Effects of mutated replicase and movement protein genes on attenuation of tobacco mosaic virus  

作　　者：杨恭 邱并生 魏军亚 刘广超 

出　　处：《Science China(Life Sciences)》2001年第6期628-636,共9页中国科学（生命科学英文版）

基　　金：the National Natural Science Foundation of China.

摘　　要：Our previous reports showed that one opal mutation (UGA) and one ochre mutation (UAA) respectively located in the replicase and movement protein (MP) genes of the attenuated tomato mosaic virus K(ToMV-K) contribute to the viral attenuation. To explore a wider application of this attenuation pattern to other plant viruses, we have constructed three mutants which respectively contain one opal mutation of the replicase gene and/or one ochre mutation of the MP using PCR-mediated site-directed mutagenesis from a virulent tobacco mosaic virus isolated from China (TMV-Cv). Plant infection performed by in vitro transcripts revealed that the MP truncated mutant TMV-Cvmp and the replicase-MP truncated mutant TMV-Cvrase-mp were infectious on both local lesion (Nicotiana tabacum cv. Xanthi NC) and systemic (N. tabacum cv. K326) host plants, while the replicase truncated mutant TMV-Cvrase was non-infectious. The K326 plant infected by TMV-Cvrease-mp displayed on|y a little mild mosaic. By electronic microscopy (EM), plant re-inoculation, RNA Dot-blot, RT-PCR and sequencing we demonstrated that the progeny viruses of TMV-Cvmp and TMV-Cvrease-mp shared similar morphological character with TMV-Cv, owned the abilities to infect, replicate and propagate in the assayed plants, and maintained the mutated sites during infection. These data showed that both the opal and the ochre mutations are able to cooperatively induce the attenuated phenotypes of TMV-Cvrase-mp on plants, indicating that the mutation pattern of ToMV-K could be used to attenuate other virulent plant viruses.Our previous reports showed that one opal mutation (UGA) and one ochre mutation (UAA) respectively located in the replicase and movement protein (MP) genes of the attenuated tomato mosaic virus K(ToMV-K) contribute to the viral attenuation. To explore a wider application of this attenuation pattern to other plant viruses, we have constructed three mutants which respectively contain one opal mutation of the replicase gene and/or one ochre mutation of the MP using PCR-mediated site-directed mutagenesis from a virulent tobacco mosaic virus isolated from China (TMV-Cv). Plant infection performed by in vitro transcripts revealed that the MP truncated mutant TMV-Cvmp and the replicase-MP truncated mutant TMV-Cvrase-mp were infectious on both local lesion (Nicotiana tabacum cv. Xanthi NC) and systemic (N. tabacum cv. K326) host plants, while the replicase truncated mutant TMV-Cvrase was non-infectious. The K326 plant infected by TMV- Cvrease-mp displayed only a little mild mosaic. By electronic microscopy (EM), plant re-inoculation, RNA Dot-blot, RT-PCR and sequencing we demonstrated that the progeny viruses of TMV-Cvmp and TMV-Cvrease-mp shared similar morphological character with TMV-Cv, owned the abilities to infect, replicate and propagate in the assayed plants, and maintained the mutated sites during infection. These data showed that both the opal and the ochre mutations are able to cooperatively induce the attenuated phenotypes of TMV-Cvrase-mp on plants, indicating that the mutation pattern of ToMV-K could be used to attenuate other virulent plant viruses.

关 键 词：tobacco mosaic virus (TMV) REPLICASE movement protein (MP) ATTENUATION mutation. 

分 类 号：Q753[生物学—分子生物学]