Studies on secondary metabolites contained in virus free plantlet of Rehmannia glutinosa

认为几乎所有大田栽培的紫茎泽兰试管苗都可能感染病毒。因此，对鲜叶进行了电镜分析，检测到包括TMV在内的三种病毒。为了消除病毒，建立了茎尖组织培养无性系繁殖技术。从茎尖组织培养中再生植株和去除病毒是成功和常规的。通过对烟草花叶病毒（TMV）再侵染试验，分别测定了大田栽培2、3、4年后的再侵染率为26%、31%、68%，建立了环烯醚萜苷类化合物的HPLC定量分析方法，并对栽培根的质量进行了评价。无病毒根和病毒感染根的环烯醚萜类化合物含量无明显差异，但前者的含量高于后者。但也观察到了显著的变化，即主要环烯醚萜苷类物质梓醇在细菌感染后消失，而病毒感染则加速了这种消失。同样的现象也发生在其他环烯醚萜苷上。另外，从病根中分离得到两个酚苷类化合物，其结构分别为类毛蕊花糖苷和6 ′-O-半乳糖基乳糖苷。通过真菌接种产生的酚苷及其抗菌活性的实验表明，这两种酚苷可能是毛茛根中的植物抗毒素。glutinosa。因此，认为红毛菊不寻常的次生代谢可能与红毛菊的次生代谢有关。病毒感染间接通过真菌感染发生。

It is considered that almost all plantlets of Rehmannia glutinosa cultivated in field may be infected with virus. Therefore, the fresh leaves have been analyzed by the electron microscopy and three viruses including TMV are detected. In order to eliminate the viruses, the clonal propatation by shoot tip tissue culture has been set up. The plantlet regeneration from tip tissue culture and the elimination of viruses are successfully and routinely carried out. Experiments on reinfection with TMV are investigated and the reinfection rate is estimated as 26%, 31% and 68% after cultivation in field for 2,3 and 4 years, respectively.To confirm the relation between virus infection and secondary metabolites, the quantitative analysis method by HPLC for iridoid glycosides has been established and estimated the quality of cultivated root. The clear difference between the virus free root and virus infected root was not found except the former containes relatively higher amount of iridoids than the later. However, the remarkable variation is observed, that is, the major iridoid glycoside, catalpol is disappered in the diseased root by bacterial infection which is accelerated by virus infection. The same phenomenon is occurred on other iridoid glycosides. Moreover, two phenolic glycosides have been isolated from the diseased root and the structures are elucidated as acteoside and 6'-0-galactosylacteoside. From the experiments concerning the production of those by fungal inoculation and the antibiotic activity it appears that two phenolic glycosides may be considered as phytoalexin in the root of R. glutinosa. It is concluded that the unusual secondary metabolism in R. glutinosa by virus infection occurres indirectly through fungal infection.