The effect of satellite RNAs on replication of cucunber mosaic virus genomic RNAs in vitro

RNA - dependent RNA polymerase extracted from the cucumber cotyledons four days afterinoculation by CMV-B-1 containing attenuation satellite RNA was used to initiate synthesis of(-)sense RNA from(+)sense RNA,using both CMV genomic or satellite RNAs as tem-plates.In presence of satellite RNA,the synthesis of CMV genomic RNA1,RNA2 and RNA4was inhibited.However,different satellite RNAs showed different effects on the synthesis of viralRNAs.Adisease-attenuated satellite RNA-1 decreased the synthe.is of CMV RNA4,but thetomato necrosis-induced satellite RNA-D increased the synthesis of CMV RNA4.The resultindicated that the satellite RNAs could interfere with synthesis of CMV coat protein in the CMV-infected tissues and modulate plant symptoms by regulating the synthesis of CMV RNA1,RNA2 and RNA4.