The genomic dsRNAs extracted from individual plants collected from France and Italy, infected by maize rough dwarf fjivirus (MRDV), showed distinct electrophoretic mobilities. The different sizes of the genomic segments were randomly scattered throughout all the ten genomic complements, even when derived from the same field. However, different genomic electropherotypes were not correlated with symptom expression, differently from what reported for phenotypic variants of rice dwarf phytoreovirus (Ando et al., Ann. Phytopathol. Soc. Jpn. 62: 466-471, 1996). Occasionally, up to four electropherotypes were harbored in the same plant with MRDV typical symptoms. MRDV dsRNAs purified from a mixture of plants collected in the field showed an electrophoretic rnigration pattern refiecting a mixture of individual profiles. MRDV vectors (Laodelphax striatellus Fallén) were allowed to feed for 7 days on single plants showing obvious infection symptoms and, after the incubation period (18 days) were transferred in groups of 5 insects per plant onto barley seedlings. Four different MRDV electropherotypes have been thus isolated and kept in culture. Reverse transcription and polymerase chain reaction have been used to generate cognate SI0 segments of the different electropherotypes. SI0 has been chosen because the sequence of the 'type' isolate is known (Marzachì et al., Europ. J. Plant Path. 102: 601-605). Sequencing studies are in progress. Whether the changes are due to single point mutations as for rice ragged stunt oryzavirus (Suga et al., Arch. Virol. 140: 1503-1509, 1995) or to nucleotide shifts in the open reading frames or genomic reassortment events as in the case of rice dwarf phytoreovirus (Murao et al., J. Gen. Virol. 75: 1843-. 1848, 1994; Uyeda et al., Virology 212: 724-727, 1995) is to be verified. It is however possible that the molecular confirmation of the plant-infecting reovirus classification scheme, derived basically from morphological characters ,and vector relationships, could find further acknowledgment at this level.
HETEROGENEITY OF MAIZE ROUGH DWAW FIJIVIRUS GENOMIC SEGMENTS
P CACIAGLI;
1998
Abstract
The genomic dsRNAs extracted from individual plants collected from France and Italy, infected by maize rough dwarf fjivirus (MRDV), showed distinct electrophoretic mobilities. The different sizes of the genomic segments were randomly scattered throughout all the ten genomic complements, even when derived from the same field. However, different genomic electropherotypes were not correlated with symptom expression, differently from what reported for phenotypic variants of rice dwarf phytoreovirus (Ando et al., Ann. Phytopathol. Soc. Jpn. 62: 466-471, 1996). Occasionally, up to four electropherotypes were harbored in the same plant with MRDV typical symptoms. MRDV dsRNAs purified from a mixture of plants collected in the field showed an electrophoretic rnigration pattern refiecting a mixture of individual profiles. MRDV vectors (Laodelphax striatellus Fallén) were allowed to feed for 7 days on single plants showing obvious infection symptoms and, after the incubation period (18 days) were transferred in groups of 5 insects per plant onto barley seedlings. Four different MRDV electropherotypes have been thus isolated and kept in culture. Reverse transcription and polymerase chain reaction have been used to generate cognate SI0 segments of the different electropherotypes. SI0 has been chosen because the sequence of the 'type' isolate is known (Marzachì et al., Europ. J. Plant Path. 102: 601-605). Sequencing studies are in progress. Whether the changes are due to single point mutations as for rice ragged stunt oryzavirus (Suga et al., Arch. Virol. 140: 1503-1509, 1995) or to nucleotide shifts in the open reading frames or genomic reassortment events as in the case of rice dwarf phytoreovirus (Murao et al., J. Gen. Virol. 75: 1843-. 1848, 1994; Uyeda et al., Virology 212: 724-727, 1995) is to be verified. It is however possible that the molecular confirmation of the plant-infecting reovirus classification scheme, derived basically from morphological characters ,and vector relationships, could find further acknowledgment at this level.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
