Detection of a Region of the Coat Protein Gene of Grapevine Fanleaf Virus by RT-PCR in the Nematode Vector Xiphinema index . D. ESMENJAUD, Research Scientists, Lahoratoire de Biologie des Invertebres, Institut National de la Recherche Agronomique, B.P. 2078, 06606 Antibes Cedex, France. P. ABAD, Research Scientists, Lahoratoire de Biologie des Invertebres, Institut National de la Recherche Agronomique, B.P. 2078, 06606 Antibes Cedex, France; L. PINCK, Research Scientist, Institut de Biologie Moleculaire des Plantes du CNRS and Universite Louis Pasteur, Laboratoire de Virologie, 12 rue General Zimmer, 67084 Strasbourg, France; and B. WALTER, Research Scientist, Laboratoire de Pathologie Vegetale, 1NRA, B.P. 507, 68021 Colmar Cedex, France. Plant Dis. 78:1087-1090. Accepted for publication 15 June 1994. Copy right 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-1087.

A region of the coat protein (CP) gene of grapevine fanleaf virus (GFLV) was detected by RT-PCR in the nematode vector Xiphinema index. The reverse transcription step was performed with total RNA extracted from viruliferous X. index. From the synthesized first cDNA strand, an 810-nucleolide fragment (nt 2515 3324 of GFLV-RNA2) was amplified by two 25-mer primers designed in the CP gene. Specific detection was successfully accomplished with samples of one or 10 viruliferous nematodes. Preliminary analysis and comparison of the 207-nt sequence of a stretch (nt 2549-2755 of GFLV-RNA2) of five different RT-PCR amplified fragments, obtained from 10 nematodes of a same sample in a diseased vineyard, indicated substantial variations in the GFLV CP gene. The deduced amino acid sequences showed important mutations essentially for two clones in four positions (residues 180, 188, 217, and 234 of the CP).

Keyword(s): nepovirus detection