病毒学报

本文报道了三生烟在接种带卫星RNA的黄瓜花叶病毒(CMV-S52)后,或接种后用强毒CMV攻击,其病状表现、组织中病毒含量,病毒基因组RNA合成与卫星RNA合成的关系.植物在接种CMV-S52后7～10天,所有接种植物都表现出不同程度的轻度花叶症状,此期正是组织内病毒含量最高,而卫星dsRNA占总dsRNA百分比较低时期.接种后不同时间的测定证明,组织内病毒基因组dsRNAl和dsRNA2的合成水平均较低,而卫星dsRNA则始终保持较高的合成水平;到接种后15天病状消失时,卫星dsRNA占总dsRNA合成百分比的84.79％之多. 用CMV-S52保护接种后再用强病毒攻击,植物中的病毒含量、病毒ssRNA合成不增加或稍有增加;而基因组dsRNA和卫星dsRNA合成都有增加,但卫星dsRNA合成仍占绝对优势.保护作用的效果,取决于攻强病毒时已存在于组织内的卫星RNA与基因组RNA合成量的相对比例。讨论了卫星RNA的保护机理。

The paper prescnts the effect of sat-RNA on virus accumulation, syn-thesis of virai genome RNA and symptoms expressed in the tobacco plant prote,cted with CMV-S52, a sat-RNA-containing strain, and in the tobacco p lants challcnged by a virulent CMV after protection.For the plants protected with CMV-S52, the symptom expression was found to be almost synchronous with the accumulation of virus in the tis sues,while synthesis of sat-dsRNA was more rapid than that of virus gen- ome dsRNA, constituting up to 84.7% of the total dsRNA synthesized on the 15th day after inoculation, and the decrease of virus accumulation seemed to be related to the increase of sat-RNA. In plants challenged by a virulent CMV after protection with CMV-S52, the synthesis of virai ssRNA and its infectivity did not increase,or only slightly in some cases,while the dsRNA synthesis of both genomic and sat-RNA was increased, and that of sat-RNA was the highest.The results also indicate that the protective role of sat-RNA probably functions at the virus-RNA replication Ievel. The protective effect of sat-RNA in plants challenged by the virulent strain appears to depend on the relative ratio between the genomic and sat-RNA synthesized.