icvg 2009 part I pp 1-131.pdf - Cornell University

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GRAPEVINE VIROLOGY HIGHLIGHTS 2006-09
Giovanni P. MARTELLI
Dipartimento di Protezione delle Piante e Microbiologia Applicata, Università degli Studi and Istituto di Virologia Vegetale del CNR,
Unità Organizzativa di Bari, 70126 BARI, Italy
G.P. Martelli, Tel: +39.080.5442914; Fax:+39.080.544291; E-mail: martelli@agr.uniba.it
Summary
Consistently with the comparable presentations given in the
previous ICVG Meetings, this report summarizes the relevant
information contained in the 200 or so papers on grapevine
virology published since the Stellenbosch Meeting in 2006.
SPECIALIZED MEETINGS AND REVIEWS
Two such Meetings entitled “The Syrah vine health
Symposium” and “Grapevine leafroll disease: an increaing
problem for California vineyards” organized by the
University of California, were held at Davis (USA) in 2007
and 2008, respectively. These Meetings, open to
international participation, reviewed the state-of-the-art of
the diseases dealt with. No ultimate conclusions were
reached on the origin of Syrah decline, although the fact
that this disease is graft-transmissible, perennates in
propagating material, develops in quite different
geographical areas under a wide range of environmental
conditions and has a robust association with at least one
virus of the rugose wood complex (Grapevine rupestris
stem pitting-associated virus, GRSPaV) should favour a
viral aetiology.
As reviewed by Fuchs et al. (2007), studies financed
by the European Commission for assessing the risk of
recombination in grapevines transformed with the coat
protein (CP) gene of Grapevine fanleaf virus (GFLV)
showed that no such event occurred in transgenic plants.
Furthermore, the original variability of Grapevine virus A
(GVA) and Grapevine virus B (GVB) used for infection of
plants transformed with the CP gene of both viruses was
preserved even in the presence of high transcript
accumulation and systemic plant infection. Thus, transgenic
grapes may not represent a threat to the crop and the
environment. A similar subject was addressed in an article
reviewing the outcome of the investigations carried out by
several Europen laboratories in the framework of the EU-
FP6-Coordination Network ResisVir (Laimer et al., 2009).
Finally, the intriguing properties of GVA were reviewed by
Mawassi (2007) who concluded that in spite of the apparent
simplicity and small size of its genome, GVA is not a
simple virus.
SURVEYS AND NEW RECORDS OF KNOWN
DISEASES, VIRUSES AND VECTORS
The evaluation of the sanitary status of national
grapevine industries continues to attract the interest of
technicians of various countries. Thus, field surveys were
conducted in the Czech Republic (Kominek, 2008), Iran
(Bashir & Hajizadeh, 1997), Chile (Fiore et al., 2008;
2009), Lebanon (Hanna et al.,2008) and Croatia, some
being specifically directed to the occurrence and
distribution of leafroll viruses in Tunisia (Mahfoudhi et al.,
2008), Turkey (Akbas et al., 2007) and the USA (Fuchs et
al., 2009). Several molecular variants of GRSPaV were so
consistently found in Japanese vines of Vitis labrusca cvs
Pione and Kyoho affected by rugose wood, to suggest their
involvement in the aetiology of this disease (Nakaune et al.,
2008a). Grapevine vein necrosis and grapevine vein mosaic
were recorded for the first time from Syria (Mlsmanieh et
al., 2006a, 2006b), Grapevine virus A (GVA) from
Germany (Ipach & Kling, 2008), Grapevine leafrollassociated
virus 9 (GLRaV-9) from Washington State
(Jarugula et al.,2008) and Australia (Habili et al., 2008),
GLRaV-7 from California (Morales & Monis, 2007),
GLRaV-5 from Argentina (Gomez-Talquenca et al., 2009),
GLRaV-7 and GLRaV-9 from Chile (Engel et al., 2008a),
GLRaV-4 from Chile (Escobar et al., 2008), GFLV from
Washington State (Merkuria et al., 2008), GLRaV-3 from
American Vitis species in Washingon State (Soule et al.,
2006). An investigation for the presence of Xiphinema
index in the vineyards of the Bekaa valley (Lebanon),
revealed that 14% of the sampled plantings contained the
nematode (Jawar et al., 2006). An intriguing finding came
from Slovenia, where Raspberry bushy dwarf virus
(RBDV), a member of the genus Idaeovirus, was detected
by nested RT-PCR in individuals of the longidorid
nematode Longidorus juvenilis extracted from 4 of 5 soil
samples (Mavric Plesco et al., 2009). Idaeoviruses are not
known to be nematode-borne, thus if L. juvenilis is able to
transmit RBDV remains to be established. So far, this virus
has only been found in Slovenia, primarily in white-berried
cultivars. It is irregularly distributed in infected vines and is
not transmitted through seeds in cv. Laski Rizling, contrary
to raspberry, where up to 77% seed transmission has been
recorded (Mavric-Plesco et al., 2009).
NEW DEVELOPMENTS IN TAXONOMY AND
RECORD OF NEW VIRUSES
The continuous flow of molecular information is
affecting taxonomy to an increasing extent. The major
changes occurred recently, that involve also virus species
pathogenic to grapevines, consist in the re-arrangement of
the plant infecting members of the new order
Picornavirales. In particular: (i) the former family
Comovidae was cancelled and substituted for by the new
family Secoviridae, which now includes the genera
Comovirus, Fabavirus, Nepovirus, Sequivirus, Waikavirus,
Cheravirus, Sadwavirus and Torradovirus. Since the extant
genera Comovirus, Fabavirus and Nepovirus still represent
a homogenous grouping, they were assigned to the
Progrès Agricole et Viticole, 2009, Hors Série – Extended abstracts 16 th Meeting of ICVG, Dijon, France, 31 Aug – 4 Sept 2009