促石蒜属植物生物碱积累的核心微生物组构建及其作用机制研究

石蒜科生物碱是石蒜科植物特有的一类具多种药用活性的次级代谢物，然而，植物中低含量限制了其开发和利用。前期，申请人从石蒜中分离到多株能促生物碱积累的内生细菌，但单一菌株仅促进少数生物碱积累且不稳定。因此，需构建有效且稳定促进多生物碱积累的微生物组并解析作用机制。本项目拟通过宏基因组分析石蒜属多种植物内生细菌组成和功能，结合靶向代谢组，确定具促生物碱积累潜力的细菌种属；利用高通量培养法，分离石蒜属植物内生细菌，建立菌种库；根据宏基因组显示的群落结构，组合目标菌株，构建“初始核心微生物组”，通过菌株增减、比例调整，优化其促生物碱积累能力；将“优化核心微生物组”推广至石蒜属各种植物，检测促生物碱积累广谱性，结合转录组学等手段，解析其作用机制的异同。本研究有望缓解加兰他敏等临床应用石蒜科生物碱供需压力，促进其他石蒜科生物碱的开发和利用；也将为研究微生物组与植物生物碱合成间关系提供一种可参考模式系统。

Plants of Amaryllidaceae are unique producers of Amaryllidaceae alkaloids, which are known for their various medicinal activities. However, the low content of these alkaloids in planta remains a limit to their pharmaceutical development and utilization. In the previous study, we have isolated bacterial endophytes from Lycoris radiata and have proved that several strains are able to enhance the alkaloid accumulation in the host plant, but individual strains can only target one or two alkaloids and their beneficial influences cannot last for a longer time. Thus, it is necessary to construct a synthetic bacterial community that can enhance the accumulation of diverse alkaloids in planta more efficiently in a longer time; and their promotion mechanisms are also important to be elucidated. This project will analyze the composition and function of bacterial endophytes in several species in Lycoris using Metagenomics. Combined with the technique of metabonomics, we will analyze the correlations between certain bacterial taxa and alkaloids. The bacterial taxa that have potential to enhance the alkaloid accumulation will be defined. Moreover, the bacterial endophytes in different species in Lycoris will be isolated as many as possible, in order to establish a bank of bacterial endophytes and obtain the targeted bacterial taxa. According to the bacterial composition observed in the metagenomics, bacterial endophytes that are abundant in all the tested plant species will be assembled, which will be referred as the “Original Core Microbiome” in Lycoris. We will test the stability of “Original Core Microbiome” in synthetic media or in planta and further its influences on the alkaloid accumulation in L. radiata and Lycoris aurea, two typical species of Lycoris. Then the composition and bacteria ratio in the “Original Core Microbiome” will be adjusted to improve its stability and function. Finally, we are hoping to obtain the “Optimized Core Microbiome” that can enhance the alkaloid accumulation efficiently and stably in planta. The function of “Optimized Core Microbiome” will be further tested in different species in Lycoris and its promotion mechanisms will be illustrated using transcriptomics and physiological or biochemical experiments. The results of this study will provide a reference model for further studying the interaction between plant microbiome and alkaloid synthesis. Moreover, this project will relieve the supply and demand pressure of Galanthamine that has already been used clinically to treat the Alzheimer’s Disease and promote the pharmaceutical development and utilization of other Amaryllidaceae alkaloids, which have great application values.