三七根际皂苷介导的根系与土壤微生物负反馈调节机制

植物-土壤的负反馈调节是自然生态系统中植物调节自身种群时空分布，维系物种多样性和相对丰度的一个重要机制。然而，在农业生态系统中，由于单一作物的连续种植，这种负反馈调节常导致连作障碍。三七是我国独具特色的大宗药用作物，连作障碍严重制约三七产业的健康发展。本课题组研究发现根腐病仅是三七连作障碍的主要表现形式，由根际皂苷介导的三七根系与土壤微生物之间的负反馈调节可能是连作障碍形成的主要原因。因此，本项目拟深入研究：①三七根际自毒皂苷影响三七根系抗病性的效应和机制；②三七根际皂苷影响根腐病菌积累和侵染的效应和机制；③三七根际皂苷引起根际微生物结构和功能变化的效应和机制。通过这些研究可以深入解析三七根系—土壤微生物负反馈调节机制，明确连作障碍的形成原因，为克服三七连作障碍关键技术的研发提供理论依据。

The negative plant-soil feedback (NPSF) in natural ecological system play an important role in regulating plant population spatial and temporal distribution and maintaining plant diversity and their relative abundance. In agricultural system, however, NPSF is the main obstacle for the sustainable crop production due to monoculture of crops. Sanqi ginseng [Panax notoginseng (Burk.) F. H. Chen], one of the most important Chinese herbal medicine, is hampered by NPSF due to soil-borne pathogens and autotoxic compounds. Our recent research demonstrated that the root rot caused by the infection of soil-borne pathogens was only the external symptom of replant failure. The negative feedback between root and soil microorganisms mediated by rhizosphere ginsenosides may be the main factor for replant failure. In this study, we aim to (1) study the effect and mechanism of autotoxic ginsenosides in rhizosphere to disturb the resistance of root to soil-borne pathogens; (2) explore the effect and mechanism of rhizosphere ginsenosides to the growth and infection of root rot pathogens or their accumulation in rhizosphere; (3) study the effect and mechanism of rhizosphere ginsenosides to change soil microbial community and function in rhizosphere. Based on these studies, we can explore the negative root-soil microorganisms feedback mediated by rhizosphere ginsenosides of P. notoginseng. These studies will benefit us to further understand the mechanism of replant failure and develop new techniques to conquer replant failure of P. notoginseng.