Browsing by Author "Bennani, B."
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- Citrus variegation virus: Molecular variability of a portion of the RNA 3 containing the coat protein gene and design of primers for RT-PCR detectionPublication . Bennani, B.; Mendes, Celso; Zemzami, M.; Azeddoug, H.; Nolasco, GustavoThe coat protein gene and part of the intergenic region of the RNA 3 of several isolates of Citrus variegation virus (CVV) producing either infectious variegation or crinkly leaf symptoms were amplified by RT-PCR, cloned and sequenced. Some isolates were composed of a mixture of sequence variants. The coat protein gene appeared to be highly conserved (lowest similarity among all CVV sequences 93%), especially at the N-terminal, indicating at the molecular level that both types of symptoms are indeed produced by the same virus species. No relationship could be found with the geographic origin. Sequences obtained from isolates producing infectious variegation clustered in a different branch of a dendrogram than those originating from crinkly leaf symptoms. Both clusters could further be distinguished by two parsimonious sites in the coat protein gene. In the short stretch of the intergenic RNA 3 region analysed, a stable hairpin exists in addition to the previously reported hairpin that constitutes the core promoter for the RNA 4 transcription. This second hairpin could also be recognised in the other subgroup 2 Ilarviruses. Surprisingly, at the nucleotide and amino acid levels and in the secondary features of the intergenic region, CVV appeared closer to the other subgroup 2 Ilarviruses than to Citrus leaf rugose virus to which it is serologically related and has been considered to be evolutionary related. Using primers designed for the conserved regions, the virus was detected with a prevalence of 25% and 13% in Portuguese and Moroccan citrus collections. A group of RT-PCR positives was further confirmed by ELISA and biological indexing.
- Variability of a portion of RNA 3 containing the coat protein gene of Citrus variegation virus (CVV) using single-strand conformation polymorphism (SSCP)Publication . Bennani, B.; Zemzami, M.; Nolasco, Gustavo; Azeddoug, H.A portion of RNA 3 of Citrus variegation virus (CVV), comprising part of the intergenic region and the coat protein (CP) gene from eight viral isolates, was amplified by RT-PCR and cloned. The clones were compared for intra and inter-isolate variations by single-strand conformation polymorphism analysis. Some of the results were compared with sequence data previously obtained. The test discriminated between clones differing in as little as 3.2% of the nucleotides. Most isolates included several variants, in some cases with a predominant pattern, which, however, could no longer be recognised in new RT-PCR products obtained 13 months later. This procedure can there-fore be used to identify and detect variations between CVV isolates. It is rapid, inexpensive and may reduce the amount of sequencing needed for comparing viral isolates.