Histology and ultrastructure of oat blue dwarf virus infected oats

Abstract

1972. Histology and ultrastructure of oat blue dwarf virus infected oats. Can. J. Bot. 50: 2511-2519. The oat blue dwarf virus is a small spherical virus (28-30 nm) in diameter and is obligatorily transmitted by the aster leafhopper Mncrosreles fascfions StB1. The virus causes abnormalities in the phloem development of infected plants. Hyperplasia and limited hypertrophy of phloic procambium, in a given procambial strand, begin only after the maturation of the first protophloem sieve-tube element in that particular localized area. The majority of phloem elements produced in hyperplastic areas are parenchymatous, have truncated end walls, and lack sieve plates. Electron-microscopic observations substantiated the hypothesis that the virus was phloem-limited by revealing virus particles only in phloem elements. The greatest accumulation of virus particles was observed in the region between immature and fully vacuolated phloem elements, implicating virus synthesis in immature elements. Crystals of virus particles were often large enough to be seen by light microscopy. ZEYEN, R. J., et E. E. BANTTARI. 1972. Histology and ultrastructure of oat blue dwarf virus infected oats. Can. J. Bot. 50: 2511-2519. Le virus bleu-nain de l'avoine est un petit virus sphirique ayant un diamttre de 28-30 nm, et transmis obligatoirement par Macrosteles fascifrons St%. Ce virus cause des anomalies dans le developpement du phlotme des plantes infectees. Dans un faisceau donne du procambium, une hyperplasie et une hypertrophie limitte dkbutent seulement aprts la maturation du premier element de vaisseau criblt du protophlotme dans cette rtgion precise. La majorite des tltments du phlotme produits dans les regions d'hyperplasie sont parenchymateux, ont des parois terminales tronquees et ne posstdent pas de plaques criblks. Des observations au microscope tlectronique ont supporte l'hypothbe que le virus est limit6 au phlotme; en effet, des particules du virus ont CtC observtes uniquement dans les elements de phlotme.La plus forte accumulation de particules virales a t t t observie dans la rtgion comprise entre les elements immatures et les elements completement vacuoles du phlotme; ceci implique une synthtse virale dans les elkments immatures. Des cristaux de particules virales etaient parfois assez gros pour &tre visibles en microscopic optique.[Traduit par le journal]

A phloem-limited fijivirus induces the formation of neoplastic phloem tissues that house virus multiplication in the host plant

“…It is interesting to point out that although the tumour-inducing plant viruses consist of diverse virus families with different genome properties and replication strategies (DNA or RNA), they are all similarly characterised with phloem-limited accumulations in their natural host plants. More importantly, they similarly induce hyperplastic development of phloem tissue 8 9 11 14 ; therefore, virus accumulation and replication of those RNA viruses in the tumour tissue need to be analysed in great detail. In this study, immunofluorescence experiments showed that RBSDV exclusively accumulates in phloem and neoplastic cells ( Fig.…”

“…This is exemplified by the bacterium Agrobacterium tumefaciens , which induces crown gall tumour and is the most intensively studied plant tumour-inducing agent 6 . Many plant viruses are known to induce enation, tumour or gall formations in host plants; these types of viruses belong to the Reoviridae , Luteoviridae , Geminiviridae and Tymoviridae families 7 8 9 10 11 12 13 14 15 .…”

Occurrence of paracrystalloids and their particles in resistant and susceptible carnation plants infected with Fusarium oxysporum f.sp. dianthi race 2

“…Unbound crystalline bodies have likewise been illustrated from plants infected by viruses, for example in oats infected with the blue dwarf virus (Zeyen and Banttari 1972), solely insect-transmitted, or by other pathogens (Fattah and Webster 1984;Sanger et al 1998). The 28-30 nm virus particles forming the crystalline bodies described by Zeyen and Banttari (1972) were equally numerous in phloem cells, even intermixed with degraded host tissue, and in this respect may show features analogous to those described here. However, the OPs were smaller, and not detected in cells remote from colonized tissue, occurring even in cell walls in the susceptible cv., a location where virus particles are not expected to occur.…”

Identification and Genomic Characterization of a New Virus ( Tymoviridae Family) Associated with Citrus Sudden Death Disease

“…In the case of infections with low titers of members of the Marafivirus genus, infected tissues present almost imperceptible alterations of mitochondria and/or chloroplasts (31) or hyperplasia and hypertrophy of phloem and adjacent parenchyma cells (3,38), as seen with GAMaV and OBDV. Anatomical analyses of the bark tissues from CSD-affected trees showed, below the graft union, overproduction and degradation of phloem and collapse and necrosis of sieve tubes and companion cells, but there was no reference to mitochondria or chloroplast morphological alterations (30), which is in agreement with expectations with respect to morphological alterations for marafiviruses.…”