人参体细胞胚胎发生过程中内源激素变化和基因表达研究

Changes of endogenous hormone and gene expression during process of somatic embryogenesis in Panax ginseng

目的探讨外源激素-内源激素-特异基因之间的关系,为阐明人参体细胞胚胎发生的分子机制奠定基础。方法对人参不同发生途径,不同时期的培养物进行AFLP分析,对体细胞胚胎发生不同时期培养物的内源IAA和ABA以及皂苷的量进行了测定。结果在早期胚时期IAA的量最高,在成熟胚时期ABA的量最高,而ABA/IAA的值在成熟胚时较高;不同发生途径,不同时期的培养物基因表达不同;体胚发生试管苗总皂苷的量比子叶胚时期高出4倍多。结论IAA的存在是维持人参体胚正常发育到早期胚的条件,ABA与胚性启动,体胚发生、发育相关,尤其对胚胎发育后期有较大的影响;在不同生理状态或不同的培养条件下产生了不同的基因调控类型,不同的发育过程会有特异基因表达,导致了人参分化情况的不同;随着形态建成的逐步完成,也是次生代谢产物逐渐积累的过程。

Objective To study the relationship during exogenous hormone-endogenous hormoneidiogene,and establish the foundation to illuminate the molecule mechanism during process of somatic embryogenesis in Panax ginseng. Methods AFLP Analysis on the period of different culture in development pathway of P. ginseng was carried out simultaneously, the endogenous IAA, ABA, and the saponin content in the period of different cultures during process of somatic embryogenesis in P. ginseng were determined. Results It indicated the content of IAA was the highest in early embryo period and ABA was the highest in the mature embryo period. The ratio of ABA/IAA was higher at the stage of mature embryo than that of others. The gene expression was different in the different period cultures during process of somatic embryogenesis in P. ginseng. The total saponin content of test-tube plantlet is four fold higher than that in the period of cotylen embryo. Conclusion The condition that maintains normal development of somatic embryogenesis in P. ginseng is the presence of IAA. ABA correlates with the embryo priming, somatic embryogenesis and development. Especially, it influences the later period of somatic embryogenesis. It produces the different types of gene regulation in different physiology condition or different culture conditions. There is idiogene expression in the different development processes, which induces the different cell differentiation. With gradually completion of morphogenesis, it is the accumulative process of secondary metabolite.