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Molecular Pathogens
MP2011, Vol.2, No.2
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Research Article Open Access
Biological and Molecular Characterization of The Fig Mosaic Disease
Elsayed E. Hafez
1
, A. A. El-Morsi
2
, A. A. Abdelkhalek
1
1. Mubarak City for Scientific Research and Technology Applications, Arid Lands and Development Research Institute (ARADI), 21934, Alexandria, Egypt
2. Mansoura University, Faculty of Science, Botany department, Mansoura, Egypt
Corresponding author;
Authors
Molecular Pathogens 2011, Vol 2 No 2 DOI: 10.5376/mp.2011.02.0002
Received: 14 Feb., 2011
Accepted: 23 May, 2011
Published: 27 Jun., 2011
This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article as:
Hafez et al., 2011, Biological and Molecular characterization of the Fig Mosaic disease, Molecular Pathogens, Vol.2 No.2 (doi: 10.5376/mp.2011.02.0002)
Abstract
Fig Mosaic Virus
(FMV) causes a serious problem for the fig plant (
Ficus carica
L.) in Egypt and all over the world. Not
all of the previous studies agreed on a precise description for viral particle and its genome; in addition, there have been conflicts in
those results. A number of samples from naturally infected fig plants exhibiting characteristic
fig mosaic virus
-associated symptoms
were collected from different fields in the north coast of the western desert that extends from west of Alexandria to Marsa Matrouh.
The electron microscopy of ultra thin sections of FMV-infected leaves judged by I-ELISA revealed the presence of so-called double
membrane bodies (DMBs) in parenchyma cells with two types: Rounded to ovoid, 160~200 nm in size and elongated; straight to
slightly flexuous, up to or exceeding 1 µm in length. Also accumulation of starch grain was recorded as ultrastructure change of leaf
of
F. carica
L. affected by FMV-infection. Using potyvirus genus-specific primers, 969 bp of the viral Nuclear Inclusion Body (
NIB
)
gene were amplified. For further confirmation, two degenerate primers were designed based on the amino acids sequences of 69
different FMV coat protein genes; amplicones with 374 bp were obtained. Both the amplicones 969 bp of the
NIB
and the 374bp of
the coat protein genes were sequenced. The sequence and phylogenetic analysis indicated that the Egyptian FMV isolate was closely
related to other FMV isolates, especially the Italian and Arkansas isolates with similarity not exceeding 55%.
Keywords
Fig Mosaic virus
,
Potyviruses
, Electron microscope, Plant disease
Background
The first known reports of fig mosaic disease (FMD)
were submitted by Condit in 1922 and Swingle in
1928 (cited in Alfieri, 1967), but the first critical study
was conducted by Condit and Horne (1933). The
disease has been widespread in several fig-growing
countries, including Egypt. Although it was not sap-
or seed-transmissible (Martelli et al., 1993; Elbeaino
et al., 2006), successful transmission of the disease by
an eriophyid mite,
Aceria ficus
Cotte, has been
reported by Flock and Wallace (1955). The aetiology
and mechanical transmission of the disease is still
uncertain (Martelli et al., 1993). The disease was
thought to be of viral origin since ultrastructural
observations revealed the occurrence of intracyto-
plasmic enveloped spherical bodies in infected fig
cells (Bradfute et al., 1970; Plavsic and Milicic, 1980;
Appiano et al., 1990). In the following years, the
agents of the disease were called “disease-associated
bodies” (DABs) or round to ovoid double membrane
bodies (DMB), which had an envelope consisting of a
unit membrane approximately 12 nm thick and
90~200 nm in diameter in the cytoplasm of
parenchyma cells differed in shape and size (Bradfute
et al., 1970; Martelli et al., 1993; Appiano et al., 1995).
DMBs contain proteinaceous material, fine fibrils, and
are often next to aggregates of convoluted electron-
dense filamentous elements that contain carbohydrates
and are partially digested by pronase (Appiano and
Conti, 1993; Castellano et al., 2007). They are also
insensitive to tetracycline (Martelli et al., 1993).
Because of this and of their cytochemical and
ultrastructural properties, DMBs were suggested to
represent possible particles of an uncharacterized virus
(Martelli et al., 1993; Ahn et al., 1996).
Putative
potyviruses
were reported from Croatia
(Grbelja, 1983), and then the pathogen was assumed
to be a member of the family
Potyviridae
by Brunt et
al. (1996). Some double membrane-bound bodies
(DMBs) and rod-shaped virus particles (720 nm in