辽宁省玉米矮花叶病毒外壳蛋白基因序列分析及株系鉴定

Sequence in Viral Coat Protein Gene of Maize Drawf Mosaic Virus and Identification of the Virus Strains in Liaoning Province

对辽宁地区近年发生的玉米矮花叶病毒株系进行了鉴定。电镜下病毒粒子形态呈线条状 ,大小为 (420～750)nm×(13～15)nm ,超薄切片中有风轮状内含体。以病毒RNA为模板 ,按已知的玉米矮花叶病毒外壳蛋白 (CP)基因核苷酸序列合成引物 ,逆转录合成cDNA ,以此为模板进行PCR ,扩增出了1kb左右的CP基因片段 ,将这一片段插入到载体pUC19中转化E.coliDH5a菌株 ,得到了CP基因克隆。cDNA序列分析表明 ,和中国已报道的玉米矮花叶病毒B株系 (MDMV -B)外壳蛋白基因序列同源率达98.4% ,氨基酸序列同源率99.4%。由此认为引起辽宁地区玉米矮花叶病的毒原为MDMV 。

The strains of maize drawf mosaic virus(MDMV) in Liaoning Province were identified by TEM observation and sequencing nucleotide and amino acid of the viral CP. The viral particles were flexous rods (420～750)nm ×(13～15)nm. Scroll,pinwheel and boundle inclusions were found in the super-thinned slide by TEM observation. Using the virus' RNA as template the cDNA was synthesized with the primer designed according to the reported MDMV coat protein genes. The specific fragment of about 1kb corresponding in size to MDMV CP genes was amplified by PCR using the cDNA as template. The product of PCR was then inserted into pUC vector and transformed into E.coli DH5a strain to obtain the desired clones of CP gene. Sequence analysis indicated that the cloned gene sequence showed 98.7% homologous in nucleotide sequence and 99.4% in amino acid sequence respectively, comparing with the reported MDMV-B viral CP gene sequence(CK). The results demonstrated that the virus, which had caused the maize drawf and mosaic in Liaoning Province was MDMV and the popular strain was the strain B.