VARIATION AND REASSORTMENT WITHIN THE RICE DWARF VIRUS GENOME

Although nucleotide sequences of different isolates of rice dwarf phytoreovirus are highly conserved genome variants can be identified from mobility differences detected in polyacrylamide electrophoresis gels. These differences may be due to base substitutions, deletions, or rearrangements of the dsRNAs. Using known variants, segment reassortment has been experimentally demonstrated for the first time with plant reoviruses, although with some other members of the Reoviridae, it is well documented. The technique for making genetic resassortants could be used to identify genes involved in certain characters such as insect transmissibility, types of symptom expression, and host specificity.