广州地区SCMV玉米分离物外壳蛋白基因的序列分析及其引致的生理病变

外壳蛋白(CP)基因序列分析结果表明,广州地区甜玉米上的甘蔗花叶病毒(SCMV)分离物属于玉米变异组,与我国其他地区玉米上的SCMV分离物有较大差异。其CP基因核苷酸同一率与广东甜玉米分离物(AJ310105)为91.6%,而与我国其他地区玉米分离物同一率为85.1%-87.1%。通过对该分离物侵染甜玉米所致的细胞病变进行超薄切片电镜观察,结果表明,除多种细胞器病变外,还有4种类型的内含体,即风轮体、卷筒体、束状体和片层集聚体,部分束状体与胞间连丝相连,可能与病毒胞间运转有关。该分离物机械摩擦接种侵染甜玉米后,引致寄主植物叶组织PAL和SOD酶活性较大的变化,其中PAL活性在侵染早期比对照低,随后比对照高,SOD活性比对照稍高,而POD和CAT酶活则与对照无显著差异。

Coat Protein Gene Sequence of a Maize Isolate of SCMV from Guangzhou and Maize Cytopathological and Physiological Alteration Caused by Its Infection

An isolate of Sugarcane mosaic virus(SCMV),named SCMV mz-gz1,was obtained from sweet maize in Guangzhou,China.Viral CP gene sequence analysisIt was revealed that this isolate was a unique molecular variant in MZ group of SCMV.It shares 91.6% identity with GD isolate(AJ310105) previously obtained from sweet maize in the same area,while 85.1%~87.1% identity with isolates from maize in other areas of China.Cytopathological alternations in sweet maize leaves caused by the infection of SCMV were investigated by electron microscope.In addition to the host cell organella damages,4 kinds of inclusions including pinwheel,scroll,bundle and laminated aggregate were observed in the cytoplasm.The situation of some bundle inclusions linked with plasmodesmata implied that they could be involved in virus movement between host cells.PAL,SOD,POD and CAT activities in the leaves of sweet maize inoculated mechanically with SCMV mz-gz1 were tested every day within one week postinoculation.The results showed that PAL activity was lower in early stage(1 day after inoculation) and higher after that than mimic treatment,meanwhile SOD activity was increased slightly,and POD and CAT activities were not changed significantly by virus infection.