黄花蒿内生菌株B501产生的青蒿素合成促进物研究

从数十株黄花蒿内生菌中筛选得到一株（编号B501）可产生青蒿素生物合成促进物的菌株。本项目拟采取植物化学、细胞生物学等领域的多种先进技术和方法，研究这些促进物的结构与促进青蒿素生物合成的机理。本研究有王发现新型植物激素并为揭示某些植物内生菌调节宿主植物次生物质合成的内在规律奠定基础，推动我国植物学等相关学科的发展。

Artemisia annua L. (Asteraceae) is presently the sole natural source of antimalarial drug artemisinin owing to the great difficulty in the total synthesis of this sesquiterpene lactone with an endo-peroxide bridge. Much renewed attention is thus being paid to the biosynthesis and accumulation of the lactone in the species. The isolation of the dominant endophytic fungus Colletotrichum sp. B501 from Artemisia annua possessing plant growth promoting effects impeled us to investigate its regulation on the key biosynthetic step(s) of the lactone in the host. Our results demonstrated the observerd growth enhancement of A. annua in the presence of the endophyte was probably the consequence of the hormonal substance, indole-3-acetic acid synthetized and released by Colletotrichum sp. B501. Furthermore, the oligosaccharide elicitor from the mycelial wall of the endophyte could also promote the production of artemisinin in the host. Our experiment suggested that the oligosaccharide elicitor triggered the programmed cell death, which may provide the substance or chemical signal for artemisinin biosynthesis. In our work devoted to the search for ecological benefit of the metabolites from fungal endophytes in Artemisia annua, we have found additionally 3 novel metabolites 6-isoprenylindole-3-carboxylic acid, 3b,5a-dihydroxy-6b-acetoxy-ergosta-7,22-diene and 3b, 5a-dihydroxy- 6b-phenylacetyloxy-ergosta-7,22-diene, all exhibiting remarkable inhibition to phytopathogens and 12 new antimicrobial compounds from other endophytic fungi from A. annua. Our results disclosed at least in part the fact of strong adaptability of A. annua as one of the few most dominant Artemisia species in suceessional fields. Technically, from the hairy root culture system we used herewith to explore the role of endophytic elicitor we have established a model which can be applied as well for investigating the plant defense response, and for assessing the function of fungal elicitor in regulating the biosynthesis and accumulation of important secondary metabolites in the biotechnological process of the other species