DETECTION OF FLMaV1 AND FLMaV2 IN THE MEDITERRANEAN REGION AND STUDY ON SEQUENCE VARIATION OF THE HSP70 GENE
T. Elbeaino, S. Nahdi, M. Digiaro, A. Alabdullah, G.P. Martelli
The presence of Fig leaf mottle-associated virus 1 (FLMaV-1) and Fig leaf mottle-associated virus 2 (FLMaV-2) was investigated in fig orchards of six Mediterranean countries. A total of 415 samples coming from Albania, Algeria, Lebanon, Syria, Tunisia and Italy were collected and tested by PCR, which detected the presence of at least one of the tested viruses in all surveyed countries. Except for Algeria and Syria, where FLMaV-1 was absent, both viruses were found in all surveyed countries with mean infection rates of 34% and 18.5% for FLMaV-1 and FLMaV-2, respectively. More than 7% of the samples were infected with both viruses. As ascertained by dsRNA analysis, 25 out of 65 samples (ca. 38.5%) showed visible bands in polyacrylamide gel electrophoresis. Single strand conformation pattern (SSCP) analysis of a portion of the viral HSP70 gene from figs of different geographical origin showed heterogeneous patterns for both viruses. The HSP70 gene variability was confirmed by sequence analysis. The level of nucleotide variability between the isolates reached 18% for FLMaV-1 and 15% for FLMaV-2. While the deduced amino acid sequence variability maintained almost the same range of divergence in the case of FLMaV-1 (19%), this level decreased to 6% in the case of FLMaV- 2. The position of the isolates in phylogenetic trees constructed with HSP70 sequences did not correspond to their geographical origin, except for the Lebanese isolates which grouped together in a single cluster.