15种植物的单宁提取物对烟草花叶病毒(TMV)的抑制作用

 测定了15种植物的乙醇粗提物对TMV的体外抑制作用,其中11种具有明显效果,这11种植物粗提物经水/氯仿萃取,水萃取物具有明显抑制TMV效果,而氯仿萃取物抑制效果差。水萃取物用明胶去除单宁后,基本失去抑制TMV的能力,表明单宁在其中起着重要作用。从杠板归与假槟榔种子中提取的总单宁对TMV具有明显的抑制作用;病毒粒体样品在分别加入这2种植物总单宁后,电镜下表现为聚集结合;TMV分别与这2种植物的单宁混合后,通过透析,可恢复大部分侵染力,表明单宁对病毒并无直接毒害作用;TMV外壳蛋白(CP)与单宁混合后,在蛋白质的聚丙烯酰胺凝胶电泳中表现为结合现象;单宁对TMV体内抑制复制效果不明显;单宁在接种TMV前后施用并没有降低TMV侵染力;这些结果表明这2种植物单宁对TMV抑制作用可能是与TMV-CP结合而引起病毒侵染力下降或影响病毒CP对侵染位点的识别。

Inhibition of the infectivity of TMV by tannins

The anti TMV activities in vitro were determined with ethanol extracts from 15 species of plants. The extracts of 11 species of plants showed significant anti TMV activity. The water phase showed strong anti TMV activity while chloroform phase showed little inhibiting effect. The water phase lost most inhibitory effect by discarding tannins using gelatin. It showed that tannins may play roles in reducing infectivity. Tannins extracted from Polygonum perfoliatum or Archontophoenix alexandrae seeds strongly inhibited TMV infectivity. TMV virions seemed to be aggregated when incubated with the tannins. The fact that infectivity of TMV recovered by dialysis from incubations in vitro with tannins showed that the virus regained infectivity, and the tannins did not possess direct viricidal effect. It seems that TMV coat protein binds the tannins. The tannins did not affect multiplication of TMV in infected leaf discs. Tannins did not reduce infectivity when applied either before or after TMV inoculation. It is proposed that tannins from P. perfoliatum or A. alexandrae inhibit TMV by binding to TMV coat protein to reduce TMV activity or to interfere with recognition site for viral coat protein.