黄瓜花叶病毒株系间交叉保护作用与卫星RNA干扰作用的比较研究

COMPARATIVE STUDIES ON CROSS-PROTECTION AMONG CUCUMBER MOSAIC VIRUS STRAINS AND ITS SATELLITE PROTECTION EFFECTS

用除了卫星RNA和含有卫星RNA的CMV分离物在烟草和甜椒上进行了两组不同设计的温室实验。一组在不同保护接种后,在不同时间攻强毒CMV;另一组在不同保护接种后,在同一时间攻强毒CMV。攻毒后进行寄主症状调查、病情指数统计以及强毒CMV的A蛋白夹层ELISA测定,发现交叉保护和卫星RNA干扰作用在体內都存在,但其作用时间和程度不同。交叉保护在保护接种后10—15d以前明显,15d以后很弱;而卫星RNA干扰作用则很强,尤其在保护接种10d以后保护很完全,并且维持到30d以后。用凝胶电泳纯化与生物学单斑分离法相结合,获得了除去卫星RNA的CMV分离物。除去卫星RNA前后,CMV在不同寄主上引起的症状有很大变化,同时上述分离物在烟草上多次转接后在子代病毒中又发现卫星RNA。

Tobacco and pepper plants were preinoculated by attenuated CMV with or without satellite RNA, then challenged by a virulent CMV devoid of satellite RNA. There are two sets of protection experiments: (1) After preinoculation, the plants were challenged at the different time; (2) After preinoculation, the plants were challenged at the same time. After challenge the protection effects were detected by symptom survey, protein A sandwich EEISA of the virulent CMV strain and dot-blot hybridization of satellite RNA. The investigation of symptom expression, virus accumulation and disease index change demonstrated that the conventional cross-protection, although presents, showed visibly in 10—15 days after preinoculation and is generally not very strong. Satellite protection effects are more effective, in particular 15 days after preinoculation. The results revealed that the protection effects of CMV containing satellite RNA is different from the conventional cross-protection, the latter is superposed or supplanted by the former in the plant. Satellite RNA was elimited by two gelelutions followed by single lession selection in C. quinoa. No satellite appeared during the 2 month protection experiments, but when the isolates were propagated in tobacco, plenty of it appeared after 4 passages. This result constitutes an invitation to explore the possible origin of satellite RNA from host genetic apparatus, or from de novo generation.