Molecular variability of Citrus exocortis viroid in a single naturally infected citrus tree

We report the nucleotide sequence of Citrus exocortis viroid (CEVd) from a single natural infected citrus tree of the clementinier variety (Citrus clementina) in Tunisia. The sequence variability of this viroid from its natural host without using an alternative passage by an indicator host or an artificial inoculation was found to occur at 14 positions, giving a variability of 3.8%. This work confirms that naturally - occurring viroids belonging to the Pospiviroid genera contain a mixture of sequence variants. In addition, this study confirms the worldwide distribution of this viroid.