Caulimoviral sequences in Dahlia variabilis in Egypt

Abstract

The presence of Dahlia mosaic virus D10 (DMV-D10) was confirmed for the first time in dahlia (Dahlia variabilis) in Egypt. DMV-D10 was recently described as a caulimovirus that exists as an endogenous pararetroviral sequence (EPRS). DMV-D10 was confirmed by amplification of the ORF1 (encoding for the movement protein) using species specific primers (D10F1/R1). The expected size (900 bp) was amplified from 36 samples with no evidence of infection with either DMV or DCMV. The same dahlia plants were tested for the presence of CMV, INSV, TSV, and TSWV and they were all negative. Sequence comparisons of the Egyptian DMV-D10 ORF1, GenBank accession HM007162, amplified from these samples revealed that the amplicon had the highest sequence identity (96%) with that of DMV-D10 (isolated from US dahlia cultivars). Cluster dendogram based on the amino acid sequences of movement protein of all known caulimoviruses placed D10-US (isolated from US dahlia cultivars), D10 – NZ (isolated from New Zealand dahlia cultivars), D10-DC (isolated from D. coccinea) and D10-Egypt (isolated from Egyptian dahlia cultivars) in one clade.

Key words: Dahlia variabilis, endogenous pararetroviral sequence, DMV-D10.