人参-病原菌互作的分子生态机制研究

项目名称： 人参-病原菌互作的分子生态机制研究

项目编号： No.31270479

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 生物科学

项目作者： 赵雪淞

作者单位： 辽宁工程技术大学

项目金额： 79万元

中文摘要： 名贵药用植物人参的真菌病害十分严重，而人参与病原真菌相互作用的分子生态机制尚不明确。我们前期研究表明：人参可能通过次生代谢物人参皂苷防御病原菌的侵害，而人参最主要的病原菌毁灭柱孢菌可能是通过产生人参皂苷降解酶解除了人参皂苷毒性,并且将降解产物转化为自身的生长促进因子或是寄主识别因子，从而寄生成功。为了验证上述假设，本项目拟研究毁灭柱孢菌产生的人参皂苷降解酶的分子特征和酶学性质，在此基础上分离鉴定该酶基因的结构和特征，进而用基因敲除方法构建人参皂苷降解酶基因缺失突变体，研究突变体对人参皂苷的敏感性和对人参的致病力，从分子水平上探讨毁灭柱孢菌人参皂苷降解酶在其致病性中的作用，阐明人参皂苷在人参-病原菌互作中的生态功能及其分子机制。研究结果将为阐明植物-微生物相互作用的规律和生物共进化原理提供证据，也将为人参病害防治提供可行思路。

中文关键词： 人参；人参皂苷；毁灭柱孢菌；相互作用；致病机制

英文摘要： Ginseng is a highly valued herb which has a large number of structurally different ginsenosides present in relatively high abundance, while it is attacked in commercial ginseng gardens by a diverse array of fungi including Cylindrocarpon destructans. The ecological mechanism of plant-pathogen interactions are not clear. Our previous study found that ginsenosides from panax ginseng C.A Maye inhibited the growth of the five ginseng nonpathogens, while it promoted the growth of the ginseng pathogen C. destructans. The subsequent analysis of enzymatic degradation of ginsenosides by the test fungi showed that C. destructans can hydrolyze ginsenosides by extracellular glycosidase.These results indicated that ginsenosides might act as host chemical defenses, while the ginseng root pathogenic fungi C. destructans might counter their toxicity by converting ginsenosides into growth or host recognition factors using ginsenoside-degrading enzyme. In order to clarify the significance of the ginsenoside-degrading enzymes in the pathogenic behavior of C. destructans and the ecological role of ginsenosides in ginseng-pathogen interactions, we intend to study the purification and biochemical characterization of these saponinases, and then study the gene cloning and characterization of them with the peptide information provided a

英文关键词： ginseng；ginsenosides；Cylindrocarpon destructans (Ilyonectria destructan；interaction；pathogenic mechanism