大豆花叶病毒侵染大豆抗感近等基因系后叶片超微结构变化的比较

Cellular Ultrastructure Analysis in Soybean Resistant Lines and Susceptible Lines of NILs Infected by SMV

采用齐黄1号×南农1138-2组合构建的抗病和感病的近等基因系F10∶11群体,接种大豆花叶病毒SC3株系10和20 d后,调查它们的发病情况,并运用透射电镜观察抗病与感病家系间2个时期叶片超微结构变化。结果表明:抗病家系两个时期均没有可见的外部症状,叶肉细胞的超微结构未受到明显破坏,但在接种20 d后,在叶肉细胞中发现了病毒粒子。感病家系接种10 d后出现花叶症状,接种20 d后叶片开始变黄;叶肉细胞中存在大量的病毒聚集体和风轮状内含体,叶绿体和线粒体受损明显,叶绿体片层结构扭曲肿胀,线粒体肿胀、内嵴模糊;随着接种天数的增加,叶绿体和线粒体被膜受损,出现不同程度的降解;在病毒和叶绿体外膜处发现了异形增生物,而且后期增多;病毒周围存在大量的可能和病毒的移动或组装相关的空泡和小囊泡。研究结果表明抗感近等基因系在SMV侵染后外部症状和叶片内部超微结构受损程度上都存在明显差异。

Cross of Qihumlg I and Nannong t 138-2 was selected to construct near isogenic lines （NILs） . The uhra-structural alterations of resistant lines and susceptible lines of NILs were studied after 10 and 20 d inoculation with SMV strain SC3. In resistant lines, there were no visible external symptoms and obvious damage of mesophyll cell ultrastructure during the two periods. But in the 20 d inoculation, the virus particles were observed, bound in a region with short form and could not configurate the inclusion bodies. In susceptible lines, lots of thread-like SMV particles, cylindrical inclusion bodies and pinwheel inclusion bodies were observed. Great damages of chloroplasts and mitochondrial emerged in the cell, the chloroplast lamellar structure distorted and swelled, the mitochoudrial crest swelled and appeared vague. As the disease developed, the chloroplast and mitochondrial membrane were damaged and degraded in various degree. Shaped growths were found on outer membranes of virus and chloroplast, and increased afterwards. Virus were surrounded by large number of vacuoles and vesicles, which may be relevant to transfer or assembling of the virus.