Comparative study between Potato Dwarf Virus (PRDV) and potato virus P (PVP)?

G. MASSA. M.E. SEGRETÍN, M. COLAVITA, F.F. BRAVO-ALMONACID, S. FEINGOLD; BRAVO ALMONACID FF

Bilbao, España

Congreso; 16th Trienal Conference of the European Association for Potato Research (EAPR 2005).; 2005

Free trade of biological material is often hampered by phytosanitary and quarantine requirements. Virus is one of the main concerns when exporting or importing potato seed. Potato Rough Dwarf Virus (PRDV, Carlaviridae) was originally described in Argentina by Butzonitch et al. (1996). A few years earlier, a Potato Virus P (PVP) was reported in Brazil (Daniels, et al., 1993) and also catalogued as a Carlavirus (Jeffries, 1998). Immunological evidences indicate a high degree of similarity between PRDV and PVP (Butzonitch, et al, 1996). One methodology for virus classification is by symptom comparison when infecting a set of differential plants, including Solanaceae and non Solanaceae species (Table 1). This methodology requires a trained eye, and often slightly differences in symptoms can go undetected. Observed symptoms are then associated with virus presence detected by ELISA. Nonetheless, the distribution of virus within the plant is not always even. For example, the potato leafroll virus (PLRV)  shows great variations in ELISA values depending which tissue is tested (Brown, et al., 1994). In the past years DNA or RNA sequence comparison had been used, complementing phenotypic data,  to unveil phylogenic relationships between viruses. For CP or replication protein genes, it is accepted that same species share an homology of at least 72% of nucleotide or 80% of aminoacid sequences (Adams et al., 2004). These figures are significantly lower for non genic sequences. Previous work  have shown that intergenic regions between the replicase gene and the  triple gene block,  and between the latter and the coat protein (CP) gene (figure 1) have been very informative for phylogeny studies in Flexiviradae in general and Carlaviridae in particular (Adams et al., 2004).