Novel Variants of Citrus Viroid-III in Fars Province
2011
Aliakbar Bagherian | keramatollah Izadpanah
Citrus viroid-III (CVd-III) has narrow host range and induces specific symptoms on Etrog citron consist of petiole wrinkle and browning plus leaf twist, leaf droop and bent leaf induced by point necroses of the mid vein. Citrus Viroid-III causes significant reduction of the trunk cross section in Valencia scion and trifoliate rootstock, and the canopy volume of infected trees. In this study a number of citrus trees with or without symptoms were sampled and subjected to RNA extraction followed by RT-PCR, cloning and sequencing of PCR products. Molecular properties (nucleotide composition, primary and secondary structures, molecular weights, phylogenetic relationships and percent nucleotide similarity) of viroid variants were compared. Three novel variants of CVd-III (1, 2 and 3) from Fars were selected and used for comparison with a number of other CVd-III sequences from GenBank. CVd-III-2 had 99 % sequence homology to CVd-III-3 but these two variants had only 93% homology with CVd-III-1. It was shown that on the basis of homology, CVd-III isolates from Fars province clustered in different groups.
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