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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #224810
Title: First Report of the Occurrence of Grapevine fanleaf virus in the Pacific Northwest Region Vineyards

Author
item MEKURIA, T - WASHINGTON STATE UNIV
item Martin, Robert
item NAIDU, R - WASHINGTON STATE UNIV

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/14/2008
Publication Date: 8/1/2008
Citation: Mekuria, T., Martin, R.R., Naidu, R.A. 2008. First report of the occurrence of Grapevine fanleaf virus in the Pacific Northwest region vineyards. Plant Disease. 92:1250.

Interpretive Summary: Grapevine fanleaf virus (GFLV) is one of the most important diseases of grapevines worldwide. This virus has not been detected in the Pacific Northwest previously. In a recent survey of nematodes in Oregon vineyards, Xiphinema index, the vector of GFLV, was not detected. Thus, the risk of GFLV becoming a serious problem in Oregon is still very low. The viruses identified in two Washington vineyards were 100% identical, suggesting they came from the same source, and since they are in the same cultivar it could well be that the viruses came in on planting stocks. The vineyards will be sampled for X. index this summer to assess the potential risk of this virus to the Washington grape and wine industries.

Technical Abstract: Grapevine fanleaf virus (GFLV, genus: Nepovirus, family: Comoviridae), responsible for fanleaf degeneration disease is one of the most important viral diseases of wine grapes (Vitis vinifera) worldwide. During our reconnaissance studies, cambial scrapings from dormant wood cuttings of the wine grape cultivar Chardonnay collected in two separate vineyards tested positive for GFLV by single-tube reverse transcription-polymerase chain reaction (RT-PCR) with oligonucleotide primers designed to amplify a 322 base-pair DNA fragment specific to the coat protein. The virus was found in two vines as mixed infection with Grapevine leafroll-associated virus (GLRaV)-3 in one vineyard and in three vines as mixed infection with GLRaV-1, GLRaV-3 and Grapevine virus A in the other vineyard. None of the other samples collected randomly from the two vineyards tested positive for GFLV, either alone or in combination with other viruses. In order to confirm the RT-PCR results, the 322 base-pair amplicons were cloned into pCR2.1 (Invitrogen Corp., Carlsbad, CA). Three independent clones per amplicon were sequenced from both orientations. Pairwise comparison of these sequences showed 100% nucleotide sequence identity among themselves, indicating that GFLV isolates from the two vineyards may be identical. A comparison of the consensus sequence (to be added) with corresponding sequences of other GFLVs deposited in the GenBank showed 89-91% identity at the nucleotide level and 95-99% identity at the amino acid level. In enzyme-linked immunosorbent assay (ELISA), these samples tested positive with GFLV-specific antibodies further confirming the presence of the virus in samples that were positive in RT-PCR. Thus, RT-PCR and ELISA results confirmed the presence of GFLV in Chardonnay samples. To our knowledge, this is the first report of GFLV in wine grapes in the Pacific Northwest region. Results from our study and previous reports indicate the wide distribution of GFLV in several wine grape cultivars in the United States. Further investigations are being carried out on GFLV distribution.