Molecular analyses of European A, B and P type sources of Beet necrotic yellow vein virus and detection of the rare P type in Kazakhstan

Nucleotide sequence analyses revealed that the genomes of the various Europ ean types of Beet necrotic yellow vein virus (BNYVV), i.e. the A, B and P t ypes, are strongly conserved. Almost identical sequences were found, for in stance, for A types originating from The Netherlands, Italy and former Yugo slavia; these sequences were also almost identical to those determined c. 1 5 years ago by Bouzoubaa et al. (1985; 1986 and 1987). This sequence stabil ity of BNYVV types is in contrast to a pronounced sequence variability obse rved with Beet soil-borne pomovirus, another Polymyxa-transmitted sugar bee t virus with rod-shaped particles. Sequences of RNA 1, 2 and 4 of BNYVV sou rces from Kazakhstan were almost identical to those of the P type of BNYVV which so far had been found only in a small area around the French town of Pithiviers. RNA 5, which in Europe is found also only in the Pithiviers are a, was detected in the bait plants grown in two out of three soil samples f rom different fields in Kazakhstan. It closely resembled RNA 5 from the Pit hiviers area, but was very different from RNA 5 from various East Asian BNY VV sources.