Gomphrena globosaL. plants infected with cole latente virus (CLV) demonstrated consistently the presence of slender rods. These particles, considered as CLV, were about 15 mµ wide and 650 mµ in normal length (NL). The NL was determined in a series of comparative measurements using turnip mosaic virus (NL = 750 mµ) as a standard. Morphological characteristics of CLV permit its inclusion in the potato virus S group, in Brandes' system of classification of elongated plant viruses.
Thin section profiles of root and leaf tissues, from CLV-infected cole, showed the frequent occurrence of fibrillar aggregates in the cytoplasm. The particles component of these aggregates were identified as CLV in situ due to the constant association with the infection and their mophological similarities with the particles found in leaf dip preparations. CLV-particles appeared with their longer axis laying side--by-side within these aggregates, often forming a spiral arrangement. Vesiculated areas were occasionally seen in the cytoplasm, with virions in or around them. Virus particles were found in most of the examined cells, except within the tracheids and sieve tubes in the leaf, and within the meristematic zone, in th root. Besides these abnormalities, no other remarkable changes in normal cell structure could be noticed, in agreement with the lack of external symptoms.


 

 

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Recebido para publicação em 25 de março de 1970

 

 

1 Êste trabalho recebeu subvenções da FAPESP (C. Agron.69/879 e 70/076), do CNPq (TC 12275) e do convênio CAPES/BID/BNDE.
2 Bolsistas CNPq